bluuebunny/crossref_metadata_2025 huggingface dataset:
Micropropagation of Rhododendron prinophyllum by Ovary Culture
Authors: Dai Chaoxi , Lambeth Victor N. , Taven Ron , Mertz Dan
Published: September 2022

Using ovaries from dormant flower buds of Rhododendron prinophyllum (Small) Millais as a source for micropropagation, shoot and root regeneration were studied in vitro. Ovaries placed on Anderson's rhododendron shoot tip multiplication medium with 4 mg·liter−1 IAA and 15 mg·liter−1 2iP in darkness for 1 month, then under 16-hr cool-white fluorescent light (35–50 μmol·s−1·m−2) regenerated 20-50 shoots/ovary from ovary wall and calli. After three transfers on Economou and Read's shoot propagation medium, hundreds of shoots were produced per ovary. Shoots 1 to 2 cm in length transferred to root induction media resulted in 90% rooting in 1 to 2 months. Rooted plantlets transplanted to potting mixture had nearly 100% survival. Chemical names used: 1H-indole-3-acetic acid (IAA); N-(3-methyl-2-butenyl)-1H-purin-6-amine (2iP).
‘Shamrock’ Apple
Authors: Lane W. D. , MacDonald R. A.
Published: September 2022

‘Shamrock’ apple (Malus domestica Borkh.) is a green apple nearly identical in appearance, texture, and taste to ‘Granny Smith.’ It differs from ‘Granny Smith’ by maturing 6 weeks earlier and by having a more favorable tree growth habit. It develops full maturity and good quality in northern tree fruit production areas where ‘Granny Smith’ does not mature before cold weather slows growth. ‘Shamrock’ is introduced to allow growers in northern areas to compete with ‘Granny Smith’ imported from production areas with long growing seasons. It also may extend the season for ‘Granny Smith’-type apples where ‘Granny Smith’ is presently grown.
Apomictic Crabapples and Their Potential for Research and Fruit Production
Authors: Olien William C.
Published: September 2022

The desire to propagate plants with useful and predictable characteristics vegetatively has been a major concern since the beginning of agriculture. Clonal propagation of apple varieties by grafting onto rootstocks dates back to ancient times (72). A range of techniques for vegetative propagation have been developed over the years, including advances in layering, rooting cuttings, grafting and budding, and the relatively recent approach of micropropagation (31). Vegetative propagation is costly and inefficient compared to seed propagation. For crops with short generation time, repetitive inbreeding or hybrid crosses of inbred lines allows the propagation of nearly genetically uniform populations by sexually produced seed (1). However, generation time in perennial tree crops, including Malus spp., is too long to make this approach practical. As a result, sexually produced seedling populations are highly variable. For this reason, the limited numbers of apomictic species among perennials constitute extremely valuable exceptions, allowing efficient propagation of genetically uniform populations from seed.
Orchard Systems Research with Deciduous Trees: A Brief Introduction
Authors: Barritt Bruce H.
Published: September 2022

An orchard system is the integration of all the horticultural factors involved in establishing and maintaining a planting of fruit trees. These factors include tree density and arrangement, cultivar, root-stock and interstock, tree size and form, pruning and training techniques needed to maintain the desired configuration, mechanical training and harvesting, and support systems. An orchard system is a blueprint for the orchardist to follow throughout the life of a planting.
Gibberellic Acid Increases Flower Number in Zantedeschia elliottiana and Z. rehmannii
Authors: Corr Brian E. , Widmer Richard E.
Published: September 2022

Gibberellic acid (GA3) was applied to Zantedeschia elliottiana (W. Wats.) and Z. rehmannii (Engl.) (yellow and pink calla lily) at 0, 50, 100, 500, or 1000 ppm, either as a preplant rhizome 10-min soak or as a foliar spray. Soaking rhizomes in 500 ppm GA3 prior to planting increased number of flowering shoots and flowers per shoot. Leaves on treated plants were narrower, but length was unaffected. Flower height was not affected. Foliar sprays did not alter any measured parameter. A preplant GA soak may be useful in the production of Zantedeschia as flowering potted plants. Chemical name used: (1α, 2β, 4aα, 4bβ, 10β)-2,4a,7-trihydroxy-1-methyl-8-methylenegibb-3-ene-1,10-dicarboxylic acid 1,4a-lactone (GA3).
Prolonged Flooding Effects on Anatomy of Highbush Blueberry
Authors: Abbott John D. , Gough R. E.
Published: September 2022

Roots of flooded highbush blueberry (Vaccinium corymbosum L.) plants examined by light and scanning electron microscopy exhibited enlarged epidermal cells, compressed cortical cells, and disrupted vascular tissue. The stems of flooded plants showed disrupted epidermal tissue, condensed outer cortical cells, and large aerenchyma-like mid-cortical tissue. Leaves from flooded plants showed an increase in intercellular spaces in the spongy mesophyll and a disrupted palisade layer. There were no apparent differences in inflorescence bud anatomy, although inflorescences were small and delayed in development.
Isozyme Verification of Hybrids in Koelreuteria
Authors: McArdle Alice Jacot , Santamour Frank S.
Published: September 2022

One-year-old interspecific hybrids of Koelreuteria paniculata Laxm. and K. bipinnata Franch., as well as intraspecific hybrids of K. paniculata, were verified on the basis of anodal isoperoxidase banding patterns from petiole tissue. No band was unique to any one species or cultivar, and the efficacy of this technique therefore depended on the isozyme phenotypes of the individual parents involved. Since parental banding patterns are distinctly different, isozyme analysis is an effective means of establishing Koelreuteria hybridity because of the codominant expression of isozyme bands.
Competition Between Sweet Potato Cultivars in Small Plots
Authors: Walker D. W. , Randle W. M.
Published: September 2022

