Patent Publication Number: US-8524993-B2

Title: Celery cultivar ADS-20

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a new and distinctive celery ( Apium graveolens  var.  dulce ) variety, designated ADS-20. All publications cited in this application are herein incorporated by reference. 
     There are numerous steps in the development of any novel, desirable plant germplasm. Plant breeding begins with the analysis, definition of problems and weaknesses of the current germplasm, the establishment of program goals, and the definition of specific breeding objectives. The next step is selection of germplasm that possesses the traits to meet the program goals. The goal is to combine in a single variety or hybrid an improved combination of desirable traits from the parental germplasm. These important traits may include improved flavor, increased stalk size and weight, higher seed yield, improved color, resistance to diseases and insects, tolerance to drought and heat, and better agronomic quality. 
     All cultivated forms of celery belong to the species  Apium graveolens  var.  dulce  that is grown for its edible stalk. As a crop, celery is grown commercially wherever environmental conditions permit the production of an economically viable yield. In the United States, the principal growing regions are California, Florida, Texas, Arizona and Michigan. Fresh celery is available in the United States year-round, although the greatest supply is from November through January. For planting purposes, the celery season is typically divided into two seasons: summer and winter, with Florida, Texas and the southern California areas harvesting from November to July, and Michigan and northern California harvesting from July to October. Celery is consumed as fresh, raw product and as a cooked vegetable. 
     Celery is a cool-season biennial that grows best from 60° F. to 65° F. (16° C. to 18° C.), but will tolerate temperatures from 45° F. to 75° F. (7° C. to 24° C.). Freezing damages mature celery by splitting the petioles or causing the skin to peel, making the stalks unmarketable. This can be a problem for crops planted in the winter regions; however, celery can tolerate minor freezes early in the season. 
     The two main growing regions for celery in California are located along the Pacific Ocean: the central coast or summer production area (Monterey, San Benito, Santa Cruz and San Luis Obispo Counties) and the south coast or winter production area (Ventura and Santa Barbara Counties). A minor region (winter) is located in the southern deserts (Riverside and Imperial Counties). 
     In the south coast, celery is transplanted from early August to April for harvest from November to mid-July; in the Santa Maria area, celery is transplanted from January to August for harvest from April through December. In the central coast, fields are transplanted from March to September for harvest from late June to late December. In the southern deserts, fields are transplanted in late August for harvest in January. 
     Commonly used celery varieties for coastal production include Tall Utah 52-75, Conquistador and Sonora. Some shippers use their own proprietary varieties. Celery seed is very small and difficult to germinate. All commercial celery is planted as greenhouse-grown transplants. Celery grown from transplants is more uniform than from seed and takes less time to grow the crop in the field. Transplanted celery is traditionally placed in double rows on 40-inch (100-cm) beds with plants spaced between 6.0 and 7 inches apart. 
     Celery requires a relatively long and cool growing season (The physiology of vegetable crops by Pressman, CAB Intl., New York, 1997). Earlier transplanting results in a longer growing season, increased yields, and better prices. However, celery scheduled for Spring harvest often involves production in the coolest weather conditions of Winter, a period during which vernalization can occur. If adequate vernalization occurs for the variety, bolting may be initiated. Bolting is the premature rapid elongation of the main celery stem into a floral axis (i.e., during the first year for this normally biennial species). Bolting slows growth as the plant approaches marketable size leaves a stalk with no commercial value. Different varieties have different vernalization requirements, but in the presence of bolting, the length of the seed stem can be used as a means of measuring bolting tolerance that exists in each different variety. The most susceptible varieties reach their vernalization requirement earlier and have time to develop the longest seed stems, while the moderately tolerant varieties take longer to reach their vernalization requirement and have less time to develop a seed stem which would therefore be shorter. Under normal production conditions, the most tolerant varieties may not achieve their vernalization requirement and therefore not produce a measurable seed stem. 
     The coldest months when celery is grown in the United States are December, January and February. If celery is going to reach its vernalization requirements to cause bolting, it is generally younger celery that is exposed to this cold weather window. This celery generally matures in the months of April and May which constitutes what the celery industry calls the bolting or seeder window. The bolting or seeder window is a period where seed stems are generally going to impact the quality of the marketable celery and this is most consistently experienced in celery grown in the Southern California region. The presence of seed stems in celery can be considered a major marketable defect as set forth in the USDA grade standards. If the seed stem is longer than twice the diameter of the celery stalk or eight inches, the celery no longer meets the standards of US Grade #1. If the seed stem is longer than three times the diameter of the celery stalk, the celery is no longer marketable as US Grade #2 ( United States Standards for Grades of Celery , United States Department of Agriculture, reprinted January 1997). 
     Celery is an allogamous biennial crop. The celery genome consists of 11 chromosomes. Its high degree of out-crossing is accomplished by insects and wind pollination. Pollinators of celery flowers include a large number of wasp, bee and fly species. Celery is subject to inbreeding depression, which appears to be dependent upon the genetic background as some lines are able to withstand selfing for three or four generations. 
     Celery flowers are protandrous, with pollen being released 3-6 days before stigma receptivity. At the time of stigma receptivity the stamens will have fallen and the two stigmata unfolded in an upright position. The degree of protandry varies, which makes it difficult to perform reliable hybridization, due to the possibility of accidental selfing. 
     Celery flowers are very small, which significantly hinders easy removal of individual anthers. Furthermore, different developmental stages of the flowers in umbels makes it difficult to avoid uncontrolled pollinations. The standard hybridization technique in celery consists of selecting flower buds of the same size and eliminating the older and younger flowers. Then, the umbellets are covered with glycine paper bags for a 5-10 day period, during which the stigmas become receptive. At the time the flowers are receptive, available pollen or umbellets shedding pollen from selected male parents are rubbed on to the stigmas of the female parent. 
     Celery plants require a period of vernalization while in the vegetative phase in order to induce seed stalk development. A period of 6-10 weeks at 5° C. to 8° C. when the plants are greater than 4 weeks old is usually adequate. Due to a wide range of responses to the cold treatment, it is often difficult to synchronize crossing, since plants will flower at different times. However, pollen can be stored for 6-8 months at −10° C. in the presence of silica gel or calcium chloride with a viability decline of only 20-40%, thus providing flexibility to perform crosses over a longer time. 
     For selfing, the plant or selected umbels are caged in cloth bags. These are shaken several times during the day to promote pollen release. Houseflies ( Musca domestica ) can also be introduced weekly into the bags to perform pollinations. 
     Choice of breeding or selection methods depends on the mode of plant reproduction, the heritability of the trait(s) being improved, and the type of cultivar used commercially (e.g., F 1  hybrid cultivar, pureline cultivar, etc.). For highly heritable traits, a choice of superior individual plants evaluated at a single location will be effective, whereas for traits with low heritability, selection should be based on mean values obtained from replicated evaluations of families of related plants. Popular selection methods commonly include pedigree selection, modified pedigree selection, mass selection, and recurrent selection. 
     The complexity of inheritance influences the choice of breeding method. Backcross breeding is used to transfer one or a few favorable genes for a highly heritable trait into a desirable cultivar. This approach has been used extensively for breeding disease-resistant cultivars. Various recurrent selection techniques are used to improve quantitatively inherited traits controlled by numerous genes. The use of recurrent selection in self-pollinating crops depends on the ease of pollination, the frequency of successful hybrids from each pollination, and the number of hybrid offspring from each successful cross. 
     Each breeding program should include a periodic, objective evaluation of the efficiency of the breeding procedure. Evaluation criteria vary depending on the goal and objectives, but should include gain from selection per year based on comparisons to an appropriate standard, the overall value of the advanced breeding lines, and the number of successful cultivars produced per unit of input (e.g., per year, per dollar expended, etc.). 
     Promising advanced breeding lines are thoroughly tested and compared to appropriate standards in environments representative of the commercial target area(s) for at least three years. The best lines are candidates for new commercial cultivars; those still deficient in a few traits are used as parents to produce new generations for further selection. 
     These processes, which lead to the final step of marketing and distribution, usually take from ten to twenty years from the time the first cross or selection is made. Therefore, development of new cultivars is a time-consuming process that requires precise forward planning, efficient use of resources, and a minimum of changes in direction. 
     A most difficult task is the identification of individuals that are genetically superior, because for most traits the true genotypic value is masked by other confounding plant traits or environmental factors. One method of identifying a superior plant is to observe its performance relative to other experimental plants and to a widely grown standard cultivar. If a single observation is inconclusive, replicated observations provide a better estimate of its genetic worth. 
     The goal of celery plant breeding is to develop new, unique and superior celery cultivars. The breeder initially selects and crosses two or more parental lines, followed by repeated selfing and selection, producing many new genetic combinations. The breeder can theoretically generate billions of different genetic combinations via crossing, selfing and mutations. The breeder has no direct control at the cellular level. Therefore, two breeders will never develop the same line, or even very similar lines, having the same celery traits. 
     Each year, the plant breeder selects the germplasm to advance to the next generation. This germplasm is grown under unique and different geographical, climatic and soil conditions and further selections are then made, during and at the end of the growing season. The cultivars that are developed are unpredictable. This unpredictability is because the breeder&#39;s selection occurs in unique environments, with no control at the DNA level (using conventional breeding procedures), and with millions of different possible genetic combinations being generated. A breeder of ordinary skill in the art cannot predict the final resulting lines he/she develops, except possibly in a very gross and general fashion. The same breeder cannot produce the same line twice by using the exact same original parents and the same selection techniques. This unpredictability results in the expenditure of large research monies to develop superior celery cultivars. 
     The development of commercial celery cultivars often starts with crosses between different commercial varieties and/or germplasm at different stages in development. Pedigree breeding and recurrent selection breeding methods are used to develop cultivars from breeding populations. Breeding programs combine desirable traits from two or more varieties or various broad-based sources into breeding pools from which cultivars are developed by selfing and selection of desired phenotypes. The new cultivars are crossed with other varieties and the hybrids from these crosses are evaluated to determine which have commercial potential. 
     Pedigree breeding is used commonly for the improvement of self-pollinating crops or inbred lines of cross-pollinating crops. Two parents which possess favorable, complementary traits are crossed to produce an F 1 . An F 2  population is produced by selfing one or several F 1 &#39;s or by intercrossing two F 1 &#39;s (sib mating). Selection of the best individuals usually begins in the F 2  population; then, beginning in the F 3 , the best individuals in the best families are selected. Replicated testing of families, or hybrid combinations involving individuals of these families, often follows in the F 4  generation to improve the effectiveness of selection for traits with low heritability. At an advanced stage of inbreeding (i.e., F 6  and F 7 ), the best lines or mixtures of phenotypically similar lines are tested for potential release as new cultivars. 
     Mass and recurrent selections can be used to improve populations of either self- or cross-pollinating crops. A genetically variable population of heterozygous individuals is either identified or created by intercrossing several different parents. The best plants are selected based on individual superiority, outstanding progeny, or excellent combining ability. The selected plants are intercrossed to produce a new population in which further cycles of selection are continued. 
     Backcross breeding has been used to transfer genes for a simply inherited, highly heritable trait into a desirable homozygous cultivar or line that is the recurrent parent. The source of the trait to be transferred is called the donor parent. The resulting plant is expected to have the attributes of the recurrent parent (e.g., cultivar) and the desirable trait transferred from the donor parent. After the initial cross, individuals possessing the phenotype of the donor parent are selected and repeatedly crossed (backcrossed) to the recurrent parent. The resulting plant is expected to have the attributes of the recurrent parent (e.g., cultivar) and the desirable trait transferred from the donor parent. 
     In the strictest sense, the single-seed descent procedure refers to planting a segregating population, harvesting a sample of one seed per plant, and using the one-seed sample to plant the next generation. When the population has been advanced from the F 2  to the desired level of inbreeding, the plants from which lines are derived will each trace to different F 2  individuals. The number of plants in a population declines each generation due to failure of some seeds to germinate or some plants to produce at least one seed. As a result, not all of the F 2  plants originally sampled in the population will be represented by a progeny when generation advance is completed. 
     In addition to phenotypic observations, the genotype of a plant can also be examined. There are many laboratory-based techniques available for the analysis, comparison and characterization of a plants genotype. Among these are Isozyme Electrophoresis, Restriction Fragment Length Polymorphisms (RFLPs), Randomly Amplified Polymorphic DNAs (RAPDs), Arbitrarily Primed Polymerase Chain Reaction (AP-PCR), DNA Amplification Fingerprinting (DAF), Sequence Characterized Amplified Regions (SCARs), Amplified Fragment Length polymorphisms (AFLPs), Simple Sequence Repeats (SSRs—which are also referred to as Microsatellites), and Single Nucleotide Polymorphisms (SNPs). 
     Isozyme Electrophoresis and RFLPs have been widely used to determine genetic composition. Shoemaker and Olsen, ( Molecular Linkage Map of Soybean  ( Glycine max ) p. 6.131-6.138 in S. J. O&#39;Brien (ed) Genetic Maps: Locus Maps of Complex Genomes, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., (1993)) developed a molecular genetic linkage map that consisted of 25 linkage groups with about 365 RFLP, 11 RAPD, three classical markers and four isozyme loci. See also, Shoemaker, R. C.,  RFLP Map of Soybean , p 299-309, in Phillips, R. L. and Vasil, I. K., eds.  DNA - Based Markers in Plants , Kluwer Academic Press, Dordrecht, the Netherlands (1994). 
     SSR technology is currently the most efficient and practical marker technology; more marker loci can be routinely used and more alleles per marker locus can be found using SSRs in comparison to RFLPs. For example, Diwan and Cregan described a highly polymorphic microsatellite locus in soybean with as many as 26 alleles. (Diwan, N. and Cregan, P. B.,  Theor. Appl. Genet.  95:22-225, 1997.) SNPs may also be used to identify the unique genetic composition of the invention and progeny varieties retaining that unique genetic composition. Various molecular marker techniques may be used in combination to enhance overall resolution. 
     Molecular markers, which include markers identified through the use of techniques such as Isozyme Electrophoresis, RFLPs, RAPDs, AP-PCR, DAF, SCARs, AFLPs, SSRs, and SNPs, may be used in plant breeding. One use of molecular markers is Quantitative Trait Loci (QTL) mapping. QTL mapping is the use of markers which are known to be closely linked to alleles that have measurable effects on a quantitative trait. Selection in the breeding process is based upon the accumulation of markers linked to the positive effecting alleles and/or the elimination of the markers linked to the negative effecting alleles from the plant&#39;s genome. 
     Molecular markers can also be used during the breeding process for the selection of qualitative traits. For example, markers closely linked to alleles or markers containing sequences within the actual alleles of interest can be used to select plants that contain the alleles of interest during a backcrossing breeding program. The markers can also be used to select toward the genome of the recurrent parent and against the markers of the donor parent. This procedure attempts to minimize the genomic contribution from the donor parent that remains in the selected plants, and can reduce the number of back-crosses necessary to generate coisogenic plants. This procedure is often called genetic marker enhanced selection or marker-assisted selection. Molecular markers may also be used to identify and exclude certain sources of germplasm as parental varieties or ancestors of a plant by providing a means of tracking genetic profiles through crosses. 
     Mutation breeding is another method of introducing new traits into celery varieties. Mutations that occur spontaneously or are artificially induced can be useful sources of variability for a plant breeder. The goal of artificial mutagenesis is to increase the rate of mutation for a desired characteristic. Mutation rates can be increased by many different means including temperature, long-term seed storage, tissue culture conditions, radiation (such as X-rays, Gamma rays, neutrons, Beta radiation, or ultraviolet radiation), chemical mutagens (such as base analogs like 5-bromo-uracil), alkylating agents (such as sulfur mustards, nitrogen mustards, epoxides, ethyleneamines, sulfates, sulfonates, sulfones, or lactones), azide, hydroxylamine, nitrous acid or acridines. Once a desired phenotype is observed the genetic mutation responsible for that trait may then be incorporated into existing germplasm by traditional breeding techniques. Details of mutation breeding can be found in  Principles of Cultivar Development  by Fehr, Macmillan Publishing Company, 1993. 
     The production of double haploids can also be used for the development of homozygous varieties in a breeding program. Double haploids are produced by doubling a set of chromosomes from a heterozygous plant to produce a completely homozygous individual. For example, see Wan et al.,  Theor. Appl. Genet.,  77:889-892, 1989. 
