bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of a Rapid Method for Screening the Capacity of Leaves to Export Photosynthate
Authors: Potter J. R.
Published: February 2019

A method was developed to rapidly screen genotypes for capacity of leaves to export photosynthate, with the expectation that rapid export should promote growth. Vegetative plants of 13 cultivars of Pisum sativum L. (pea) were screened based on changes in specific leaf weight (SLW) at dawn before and after exposing plants to CO2-enriched air (1200 ppm) for one diurnal cycle. Three cultivars (Nofila, Little Marvel, Sugar Daddy) had relatively little increase in SLW and were designated rapid exporters; based on this criterion `Alaska', `Oregon Sugar Pod II', and `Manoa' were slow exporters. The increase in SLW was due to starch and sugars. Neither single leaf net photosynthetic nor dark respiration rates consistently differed among cultivars when measured at 1200 or 350 ppm CO2 (normal air). The difference between rapid and slow exporters persisted after plants were grown for 2 weeks at 1200 vs. 350 ppm CO2. However, the relative growth rate (RGR) of whole-plant dry mass did not differ consistently among cultivars at either CO2 level, except it was high for `Alaska', a slow exporter. The high RGR for `Alaska' was due in part to a high ratio of whole plant leaf area to dry mass early in the growth period. Thus, although the rapid exporters accumulated relatively low levels of starch and sugars, this trait did not dominate other growth determining traits.
Using Soybean Oil as a Pesticide on Nursery Stock
Authors: Deyton D.E. , Sams C.E. , Fare D.C. , Moran R.E. , Pless C.D.
Published: February 2019

Our research has previously shown that soybean oil can substitute for petroleum oil for controlling insects on fruit trees. Soybean oil may also be a safe, environmentally friendly pesticide to use on nursery stock. The objectives of these experiments were to evaluate phytotoxicity of soybean oil to nursery stock and efficacy for mite control. Four replications of container-grown plants of `Alberta' spruce, `Emerald' arborvitae, `Leyland' cypress, Canadian hemlock, and `Andorra' juniper were sprayed on 26 Mar. with 0%, 1.0%, 2.0%, or 3.0% soybean oil; or 2.0% petroleum oil. None of the oil treatments caused phytotoxicity. The same plants were sprayed on 1 Aug. with 0%, 1.0%, 2.0%, or 3.0% soybean oil. Application of 1% or 2% soybean oil appeared to be non-phytotoxic to spruce, but 3% soybean oil caused slight terminal necrosis. Arborvitae, cypress, hemlock, and juniper were not injured by spraying 1% to 3% soybean oil in the summer. Container-grown burning bush plants with mite infestations were sprayed on 20 Sept. with 0%, 1.0%, 2.0%, or 3.0% soybean oil; or with 1.0% SunSpray petroleum oil. Container-grown mite-infested `Andorra' juniper plants received the same treatments, except for the 3% soybean oil. Application of 1% or 2% soybean oil to burning bush or to juniper shrubs resulted in >97% and 87% control of mites 7 and 14 days, respectively, after treatment.
Variance Components and Estimates of Broad-sense Heritability of Nut and Kernel Traits in Hazelnut
Authors: Yao Qiang , Mehlenbacher Shawn A.
Published: February 2019

Seventy-seven trees representing 41 hazelnut (Corylus avellana L.) genotypes were to evaluate variance components and broad-sense heritability for 10 nut and kernel traits from 1994 to 1996. All effects in the models were assumed to be random. All traits had extremely high heritability. This indicated that nearly all of the phenotypic variation had a genetic basis. Knowledge of variance components may help us efficiently allocate resources. Broad-sense heritability estimates were larger than those in narrow sense, suggesting the presence of nonadditive genetic variation in the population.
The Morphology of Postharvest Pitting of White Grapefruit
Authors: Petracek Peter D. , Davis Craig
Published: February 2019

Postharvest pitting of citrus fruit is a recently defined peel disorder that is caused by high-temperature storage (>10°C) of waxed fruit. We examined the anatomy of pitted white grapefruit peel to improve our understanding of this disorder and assist in its diagnosis. Scanning, light, and transmission micrographs showed that postharvest pitting is characterized by the collapse of oil glands. Cells enveloping the oil glands are the cells of primary damage. Oil gland rupture may occur anywhere around the oil gland, but often occurs in regions farthest from the epidermal cells. Adjacent parenchyma cells are damaged as the oil spreads. Epidermal and hypodermal cells are often damaged during severe oil gland collapse. In contrast, chilling injury is characterized by the collapse of epidermal and hypodermal cells. Oil glands are affected only in severe cases of chilling injury. Oleocellosis (oil spotting) is often characterized by the collapse of epidermal and hypodermal cells, but cells enveloping the oil gland are typically not damaged. Physical damage is characterized by damage of epidermal cells, a wound periderm, and presence of secondary pathogens.
Changes in Anthocyanin Concentration, Phenylalanine Ammonia Lyase, and Glucosyltransferase in the Arils of Pomegranates Stored in Elevated Carbon Dioxide Atmospheres
Authors: Holcroft Deirdre M. , Gil Maria I. , Kader Adel A.
Published: February 2019