Field experimentation with sweet potatoes [Ipomoea batatas (L.) Lam.] is difficult because extraneous sources of error often require extensive replication and multiple experiments (1). These problems are compounded when cultivars of different growth habits are compared in adjacent plots. Because sweet potato plants produce extensive prostrate vines, there has been considerable controversy among researchers as to whether cultivars planted in adjacent rows compete with one another such that cultivar evaluation is compromised. This controversy was recently asserted by Bouwkamp (2), who used turning point tests and showed that the competitive effects of cultivars do not affect sweet potato yield trial results enough to justify the use of multi-row plots (2).
Increasing Root Regeneration and Shoot Growth in Two Oak Species with Spray Applications of IBA
Authors: Cappiello Paul E. , Kling Gary J.
Published: September 2022

The genus Quercus comprises a major group of woody landscape plants that differ widely in root system morphology and recovery from transplanting (2, 6). Quercus alba has a coarse root system and is more difficult to transplant than the more fibrous-rooted Quercus rubra (2).
Multiplication of the Tree Fern Cyathea dregei
Authors: Finnie J. F. , Staden J. van
Published: September 2022

Cyathea dregei (Alsophila dregei) Kunze, is a tree fern indigenous to Southern Africa. Due to its popularity for landscape gardens and water features, this species has been over-exploited from the wild and currently is classified as a protected plant. For this reason, attempts were made to multiply this plant by partial tissue culture (2). This simple system was adopted because it eliminates the multiple stages of culture recommended by Murashige (4), but nevertheless allows the production of large numbers of pathogen-free sporophytes (2).
‘Georgiagem’ Blueberry
Authors: Austin M. E. , Draper A. D.
Published: September 2022

‘Georgiagem’, a new low-chilling cultivar. is the first highbush blueberry (Vacciniwn corymbosum L.) cultivar developed from the cooperative blueberry breeding program of the Georgia Agricultural Experiment Station and the USDA. Although ‘Georgiagem’ originated mostly from tetraploid highbush blueberry parentage, it obtained adaptation to the southern U.S. environment from the diploid species, V. darrowi, selected from the wild in Florida (2). ‘Georgiagem’ is early ripening, moderately productive, and has fruit of medium size with good color, small stem scar, firmness, and pleasant flavor.
Introduction to the Symposium
Authors: Read Paul E.
Published: September 2022

The influence of the stock plant (mother plant, donor plant) has long been known to exert a profound effect on subsequent propagation capability of its propagules. Both treatments applied to the stock plant and the environment under which the stock plant is grown have a strong influence on subsequent propagation. These effects may include an increase in size or number of cuttings and improved root regeneration by cuttings taken from such stock plants. Nutrition, light, temperature, genotype, plant growth regulator applications, physical manipulations, and season of the year have all been reported to influence macropropagation efforts. Similarly, the influence of these same factors often has been reported to have a strong effect on the performance of propagated explants taken from stock plants so treated. From the early work of Kraus and Kraybill (18) in 1918, we can see that the carbohydrate: nitrogen ratio was shown to be an important factor in the rooting of tomato cuttings. Micronutrition of stock plants also has been given some attention, as exemplified by the work of Weiser and Blaney (25). Dhillon (5) also has pointed out that nutrient effects often are modified by light. Reduced light intensity has been reported to enhance the rooting of dahlia, forsythia, and weigelia (3, 19). Etiolation, or extreme light reduction, frequently has been reported to also improve rooting (9. 17). Other authors have reported that reduced stock plant light intensities can lead to better rooting of the cuttings of several species (1, 11, 21). Increases in endogenous auxin level generally are believed to occur under reduced light, thus enhancing rooting (20). Whally (26) has reviewed literature on photoperiod effects on rooting of numerous ornamental species. Keeping stock plants in a vegetative condition by the use of night interruption or day extension has enabled researchers to provide a continuous supply of cuttings (14, 15, 24). Bachelard and Stowe (2) and von Hentig (16) have reported direct effects of stock plant photoperiod on the rooting of cuttings.
Stock Plant Lighting and Adventitious Root Formation
Authors: Hansen Jürgen
Published: September 2022

Root formation in cuttings is influenced by the light conditions during the growth of stock plants. Exclusion of light from the entire shoot prior to propagation stimulates the formation of roots in some woody species. Localized etiolation of that part of the stem, which will become the cutting base, also can be effective (9, 14, 15).
Influence of Agronomic and Climatic Factors on the Response of Apple Fruit to Controlled Atmosphere Storage
Authors: Sharples Richard O. , Johnson David S.
Published: September 2022

Variability in the quality of stored apple fruit and their susceptibility to physiological disorders are influenced by effects of climatic and growing conditions on the structure, composition, and maturity of the fruit when harvested. Thus, potential storage life of the crop from any particular orchard will be determined by the interaction of a wide range of preharvest factors, many of which are within the control of the fruit grower (24).
Interactions of Oxygen, Carbon Dioxide, Temperature, and Ethylene that may Induce Injuries in Vegetables
Authors: Lougheed E. C.
Published: September 2022

This review is restricted to the effects of combinations of at least two of the following factors—O2, CO2, and temperature—that may interact with ethylene and relative humidity to induce disorders in vegetables.
Bioreactor Production of Alfalfa Somatic Embryos
Authors: Stuart David A. , Strickland Steven G. , Walker Keith A.
Published: September 2022