     Descriptions of other breeding methods that are commonly used for different traits and crops can be found in several reference books (e.g.,  Principles of Plant Breeding  John Wiley and Son, pp. 115-161, 1960; Allard, 1960; Simmonds, 1979; Sneep et al., 1979; Fehr, 1987; A Carrots and Related Vegetable  Umbelliferae @, Rubatzky, V. E., et al., 1999). 
     Proper testing should detect any major faults and establish the level of superiority or improvement over current cultivars. In addition to showing superior performance, there must be a demand for a new cultivar that is compatible with industry standards or which creates a new market. The introduction of a new cultivar will incur additional costs to the seed producer, the grower, processor and consumer for special advertising and marketing, altered seed and commercial production practices, and new product utilization. The testing preceding release of a new cultivar should take into consideration research and development costs as well as technical superiority of the final cultivar. For seed-propagated cultivars, it must be feasible to produce seed easily and economically. 
     Celery in general is an important and valuable vegetable crop. Thus, a continuing goal of celery plant breeders is to develop stable, high yielding celery cultivars that are agronomically sound to maximize the amount of yield produced on the land. To accomplish this goal, the celery breeder must select and develop celery plants that have the traits that result in superior cultivars. 
     The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification. 
     SUMMARY OF THE INVENTION 
     The following embodiments and aspects thereof are described in conjunction with systems, tools, and methods which are meant to be exemplary and illustrative, not limiting in scope. In various embodiments, one or more of the above-described problems have been reduced or eliminated, while other embodiments are directed to other improvements. 
     According to the invention, there is provided a novel celery cultivar designated ADS-20. This invention thus relates to the seeds of celery cultivar ADS-20, to the plants of celery cultivar ADS-20 and to methods for producing a celery plant by crossing celery ADS-20 with itself or another celery plant, to methods for producing a celery plant containing in its genetic material one or more transgenes and to the transgenic celery plants produced by that method. This invention also relates to methods for producing other celery cultivars derived from celery cultivar ADS-20 and to the celery cultivar derived by the use of those methods. This invention further relates to hybrid celery seeds and plants produced by crossing celery cultivar ADS-20 with another celery line. 
     In another aspect, the present invention provides regenerable cells for use in tissue culture of celery cultivar ADS-20. The tissue culture will preferably be capable of regenerating plants having essentially all of the physiological and morphological characteristics of the foregoing celery plant, and of regenerating plants having substantially the same genotype as the foregoing celery plant. Preferably, the regenerable cells in such tissue cultures will be callus, protoplasts, meristematic cells, leaves, pollen, embryos, roots, root tips, anthers, pistils, flowers, seeds, petioles and suckers. Still further, the present invention provides celery plants regenerated from the tissue cultures of the invention. 
     Another aspect of the invention is to provide methods for producing other celery plants derived from celery cultivar ADS-20. Celery cultivars derived by the use of those methods are also part of the invention. 
     The invention also relates to methods for producing a celery plant containing in its genetic material one or more transgenes and to the transgenic celery plant produced by those methods. 
     In another aspect, the present invention provides for single gene converted plants of ADS-20. The single transferred gene may preferably be a dominant or recessive allele. Preferably, the single transferred gene will confer such traits as male sterility, herbicide resistance, insect resistance, modified fatty acid metabolism, modified carbohydrate metabolism, resistance for bacterial, fungal, or viral disease, male fertility, enhanced nutritional quality and industrial usage or the transferred gene will have no apparent value except for the purpose of being a marker for variety identification. The single gene may be a naturally occurring celery gene or a transgene introduced through genetic engineering techniques. 
     The invention further provides methods for developing celery plant in a celery plant breeding program using plant breeding techniques including recurrent selection, backcrossing, pedigree breeding, restriction fragment length polymorphism enhanced selection, genetic marker enhanced selection and transformation. Seeds, celery plants, and parts thereof, produced by such breeding methods are also part of the invention. 
     In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference by the study of the following descriptions. 
     DEFINITIONS 
     In the description and tables which follow, a number of terms are used. In order to provide a clear and consistent understanding of the specification and claims, including the scope to be given such terms, the following definitions are provided: 
     Allele. An allele is any of one or more alternative form of a gene, all of which relate to one trait or characteristic. In a diploid cell or organism, the two alleles of a given gene occupy corresponding loci on a pair of homologous chromosomes. 
     Backcrossing. Backcrossing is a process in which a breeder repeatedly crosses hybrid progeny back to one of the parents, for example, a first generation hybrid F 1  with one of the parental genotype of the F 1  hybrid. 
     Blackheart. Blackheart is due to a lack of movement of sufficient calcium that causes the plant to turn brown and begin to decay at the growing point of the plant. Celery in certain conditions, such as warm weather, grows very rapidly and is incapable of moving sufficient amounts of calcium to the growing point. 
     Bolting. The premature development of a flowering or seed stalk, and subsequent seed, before a plant produces a food crop. Bolting is typically caused by late planting when temperatures are low enough to cause vernalization of the plants. 
     Bolting Period. Also known as the bolting or seeder window, and generally occurs in celery that is transplanted from the middle of December through January and matures in April to May. The intensity and actual weeks that bolting may be observed vary from year to year, but it is generally observed in this window. 
     Bolting Tolerance. The amount of vernalization that is required for different celery varieties to bolt is genetically controlled. Varieties with increased tolerance to bolting require greater periods of vernalization in order to initiate bolting. A comparison of bolting tolerance between varieties can be measured by the length of the flowering or seed stem under similar vernalization conditions. 
     Brown Stem. A disease caused by the bacterium  Pseudomonas cichorii  that causes petiole necrosis. Brown Stem is characterized by a firm, brown discoloration throughout the petiole. 
     Celeriac or Root celery ( Apium graveolens  L. var.  rapaceum ). A plant that is related to celery but instead of having a thickened and succulent leaf petiole as in celery, celeriac has an enlarged hypocotyl and upper root that is the edible product. 
     Celery Heart. The center most interior petioles and leaves of the celery stalk. They are not only the smallest petioles in the stalk, but the youngest as well. Some varieties are considered heartless because they go right from very large petioles to only a couple of very small petioles. The heart is comprised of the petioles that are closest to the meristem of the celery stalk. Most straw and process type varieties have very little heart development. 
     Consumable. Means material that is edible by humans. 
     Crackstem. The petiole can crack or split horizontally or longitudinally. Numerous cracks in several locations along the petiole are often an indication that the variety has insufficient boron nutrition. A variety&#39;s ability to utilize boron is a physiological characteristic which is genetically controlled. 
     Dry weight. The weight of the celery after all water has been removed from celery. 
     Dry weight percentage. The calculation of the dry weight of the celery divided by the original weight of the celery before the removal of the water. 
     Durable. Means long-lasting, sturdy and resilient celery, that is able to resist breakage and ruptures through normal harvesting, processing, packaging, shipment and usage. 
     Edible celery ( Apium graveolens  L. var.  dulce ). An  Apium graveolens  L. var.  dulce  celery that is considered suitable for ingestion by humans based upon the flavor and the texture of the celery. 
     Efficiency. Efficiency as presented here is the percentage by weight of the four-inch or three-inch sticks compared to the gross weight. More efficient varieties have a greater percentage of the gross weight being converted into useable finished product (i.e., four-inch or three-inch sticks). 
     Essentially all the physiological and morphological characteristics. A plant having essentially all the physiological and morphological characteristics of the recurrent parent, except for the characteristics derived from the converted gene. 
     External diameter. The average diameter of the petiole cylinder measured from the outside of the cylinder wall to the outside of the opposite cylinder wall. 
     Feather Leaf. Feather Leaf is a yellowing of the lower leaves and generally occurs in the outer petioles but can also be found on inner petioles of the stalk. These yellowing leaves which would normally remain in the harvested stalk are considered unacceptable. These petioles then have to be stripped off in order to meet USDA standards which effectively decreases the stalk size and yield. 
     Flare. The lower, generally wider portion of the petiole which is usually a paler green or white. 
       Fusarium  Yellows. A fungal soilborne disease caused by  Fusarium oxysporum  f. sp.  apii  Race 2. Infected plants turn yellow and are stunted. Some of the large roots may have a dark brown and a water-soaked appearance. The water-conducting tissue (xylem) in the stem, crown, and root show a characteristic orange-brown discoloration. In the later stages of infection, plants remain severely stunted and yellowed and may collapse. 
     Gene. As used herein, “gene” refers to a segment of nucleic acid. A gene can be introduced into a genome of a species, whether from a different species or from the same species, using transformation or various breeding techniques. 
     Gross Yield (Pounds/Acre). The total yield in pounds/acre of trimmed celery plants (stalks). 
     Internal diameter. The average diameter of the petiole cylinder measured from the inside of the cylinder wall to the inside of the opposite cylinder wall. 
     Leaf Celery ( Apium graveolens  L. var.  secalinum ). A plant that has been developed primarily for leaf and seed production. Often grown in Mediterranean climates, leaf celery more closely resembles celery&#39;s wild ancestors. The stems are small and fragile and vary from solid to hollow and the leaves are fairly small and are generally bitter. This type is often used for its medicinal properties and spice. 
     Leaf Margin Chlorosis. A magnesium deficiency producing an interveinal chlorosis which starts at the margin of leaves. 
     Maturity Date. Maturity in celery can be dictated by two conditions. The first, or true maturity, is the point in time when the celery reaches maximum size distribution, but before defects such as pith, yellowing, Feather Leaf or Brown Stem appear. The second, or market maturity is an artificial maturity dictated by market conditions, i.e, the market requirement may be for 3 dozen sizes so the field is harvested at slightly below maximum yield potential because the smaller sizes are what the customers prefer at that moment. 
     MUN. MUN refers to the MUNSELL Color Chart which publishes an official color chart for plant tissues according to a defined numbering system. The chart may be purchased from the Macbeth Division of Kollmorgen Instruments Corporation, 617 Little Britain Road, New Windsor, New York 12553-6148. 
     Petiole. A petiole is the stem or limb of a leaf, the primary portion of the celery consumed. 
     Pith. Pith is a sponginess/hollowness/white discoloration that occurs in the petioles of varieties naturally as they become over-mature. In some varieties it occurs at an earlier stage causing harvest to occur prior to ideal maturity. Pith generally occurs in the outer older petioles first. If it occurs, these petioles are stripped off to make grade and effectively decreases the stalk size and overall yield potential. 
     Petiole depth. The average measurement in millimeters of the depth of the celery petiole at its narrowest point. The petiole depth measurement is taken from the outside of the petiole (which is the part of the petiole that faces the outside of the stalk) and is measured to the inside of the petiole or cup or the inner most point of the petiole that faces the center of the stalk or heart. 
     Petiole width. The average measurement of the width of the celery petiole in millimeters at its widest point. The measurement is taken from the side or edge of petiole to the opposite side or edge of the petiole. The measurement is taken 90 degrees from petiole depth. 
     Phthalides. One of the chemical compounds that are responsible for the characteristic flavor and aroma of celery. 
     Plant Height. The height of the plant from the bottom of the base or butt of the celery plant to the top of the tallest leaf. 
     Quantitative Trait Loci. Quantitative Trait Loci (QTL) refers to genetic loci that control to some degree, numerically representable traits that are usually continuously distributed. 
     Regeneration. Regeneration refers to the development of a plant from tissue culture. 
     Ribbing. The texture of the exterior surface of the celery petiole can vary from smooth to ribby depending on the variety. Ribbing is the presence of numerous ridges that run vertically along the petioles of the celery plant. 
     Sanitized. Means washed, cleansed or sterilized celery so the limb&#39;s surface is free of dirt, insects, microbial infestation, bacterial infestation, fungal infestation or other surface contaminates. The process of sanitization involves washing the limbs in order to remove surface contamination such as dirt and insects and the utilization of a sanitization material or process in order to remove or kill surface contamination by microbial, bacterial and fungal agents. 
     Sanitization Treatment. Treating celery with a chemical or process so as to sanitize the celery. The chemical or process is selected from the group consisting of ascorbic acid, peroxyacetic acid also known as TSUNAMI, sodium hypochlorite (chlorine), bromine products (sodium hypobromine), chlorine dioxide, ozone based systems, hydrogen peroxide products, trisodium phosphate, quaternary ammonium products, ultraviolet light systems, irradiation, steam, ultra heat treatments, and high pressure pasteurization. 
     Shear strength or pressure. Means the force in grams that a celery can withstand prior rupturing or cutting of the wall of the celery petiole. 
     Seed Stem. A seed stem is the result of the elongation of the main stem of the celery, which is usually very compressed to almost non-existent, to form the flowering axis. The seed stem or flowering axis can reach several feet in height during full flower. The length of the seed stem is measured as the distance from the top of the basal plate (the base of the seed stem) to its terminus (the terminal growing point). 
     Single gene converted. Single gene converted or conversion plant refers to plants which are developed by backcrossing, or via genetic engineering, wherein essentially all of the desired morphological and physiological characteristics of a line are recovered in addition to the single gene transferred into the line via the backcrossing technique or via genetic engineering. 
     Stalk. A stalk is a single celery plant that is trimmed with the top or foliage and the roots removed. 
     Stringiness. Stringiness is a physiological characteristic that is generally associated with strings that get stuck between the consumer&#39;s teeth. There are generally two sources of strings in celery. One is the vascular bundle which can be fairly elastic and behave as a string. The second is a strip of particularly strong epidermis cells called schlerenchyma which are located on the surface of the ridges of the celery varieties that have ribs. 
     Suckers. Suckers are auxiliary shoots that form at the base of the stalk or within the auxiliary buds between each petiole. If these shoots form between the petioles of the stalk, several petioles have to be stripped off causing the celery to become smaller and the functional yields to be decreased. 
     Theoretical Maximum Yield. If you assume 100% 2 dozen size and a 47,000 plant population per acre and 70 pound cartons, your theoretical maximum yield would be 68.5 tons. 
     Vascular Bundle. In celery, the xylem and phloem run vertically through the petiole near the epidermis in groups or traces called vascular bundles. 
     Vacuum. The negative pressure (in inches mercury) required to rupture or break the celery petiole, measured in inches of mercury. 
     Vegetable material. Means products that are derived from, but not limited to, vegetables, fruit, grains and other plants. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Celery cultivar ADS-20 is a conventional or carton celery type with the primary purposes of being supplied to customers as a 14 inch whole stalk or in an approximately 9 inch heart configuration. It produces a very nice green, compact, cylindrical stalk that is surprisingly and especially valuable due to its very strong bolting tolerance. Unlike, most commercial varieties (slight vernalization requirement) that bolt fairly easily under conditions with moderate bolting pressure and compared to Hill&#39;s Special that is bolting tolerant (moderate vernalization requirement), ADS-20 is very bolting tolerant (high vernalization requirement). This increased tolerance to bolting (requirement for an increased vernalization period) means cultivar ADS-20 can be grown in increasingly colder production areas with out detrimental impact from the USDA Grade Standards. This is especially important because competition for the climatically moderated coastal lands is increasing, whether by other crops or real estate. The increased bolting tolerance of ADS-20 also allows for celery pricing to remain fairly consistent when most production input costs are increasing. This is possible because one of the largest costs associated with celery production is the component associated with land rent or prorated land value and the colder inland lands are less expensive than premium coastal land. ADS-20 may also be used to extend the production windows in the celery production areas of Northern California like Santa Maria and Salinas when the weather is to cool for the production of traditional varieties. 
     Celery cultivar ADS-20 is not identified as having particularly strong tolerance to  Fusarium oxysporum  f. sp.  apii  Race 2, however, it has slightly improved tolerance when compared with Hill&#39;s Special.  Fusarium  tolerance is not a critical feature for this variety because in the cool weather period when this cultivar is grown in order to capitalize on its tolerance to bolting the same temperatures that are responsible for vernalization are responsible for keeping the disease,  fusarium , inactive in the soil. It is generally considered that under 50° F.  fusarium  is not influential. Generally the only time when this may become an issue is late in the traditional bolting window when temperatures can fluctuate and become elevated. If they occur, these warmer temperatures generally occur in May and by this time ADS-20 will have done most of its growth and established most of its root system so  fusarium  has less impact on the final crop. As long as ADS-20 is constrained to this March to May celery harvest window in the Southern California region, it has adequate tolerance to  fusarium  if planted in ground that has elevated  fusarium  levels. 
     Celery cultivar ADS-20 has the following morphologic and other characteristics (based primarily on data collected at Oxnard, Calif.). 
     