The influence of CO2 on color and anthocyanin concentration in the arils of `Wonderful' pomegranate (Punica granatum L.) was investigated. Pomegranates were placed in jars ventilated continuously with air or air enriched with 10% or 20% CO2 at 10°C for 6 weeks. Samples were taken initially, and after 1, 2, 4, and 6 weeks and anthocyanin concentration was measured by HPLC. The arils of the pomegranates stored in air were deeper red than those stored in CO2-enriched atmospheres. This increase in red color resulted from an increase in anthocyanin concentration. Arils from fruit stored in air+10% CO2 had a lower anthocyanin concentration than air-stored fruit, and atmospheres enriched with 20% CO2 suppressed anthocyanin biosynthesis. Anthocyanin concentration was well-correlated to the activity of phenylalanine ammonia lyase (PAL), but not to glucosyltransferase (GT) activity. Moderate CO2 atmospheres (10%) prolong the storage life and maintain the quality of pomegranates, including an adequate red color of the arils.
Application of Gene-specific mRNA Differential Display for Identification of cDNAs that Encode Small HSPs Correlated with the Heat-induced Chilling Tolerance of Tomato Fruit
Authors: Vlachonasios Konstantinos E. , Kadyrzhanova Dina K. , Dilley David R.
Published: February 2019

Heat-treatment of mature-green tomato fruit (Lycopersicon esculentum) for 48 h at 42°C has been shown to prevent chilling injury from developing after 2 or 3 weeks at 2°C. Using mRNA differential display, we recently cloned and characterized a cDNA that encodes a cytosolic class II small heat-shock protein (Le HSP17.6). The mRNA of Le HSP17.6 is up-regulated during heat shock and the level of transcription remains high during subsequent storage at chilling temperatures. We used mRNA differential display with gene-specific primers from the other small HSPs families and find that the transcription of the other small heat-shock proteins is up-regulated during heat shock and persists at elevated levels at 2°C for at least 2 weeks. When the fruits are returned to a permissive ripening temperature after the chilling period, the mRNA of the small HSPs declines slowly for 3 days. These results suggest that the persistence of the small heat-shock proteins at low temperatures may provide protection against chilling injury.
Identification of Heritable Resistance to Tomato Spotted Wilt Virus (TSWV) as Derived from Lycopersicon chilense Interspecific Hybrid Breeding Line LA 1938
Authors: Canady M.A. , Stevens M.R. , Scott J.W.
Published: February 2019

Nineteen interspecific hybrid breeding lines were tested for resistance to a TSWV isolate using enzyme-linked immunosorbent assay (ELISA) to check for presence of the virus after inoculation. These lines were all BC1F6 lines derived from L. esculentum crosses with seven L. chilense accessions. All of these lines had been selected for high tolerance/resistance to tomato mottle virus (ToMoV), a geminivirus [Scott et al., Bemisia 1995: Taxonomy, Biology, Damage Control and Management 30: 357–367 (1996)]. The initial TSWV screening indicated that eight of the 19 original lines had “possible” TSWV resistance. Seed from these selected eight lines were then planted and inoculated with TSWV ≈3 weeks after emergence. Three weeks later, ELISA results indicated that all plants from all lines were infected with TSWV. However, none of the plants from Y118 (derived from the LA 1938 cross) showed visual TSWV symptoms. The Y118-derived plants were allowed to grow for several months, and at no time developed significant visual symptoms of the virus. The consistent lack of TSWV symptoms prompted a second ELISA test on the Y118 plants, and the results indicated the plants were completely free of TSWV. Further tests were then initiated with F2 (L. esculentum × Y118) seed, and results indicate a single dominant gene is responsible for TSWV resistance. Data from this segregating population, including a molecular marker study which screened 800 randomly amplified polymorphic DNA (RAPD) primers, will be presented. Approximately two to five RAPD primers are possibly linked to TSWV resistance.
Analysis of Horticultural Performance of Ethylene-insensitive Petunias and Tomatoes
Authors: Gubrium E.K. , Clark D.G. , Klee H.J. , Nell T.A. , Barrett J.E.
Published: February 2019