There has been a great deal of interest recently in the development of artificial seed as a cloning method for plants (1, 6, 9). The idea is intriguing, since it proposes clonal propagation of plants by somatic embryogenesis without recombination of the genome that normally occurs in zygotic embryo formation. Once a suitably developed embryo is achieved, a delivery system composed of gels, nutrients, and a membrane can be used to encapsulate and protect the embryo prior to planting in the greenhouse or field. Efficient and economical manufacture of somatic embryos and surrounding matrix must be achieved in order to make this system work like true seed. To be of commercial importance, this delivery system should satisfy a number of criteria, including high production volume, high genetic fidelity, and good germination of the embryo from the gel.
Hormonal Aspects of Bud and Seed Dormancy in Temperate-zone Woody Plants
Authors: Powell L. E.
Published: September 2022

Perennial woody plants of the temperate zone typically are challenged each winter by freezing temperatures. Their capacity to survive these winter temperatures is due in part to an evolved dormancy mechanism, often called rest. This mechanism exerts a commanding influence on growth and development. The physiology of rest has been studied extensively and much is known, but its more basic biochemical aspects are little understood. It is commonly assumed to be hormonally controlled. This review will summarize the physiological aspects of the rest mechanism and the evidence for hormonal involvement.
Postharvest Senescence: An Introduction to the Symposium
Authors: Huber Donald J.
Published: September 2022

Senescence has long been a concern of postharvest scientists. The essential interests are two-fold. On the one hand, the premature senescence of many commodities, often accelerated due to adverse handling and storage conditions, renders them useless to the consumer. On the other hand, for many other commodities, notably fruits and cut flowers, the early manifestations of senescence form the basis of desirable quality attributes. The objectives of postharvest handling practices in the latter case are to: a) arrest continued developm ent during storage and b) ensure that normal development occurs following storage. For these reasons, an appreciation of the underlying causes of senescence becomes crucial to our understanding of how best to control and regulate the process. The symposium speakers will focus on the mechanisms and control of senescence in three horticultural commodity groups: leafy vegetables, fruits, and cut flowers.
Senescence and Homeostasis in Postharvest Research
Authors: Romani Roger J.
Published: September 2022

My aim in this brief presentation is to illustrate how the interplay of senescence and homoeostasis can offer a context within which to question and, in part, explain various postharvest phenomena. I should like to begin by briefly noting the status of principal phenomena and related paradigms that have influenced postharvest research, namely the respiratory climacteric, ethylene, and molecular (genetic) determinants.
Effect of Postharvest Heat Treatment and Storage on Sugar Metabolism in Polyethylene-wrapped Muskmelon Fruit
Authors: Lingle Sarah E. , Lester Gene E. , Dunlap James R.
Published: September 2022

Postharvest sugar content and activities of four enzymes of sucrose metabolism were followed in the edible mesocarp tissue of the netted muskmelon (Cucumis melo L., var. reticulatus, cv Magnum 45). Melons harvested at full-slip were shrink film-wrapped to inhibit water loss and/or heated to 45°C for 3 hr before storage at 4°C for up to 18 days. Sucrose content of edible mesocarp remained constant between harvest and 12 days of storage. The sucrose content of nonheated fruit declined between 12 and 18 days of storage, but there was no coincident increase in glucose or fructose. There was little acid invertase activity. Neutral invertase activity did not vary significantly with storage, but was slightly higher in heated, wrapped fruit than in nonheated, wrapped fruit. Sucrose synthase activity increased with storage, and was higher in heated than nonheated fruit. There was no discernible pattern of sucrose-phosphate synthase activity. No enzyme activity was correlated with the content of any sugar.
In Vitro Culturabiiity of Ovules from 10 Seedless Grape Clones
Authors: Goldy R. G. , Amborn U.
Published: September 2022

One trait desired by consumers for table grapes (Vitis spp.) is seedlessness, which is caused by either embryo abortion (stenospermocarpy) or parthenocarpy (2). Inheritance of stenosperm ocarpy is poorly understood and still under investigation (4, 5, 7, 8). Breeders have developed seedless grapes by using stenospermocarpic parents as pollen sources (2, 7, 8). In vitro culture of stenospermocarpic ovules/embryos prior to abortion makes it possible to hybridize seedless females with seedless males, in hope of increasing the number of seedless progeny (1, 3, 6).
GA 244-15 BWT, GA 7-1 BWT, and GA 12-4 BWT Bacterial Wilt-tolerant Solanum Germplasm
Authors: Jaworski Casimir A. , Phatak Sharad C. , Gitaitis Ronald D. , Ghate Suhas R.
Published: September 2022

Bacterial wilt or brown rot caused by Pseudomonas solanacearum E. F. Sm. is a major limiting factor in potato (Solanum tuberosum L.) production in the warm, humid regions of the world, including the coastal plain region of southeastern United States (6, 7).
Selected Topics on Induced Chromosome Changes in Tissue-cultured Cells
Authors: Griesbach R. J.
Published: September 2022

There is ample evidence that chromosomal changes can be induced in cultured cells. These changes can involve either an increase or decrease in chromosome number or a change in chromosome structure and can be brought about by both physical and chemical agents.
Vegetable Cultivar Testing: Introduction to the Symposium
Authors: Wien H. C.
Published: September 2022