       
         
           
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 VARIETY DESCRIPTION INFORMATION 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
            
               
                 Maturity: 132 days in Oxnard, California 
               
               
                 Plant Height: 72.0 cm 
               
               
                 Number of Outer Petioles (&gt;40 cm): 12.1 
               
               
                 Number of Inner Petioles (&lt;40 cm): 7.2 
               
               
                 Stalk Shape: Cylindrical 
               
               
                 Stalk Conformation: Compact 
               
               
                 Heart Formation: Moderate to Full 
               
               
                 Petiole Length (from butt to first joint): 34.9 cm 
               
               
                 Petiole Length Class: Long (&gt;30 cm) 
               
               
                 Petiole Width (at midpoint): 26.9 mm 
               
               
                 Petiole Thickness (at midpoint): 9.9 mm 
               
               
                 Cross Section Shape: Cup 
               
               
                 Color (un-blanched at harvest): MUN 5GY 6/6 (green) 
               
               
                 Anthocyanin: Absent 
               
               
                 Stringiness: Moderate 
               
               
                 Ribbing: Smooth 
               
               
                 Glossiness: Moderate Glossy 
               
               
                 Leaf Blade Color: MUN 5GY 4/4 (dark green) 
               
               
                 Bolting: Tolerant/Resistant 
               
               
                 Adaxial Crackstem (Boron Deficiency): Tolerant 
               
               
                 Abaxial Crackstem (Boron Deficiency): Tolerant 
               
               
                 Leaf Margin Chlorosis (Magnesium Deficiency): Tolerant 
               
               
                 Blackheart (Calcium Deficiency): Tolerant 
               
               
                 Pithiness (Nutritional Deficiency): Tolerant 
               
               
                 Feather Leaf: Tolerant 
               
               
                 Sucker Development: Tolerant 
               
               
                   Fusarium  Yellows, Race 2 ( Fusarium oxysporum ): Slight to Moderate 
               
               
                 Tolerance 
               
               
                 Brown Stem: Tolerant 
               
               
                   
               
            
           
         
       
     