Choice of the most appropriate cultivars is a key decision that vegetable growers face every growing season, and one on which the profitability of the crop depends. Evaluation of cultivars for adaptation to local growing conditions is therefore of crucial importance to extension and research personnel that serve the vegetable industry and the companies that are developing and releasing vegetable cultivars. The present-day climate of restricted budgets and pressure to move from applied to more basic research has forced experiment station and university personnel in North America to abandon or greatly reduce vegetable cultivar testing. The seed industry has traditionally relied on both public institutions and its own grower–cooperators to evaluate the merits of new lines. Increasingly, seed companies face requests for funding of these public trials, or are asked to pay entry fees to submit new cultivars for testing.
Estimating Chill Units at Low Latitudes
Authors: del Real Laborde José Ignacio
Published: September 2022

Deciduous fruit species are generally of temperate-zone origin. When they are grown under subtropical conditions, climatic requirements may not be fulfilled and their growth and yield reduced (10, 12, 13, 15, 30, 31, 35, 55, 59, 62, 63). Cultural practices designed to improve plant growth and yields are necessary in areas with mild winters (23, 24, 29, 33, 46, 53, 57). Proper cultivar selection is needed to obtain genotypes most compatible with the climate (30, 31). Even plants that appear to be well-acclimated may require cultural or chemical means to break rest in warm winters. Rest-breaking practices, in order to be fully effective, must be performed at the optimal time, which can have an action window of only a few days. Therefore, the need for reliable methods to evaluate tree response to environmental conditions during rest is an important concern of fruit growers in low latitudes.
Cultivar Evaluation for Early and Extended Production of Chinese Cabbage in Eastern Pennsylvania
Authors: Palada M. C. , Ganser S. , Harwood R. R.
Published: September 2022

Cultivars of heading and loose-leaf types of Chinese cabbage (Brassica campestris L. Group (Pekinensis) were field-planted in the spring (25 Mar., 18 Apr., and 5 May) and fall (19 Aug. and 10 and 30 Sept.) to determine optimum dates for early and extended production in the northeast. All cultivars of heading Chinese cabbage developed flower stalks (bolting) in 25 Mar. and 18 Apr. plantings when mean minimum temperatures were −1.7° and 3.9°C, respectively. Bolting was virtually absent in fall planting for both types. Optimum dates for early spring planting were 5 May for heading types and 25 Mar. for loose-leaf cultivars. Late fall plantings (10 and 30 Sept.) resulted in no head formation and reduced yields for heading Chinese cabbage. For both types, marketable yields were generally higher in spring than in fall plantings.
Leaf Area Prediction Models for Cucumber from Linear Measurements
Authors: Robbins N. Suzanne , Pharr David M.
Published: September 2022

Length and width measurements of leaf lamina from six fresh-market and nine pickling cucumber (Cucumis sativus L.) cultivars were used in the development of leaf area prediction models. Models using the single independent variable of length (L) were selected from regression analysis using length (L), width (W), and measured leaf areas (A) of 188 ‘Calypso’ cucumber leaves. Tests for equality of regressions (α= 0.05) indicated that a single model accurately predicted leaf area for greenhouse-grown ‘Calypso’ cucumbers (grown in a soil medium) as well as 15 field-grown cultivars. A separate prediction model was required for ‘Calypso’ cucumber plants grown in hydroponic sand culture. Inclusion of leaf width in a multiple regression model provided accurate leaf area prediction for all environments, culture systems, and cultivars tested.
Influence of Root and Shoot on N2 Fixation in Cowpea
Authors: Miller J. Creighton , Scott Lisa M. , Fernandez George C. J.
Published: September 2022

Reciprocal and self-grafts were made using four cowpea [Vigna unguiculata (L.) Walp.] genotypes, ‘H-Brown Crowder’, ‘H-Calico Crowder’, ‘L-Bush Purple Hull’, and ‘L–TX460’, previously identified for their high (H) or low (L) N2 fixation efficiency. Grafts were made on day 12, and N2 fixation variables were evaluated 38 days after planting. Highest nitrogenase activity was obtained in the self grafts of high N2 fixing lines, whereas nitrogenase activity of low N2-fixing genotypes was generally increased by grafting onto high N2-fixing stocks. Nodule number was influenced only by rootstock. Whether rootstock or scion is the limiting factor in N2 fixation efficiency may be cultivar-specific.
Differential Growth Responses of Fractionated Turfgrass Seed Leachates
Authors: Buta J. G. , Spaulding D. W. , Reed A. N.
Published: September 2022

Seed leachates of ‘Kentucky 31’ and ‘Rebel’ tall fescue (Festuca arundinacea Schreb.), ‘Citation’ and ‘Manhattan’ perennial ryegrass (Lolium perenne L.), annual ryegrass (Lolium multiflorum Lam.), annual bluegrass (Poa annua L.), and ‘Mystic’ and ‘Victa’ Kentucky bluegrass (Poa pratensis L.) were evaluated for inhibition of lettuce (Lactuca sativa L. ‘Grand Rapids’) germination and seedling growth (a widely used bioassay for allelopathic effects). Different degrees of inhibition of lettuce seedling growth were found in the turfgrass cultivars ‘Rebel’ > ‘Ky31’, ‘Victa’ > ‘Mystic’, ‘Citation’ = ‘Manhattan’, and in annual bluegrass and annual ryegrass. Grass seed leachates were separated into organic and inorganic fractions using XAD-2 polystyrene resin. Organic fractions were inhibitory to lettuce seedling growth. Inorganic fractions were also inhibitory to lettuce seedling growth at high concentrations but were stimulatory at low concentrations. Germination of lettuce was not affected by leachates or their fractions.
Inheritance of Resistance of Sweet Corn Inbred IL677a to Puccinia sorghi Schw.
Authors: Kim Soon Kwon , Brewbaker James L.
Published: September 2022

The inheritance of resistance of the popular sweet corn (Zea mays L.) inbred IL677a to Puccinia sorghi was determined in Hawaii. Rust symptoms on leaves of IL677a are unusual in that the first several leaves show susceptible symptoms followed by “late resistant” reddish-purple flecking. A total of 1856 individual plants were rated for resistance to P. sorghi. The segregation in the F2 and backcross generations indicated that resistance was controlled by a single recessive gene, very closely linked to Rp-d (chromosome 10). This resistance gene is designated as rp-677a.
Effect of Ethylene on Spathe Regreening in Zantedeschia Hybrids
Authors: Funnell K. A. , Downs C. G.
Published: September 2022

Quality in terms of color of Zantedeschia hybrid flowers is affected by the regreening of the spathe, which is associated with an increase in total chlorophyll (7). Ethylene has been used commercially to degreen citrus (5), celery, and tobacco (1). If ethylene could prevent regreening or induce degreening in Zantedeschia flowers, quality would be prolonged. However, ethylene has induced senescence in many cut flower species (4), and cut flowers have produced detrimental levels of ethylene (6). Although cut flowers of Z. elliottiana have been reported to emit “considerable gas” (8), leaves, not cut flowers, were tested (2). The aim of this work was to measure ethylene production from cut Zantedeschia flowers and the rate of spathe regreening after exposure to ethylene.
New Directions in Rootstock Breeding: Introduction to the Symposium
Authors: Cummins James N. , Aldwinckle Herb S.
Published: September 2022

Orchard production systems have experienced rapid and dramatic changes over the past 3 decades in both the techniques and geno-types used. We expect this rate of change to accelerate in the future. As production costs escalate, the demand will become ever stronger for systems providing early, heavy, reliable yield fo high-quality, easy-to-harvest fruit. These systems must, however, be reasonably priced and durable. The grower will be less able to afford tree losses, whether due to biotic, climatic, or edaphic hazard, and will need to economize on use of machinery and chemical pesticides. Growth regulators will be employed only where there are effective, economically justified, and environmentally acceptable.
Criteria and Procedures for Evaluating Apomictic Rootstocks for Apple
Authors: Schmidt Hanna
Published: September 2022

Breeding apomictic apple seedling rootstocks in a country where vegetatively propagated material is grown nearly exclusively is a tremendous challenge. When the program was started 25 years ago, virus infection was widespread in apples. Used as rootstocks, seedlings have the advantage of being free from viruses, because these viruses are not seed-transmitted. In Germany, a functional system has been developed to produce and distribute pomologically valuable, virus-free (VF) plant material in quantities sufficient for the nurseryman. The standard of orchard performance for apple rootstocks is high, with the dwarfing M.9 being the most important rootstock in our country. Apomictic seedlings have to compete with this and other horticulturally excellent stocks.
Breeding Dwarfing Rootstocks for Sweet Cherries
Authors: Schmidt Hanna , Gruppe Werner
Published: September 2022

To remain economically viable, the worldwide sweet cherry industry requires a tree much smaller than that on which current production is based. Labor requirements and high land costs would be reduced with compact trees. Among the different approaches to reduce tree size, we have concentrated our efforts on the breeding of rootstocks that would dwarf the scion cultivars grafted onto them.
Effects of Simulated Acidic Fog on Strawberry Productivity
Authors: Musselman Robert C. , Sterrett Jerry L. , Voth Victor
Published: September 2022

Field plots of strawberry (Fragaria × ananassa Duch cv. Chandler) were exposed to two 1-hr nighttime simulated fog episodes per week at specific acidities from pH 1.6 to 3.2, or no fog. Small, distinct, irregularly shaped, rust-colored lesions developed on foliage and fruit after a single 1-hr exposure to acidic fog at low pH. Fog episodes at pH 1.6 resulted in death of the plants after 8 weeks. Strawberries tolerated short-term exposure to acidic fog at pH 2.0 or higher, with little or no negative effect on growth, yield, or fruit soluble solids. However, calyx injury from acidic fog reduced marketability at pH levels up to 2.8. ‘Douglas’, ‘Chandler’, ‘Selva’, ‘Parker’, and ‘Soque!’ differed in magnitude of response to acidic fog in greenhouse exposures.
Some Current Options in the Use of Plant Variety Protection in Horticulture
Authors: Davis David W. , Luby James J.
Published: September 2022

The large number of horticultural crops represents a great genetic diversity. This diversity is important in numerous ways such as in pollination control, product use, and environmental requirements for the production and handling of seeds, propagules, and the commercial product, to name only a few. The diversity is reflected further in the business structure of horticulture and, most relevant to our discussion, to relationships at the interface between the public and the private sectors in crop improvement.
Plant Growth Regulator Reduction of Bypass Shoot Development in Azalea
Authors: Whealy C. A. , Nell T. A. , Barrett J. E.
Published: September 2022

Foliar spray applications to ‘Gloria’ azalea (Rhododendron obtusum) of daminozide, chlormequat chloride, daminozide/chlormequat chloride combination, ancymidol, paclobutrazol, fluometralin, NAA, and IBA were applied prior to bypass shoot development. All treatments except IBA reduced bypass shoot length. NAA treatments were phytotoxic, and fluometralin inhibited flowering. Rate of flower development was retarded by daminozide, chlormequat chloride, and daminozide/chlormequat chloride combination, but was unaffected by ancymidol, paclobutrazol, fluometralin, NAA, and IBA. Paclobutrazol was the most efficient and effective treatment in reducing bypass shoot length without affecting flower size or time to flower. Chemical names used: butanedioic acid mono (2,2-dimethylhydrazide) (daminozide); 2-chloro-N,N,N-trimethyl-ethanaminium chloride (chlormequat chloride): α-cyclopropyl-α-(4-methoxyphenyI)-5-pyrimidinemethanol (ancymidol): β,[(4-chlorophenyl)methyl)-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol): 2-chloro-N-[2,6-dinitro-4-trifluoromethyl)phenyl]-N-ethyl-6-fluorobenzenemethanamine (fluometralin): 1-naphthaleneacetic acid (NAA): 1H-indole-3-butyric acid (IBA).
Effect of Night Interruption Photoperiod Treatment on Subsequent Growth of Acer rubrum Cuttings
Authors: Smalley Timothy J. , Dirr Michael A.
Published: September 2022