     This invention is also directed to methods for producing a celery plant by crossing a first parent celery plant with a second parent celery plant, wherein the first parent celery plant or second parent celery plant is celery cultivar ADS-20. Further, both the first parent celery plant and second parent celery plant may be from cultivar ADS-20. Therefore, any breeding methods using celery cultivar ADS-20 are part of this invention, such as selling, backcrosses, hybrid breeding, and crosses to populations. Any plants produced using celery cultivar ADS-20 as at least one parent are within the scope of this invention. 
     Additional methods include, but are not limited to, expression vectors introduced into plant tissues using a direct gene transfer method such as microprojectile-mediated delivery, DNA injection, electroporation and the like. More preferably, expression vectors are introduced into plant tissues by using either microprojectile-mediated delivery with a biolistic device or by using  Agrobacterium -mediated transformation. Transformant plants obtained with the protoplasm of the invention are intended to be within the scope of this invention. 
     FURTHER EMBODIMENTS OF THE INVENTION 
     With the advent of molecular biological techniques that have allowed the isolation and characterization of genes that encode specific protein products, scientists in the field of plant biology developed a strong interest in engineering the genome of plants to contain and express foreign genes, or additional, or modified versions of native, or endogenous, genes (perhaps driven by different promoters) in order to alter the traits of a plant in a specific manner. Such foreign additional and/or modified genes are referred to herein collectively as “transgenes”. Over the last fifteen to twenty years several methods for producing transgenic plants have been developed, and the present invention, in particular embodiments, also relates to transformed versions of the claimed line. 
     Plant transformation involves the construction of an expression vector that will function in plant cells. Such a vector consists of DNA comprising a gene under control of or operatively linked to a regulatory element (for example, a promoter). The expression vector may contain one or more such operably linked gene/regulatory element combinations. The vector(s) may be in the form of a plasmid, and can be used alone or in combination with other plasmids, to provide transformed celery plants, using transformation methods as described below to incorporate transgenes into the genetic material of the celery plant(s). 
     Expression Vectors for Celery Transformation: Marker Genes 
     Expression vectors include at least one genetic marker, operably linked to a regulatory element (a promoter, for example) that allows transformed cells containing the marker to be either recovered by negative selection, i.e., inhibiting growth of cells that do not contain the selectable marker gene, or by positive selection, i.e., screening for the product encoded by the genetic marker. Many commonly used selectable marker genes for plant transformation are well known in the arts, and include, for example, genes that encode for enzymes that metabolically detoxify a selective chemical agent which may be an antibiotic or a herbicide, or genes that encode an altered target which is insensitive to the inhibitor. 
     One commonly used selectable marker gene for plant transformation is the neomycin phosphotransferase II (nptII) gene, isolated from transposon Tn5, which when placed under the control of plant regulatory signals confers resistance to kanamycin (Fraley et al.,  Proc. Natl. Acad. Sci. U.S.A.,  80:4803 (1983)). Another commonly used selectable marker gene is the hygromycin phosphotransferase gene which confers resistance to the antibiotic hygromycin (Vanden Elzen et al.,  Plant Mol. Biol.,  5:299 (1985)). 
     Additional selectable marker genes of bacterial origin that confer resistance to antibiotics include gentamycin acetyl transferase, streptomycin phosphotransferase, and aminoglycoside-3′-adenyl transferase, the bleomycin resistance determinant (Hayford et al.,  Plant Physiol.  86:1216 (1988), Jones et al.,  Mol. Gen. Genet.,  210:86 (1987), Svab et al.,  Plant Mol. Biol.  14:197 (1990), Hille et al.,  Plant Mol. Biol.  7:171 (1986)). Other selectable marker genes confer resistance to herbicides such as glyphosate, glufosinate, or bromoxynil (Comai et al.,  Nature  317:741-744 (1985), Gordon-Kamm et al.,  Plant Cell  2:603-618 (1990) and Stalker et al.,  Science  242:419-423 (1988)). 
     Selectable marker genes for plant transformation that are not of bacterial origin include, for example, mouse dihydrofolate reductase, plant 5-enolpyruvylshikimate-3-phosphate synthase and plant acetolactate synthase (Eichholtz et al.,  Somatic Cell Mol. Genet.  13:67 (1987), Shah et al.,  Science  233:478 (1986), Charest et al.,  Plant Cell Rep.  8:643 (1990)). 
     Another class of marker genes for plant transformation require screening of presumptively transformed plant cells rather than direct genetic selection of transformed cells for resistance to a toxic substance such as an antibiotic. These genes are particularly useful to quantify or visualize the spatiotemporal expression of a gene and are frequently referred to as reporter genes because they are fused to a gene or gene regulatory sequence. Commonly used genes for screening presumptively transformed cells include α-glucuronidase (GUS), α-galactosidase, luciferase, chloramphenicol, and acetyltransferase (Jefferson, R. A.,  Plant Mol. Biol. Rep.  5:387 (1987), Teeri et al.,  EMBO J.  8:343 (1989), Koncz et al.,  Proc. Natl. Acad. Sci. U.S.A.  84:131 (1987), DeBlock et al.,  EMBO J.  3:1681 (1984)). 
     In vivo methods for visualizing GUS activity that do not require destruction of plant tissues are available (Molecular Probes publication 2908, IMAGENE GREEN, p. 1-4 (1993) and Naleway et al.,  J. Cell Biol.  115:151a (1991)). However, these in vivo methods for visualizing GUS activity have not proven useful for recovery of transformed cells because of low sensitivity, high fluorescent backgrounds and limitations associated with the use of luciferase genes as selectable markers. 
     More recently, a gene encoding Green Fluorescent Protein (GFP) has been utilized as a marker for gene expression in prokaryotic and eukaryotic cells (Chalfie et al.,  Science  263:802 (1994)). GFP and mutants of GFP may be used as screenable markers. 
     Expression Vectors for Celery Transformation: Promoters 
     Genes included in expression vectors must be driven by a nucleotide sequence comprising a regulatory element, such as a promoter. Several types of promoters are now well known in the arts, as are other regulatory elements that can be used alone or in combination with promoters. 
     As used herein, “promoter” includes reference to a region of DNA upstream from the start of transcription and involved in recognition and binding of RNA polymerase and other proteins to initiate transcription. A “plant promoter” is a promoter capable of initiating transcription in plant cells. Examples of promoters under developmental control include those which preferentially initiate transcription in certain tissues, such as leaves, roots, seeds, fibers, xylem vessels, tracheids, or sclerenchyma. These promoters are referred to as “tissue-preferred”. Promoters which initiate transcription only in certain tissue are referred to as “tissue-specific”. A “cell type” specific promoter primarily drives expression in certain cell types in one or more organs, for example, vascular cells in roots or leaves. An “inducible” promoter is a promoter which is under environmental control. Examples of environmental conditions that may effect transcription by inducible promoters include anaerobic conditions or the presence of light. Tissue-specific, tissue-preferred, cell type specific, and inducible promoters constitute the class of “non-constitutive” promoters. A “constitutive” promoter is a promoter which is active under most environmental conditions. 
     A. Inducible Promoters 
     An inducible promoter is operably linked to a gene for expression in celery. Optionally, the inducible promoter is operably linked to a nucleotide sequence encoding a signal sequence which is operably linked to a gene for expression in celery. With an inducible promoter the rate of transcription increases in response to an inducing agent. 
     Any inducible promoter can be used in the instant invention. See Ward et al.,  Plant Mol. Biol.  22:361-366 (1993). Exemplary inducible promoters include, but are not limited to, that from the ACEI system which responds to copper (Meft et al.,  PNAS  90:4567-4571 (1993)); In2 gene from maize which responds to benzenesulfonamide herbicide safeners (Hershey et al.,  Mol. Gen. Genetics  227:229-237 (1991) and Gatz et al.,  Mol. Gen. Genetics  243:32-38 (1994)) or Tet repressor from Tn10 (Gatz et al.,  Mol. Gen. Genetics  227:229-237 (1991). A particularly preferred inducible promoter is a promoter that responds to an inducing agent to which plants do not normally respond. An exemplary inducible promoter is the inducible promoter from a steroid hormone gene, the transcriptional activity of which is induced by a glucocorticosteroid hormone. Schena et al.,  Proc. Natl. Acad. Sci. U.S.A.  88:0421 (1991). 
     B. Constitutive Promoters 
     A constitutive promoter is operably linked to a gene for expression in celery or the constitutive promoter is operably linked to a nucleotide sequence encoding a signal sequence which is operably linked to a gene for expression in celery. 
     Many different constitutive promoters can be utilized in the instant invention. Exemplary constitutive promoters include, but are not limited to, the promoters from plant viruses such as the 35S promoter from CaMV (Odell et al.,  Nature  313:810-812 (1985) and the promoters from such genes as rice actin (McElroy et al.,  Plant Cell  2:163-171 (1990)); ubiquitin (Christensen et al.,  Plant Mol. Biol.  12:619-632 (1989) and Christensen et al.,  Plant Mol. Biol.  18:675-689 (1992)); pEMU (Last et al.,  Theor. Appl. Genet.  81:581-588 (1991)); MAS (Velten et al.,  EMBO J.  3:2723-2730 (1984)) and maize H3 histone (Lepetit et al.,  Mol. Gen. Genetics  231:276-285 (1992) and Atanassova et al.,  Plant Journal  2 (3): 291-300 (1992)). The ALS promoter, XbaI/NcoI fragment 5′ to the  Brassica napus  ALS3 structural gene (or a nucleotide sequence similarity to said XbaI/NcoI fragment), represents a particularly useful constitutive promoter. See PCT application WO 96/30530. 
     C. Tissue-Specific or Tissue-Preferred Promoters 
     A tissue-specific promoter is operably linked to a gene for expression in celery. Optionally, the tissue-specific promoter is operably linked to a nucleotide sequence encoding a signal sequence which is operably linked to a gene for expression in celery. Plants transformed with a gene of interest operably linked to a tissue-specific promoter produce the protein product of the transgene exclusively, or preferentially, in a specific tissue. 
     Any tissue-specific or tissue-preferred promoter can be utilized in the instant invention. Exemplary tissue-specific or tissue-preferred promoters include, but are not limited to, a root-preferred promoter, such as that from the phaseolin gene (Murai et al.,  Science  23:476-482 (1983) and Sengupta-Gopalan et al.,  Proc. Natl. Acad. Sci. U.S.A.  82:3320-3324 (1985)); a leaf-specific and light-induced promoter such as that from cab or rubisco (Simpson et al.,  EMBO J.  4(11):2723-2729 (1985) and Timko et al.,  Nature  318:579-582 (1985)); an anther-specific promoter such as that from LAT52 (Twell et al.,  Mol. Gen. Genetics  217:240-245 (1989)); a pollen-specific promoter such as that from Zm13 (Guerrero et al.,  Mol. Gen. Genetics  244:161-168 (1993)) or a microspore-preferred promoter such as that from apg (Twell et al.,  Sex. Plant Reprod.  6:217-224 (1993)). 
     Signal Sequences for Targeting Proteins to Subcellular Compartments 
     Transport of protein produced by transgenes to a subcellular compartment such as the chloroplast, vacuole, peroxisome, glyoxysome, cell wall or mitochondrion or for secretion into the apoplast, is accomplished by means of operably linking the nucleotide sequence encoding a signal sequence to the 5′ and/or 3′ region of a gene encoding the protein of interest. Targeting sequences at the 5′ and/or 3′ end of the structural gene may determine, during protein synthesis and processing, where the encoded protein is ultimately compartmentalized. 
     The presence of a signal sequence directs a polypeptide to either an intracellular organelle or subcellular compartment or for secretion to the apoplast. Many signal sequences are known in the art; for example, Becker et al.,  Plant Mol. Biol.  20:49 (1992), Close, P. S., Master&#39;s Thesis, Iowa State University (1993), Knox, C., et al., A Structure and Organization of Two Divergent Alpha-Amylase Genes from Barley”,  Plant Mol. Biol.  9:3-17 (1987), Lerner et al.,  Plant Physiol.  91:124-129 (1989), Fontes et al.,  Plant Cell  3:483-496 (1991), Matsuoka et al.,  Proc. Natl. Acad. Sci.  88:834 (1991), Gould et al.,  J. Cell. Biol.  108:1657 (1989), Creissen et al.,  Plant J.  2:129 (1991), Kalderon, et al., A short amino acid sequence able to specify nuclear location,  Cell  39:499-509 (1984), Steifel, et al., Expression of a maize cell wall hydroxyproline-rich glycoprotein gene in early leaf and root vascular differentiation,  Plant Cell  2:785-793 (1990). 
     Foreign Protein Genes and Agronomic Genes 
     With transgenic plants according to the present invention, a foreign protein can be produced in commercial quantities. Thus, techniques for the selection and propagation of transformed plants, which are well understood in the art, yield a plurality of transgenic plants which are harvested in a conventional manner, and a foreign protein can then be extracted from a tissue of interest or from total biomass. Protein extraction from plant biomass can be accomplished by known methods which are discussed, for example, by Heney and Orr,  Anal. Biochem.  114:92-6 (1981). 
     According to a preferred embodiment, the transgenic plant provided for commercial production of foreign protein is celery. In another preferred embodiment, the biomass of interest is seed. For the relatively small number of transgenic plants that show higher levels of expression, a genetic map can be generated, primarily via conventional RFLP, PCR and SSR analysis, which identifies the approximate chromosomal location of the integrated DNA molecule. For exemplary methodologies in this regard, see Glick and Thompson,  Methods in Plant Molecular Biology and Biotechnology , CRC Press, Boca Raton 269:284 (1993). Map information concerning chromosomal location is useful for proprietary protection of a subject transgenic plant. If unauthorized propagation is undertaken and crosses made with other germplasm, the map of the integration region can be compared to similar maps for suspect plants, to determine if the latter have a common parentage with the subject plant. Map comparisons would involve hybridizations, RFLP, PCR, SSR and sequencing, all of which are conventional techniques. 
     Likewise, by means of the present invention, agronomic genes can be expressed in transformed plants. More particularly, plants can be genetically engineered to express various phenotypes of agronomic interest. Exemplary genes implicated in this regard include, but are not limited to, those categorized below: 
     1. Genes that Confer Resistance to Pests or Disease and that Encode: 
     A. Plant disease resistance genes. Plant defenses are often activated by specific interaction between the product of a disease resistance gene (R) in the plant and the product of a corresponding avirulence (Avr) gene in the pathogen. A plant line can be transformed with a cloned resistance gene to engineer plants that are resistant to specific pathogen strains. See, for example Jones et al.,  Science  266:789 (1994) (cloning of the tomato Cf-9 gene for resistance to  Cladosporium fulvum ); Martin et al.,  Science  262:1432 (1993) (tomato Pto gene for resistance to  Pseudomonas syringae  pv. tomato encodes a protein kinase); Mindrinos et al.,  Cell  78:1089 (1994) (Arabidopsis RSP2 gene for resistance to  Pseudomonas syringae ). 
     B. A  Bacillus thuringiensis  protein, a derivative thereof or a synthetic polypeptide modeled thereon. See, for example, Geiser et al.,  Gene  48:109 (1986), who disclose the cloning and nucleotide sequence of a Bt δ-endotoxin gene. Moreover, DNA molecules encoding δ-endotoxin genes can be purchased from American Type Culture Collection, Manassas, Va., under ATCC Accession Nos. 40098, 67136, 31995 and 31998. 
     C. A lectin. See, for example, the disclosure by Van Damme et al.,  Plant Molec. Biol.  24:25 (1994), who disclose the nucleotide sequences of several  Clivia miniata  mannose-binding lectin genes. 
     D. A vitamin-binding protein such as avidin. See PCT application US 93/06487, the contents of which are hereby incorporated by reference. The application teaches the use of avidin and avidin homologues as larvicides against insect pests. 
     E. An enzyme inhibitor, for example, a protease or proteinase inhibitor or an amylase inhibitor. See, for example, Abe et al.,  J. Biol. Chem.  262:16793 (1987) (nucleotide sequence of rice cysteine proteinase inhibitor), Huub et al.,  Plant Molec. Biol.  21:985 (1993) (nucleotide sequence of cDNA encoding tobacco proteinase inhibitor I), Sumitani et al.,  Biosci. Biotech. Biochem.  57:1243 (1993) (nucleotide sequence of  Streptomyces nitrosporeus  α-amylase inhibitor). 
     F. An insect-specific hormone or pheromone such as an ecdysteroid and juvenile hormone, a variant thereof, a mimetic based thereon, or an antagonist or agonist thereof. See, for example, the disclosure by Hammock et al.,  Nature  344:458 (1990), of baculovirus expression of cloned juvenile hormone esterase, an inactivator of juvenile hormone. 
     G. An insect-specific peptide or neuropeptide which, upon expression, disrupts the physiology of the affected pest. For example, see the disclosures of Regan,  J. Biol. Chem.  269:9 (1994) (expression cloning yields DNA coding for insect diuretic hormone receptor), and Pratt et al.,  Biochem. Biophys. Res. Comm.  163:1243 (1989) (an allostatin is identified in  Diploptera puntata ). See also U.S. Pat. No. 5,266,317 to Tomalski et al., who disclose genes encoding insect-specific, paralytic neurotoxins. 
     H. An insect-specific venom produced in nature by a snake, a wasp, etc. For example, see Pang et al.,  Gene  116:165 (1992), for disclosure of heterologous expression in plants of a gene coding for a scorpion insectotoxic peptide. 
     I. An enzyme responsible for a hyperaccumulation of a monoterpene, a sesquiterpene, a steroid, hydroxamic acid, a phenylpropanoid derivative or another non-protein molecule with insecticidal activity. 
     J. An enzyme involved in the modification, including the post-translational modification, of a biologically active molecule; for example, a glycolytic enzyme, a proteolytic enzyme, a lipolytic enzyme, a nuclease, a cyclase, a transaminase, an esterase, a hydrolase, a phosphatase, a kinase, a phosphorylase, a polymerase, an elastase, a chitinase and a glucanase, whether natural or synthetic. See PCT application WO 93/02197 in the name of Scott et al., which discloses the nucleotide sequence of a callase gene. DNA molecules which contain chitinase-encoding sequences can be obtained from ATCC Accession Nos. 39637 and 67152. See also Kramer et al.,  Insect Biochem. Molec. Biol.  23:691 (1993), who teach the nucleotide sequence of a cDNA encoding tobacco hornworm chitinase, and Kawalleck et al.,  Plant Molec. Biol.  21:673 (1993), who provide the nucleotide sequence of the parsley ubi4-2 polyubiquitin gene. 
     K. A molecule that stimulates signal transduction. For example, see the disclosure by Botella et al.,  Plant Molec. Biol,  24:757 (1994), of nucleotide sequences for mung bean calmodulin cDNA clones, and Griess et al.,  Plant Physiol.  104:1467 (1994), who provide the nucleotide sequence of a maize calmodulin cDNA clone. 
     L. A hydrophobic moment peptide. See PCT application WO 95/16776 (disclosure of peptide derivatives of tachyplesin which inhibit fungal plant pathogens) and PCT application WO 95/18855 (teaches synthetic antimicrobial peptides that confer disease resistance), the respective contents of which are hereby incorporated by reference. 
     M. A membrane permease, a channel former or a channel blocker. For example, see the disclosure of Jaynes et al.,  Plant Sci  89:43 (1993), of heterologous expression of a cecropin-β, lytic peptide analog to render transgenic tobacco plants resistant to  Pseudomonas solanacearum.    
     N. A viral-invasive protein or a complex toxin derived therefrom. For example, the accumulation of viral coat proteins in transformed plant cells imparts resistance to viral infection and/or disease development effected by the virus from which the coat protein gene is derived, as well as by related viruses. See Beachy et al.,  Ann. rev. Phytopathol.  28:451 (1990). Coat protein-mediated resistance has been conferred upon transformed plants against alfalfa mosaic virus, cucumber mosaic virus, tobacco streak virus, potato virus X, potato virus Y, tobacco etch virus, tobacco rattle virus and tobacco mosaic virus. 
     O. An insect-specific antibody or an immunotoxin derived there from. Thus, an antibody targeted to a critical metabolic function in the insect gut would inactivate an affected enzyme, killing the insect (Taylor et al.,  Abstract # 497, Seventh Int&#39;l Symposium on Molecular Plant-Microbe Interactions (Edinburgh, Scotland) (1994) (enzymatic inactivation in transgenic tobacco via production of single-chain antibody fragments)). 
     P. A virus-specific antibody. For example, Tavladoraki et al.,  Nature  366:469 (1993), shows that transgenic plants expressing recombinant antibody genes are protected from virus attack. 
     Q. A developmental-arrestive protein produced in nature by a pathogen or a parasite. Thus, fungal endo-α-1,4-D-polygalacturonases facilitate fungal colonization and plant nutrient release by solubilizing plant cell wall homo-α-1,4-D-galacturonase. See Lamb et al.,  Bio/Technology  10:1436 (1992). The cloning and characterization of a gene which encodes a bean endopolygalacturonase-inhibiting protein is described by Toubart et al.,  Plant J.  2:367 (1992). 
     R. A developmental-arrestive protein produced in nature by a plant. For example, Logemann et al.,  Bio/Technology  10:305 (1992), have shown that transgenic plants expressing the barley ribosome-inactivating gene have an increased resistance to fungal disease. 
     S. A lettuce mosaic potyvirus (LMV) coat protein gene introduced into  Lactuca sativa  in order to increase its resistance to LMV infection. See Dinant et al.,  Molecular Breeding.  1997, 3: 1, 75-86. 
     2. Genes that Confer Resistance to an Herbicide: 