Acer rubrum L. ‘October Glory’ cuttings taken on 15 June 1984 were subjected to short-day (SDT) or short-day plus night interruption treatments (NIT) from 25 July until 22 Oct. 1984. Additional cuttings taken on 14 Aug. were subjected to the same photoperiod treatments from 10 Sept. until 22 Oct. The height of the 15 June NIT cuttings was 50 cm greater than that of the 15 June SDT cuttings at the start of the first growing season, but no significant difference in height or caliper existed after two growing seasons of container culture. The greater growth rate of the 15 June SDT cuttings compared to 15 June NIT cuttings is attributed to their greater percentage of root carbohydrate reserves at the start of the first growing season. The initial root carbohydrate reserves and the final height and caliper of the SDT and NIT 14 Aug. cuttings were not significantly different. The 14 Aug. cutting growth results approached those of the 15 June cuttings. This indicated the growth potential of cuttings taken later in the season.
Activities of Polygalacturonase, α-d-Mannosidase, and α-d- and β-d-Galactosidases in Ripening Tomato
Authors: Watkins C. B. , Haki J. M. , Frenkel C.
Published: September 2022

The activities of the enzymes polygalacturonase, α-d-mannosidase, and α-d- and β-d-galactosidase in tomato (Lycopersicon esculentum Mill) pericarp tissue were measured during ripening of two normal ripening cultivars, Sweet 100 and ACE 55 VF, the slow-ripening alcobaca mutant, and their F1 progeny. The activity of polygalacturonase increased as the fruit ripened from mature green to red stages for all tomato lines (‘Sweet 100 > ‘Sweet 100’ × alcobaca > ‘ACE 55 VF’ > ‘Ace 55 VF’ × alcobaca > alcobaca). Of the other enzymes, α-mannosidase showed the greatest quantitative differences between the tomato lines and consistently increased in activity during ripening. There was, however, no association between the activity of α-d-mannosidase and polygalacturonase. The highest β-galactosidase activity occurred in ‘Sweet 100’, but was generally similar in the other lines. The activity of α-galactosidase varied little between parents and progeny for any stage of ripeness.
Horticulture in The Gambia
Authors: Jack Isatou , Caldwell John s.
Published: September 2022

The Gambian climate is well-suited for the production of horticultural crops. There are two distinct seasons: a short wet season, from June until September, when temperatures and humidity are quite high; and a long dry seas the rest of the year. From November until March, the dry season is cool and especially suitable for the production of a wide variety of vegetables.
In Vitro Flowering in Amaranthus
Authors: Tisserat Brent , Galletta Paul D.
Published: September 2022

Shoot tip-derived plantlets of five species of Amaranthus, A. caudatus L. cv. Pan, A. gangeticus L., A. hypochondriacus L., A. retroflexus L., and A. viridis L. flowered in vitro following 8 to 32 weeks in culture. Shoot tips were cultured on Murashige and Skoog (MS) salts and (per liter) 30 g sucrose, 100 mg myo-inositol, 0.4 mg thiamine·HCl, and 8 g agar. Additions of 0.1 mg·liter–1 NAA enhanced inflorescence production but was not necessary for flower induction. Fruits of A. gangeticus and A. retroflexus dehised and their seeds dropped on the surface of agar medium and immediately germinated. In some instances, seeds of A. gangeticus germinated while still attached to the inflorescences. Seedlings derived from sterile flowers could, in turn, give rise to inflorescences. Inflorescences could be detached from flowering plant-lets and grown successfully for several months on basal nutrient medium containing 0.1 mg·liter–1 NAA. Chemical name used: 1-naphthaleneacetic acid (NAA).
A Simple Method for Production of Glomus aggregatum Inoculum Using Controlled-release Fertilizer
Authors: Coltman R. R. , Waterer D. R. , Huang R. S.
Published: September 2022

Inoculum of the vesicular–arbuscular mycorrhizal fungus (VAMF) Glomus aggegratum Schenck and Smith emend. Koske was propagated on the roots of sweetcorn (Zea mays L.) grown in sand “nurse” cultures fertilized with either modified Johnson's nutrient solutions (JNS) or Osmocote 19N–2.6P–9.9K. Shoot and root dry weights after 12 weeks increased 87% and 132%, respectively, with increasing rates of Osmocote between 0.82 g·kg–1 and 1.32 g·kg–1. However, VAMF spore production and leaf tissue P concentrations did not increase significantly over this range of Osmocote rates. Average spore production of Osmocote cultures was 3.25 million spores per 10 kg of nurse culture, 261% greater than in JNS cultures. Higher spore yields in the Osmocote compared to the JNS cultures were associated with lower P concentrations at 6 and 12 weeks after planting (WAP) and higher intensities of root colonization by the VAMF at 6 WAP.
In Vitro Propagation of Mature Persian Walnut Cultivars
Authors: McGranahan Gale , Leslie Charles A. , Driver John A.
Published: September 2022

In vitro propagation of mature cultivars of Juglans regia L. (Persian or English walnut) could have several major advantages over propagation by grafting on seedling black walnut [J. hindsii (Jeps.) Jeps.] rootstock. If commercial cultivars perform satisfactorily on their own roots, the expensive and time-consuming process of grafting could be avoided, genetic uniformity could be assured, and trees would not be subject to the lethal girdling of blackline disease (5). In addition, mature clones on their own roots might be more precocious than grafted seedlings. These factors are becoming increasingly important as walnut growers change to high-density or hedgerow orchards (D.E. Ramos, personal communication).
Ky-P7 Short-internode Muskmelon
Authors: Knavel Dean E.
Published: September 2022

Several muskmelon (Cucumis melo L.) cultivars of short-internode or bush-type plants are available, but none have attained commercial prominence. Ky-P7 is a homozygous short-internode inbred that is resistant to all races of powdery mildew (Spaerotheca fuligenea Schlecht., Poll.) in Kentucky, and has value as either a cultivar or as a parent in the development of F1 hybrids.
Introductory Remarks
Authors: Sherman W. B.
Published: September 2022

Temperate zone (deciduous) fruit crops are cultivated largely in areas far removed from their center of origin. Selection and breeding have improved climatic adaptation in these perennial crops. Current breeding programs are attempting to broaden this adaptation by developing cultivars with high mid-winter cold tolerance, late blooming to avoid spring freezes, and increased disease resistance. The attainment of these and other breeding objectives will recessitate the use of noncommercial exotic germplasm. The range of these fruits also is being extended to the subtropics and tropical highlands through selection and breeding. It is only through genetic manipulation that more productive and adapted plant materials are likely to be developed. Germplasm centers are needed to maintain and provide the array of genetic variability necessary for continued scion and rootstock improvement.
Regulatory Actions to Exclude Pests During the International Exchange of Plant Germplasm
Authors: Foster J. A.
Published: September 2022

The use of genetic material from other countries to improve domestic cultivars through breeding and selection has contributed to the progress made in the development of the fruit and nut industry in different areas of the world. Future progress by using foreign selections, desirable mutants, or wild species will surely have an important economic, aesthetic, and even social impact. As the enthusiasm for such a promising future develops into more interest in international exchange of plant germplasm, it is important to emphasize the possibility that foreign pests can be introduced into the domestic agriculture along with the desired genetic material (52). In fact, a foreign pest may minimize or completely eliminate the benefits of the contaminated imported germplasm as well as damage nearby susceptible cultivars laboriously created by plant breeding programs. Such pests may cause negative economic, aesthetic, and social consequences. Therefore, the effort to import desirable foreign germplasm must be complemented by a concentrated effort to exclude hazardous pests from the imported plant material.
Genetic Considerations in the Collection and Maintenance of Germplasm
Authors: Fitzgerald Paul J.
Published: September 2022

Plant germplasm has become a topic of interest and concern at the highest levels of our government and in many other parts of our society. Part of this concern no doubt relates to the increased awareness by leaders in the government and in the public at large that U.S. agricultural productivity and stability is dependent on plant resources that are not native to the United States. The United States, as compared to many agricultural producers in the world, has no centers of origin for important food and fiber crops. In fact, the United States has no major crop native to its geographical area. Of all the crops important to U.S. agriculture, only sunflower (Helianthus spp.), Jerusalem artichoke (Helianthus tuberosus L.), grape (Vitis spp.), pecan [Carya illinoensis (Wangenh.) C. Koch] and other hickories (Carya spp.), blueberry (Vaccinium spp.), cranberry (Vaccinium macrocarpon Aiton), and a few other miscellaneous species of minor importance are native to the United States.
Improving the Effectiveness of Graduate Seminars
Authors: Singha Suman , Gartin Stacy A.
Published: September 2022

Effective verbal communication is essential not only in teaching and extension, but also in research. Research results presented at meetings are often rendered ineffective due to a poor presentation or indecipherable slides (1). Recent reports in HortScience have addressed the preparation of posters, a popular means of communication at meetings (12, 13). However, although a person can “escape” a poor poster, this option is generally not available to the audience in a presented paper. Poor presentations accompanied by inadequate visuals create an even greater problem for students during lectures in the classroom. Graduate seminars, mandatory in virtually all institutions, can provide the training ground for developing effective communication skills, preparing audio-visuals, and understanding that to be meaningful a presentation must be tailored to the audience.
Efficacy of Ancymidol, Daminozide, Flurprimidol, Paclobutrazol, and XE-1019 when Followed by Irrigation
Authors: Barrett James E. , Bartuska Carolyn A. , Nell Terril A.
Published: September 2022

• In the article “Efficacy of Ancymidol, Daminozide, Flurprimidol, Paclobutrazol, and XE-1019 when Followed by Irrigation”, by James E. Barrett, Carolyn A. Bartuska, and Terril A. Nell (HortScience 22(6): 1287–1289, December 1987), Table 1 was printed incorrectly. The corrected table appears below.
Two Methods of Studying Rest: Temperature Alteration and Genetic Analysis
Authors: Dennis Frank G.
Published: September 2022

• In the article “Two Methods of Studying Rest: Temperature Alteration and Genetic Analysis”, by Frank G. Dennis, Jr.(HortScience 22(5):820–823, October 1987), Table 1 was printed incorrectly. The corrected table appears below.
International Approach to Teaching Floriculture
Authors: Rogers Marlin N.
Published: September 2022