     A. An herbicide that inhibits the growing point or meristem, such as an imidazolinone or a sulfonylurea. Exemplary genes in this category code for mutant ALS and AHAS enzyme as described, for example, by Lee et al.,  EMBO J.  7:1241 (1988), and Miki et al.,  Theor. Appl. Genet.  80:449 (1990), respectively. 
     B. Glyphosate (resistance conferred by mutant 5-enolpyruvlshikimate-3-phosphate synthase (EPSPS) and aroA genes, respectively) and other phosphono compounds such as glufosinate (phosphinothricin acetyl transferase (PAT) and  Streptomyces hygroscopicus  PAT bar genes), and pyridinoxy or phenoxy proprionic acids and cyclohexones (ACCase inhibitor-encoding genes). See, for example, U.S. Pat. No. 4,940,835 to Shah, et al., which discloses the nucleotide sequence of a form of EPSPS which can confer glyphosate resistance. A DNA molecule encoding a mutant aroA gene can be obtained under ATCC accession number 39256, and the nucleotide sequence of the mutant gene is disclosed in U.S. Pat. No. 4,769,061 to Comai. See also Umaballava-Mobapathie in  Transgenic Research.  1999, 8: 1, 33-44 that discloses  Lactuca sativa  resistant to glufosinate. European Patent Application No. 0 333 033 to Kumada et al., and U.S. Pat. No. 4,975,374 to Goodman et al., disclose nucleotide sequences of glutamine synthetase genes which confer resistance to herbicides such as L-phosphinothricin. The nucleotide sequence of a phosphinothricin-acetyl-transferase gene is provided in European Patent Application No. 0 242 246 to Leemans et al. DeGreef et al.,  Bio/Technology  7:61 (1989), describe the production of transgenic plants that express chimeric bar genes coding for phosphinothricin acetyl transferase activity. Examples of genes conferring resistance to phenoxy proprionic acids and cyclohexones, such as sethoxydim and haloxyfop are the Accl-S1, Accl-S2 and Accl-S3 genes described by Marshall et al.,  Theor. Appl. Genet.  83:435 (1992). 
     C. An herbicide that inhibits photosynthesis, such as a triazine (psbA and gs+ genes) and a benzonitrile (nitrilase gene). Przibilla et al.,  Plant Cell  3:169 (1991), describe the transformation of  Chlamydomonas  with plasmids encoding mutant psbA genes. Nucleotide sequences for nitrilase genes are disclosed in U.S. Pat. No. 4,810,648 to Stalker, and DNA molecules containing these genes are available under ATCC Accession Nos. 53435, 67441, and 67442. Cloning and expression of DNA coding for a glutathione S-transferase is described by Hayes et al.,  Biochem. J.  285:173 (1992). 
     D. Acetohydroxy acid synthase, which has been found to make plants that express this enzyme resistant to multiple types of herbicides, has been introduced into a variety of plants. See Hattori et al.,  Mol. Gen. Genet.  246:419, 1995. Other genes that confer tolerance to herbicides include a gene encoding a chimeric protein of rat cytochrome P4507A1 and yeast NADPH-cytochrome P450 oxidoreductase (Shiota et al.,  Plant Physiol.,  106:17, 1994), genes for glutathione reductase and superoxide dismutase (Aono et al.,  Plant Cell Physiol.  36:1687, 1995), and genes for various phosphotransferases (Datta et al.,  Plant Mol. Biol.  20:619, 1992). 
     E. Protoporphyrinogen oxidase (protox) is necessary for the production of chlorophyll, which is necessary for all plant survival. The protox enzyme serves as the target for a variety of herbicidal compounds. These herbicides also inhibit growth of all the different species of plants present, causing their total destruction. The development of plants containing altered protox activity which are resistant to these herbicides are described in U.S. Pat. Nos. 6,288,306; 6,282,837; 5,767,373; and international publication WO 01/12825. 
     F. Modified bolting tolerance in plants for example, by transferring a gene encoding for gibberellin 2-oxidase (U.S. Pat. No. 7,262,340). Bolting has also been modified using non-transformation methods; see Wittwer, S. H., et al. (1957)  Science.  126(3262): 30-31; Booij, R. et al., (1995)  Scientia Horticulturae.  63:143-154; and Booij, R. et al., (1994)  Scientia Horticulturae.  58:271-282. 
     3. Genes that Confer or Contribute to a Value-Added Trait, Such as: 
     A. Increased iron content of the celery, for example by transforming a plant with a soybean ferritin gene as described in Goto et al.,  Acta Horticulturae.  2000, 521, 101-109. 
     B. Decreased nitrate content of leaves, for example by transforming a celery with a gene coding for a nitrate reductase. See for example Curtis et al.,  Plant Cell Report.  1999, 18: 11, 889-896. 
     C. Increased sweetness of the celery by transferring a gene coding for monellin, that elicits a flavor 100,000 times sweeter than sugar on a molar basis. See Penarrubia et al.,  Biotechnology.  1992, 10: 561-564. 
     D. Modified fatty acid metabolism, for example, by transforming a plant with an antisense gene of stearyl-ACP desaturase to increase stearic acid content of the plant. See Knultzon et al.,  Proc. Natl. Acad. Sci. USA  89:2625 (1992). 
     E. Modified carbohydrate composition effected, for example, by transforming plants with a gene coding for an enzyme that alters the branching pattern of starch. See Shiroza et al.,  J. Bacteriol.  170:810 (1988) (nucleotide sequence of  Streptococcus  mutants fructosyltransferase gene), Steinmetz et al.,  Mol. Gen. Genet.  20:220 (1985) (nucleotide sequence of  Bacillus subtilis  levansucrase gene), Pen et al.,  Bio/Technology  10:292 (1992) (production of transgenic plants that express  Bacillus lichenifonnis  α-amylase), Elliot et al.,  Plant Molec. Biol.  21:515 (1993) (nucleotide sequences of tomato invertase genes), SØgaard et al.,  J. Biol. Chem.  268:22480 (1993) (site-directed mutagenesis of barley α-amylase gene), and Fisher et al.,  Plant Physiol.  102:1045 (1993) (maize endosperm starch branching enzyme II). 
     4. Genes that Control Male-Sterility 
     A. Introduction of a deacetylase gene under the control of a tapetum-specific promoter and with the application of the chemical N-Ac-PPT; see international publication WO 01/29237. 
     B. Introduction of various stamen-specific promoters; see international publications WO 92/13956 and WO 92/13957. 
     C. Introduction of the barnase and the barstar genes; see Paul et al.,  Plant Mol. Biol.  19:611-622, 1992). 
     Methods for Celery Transformation 
     Numerous methods for plant transformation have been developed, including biological and physical, plant transformation protocols. See, for example, Miki et al., “Procedures for Introducing Foreign DNA into Plants” in Methods in Plant Molecular Biology and Biotechnology, Glick B. R. and Thompson, J. E. Eds. (CRC Press, Inc., Boca Raton, 1993) pages 67-88. In addition, expression vectors and in vitro culture methods for plant cell or tissue transformation and regeneration of plants are available. See, for example, Gruber et al., “Vectors for Plant Transformation” in Methods in Plant Molecular Biology and Biotechnology, Glick B. R. and Thompson, J. E. Eds. (CRC Press, Inc., Boca Raton, 1993) pages 89-119. 
     A.  Agrobacterium -Mediated Transformation 
     One method for introducing an expression vector into plants is based on the natural transformation system of  Agrobacterium . See, for example, Horsch et al.,  Science  227:1229 (1985), Curtis et al.,  Journal of Experimental Botany.  1994, 45: 279, 1441-1449, Torres et al.,  Plant cell Tissue and Organic Culture.  1993, 34: 3, 279-285, Dinant et al.,  Molecular Breeding.  1997, 3: 1, 75-86.  A. tumefaciens  and  A. rhizogenes  are plant pathogenic soil bacteria which genetically transform plant cells. The Ti and Ri plasmids of  A. tumefaciens  and  A. rhizogenes , respectively, carry genes responsible for genetic transformation of the plant. See, for example, Kado, C. I.,  Crit. Rev. Plant Sci.  10:1 (1991). Descriptions of  Agrobacterium  vector systems and methods for  Agrobacterium -mediated gene transfer are provided by Gruber et al., supra, Miki et al., supra, and Moloney et al.,  Plant Cell Reports  8:238 (1989). See also, U.S. Pat. No. 5,591,616 issued Jan. 7, 1997. 
     B. Direct Gene Transfer 
     Several methods of plant transformation collectively referred to as direct gene transfer, have been developed as an alternative to  Agrobacterium -mediated transformation. A generally applicable method of plant transformation is microprojectile-mediated transformation wherein DNA is carried on the surface of microprojectiles measuring 1 to 4 μm. The expression vector is introduced into plant tissues with a biolistic device that accelerates the microprojectiles to speeds of 300 to 600 m/s which is sufficient to penetrate plant cell walls and membranes. Russell, D. R., et al.  Pl. Cell. Rep.  12(3, January), 165-169 (1993), Aragao, F. J. L., et al.  Plant Mol. Biol.  20(2, October), 357-359 (1992), Aragao, F. J. L., et al.  Pl. Cell. Rep.  12(9, July), 483-490 (1993). Aragao,  Theor. Appl. Genet.  93: 142-150 (1996), Kim, J.; Minamikawa,  T. Plant Science  117: 131-138 (1996), Sanford et al.,  Part. Sci. Technol.  5:27 (1987), Sanford, J. C.,  Trends Biotech.  6:299 (1988), Klein et al.,  Bio/Technology  6:559-563 (1988), Sanford, J. C.,  Physiol Plant  7:206 (1990), Klein et al.,  Biotechnology  10:268 (1992). 
     Another method for physical delivery of DNA to plants is sonication of target cells. Zhang et al.,  Bio/Technology  9:996 (1991). Alternatively, liposome and spheroplast fusion have been used to introduce expression vectors into plants. Deshayes et al.,  EMBO J.,  4:2731 (1985), Christou et al.,  Proc Natl. Acad. Sci. U.S.A.  84:3962 (1987). Direct uptake of DNA into protoplasts using CaCl 2  precipitation, polyvinyl alcohol or poly-L-ornithine have also been reported. Hain et al.,  Mol. Gen. Genet.  199:161 (1985) and Draper et al.,  Plant Cell Physiol.  23:451 (1982). Electroporation of protoplasts and whole cells and tissues have also been described. Saker, M.; Kuhne,  T. Biologia Plantarum  40(4): 507-514 (1997/98), Donn et al., In Abstracts of VIIth International Congress on Plant Cell and Tissue Culture IAPTC, A2-38, p 53 (1990); D&#39;Halluin et al.,  Plant Cell  4:1495-1505 (1992) and Spencer et al.,  Plant Mol. Biol.  24:51-61 (1994). See also Chupean et al.,  Biotechnology.  1989, 7: 5, 503-508. 
     Following transformation of celery target tissues, expression of the above-described selectable marker genes allows for preferential selection of transformed cells, tissues and/or plants, using regeneration and selection methods now well known in the art. 
     The foregoing methods for transformation would typically be used for producing a transgenic line. The transgenic line could then be crossed, with another (non-transformed or transformed) line, in order to produce a new transgenic celery line. Alternatively, a genetic trait which has been engineered into a particular celery cultivar using the foregoing transformation techniques could be moved into another line using traditional backcrossing techniques that are well known in the plant breeding arts. For example, a backcrossing approach could be used to move an engineered trait from a public, non-elite inbred line into an elite inbred line, or from an inbred line containing a foreign gene in its genome into an inbred line or lines which do not contain that gene. As used herein, “crossing” can refer to a simple X by Y cross, or the process of backcrossing, depending on the context. 
     Single-Gene Conversions 
     When the term celery plant, cultivar or celery line is used in the context of the present invention, this also includes any single gene conversions of that line. The term “single gene converted plant” as used herein refers to those celery plants which are developed by a plant breeding technique called backcrossing wherein essentially all of the desired morphological and physiological characteristics of a cultivar are recovered in addition to the single gene transferred into the line via the backcrossing technique. Backcrossing methods can be used with the present invention to improve or introduce a characteristic into the line. The term “backcrossing” as used herein refers to the repeated crossing of a hybrid progeny back to one of the parental celery plants for that line, backcrossing 1, 2, 3, 4, 5, 6, 7, 8 or more times to the recurrent parent. The parental celery plant which contributes the gene for the desired characteristic is termed the nonrecurrent or donor parent. This terminology refers to the fact that the nonrecurrent parent is used one time in the backcross protocol and therefore does not recur. The parental celery plant to which the gene or genes from the nonrecurrent parent are transferred is known as the recurrent parent as it is used for several rounds in the backcrossing protocol (Poehlman &amp; Sleper, 1994; Fehr, 1987). In a typical backcross protocol, the original cultivar of interest (recurrent parent) is crossed to a second line (nonrecurrent parent) that carries the single gene of interest to be transferred. The resulting progeny from this cross are then crossed again to the recurrent parent and the process is repeated until a celery plant is obtained wherein essentially all of the desired morphological and physiological characteristics of the recurrent parent are recovered in the converted plant, in addition to the single transferred gene from the nonrecurrent parent. 
     The selection of a suitable recurrent parent is an important step for a successful backcrossing procedure. The goal of a backcross protocol is to alter or substitute a single trait or characteristic in the original line. To accomplish this, a single gene of the recurrent cultivar is modified or substituted with the desired gene from the nonrecurrent parent, while retaining essentially all of the rest of the desired genetic, and therefore the desired physiological and morphological, constitution of the original line. The choice of the particular nonrecurrent parent will depend on the purpose of the backcross, one of the major purposes is to add some commercially desirable, agronomically important trait to the plant. The exact backcrossing protocol will depend on the characteristic or trait being altered to determine an appropriate testing protocol. Although backcrossing methods are simplified when the characteristic being transferred is a dominant allele, a recessive allele may also be transferred. In this instance it may be necessary to introduce a test of the progeny to determine if the desired characteristic has been successfully transferred. 
     Many single gene traits have been identified that are not regularly selected for in the development of a new line but that can be improved by backcrossing techniques. Single gene traits may or may not be transgenic, examples of these traits include but are not limited to, male sterility, modified fatty acid metabolism, modified carbohydrate metabolism, herbicide resistance, resistance for bacterial, fungal, or viral disease, insect resistance, enhanced nutritional quality, industrial usage, yield stability and yield enhancement. These genes are generally inherited through the nucleus. Several of these single gene traits are described in U.S. Pat. Nos. 5,777,196, 5,948,957 and 5,969,212, the disclosures of which are specifically hereby incorporated by reference. 
     Tissue Culture 
     Further reproduction of the variety can occur by tissue culture and regeneration. Tissue culture of various tissues of celery and regeneration of plants therefrom is well known and widely published. For example, reference may be had to Teng et al.,  HortScience.  1992, 27: 9, 1030-1032 Teng et al.,  HortScience.  1993, 28: 6, 669-1671, Zhang et al.,  Journal of Genetics and Breeding.  1992, 46: 3, 287-290, Webb et al.,  Plant Cell Tissue and Organ Culture.  1994, 38: 1, 77-79, Curtis et al.,  Journal of Experimental Botany.  1994, 45: 279, 1441-1449, Nagata et al.,  Journal for the American Society for Horticultural Science.  2000, 125: 6, 669-672, and Ibrahim et al., Plant Cell, Tissue and Organ Culture. (1992), 28(2): 139-145. It is clear from the literature that the state of the art is such that these methods of obtaining plants are routinely used and have a very high rate of success. Thus, another aspect of this invention is to provide cells which upon growth and differentiation produce celery plants having the physiological and morphological characteristics of variety ADS-20. 
     As used herein, the term “tissue culture” indicates a composition comprising isolated cells of the same or a different type or a collection of such cells organized into parts of a plant. Exemplary types of tissue cultures are protoplasts, calli, meristematic cells, and plant cells that can generate tissue culture that are intact in plants or parts of plants, such as leaves, pollen, embryos, roots, root tips, anthers, pistils, flowers, seeds, petioles, suckers and the like. Means for preparing and maintaining plant tissue culture are well known in the art. By way of example, a tissue culture comprising organs has been used to produce regenerated plants. U.S. Pat. Nos. 5,959,185, 5,973,234 and 5,977,445 describe certain techniques, the disclosures of which are incorporated herein by reference. 
     Additional Breeding Methods 
     This invention also is directed to methods for producing a celery plant by crossing a first parent celery plant with a second parent celery plant wherein the first or second parent celery plant is a celery plant of cultivar ADS-20. Further, both first and second parent celery plants can come from celery cultivar ADS-20. Thus, any breeding methods using celery cultivar ADS-20 are part of this invention, such as selling, backcrosses, hybrid production, crosses to populations, and the like. All plants produced using celery cultivar ADS-20 as at least one parent are within the scope of this invention, including those developed from cultivars derived from celery cultivar ADS-20. Advantageously, this celery cultivar could be used in crosses with other, different, celery plants to produce the first generation (F 1 ) celery hybrid seeds and plants with superior characteristics. The cultivar of the invention can also be used for transformation where exogenous genes are introduced and expressed by the cultivar of the invention. Genetic variants created either through traditional breeding methods using celery cultivar ADS-20 or through transformation of cultivar ADS-20 by any of a number of protocols known to those of skill in the art are intended to be within the scope of this invention. 
     The following describes breeding methods that may be used with celery cultivar ADS-20 in the development of further celery plants. One such embodiment is a method for developing cultivar ADS-20 progeny celery plants in a celery plant breeding program comprising: obtaining the celery plant, or a part thereof, of cultivar ADS-20 utilizing said plant or plant part as a source of breeding material, and selecting a celery cultivar ADS-20 progeny plant with molecular markers in common with cultivar ADS-20 and/or with morphological and/or physiological characteristics selected from the characteristics listed in Table 1. Breeding steps that may be used in the celery plant breeding program include pedigree breeding, backcrossing, mutation breeding, and recurrent selection. In conjunction with these steps, techniques such as RFLP-enhanced selection, genetic marker enhanced selection (for example SSR markers) and the making of double haploids may be utilized. 
     Another method involves producing a population of celery cultivar ADS-20 progeny celery plants, comprising crossing cultivar ADS-20 with another celery plant, thereby producing a population of celery plants, which, on average, derive 50% of their alleles from celery cultivar ADS-20. A plant of this population may be selected and repeatedly selfed or sibbed with a celery cultivar resulting from these successive filial generations. One embodiment of this invention is the celery cultivar produced by this method and that has obtained at least 50% of its alleles from celery cultivar ADS-20. 
     One of ordinary skill in the art of plant breeding would know how to evaluate the traits of two plant varieties to determine if there is no significant difference between the two traits expressed by those varieties. For example, see Fehr and Walt,  Principles of Cultivar Development , p 261-286 (1987). Thus the invention includes celery cultivar ADS-20 progeny celery plants comprising a combination of at least two cultivar ADS-20 traits selected from the group consisting of those listed in Table 1 or the cultivar ADS-20 combination of traits listed in the Summary of the Invention, so that said progeny celery plant is not significantly different for said traits than celery cultivar ADS-20 as determined at the 5% significance level when grown in the same environmental conditions. Using techniques described herein, molecular markers may be used to identify said progeny plant as a celery cultivar ADS-20 progeny plant. Mean trait values may be used to determine whether trait differences are significant, and preferably the traits are measured on plants grown under the same environmental conditions. Once such a variety is developed its value is substantial since it is important to advance the germplasm base as a whole in order to maintain or improve traits such as yield, disease resistance, pest resistance, and plant performance in extreme environmental conditions. 
     Progeny of celery cultivar ADS-20 may also be characterized through their filial relationship with celery cultivar ADS-20, as for example, being within a certain number of breeding crosses of celery cultivar ADS-20. A breeding cross is a cross made to introduce new genetics into the progeny, and is distinguished from a cross, such as a self or a sib cross, made to select among existing genetic alleles. The lower the number of breeding crosses in the pedigree, the closer the relationship between celery cultivar ADS-20 and its progeny. For example, progeny produced by the methods described herein may be within 1, 2, 3, 4 or 5 breeding crosses of celery cultivar ADS-20. 
     As used herein, the term “plant” includes plant cells, plant protoplasts, plant cell tissue cultures from which celery plants can be regenerated, plant calli, plant clumps and plant cells that are intact in plants or parts of plants, such as leaves, pollen, embryos, roots, root tips, anthers, pistils, flowers, seeds, petioles, suckers and the like. 
     Industrial Uses of Celery Cultivar ADS-20 
     Celery may be used in a variety of manner including but not limited to, use in salads, soups, being filled with cheese, soybean, vegetable, peanut butter or dairy type products, served raw, cooked, baked or frozen, served as sticks, pieces, dices, or dipped like potato chips. 
     TABLES 
     In the tables that follow, the traits and characteristics of celery cultivar ADS-20 are given compared to other cultivars. 
     Tables 2-5 compare field harvest yields between celery cultivar ADS-20 and celery cultivar Hill&#39;s Special on four different planting dates grown in relative proximity of one another in Oxnard, Calif. Data was taken in April 2010 from a total plant population of 52,800 plants per acre. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Characteristic 
                 ADS-20 
                 Hill&#39;s Special 
               
               
                   
                   
               
             
            
               
                   
                 Harvest Date 
                 Apr. 16, 2010 
                 Apr. 6, 2010 
               
               
                   
                 Plant Population 
                 52,800 
                 52,800 
               
               
                   
                 Maturity Days 
                 135 
                 125 
               
               
                   
                 Total Acres Harvested 
                 3.5 
                 1.5 
               
               
                   
                 Total Cartons Harvested 
                 6,318 
                 2,268 
               
               
                   
                 Yield in Cartons per acre 
                 1,805 
                 1,512 
               
               
                   
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                 Characteristic 
                 ADS-20 
                 Hill&#39;s Special 
               
               
                   
                   
               
             
            
               
                   
                 Harvest Date 
                 Apr. 20, 2010 
                 Apr. 14, 2010 
               
               
                   
                 Plant Population 
                 52,800 
                 52,800 
               
               
                   
                 Maturity Days 
                 135 
                 129 
               
               
                   
                 Total Acres Harvested 
                 4.1 
                 1.3 
               
               
                   
                 Total Cartons Harvested 
                 7,515 
                 1,994 
               
               
                   
                 Yield in Cartons per acre 
                 1,833 
                 1,534 
               
               
                   
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 4 
               
               
                   
                   
               
               
                   
                 Characteristic 
                 ADS-20 
                 Hill&#39;s Special 
               
               
                   
                   
               
             
            
               
                   
                 Harvest Date 
                 Apr. 26, 2010 
                 Apr. 16, 2010 
               
               
                   
                 Plant Population 
                 52,800 
                 52,800 
               
               
                   
                 Maturity Days 
                 126 
                 116 
               
               
                   
                 Total Acres Harvested 
                 7 
                 2 
               
               
                   
                 Total Cartons Harvested 
                 11,662 
                 2,900 
               
               
                   
                 Yield in Cartons per acre 
                 1,666 
                 1,450 
               
               
                   
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 5 
               
               
                   
                   
               
               
                   
                 Characteristic 
                 ADS-20 
                 Hill&#39;s Special 
               
               
                   
                   
               
             
            
               
                   
                 Harvest Date 
                 Apr. 31, 2010 
                 Apr. 22, 2010 
               
               
                   
                 Plant Population 
                 52,800 
                 52,800 
               
               
                   
                 Maturity Days 
                 132 
                 123 
               
               
                   
                 Total Acres Harvested 
                 7.5 
                 2.5 
               
               
                   
                 Total Cartons Harvested 
                 13,058 
                 3,500 
               
               
                   
                 Yield in Cartons per acre 
                 1,741 
                 1,400 
               
               
                   
                   
               
            
           
         
       
     
     As shown in Tables 2-5, compared to Hill&#39;s Special, ADS-20 required 6-10 days additional production time to reach similar maturity, but out yielded Hill&#39;s Special by 15-20%. Production occurred in the bolting window. 
     Table 6 shows a comparison between cultivars ADS-20, Hill&#39;s Special and several other cultivars in different trials grown in the prominent bolting windows of 2005, 2006, 2007, 2008, 2009 and 2010. The trial header shows the location for each trial, the harvest date and the number of hours below 50° F. that the celery was exposed to. Measurements were of the length of the seed stem (cm) for each variety and the median, average and range are presented for those measurements. Blanks in the data occur where the particular cultivar was not included in the trial. 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 6 
               
               
                   
               
             
            
               
                   
                 Oxnard, CA 
                 Oxnard, CA 
                 Oxnard, CA 
                 Piru, CA 
               
               
                   
                 Harvest: Apr. 16, 2005 
                 Harvest: May 11, 2006 
                 Harvest: Apr. 28, 2007 
                 Harvest: Apr. 28, 2007 
               
               
                   
                 263 hours &lt;50° F. 
                 796 hours &lt;50° F. 
                 782 hours &lt;50° F. 
                 1,232 hours &lt;50° F. 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                   
                 Med 
                 Avg 
                 Range 
                 Med 
                 Avg 
                 Range 
                 Med 
                 Avg 
                 Range 
                 Med 
                 Avg 
                 Range 
               
               
                   
               
               
                 ADS-20 
                 0.0 
                 0.0 
                 0-0 
                 0.0 
                 0.0 
                 0-0  
                 0.0 
                 0.0 
                 0-0 
                 0.0 
                 1.3 
                 0-9 
               
               
                 Hill&#39;s Special 
                 0.0 
                 0.6 
                 0-8 
                 0.0 
                 1.4 
                 0-18 
                 0.0 
                 5.4 
                  0-22 
                 0.3 
                 10.4 
                  0-49 
               
               
                 Tall Utah 52-70 ‘R’ 
                 23.0 
                 21.8 
                 16-28 
                 26.0 
                 28.6 
                 14-45  
                 69.0 
                 69.9 
                 41-97 
                   
                   
                   
               
               
                 Tall Utah 52-75 
                 9.0 
                 8.6 
                  3-14 
                 14.0 
                 16.8 
                 3-37 
                 63.5 
                 63.5 
                 53-71 
                   
                   
                   
               
               
                 Conquistador 
                 7.0 
                 6.3 
                 4-8 
                 7.0 
                 8.3 
                 4-16 
                   
                   
                   
                 56.5 
                 53.3 
                 30-63 
               
               
                 Sonora 
                   
                   
                   
                 4.5 
                 7.9 
                 1-23 
                 45.5 
                 48.4 
                 30-71 
                 48.0 
                 43.3 
                 12-69 
               
               
                 Command 
                   
                   
                   
                   
                   
                   
                 43.0 
                 43.3 
                 28-56 
                   
                   
                   
               
               
                 Challenger 
                   
                   
                   
                   
                   
                   
                 35.0 
                 34.9 
                 23-56 
                 57.0 
                 52.7 
                 40-61 
               
               
                 Mission 
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 ADS-1 
                 7.0 
                 7.6 
                  3-12 
                 9.0 
                 10.5 
                 7-31 
                 34.0 
                 35.5 
                 26-47 
                 48.0 
                 45.2 
                 25-57 
               
               
                 VTR 1330 
                 15.0 
                 15.3 
                 10-23 
                 16.5 
                 15.9 
                 7-23 
                 58.0 
                 56.3 
                 46-60 
                   
                   
                   
               
               
                 ADS-16 
                 13.0 
                 11.2 
                  2-16 
                 7.5 
                 9.4 
                 2-16 
                 48.0 
                 49.2 
                 38-66 
                   
                   
                   
               
               
                 Slowbolting Green #12 
                   
                   
                   
                   
                   
                   
                 25.0 
                 26.0 
                 13-43 
                 55.5 
                 50.8 
                 37-62 
               
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Oxnard, CA 
                 Santa Paula, CA 
                 Oxnard, CA 
               
               
                   
                 Harvest: May 1, 2008 
                 Harvest: Apr. 22, 2009 
                 Harvest: May 15, 2010 
               
               
                   
                 901 hours &lt;50° F. 
                 908 hours &lt;50° F. 
                 835 hours &lt;50° F. 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                   
                 Med 
                 Avg 
                 Range 
                 Med 
                 Avg 
                 Range 
                 Med 
                 Avg 
                 Range 
               
               
                   
               
               
                 ADS-20 
                 0.0 
                 0.0 
                     0-0.5 
                 0.0 
                 0.0 
                 0-0 
                 0.0 
                 0.0 
                 0-0  
               
               
                 Hill&#39;s Special 
                 0.0 
                 3.2 
                  0-18 
                 0.0 
                 5.1 
                  0-29 
                 0.0 
                 0.0 
                  0-0.5 
               
               
                 Tall Utah 52-70 ‘R’ 
                 49.0 
                 48.9 
                 39-58 
                 75.5 
                 75.3 
                 70-82 
                 37.5 
                 39.2 
                 26-55  
               
               
                 Tall Utah 52-75 
                 37.0 
                 37.9 
                 33-47 
                 58.5 
                 58.8 
                 44-73 
                 18.0 
                 19.0 
                 1-42 
               