One of the prerequisites for a thriving profession of floriculture and ornamental horticulture is a continuing supply of enthusiastic and well-trained young people, who will eventually move into leadership and management positions. We need young people who have comprehensive bases in the fundamental sciences that underlie our profession, but who also have hands-on and practical backgrounds in the applications of this science to the art and sciences of horticulture. We need people who will eventually staff and manage our greenhouses and nurseries in production- and marketing-oriented positions. We also need scientists holding advanced degrees who will fill the teaching, research, and extension positions in our colleges, universities, and research institutes in the years to come.
Calcium and the Regulation of Plant Growth and Senescence
Authors: Ferguson IB. , Drøbak B. K.
Published: September 2022

Much of the attention currently given to the function of Ca2+ in plant growth and development is centered on the role of Ca2+ as a secondary messenger. This role constitutes the link between external signals and intracellular reaction. Recent results from studies with animal cells show that a vital part of the mechanism by which Ca2+ is involved in this process is the release of Ca2+ from internal pools by D-myo-inositol-1,4,5-trisphosphate, a product of membrane phosphoinositide hydrolysis. The involvement of Ca2+ in growth responses and senescence in plants is reviewed in light of the probability of a similar system operating in plants. This probability leads to a reconsideration of the various pools of Ca2+ in plant cells, of what Ca2+ deficiency may mean, and of how Ca2+ may be involved in responses to growth regulators in senescence.
Molecular and Cellular Aspects of Calcium Action in Plants
Authors: Poovaiah B. W.
Published: September 2022

Calcium is known to be a second messenger in many developmental processes in animal systems, but it has only recently become evident that Ca is an important intracellular messenger in plants as well (9, 15, 22, 32-35, 41). The level of free Ca concentration in the cytoplasm is extremely low, and it is influenced by extracellular signals such as light, gravity, and hormones. Investigations from our laboratory indicated that Ca and its binding protein, calmodulin, play an important role in stimulus-response coupling by regulating enzyme activities, especially through protein phosphorylation (33, 34, 48). In vivo and in vitro protein phosphorylation studies have revealed Ca-dependent changes in various plant tissues (18, 37–39, 49, 50). We have also been able to influence various physiological processes such as cell elongation, abscission, senescence, and tuberization by altering extracellular and intracellular Ca levels (33). Other examples of Ca-mediated processes in plants are as follows: a) cell division, b) geotropism, c) protoplasmic streaming, d) stomatal control, e) chloroplast movement, f) secretion, g) hormone-dependent changes, h) enzyme activation, and i) protein phosphorylation (9, 33).
Evapotranspiration of Tall Fescue Turf
Authors: Kopec D. M. , Shearman R. C. , Riordan T. P.
Published: September 2022

Mini-lysimetry was used for evapotranspiration (ET) assessment of six tall fescue cultivars (Festuca arundinacea Schreb.) grown under field conditions. Crop coefficients (Kc) and fraction of available soil water were calculated. Cultivars differed in ET by as much as 18%. Turf-types had lower ET than forage-types, with ET rates of 6.6 and 7.2 mm·day–1, respectively. ‘Kenhy’ and ‘Kentucky 31’ had the highest and ‘Rebel’ and ‘Mustang’ had the lowest total ET for 16 days measured during Summer 1984. Cultivars differed in extraction of available soil water and capacity to meet ET demand. Cultivars differed in wilting tendency. ‘Mustang’ and ‘Rebel’ had low ET, but wilted early. ‘Adventure’ had a relatively high ET, but did not show signs of wilt.
Effects of Rootstocks on Wine Grape Scion Vigor, Yield, and Juice Quality
Authors: Lipe William N. , Perry Ron L.
Published: September 2022

Forty cultivars of wine grapes (Vitis spp.) grafted on ‘Dogridge’ and ‘Couderc 1613’ rootstock and self-rooted vines were planted in 1974 at the Texas Agricultural Experiment Station near Lubbock. From fourth to 13th leaf vines were evaluated for vigor, winter hardiness, yield, and juice quality (ºBrix, pH, and acids). Although each cultivar responded differently to rootstock, some general observations are made regarding acceptance or rejection of stocks. Compared to self-rooted cultivars, ‘Dogridge’ significantly increased vigor on 37% of cultivars while reducing vigor on 7%, reduced winter hardiness on 22% while increasing hardiness of 7%, and reduced yields on 32% while increasing yields on 17%. The most detrimental effect of the ‘Dogridge’ rootstock was on pH, which was increased on 50% of cultivars while reduced on none. In comparison, ‘Couderc 1613’ expressed more moderate effects on most scion cultivar parameters tested.
Fiber, Nitrate, and Protein Content of Amaranthus Accessions as Affected by Soil Nitrogen Application and Harvest Date
Authors: Walters Robert D. , Coffey David L. , Sams Carl E.
Published: September 2022

Six accessions of edible amaranths (Amaranthus spp. L.) of varied geographic and genotypic origin were grown in a soil enriched with 0, 50, or 100 kg·ha–1N. Leaves were harvested at 25, 35, 45, 55, and 65 days after germination (DAG) and analyzed for crude protein (CP), neutral detergent fiber (NDF), and NO3– N. In grain-bearing accessions, leaf CP content increased with N application but declined linearly over harvest dates. In vegetable types, leaf CP levels tended to fluctuate over time. In both types, NDF content declined with N application, whereas response to harvest date varied. Leaf NO3– increased two-fold in plants from fertilized plots compared to plants from unfertilized plots, but declined rapidly with time. Leaf content of NO3– did not exceed 239 mmol·kg–1 dry weight with any N fertilization treatment. Edible amaranth appeared to be adapted to soils and climate of the southeastern United States. A. tricolor was most susceptible to disease among the accessions evaluated.