               
                 Conquistador 
                 28.5 
                 29.3 
                 22-39 
                 59.0 
                 60.8 
                 50-83 
                   
                   
                   
               
               
                 Sonora 
                 22.5 
                 22.4 
                 17-31 
                 55.0 
                 50.3 
                 36-56 
                 11.0 
                 12.5 
                 3-27 
               
               
                 Command 
                 25.5 
                 27.1 
                 20-37 
                   
                   
                   
                   
                   
                   
               
               
                 Challenger 
                 33.5 
                 36.0 
                 30-48 
                   
                   
                   
                   
                   
                   
               
               
                 Mission 
                 32.0 
                 31.7 
                 12-53 
                   
                   
                   
                   
                   
                   
               
               
                 ADS-1 
                 25.0 
                 24.5 
                 13-38 
                 46.5 
                 45.3 
                 21-67 
                 12.0 
                 13.1 
                 2-35 
               
               
                 VTR 1330 
                 30.0 
                 29.6 
                 15-45 
                   
                   
                   
                   
                   
                   
               
               
                 ADS-16 
                 31.0 
                 30.0 
                 15-36 
                   
                   
                   
                 11.0 
                 13.2 
                 2-31 
               
               
                 Slowbolting Green #12 
               
               
                   
               
            
           
         
       
     
     As shown in Table 6, with the exception of Piru, ADS-20 had essentially no measurable seed stem development as measured in cm. Hill&#39;s Special was slightly less tolerant in all areas except Piru. Pint is a much colder production area than all of the other areas (1,232 hours below 50° F.). Under the coldest conditions of the Piru production area ADS-20 was significantly more tolerant that Hill&#39;s Special. Both ADS-20 and Hill&#39;s Special were significantly more bolting tolerant, as measured by seed stem length, than all other varieties. 
     Table 7 shows a comparison between cultivars ADS-20, Hill&#39;s Special and several other cultivars in different trials grown in a field located in Oxnard Calif. that has an extremely high level of  Fusarium oxysporum  f. sp.  apii  race 2. The field was specially developed with particularly higher levels for the purpose of evaluating varieties for  Fusarium  tolerance. The table presents a comparison between varieties for tolerance to  fusarium  as measured by the length to the joint in cm and a general rating of the celery stalk and in several of the trials a root damage rating. All ratings are based on a 0 to 5 scale with 0=death and 5=resistant. Ratings may be presented as a range in order to differentiate the amount of tolerance between stalks in the cultivar. Each trial is differentiated by the evaluation date. 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 7 
               
               
                   
               
             
            
               
                   
                 Jun. 21, 2001 
                 Dec. 1, 2008 
                 Jun. 25, 2009 
                 Dec. 5, 2009 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                   
                 Joint 
                   
                   
                 Joint 
                   
                 Joint 
                   
                 Joint 
                   
                   
               
               
                   
                 length 
                 General 
                 Root 
                 length 
                 General 
                 length 
                 General 
                 Length 
                 General 
                 Root 
               
               
                   
                 (cm) 
                 rating 
                 rating 
                 (cm) 
                 rating 
                 (cm) 
                 rating 
                 (cm) 
                 rating 
                 rating 
               
               
                   
               
               
                 ADS-20 
                 20-23 
                     2-2.5 
                 1 
                 25-28 
                 1.5-2.5 
                 18-20 
                 1-2 
                 18-20 
                 1-2 
                 1-2 
               
               
                 Hill&#39;s Special 
                 15-20 
                 1-2 
                 1 
                 18-28 
                     1-2.5 
                 15-20 
                 1-2 
                   
                   
                   
               
               
                 Tall Utah 52-70 ‘R’ 
                 13-18 
                 1 
                 1 
                 18-23 
                 0-2 
                 13-15 
                 1 
                  0-20 
                 0-2 
                 1 
               
               
                 Tall Utah 52-75 
                 13-18 
                 0.5-1     
                 1 
                 13-23 
                 1-2 
                 10-15 
                 1 
                  0-18 
                 0-2 
                 1-2 
               
               
                 Conquistador 
                 15-23 
                     1-1.5 
                 1 
                 15-23 
                     1-2.5 
                 15-20 
                 1-2 
                 18-23 
                 1-2 
                 1-2 
               
               
                 Sonora 
                 18-20 
                 1 
                 1 
                 18-20 
                 1-2 
                 15-18 
                 1-2 
                 13-23 
                 1-2 
                 1-2 
               
               
                 Challenger 
                   
                   
                   
                 23-35 
                 1-5 
                 18-23 
                 1-3 
                   
                   
                   
               
               
                 Command 
                 20-28 
                     3-3.5 
                 1 
                 25-38 
                 2.5-4     
                   
                   
                   
                   
                   
               
               
                 VTR 1330 
                 23-30 
                 1-3 
                 1-2 
                   
                   
                   
                   
                   
                   
                   
               
               
                 ADS-16 
                 25-30 
                 2-4 
                 1-2 
                   
                   
                 28-33 
                 4 
                   
                   
                   
               
               
                 ADS-1 
                 20-23 
                 3 
                 1-2 
                 25-28 
                 2.5-3.5 
                  8-20 
                 1-2 
                 23-25 
                 2-4 
                 1-3 
               
               
                   
               
            
           
           
               
            
               
                 Joint length is presented in centimeters 
               
               
                 Ratings are from 0 to 5 (0 = Dead and 5 = Resistant) and may be presented as a range expressed within the variety 
               
            
           
           
               
               
               
            
               
                   
                 Jun. 6, 2010 
                 Dec. 5, 2010 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 Joint 
                   
                   
                 Joint 
                   
                   
               
               
                   
                 length 
                 General 
                 Root 
                 length 
                 General 
                 Root 
               
               
                   
                 (cm) 
                 rating 
                 rating 
                 (cm) 
                 rating 
                 rating 
               
               
                   
               
               
                 ADS-20 
                 20-28 
                 3.5 
                 2-3 
                 23 
                 2 
                 2 
               
               
                 Hill&#39;s Special 
                   
                   
                   
                   
                   
                   
               
               
                 Tall Utah 52-70 ‘R’ 
                 13-20 
                 0-1 
                 1 
                 18-25 
                 1 
                 0-1 
               
               
                 Tall Utah 52-75 
                 15-23 
                 1 
                 1 
                   
                   
                   
               
               
                 Conquistador 
                 20-23 
                 1-2 
                 1-2 
                 20-23 
                 2 
                 0-1 
               
               
                 Sonora 
                 10-20 
                 1 
                 1 
                 18-23 
                 1-2 
                 1-2 
               
               
                 Challenger 
                 20-28 
                 2.5-3     
                 2-3 
                   
                   
                   
               
               
                 Command 
                   
                   
                   
                   
                   
                   
               
               
                 VTR 1330 
                   
                   
                   
                   
                   
                   
               
               
                 ADS-16 
                 33-35 
                 3 
                 2-3 
                   
                   
                   
               
               
                 ADS-1 
                 20-28 
                 2-3 
                 2-3 
                 23 
                 2 
                 2 
               
               
                   
               
            
           
           
               
            
               
                 Joint length is presented in centimeters 
               
               
                 Ratings are from 0 to 5 (0 = Dead and 5 = Resistant) and are presented as a range expressed within the variety 
               
            
           
         
       
     
     As shown in Table 7, ADS-20 does not possess significant tolerance to  fusarium  but is slightly improved over Hill&#39;s Special. 
     Table 8 shows data from an Oxnard, Calif. trial grown in conditions fairly free of  fusarium  and evaluated on Jun. 20, 2009. The plant population was 63,360 plants per acre. Color values are from the Munsell Color Chart. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 8 
               
               
                   
               
               
                   
                 ADS-20 
                 Hill&#39;s Special 
                 Conquistador 
                 Sonora 
                 Challenger 
                 ADS-1 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Top Width (cm) 
                 Average 
                 36.10 
                 39.00 
                 36.40 
                 40.30 
                 31.80 
                 28.60 
               
               
                   
                 Range 
                 (32-39) 
                 (36-45) 
                 (32-40) 
                 (36-46) 
                 (24-41) 
                 (22-34) 
               
               
                 Plant Height (cm) 
                 Average 
                 71.90 
                 79.00 
                 71.10 
                 60.80 
                 77.30 
                 79.30 
               
               
                   
                 Range 
                 (67-76) 
                 (74-83) 
                 (66-76) 
                 (38-70) 
                 (73-84) 
                 (74-84) 
               
               
                 Whole Plant weight (kg) 
                 Average 
                 1.17 
                 1.23 
                 1.02 
                 0.86 
                 1.05 
                 1.24 
               
               
                   
                 Range 
                 (0.85-1.57) 
                 (0.87-1.48) 
                 (0.55-1.33) 
                 (0.52-1.19) 
                 (0.70-1.37) 
                 (1.05-1.50) 
               
               
                 Trimmed Plant Weight 
                 Average 
                 0.96 
                 1.00 
                 0.80 
                 0.66 
                 0.84 
                 1.00 
               
               
                 (kg) 
                 Range 
                 (0.70-1.28) 
                 (0.74-1.20) 
                 (0.39-1.02) 
                 (0.41-0.89) 
                 (0.57-1.10) 
                 (0.83-1.23) 
               
               
                 Number of Outer 
                 Average 
                 12.10 
                 12.30 
                 12.80 
                 12.30 
                 11.80 
                 12.90 
               
               
                 Petioles (&gt;40 cm) 
                 Range 
                  (9-14) 
                 (10-14) 
                  (9-15) 
                 (11-15) 
                 (10-14) 
                 (11-15) 
               
               
                 Number of Inner 
                 Average 
                 6.60 
                 6.90 
                 8.40 
                 7.40 
                 6.90 
                 8.50 
               
               
                 Petioles (&lt;40 cm) 
                 Range 
                 (5-9) 
                 (5-9) 
                  (7-10) 
                 (6-9) 
                 (5-8) 
                  (7-10) 
               
               
                 Length of Outer Petioles 
                 Average 
                 35.17 
                 35.70 
                 32.73 
                 32.20 
                 34.67 
                 32.43 
               
               
                 to the joint (cm) 
                 Range 
                 (32-39) 
                 (31-35) 
                 (30-35) 
                 (28-35) 
                 (30-38) 
                 (29-34) 
               
               
                 Width of Outer Petioles 
                 Average 
                 26.40 
                 26.80 
                 24.13 
                 22.50 
                 25.40 
                 29.40 
               
               
                 at the midrib (mm) 
                 Range 
                 (22-30) 
                 (24-29) 
                 (21-28) 
                 (17-27) 
                 (21-30) 
                 (28-31) 
               
               
                 Thickness of Outer 
                 Average 
                 9.63 
                 10.03 
                 8.23 
                 7.53 
                 10.20 
                 9.97 
               
               
                 Petioles at midrib (mm) 
                 Range 
                  (9-11) 
                  (9-11) 
                  (7-10) 
                 (7-9) 
                  (8-14) 
                  (9-11) 
               
               
                 Petiole Color 
                   
                 5gy6/6 
                 5gy5/6  
                 5gy5/6  
                 5gy5/6  
                 5gy5/6  
                 5gy6/6 
               
               
                 Leaf Color 
                   
                 5gy3/6 
                 5gy 3/4 
                 5gy 4/4 
                 5gy 3/4 
                 5gy 3/4 
                 5gy4/4 
               
               
                 Petiole Smoothness 
                   
                 Smooth 
                 Smooth 
                 Smooth-slight 
                 Smooth-slight 
                 Ribby 
                 Smooth-Slight 
               
               
                   
                   
                   
                   
                 rib 
                 rib 
                   
                 rib 
               
               
                 Petiole Cup 
                   
                 Cup 
                 Cup 
                 Cup 
                 Cup 
                 Cup 
                 Cup 
               
               
                   
               
            
           
         
       
     
     As shown in Table 8, ADS-20 was similar to Hill&#39;s Special except top width and plant height which where smaller and more similar to Conquistador. 
     Table 9 shows data from an Oxnard, Calif. trial grown in conditions with  fusarium  and evaluated on Dec. 10, 2010. The plant population was 58,080 plants per acre. ADS-20 was compared to several varieties including Hill&#39;s Special. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 9 
               
               
                   
               
               
                   
                   
                   
                   
                   
                 Tall Utah 52- 
                   
               
               
                   
                 ADS-20 
                 Hill&#39;s Special 
                 Conquistador 
                 Sonora 
                 70 ‘R’ Strain 
                 ADS-1 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Plant Height (cm) 
                 Average 
                 52.8 
                 51.1 
                 50.9 
                 53.7 
                 49.3 
                 57.7 
               
               
                   
                 Range 
                 (47-60) 
                 (44-61) 
                 (47-58) 
                 (49-57) 
                 (43-54) 
                 (51-62) 
               
               
                 Whole Plant weight (kg) 
                 Average 
                 0.5 
                 0.5 
                 0.4 
                 0.4 
                 0.3 
                 0.4 
               
               
                   
                 Range 
                 (0.29-0.71) 
                 (0.25-0.69) 
                 (0.26-0.64) 
                 (0.29-0.73) 
                 (0.22-0.45) 
                 (0.22-0.64) 
               
               
                 Trimmed Plant Weight 
                 Average 
                 0.4 
                 0.4 
                 0.4 
                 0.4 
                 0.3 
                 0.4 
               
               
                 (kg) 
                 Range 
                 (0.26-0.63) 
                 (0.22-0.65) 
                 (0.23-0.56) 
                 (0.25-0.65) 
                  (0.2-0.41) 
                  (0.2-0.56) 
               
               
                 Number of Outer 
                 Average 
                 7.8 
                 7.3 
                 7.2 
                 9.2 
                 7.0 
                 7.2 
               
               
                 Petioles (&gt;40 cm) 
                 Range 
                  (6-10) 
                  (5-10) 
                 (6-8) 
                  (6-11) 
                  (5-10) 
                 (6-8) 
               
               
                 Number of Inner 
                 Average 
                 3.5 
                 3.5 
                 5.2 
                 5.2 
                 4.5 
                 4.4 
               
               
                 Petioles (&lt;40 cm) 
                 Range 
                 (3-4) 
                 (3-4) 
                 (3-7) 
                 (3-7) 
                 (2-6) 
                 (3-7) 
               
               
                 Length of Outer Petioles 
                 Average 
                 22.5 
                 21.8 
                 20.3 
                 22.4 
                 22.6 
                 20.5 
               
               
                 to the joint (cm) 
                 Range 
                 (19.3-26.3) 
                 (17.2-27.2) 
                 (16.7-22.7) 
                 (19.3-26.3) 
                     (19-24.7) 
                 (19.3-21.3) 
               
               
                 Width of Outer Petioles 
                 Average 
                 16.9 
                 16.5 
                 14.5 
                 15.5 
                 14.3 
                 15.7 
               
               
                 at the midrib (mm) 
                 Range 
                 (13.3-20.3) 
                 (13.1-19.1) 
                     (12-17.7) 
                 (12.3-19.3) 
                     (12-17.3) 
                 (12.7-19.7) 
               
               
                 Thickness of Outer 
                 Average 
                 6.8 
                 6.8 
                 6.4 
                 6.3 
                 6.8 
                 7.5 
               
               
                 Petioles at the midrib 
                 Range 
                 (5.7-9.3) 
                 (5.6-9.4) 
                 (3.7-7.3) 
                 (4.7-9)     
                     (6-8.7) 
                 (5.7-9.3) 
               
               
                 (mm) 
                   
                   
                   
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Petiole Color (Munsell Color Chart) 
                 5gy 6/6 
                 5gy 6/6 
                 5gy 5/6 
                 5gy 5/6 
                 5gy 6/6 
                 5gy 6/6 
               
               
                 Leaf Color (Munsell 
                 5gy 4/4 
                 5gy 4/4 
                 5gy 4/4 
                 5gy 4/4 
                 5gy 4/4 
                 5gy 4/4 
               
               
                 Color Chart) 
                   
                   
                   
                   
                   
                   
               
               
                 Smoothness 
                 Smooth - 
                 Smooth - 
                 Slight rib 
                 Smooth 
                 Ribby 
                 Smooth - 
               
               
                   
                 slight rib 
                 slight rib 
                   
                   
                   
                 slight rib 
               
               
                 Cup 
                 Slight cup - 
                 Slight cup - 
                 Cup 
                 Slight cup - 
                 Slight cup 
                 Cup 
               
               
                   
                 cup 
                 cup 
                   
                 cup 
               
               
                   
               
            
           
         
       
     
     In the particular trial shown in Table 9 all of the cultivars were fairly similar for plant height, plant weights, number of petioles and the measurements for the outer petioles. The only real differences between varieties were slightly lighter weights whole stalk and trimmed for Tall Utah 52-70 ‘R’ Strain and higher outer petiole count for Sonora. Under these  fusarium  conditions these varieties did not resemble their normal characteristics and true differences fell away. All appear to be fairly similar in response/appearance. 
     Table 10 shows data from an Oxnard, Calif. trial grown in conditions with high levels of  fusarium . This particular trial site has been specially developed with elevated  fusarium  levels in order to screen and evaluate celery varieties. This particular trial was evaluated on Dec. 9, 2008. The plant population was 58,080 plants per acre. ADS-20 was compared to several other varieties including Hill&#39;s Special. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 10 
               
               
                   
               
               
                   
                   
                   
                   
                   
                 Tall Utah 52- 
                   
               
               
                   
                 ADS-20 
                 Hill&#39;s Special 
                 Conquistador 
                 Sonora 
                 70 ‘R’ Strain 
                 ADS-1 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Plant Height (cm) 
                 Average 
                 62.7 
                 61.8 
                 51.8 
                 53.9 
                 52.2 
                 75.2 
               
               
                   
                 Range 
                 (58-68) 
                 (53-65) 
                 (45-61) 
                 (38-63) 
                 (45-59) 
                 (69-81) 
               
               
                 Whole Plant weight (kg) 
                 Average 
                 0.5 
                 0.5 
                 0.4 
                 0.4 
                 0.5 
                 0.9 
               
               
                   
                 Range 
                 (0.37-0.73) 
                  (0.3-0.89) 
                 (0.11-0.52) 
                 (0.04-0.73) 
                 (0.16-0.8)  
                 (0.46-1.5)  
               
               
                 Trimmed Plant Weight 
                 Average 
                 0.4 
                 0.4 
                 0.3 
                 0.3 
                 0.4 
                 0.7 
               
               
                 (kg) 
                 Range 
                 (0.35-0.66) 
                 (0.28-0.74) 
                  (0.1-0.48) 
                 (0.04-0.64) 
                 (0.13-0.74) 
                 (0.36-1.24) 
               
               
                 Number of Outer 
                 Average 
                 8.1 
                 7.7 
                 7.4 
                 6.6 
                 8.7 
                 9.3 
               
               
                 Petioles (&gt;40 cm) 
                 Range 
                  (7-10) 
                 (6-9) 
                 (5-9) 
                  (0-11) 
                  (6-12) 
                  (7-12) 
               
               
                 Number of Inner 
                 Average 
                 5.0 
                 5.9 
                 6.3 
                 6.5 
                 7.1 
                 4.4 
               
               
                 Petioles (&lt;40 cm) 
                 Range 
                 (3-6) 
                 (4-8) 
                 (4-9) 
                 (5-9) 
                  (6-10) 
                 (2-7) 
               
               
                 Length of Outer Petioles 
                 Average 
                 26.9 
                 25.5 
                 23.0 
                 20.8 
                 21.8 
                 29.4 
               
               
                 to the joint (cm) 
                 Range 
                     (24-29.3) 
                 (21.7-28.3) 
                 (20.7-25)     
                 (14.3-27.3) 
                 (19.3-24.3) 
                     (26-32.3) 
               
               
                 Width of Outer Petioles 
                 Average 
                 19.2 
                 18.0 
                 13.5 
                 14.9 
                 15.4 
                 20.6 
               
               
                 at the midrib (mm) 
                 Range 
                     (17-22.7) 
                 (10.7-22.3) 
                  (6.3-20.3) 
                  (7.3-19.3) 
                 (10.3-19.7) 
                 (15.3-26.3) 
               
               
                 Thickness of Outer 
                 Average 
                 8.2 
                 8.2 
                 6.2 
                 6.3 
                 6.6 
                 10.2 
               
               
                 Petioles at the midrib 
                 Range 
                 (7.7-9.3) 
                  (6-10) 
                 (3-9) 
                 (2.7-9)     
                     (5-8.7) 
                 (7.3-13)     
               
               
                 (mm) 
                   
                   
                   
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Petiole Color (Munsell Color Chart) 
                 5gy 6/6 
                 5gy 7/8 
                 5gy 7/8 
                 5gy 6/6 
                 5gy 6/6 
                 5gy 6/6 
               
               
                 Leaf Color (Munsell 
                 5gy 4/4 
                 5gy 4/4 
                 5gy 4/4 
                 5gy 4/4 
                 5gy 4/4 
                 5gy 4/4 
               
               
                 Color Chart) 
                   
                   
                   
                   
                   
                   
               
               
                 Smoothness 
                 Smooth 
                 Smooth 
                 Ribby 
                 Ribby 
                 Ribby 
                 Ribby 
               
               
                 Cup 
                 Cup 
                 Cup 
                 Cup 
                 Cup 
                 Cup 
                 Cup 
               
               
                   
               
            
           
         
       
     
     Under the  fusarium  conditions experienced in the trial shown in Table 10, ADS-1 was capable of producing the largest stalks when considering height, weights, outer petiole counts and petiole measurements for width and thickness. ADS-20 was more stunted than ADS-1, but was second to it for overall height, petiole length and petiole width. Otherwise it was very similar to Hill&#39;s Special and performed better than Conquistador and Sonora. 
     Table 11 shows a comparison between cultivar ADS-20, Hill&#39;s Special and several other cultivars grown in Oxnard, Calif. under conditions of strong bolting pressure and evaluated on May 4, 2008. An ‘*’ represents this missing data. Plant population was 58,080 plants per acre. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 11 
               
               
                   
               
             
            
               
                   
                   
                   
                 Hill&#39;s 
                 Tall Utah 
                 Tall Utah 
                   
               
               
                   
                   
                 ADS-20 
                 Special 
                 52-70 ‘R’ Strain 
                 52-75 
                 Conquistador 
               
               
                   
               
               
                 Top Width (cm) 
                 Average 
                 38.9 
                 42.9  
                 * 
                 * 
                 * 
               
               
                   
                 Range 
                 (36-42) 
                 (36-50) 
               
               
                 Plant Height (cm) 
                 Average 
                 72   
                 70.6  
                 * 
                 * 
                 * 
               
               
                   
                 Range 
                 (70-77) 
                 (69-73) 
               
               
                 Whole Plant weight (kg) 
                 Average 
                  1.1 
                 1.0 
                 * 
                 * 
                 * 
               
               
                   
                 Range 
                 (1.0-1.3) 
                  (0.8-1.16) 
               
               
                 Trimmed Plant Weight (kg) 
                 Average 
                  0.9 
                 0.8 
                 * 
                 * 
                 * 
               
               
                   
                 Range 
                  (0.8-1.07 
                  (0.7-0.98) 
               
               
                 Number of Outer 
                 Average 
                 12   
                 12.6  
                 * 
                 * 
                 * 
               
               
                 Petioles (&gt;40 cm) 
                 Range 
                 (10-14) 
                 (10-14) 
               
               
                 Number of Inner 
                 Average 
                  7.7 
                 6.5 
                 * 
                 * 
                 * 
               
               
                 Petioles (&lt;40 cm) 
                 Range 
                 (6-9) 
                 (5-8) 
               
               
                 Length of Outer Petioles 
                 Average 
                 34.7 
                 35.8  
                 * 
                 * 
                 * 
               
               
                 to the joint (cm) 
                 Range 
                 (33-39) 
                 (33-38) 
               
               
                 Width of Outer Petioles 
                 Average 
                 27.4 
                 25.0  
                 * 
                 * 
                 * 
               
               
                 at the midrib (mm) 
                 Range 
                 26-29 
                 (23-28) 
               
               
                 Thickness of Outer 
                 Average 
                 10.2 
                 9.2 
                 * 
                 * 
                 * 
               
               
                 Petioles at midrib (mm) 
                 Range 
                 (10-11) 
                 (7.3-11)  
               
               
                 Petiole Color 
                   
                 0  
                 1.9 
                 68.5 
                 58.6 
                 39.9 
               
               
                 Leaf Color 
                   
                 0  
                 0.0 
                 67.0 
                 56.0 
                 36.5 
               
               
                 Petiole Smoothness 
                   
                 (0-0) 
                  (0-14) 
                 (47-92) 
                 (45-79) 
                 (29-58) 
               
               
                 Petiole Cup 
                   
                 5gy 6/6 
                 5gy 6/6 
                 * 
                 * 
                 * 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                   
                   
                 Sonora 
                 Challenger 
                 Mission 
                 ADS-1 
               
               
                   
                   
               
               
                   
                 Top Width (cm) 
                 Average 
                 * 
                 * 
                 * 
                 * 
               
               
                   
                   
                 Range 
               
               
                   
                 Plant Height (cm) 
                 Average 
                 * 
                 * 
                 * 
                 * 
               
               
                   
                   
                 Range 
               
               
                   
                 Whole Plant weight (kg) 
                 Average 
                 * 
                 * 
                 * 
                 * 
               
               
                   
                   
                 Range 
               
               
                   
                 Trimmed Plant Weight (kg) 
                 Average 
                 * 
                 * 
                 * 
                 * 
               
               
                   
                   
                 Range 
               
               
                   
                 Number of Outer 
                 Average 
                 * 
                 * 
                 * 
                 * 
               
               
                   
                 Petioles (&gt;40 cm) 
                 Range 
               
               
                   
                 Number of Inner 
                 Average 
                 * 
                 * 
                 * 
                 * 
               
               
                   
                 Petioles (&lt;40 cm) 
                 Range 
               
               
                   
                 Length of Outer Petioles 
                 Average 
                 * 
                 * 
                 * 
                 * 
               
               
                   
                 to the joint (cm) 
                 Range 
               
               
                   
                 Width of Outer Petioles 
                 Average 
                 * 
                 * 
                 * 
                 * 
               
               
                   
                 at the midrib (mm) 
                 Range 
               
               
                   
                 Thickness of Outer 
                 Average 
                 * 
                 * 
                 * 
                 * 
               
               
                   
                 Petioles at midrib (mm ) 
                 Range 
               
               
                   
                 Petiole Color 
                   
                 55.7 
                 48.3 
                 28.0 
                 39.4 
               
               
                   
                 Leaf Color 
                   
                 54.0 
                 46.0 
                 29.0 
                 30.0 
               
               
                   
                 Petiole Smoothness 
                   
                 (47-69) 
                 (36-68) 
                 (12-47) 
                 (4-47) 
               
               
                   
                 Petiole Cup 
                   
                 * 
                 * 
                 * 
                 * 
               
               
                   
                   
               
            
           
         
       
     
     As shown in Table 11, all varieties except ADS-20 and Hill&#39;s Special had severe seed stem development and were too distorted for collection of several data points. While ADS-20 and Hill&#39;s Special were both considerably more tolerant than all other cultivars tested, ADS-20 was more uniform for tolerance to bolting than Hill&#39;s Special. 
     The use of the terms “a,” “an,” and “the,” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. For example, if the range 10-15 is disclosed, then 11, 12, 13, and 14 are also disclosed. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
     DEPOSIT INFORMATION 
     A deposit of the A. DUDA &amp; SONS, INC. proprietary CELERY CULTIVAR ADS-20 disclosed above and recited in the appended claims has been made with the American Type Culture Collection (ATCC), 10801 University Boulevard, Manassas, Va. 20110. The date of deposit was Jan. 5, 2012. The deposit of 2,500 seeds was taken from the same deposit maintained by A. DUDA &amp; SONS, INC. since prior to the filing date of this application. All restrictions will be irrevocably removed upon granting of a patent, and the deposit is intended to meet all of the requirements of 37 C.F.R. §§1.801-1.809. The ATCC Accession Number is PTA-12372. The deposit will be maintained in the depository for a period of thirty years, or five years after the last request, or for the enforceable life of the patent, whichever is longer, and will be replaced as necessary during that period. 
     While a number of exemplary aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions, and sub-combinations thereof. It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions, and sub-combinations as are within their true spirit and scope.