We are studying the horticultural performance of two model plant systems that carry a mutant gene that confers ethylene-insensitivity: Never Ripe tomatoes and petunia plants transformed with the mutant etr1-1 gene isolated from Arabidopsis thaliana. Having two model systems to compare side-by-side allows us to determine with greater certainty ethylene's role at different developmental stages. Presence of the mutant etr1-1 gene in transgenic petunias was determined using three techniques: PCR analysis, the seedling triple response assay (inhibition of stem elongation, radial swelling of stem and roots, and an exaggerated apical hook when grown in the dark and in the presence of ethylene), and the flower wilting response to pollination, which is known to be induced by ethylene. Flowers from ethylene-insensitive petunias took almost four times as long to wilt after pollination as wild-type plants. It is well known that fruit ripening in Never Ripe tomato is inhibited, and a similar delayed fruit ripening phenotype is observed in petunia plants transformed with etr1-1. In an effort to maintain ethylene-insensitive petunia plants by vegetative propagation, we observed that the rate of adventitious root formation was much lower with transgenic plants than in wild-type plants. In subsequent experiments on adventitious root formation in Never Ripe tomato, we observed the same result. Therefore, while ethylene-insensitive tomato and petunia plants appear phenotypically normal for many characters, other factors are altered by the presence of this mutation. The fact that these changes are present in two model systems helps to define the role of ethylene perception in plant growth and reproduction.
Isolation and Characterization of Putative Ethylene Receptor Genes from Zonal Geranium
Authors: Clark D.G. , Dervinis C. , Nell T.A. , Barrett J.E.
Published: February 2019

In this study, the temporal and spatial regulation of putative ethylene receptor genes was examined during ethylene and pollination-induced flower petal abscission of zonal geranium (Pelargonium × hortorum L.H. Bailey). We used the Arabidopsis thaliana ETR1 gene as a heterologous probe to isolate two full-length cDNA clones, GER1 and GER2, from an ethylene-treated geranium pistil cDNA library. Both cDNAs share a high degree of DNA sequence similarity to ETR1, and examinations of deduced amino acid sequences indicate that the proteins encoded by each gene have the conserved ethylene binding and response regulator domains found in ETR1. Experiments focused on determining the temporal regulation of these genes revealed that both genes are expressed in geranium florets much earlier than when the florets become responsive to ethylene treatment, which is sufficient to cause petal abscission in 1 hr. Both genes are expressed in pistils throughout floret development. Experiments focused on determining the spatial regulation of these genes revealed that both genes are expressed at moderate levels in leaves, pistils, anthers, and petals, and are expressed at very low levels in roots. Preliminary evidence suggests that GER2 is transcriptionally regulated by ethylene in pistils after exogenous ethylene treatment. Currently, the transcriptional regulation of these genes in pistils after pollination is unknown.
Validation of a Model for Simulating the Effect of Daminozide Application on Chrysanthemum
Authors: Lieth J.H. , Oki L.R. , Ng P. , Garcia-Navarro M.C. , Kim S.H. , Li L.-Y.
Published: February 2019

Daminozide is a growth retardant used in potted plant production as a foliar spray to inhibit shoot elongation. It has its greatest inhibitory effect immediately after application, becoming less pronounced thereafter; continued retardation is accomplished by reapplication at 7to 14-day intervals. A model for this retardation effect is useful in developing decision support tools, as well as in optimizing (perhaps minimizing) the use of this growth retardant. Such a model, as developed and described earlier, simulates the effect of a foliar spray application of daminozide at various concentrations on various days during the production cycle. The objective of this work was to validate this model for various varieties of chrysanthemum. Using the model to simulate the effect of one application of daminozide resulted in predicted plant heights very close to the observed heights for most of the varieties tested. Of four methods used to implement the multiple-application effect, two resulted in very good simulation of the observed plant heights. In summary, the model was shown to be valid for all the varieties of chrysanthemum tested.
Photoperiodic Responses of Ten Alternative Hanging Basket Species
Authors: Williams Millie S. , Starman Terri W. , Faust James E.
Published: February 2019

The photoperiodic responses were determined for the following species: Abutilon hybrid `Apricot', Diascia hybrid `Ruby Fields', Evolvulus glomeratus `Blue Daze', Orthosiphon stamineus `Lavender', Portulaca oleraceae `Apricot', Scaevola aemula `Fancy Fan Falls', Sutera cordata `Mauve Mist' and `Snowflake', Tabernamontana coronaria `Double', and Tibouchina `Spanish Shaw'. Each plant species was grown at 8-, 10-, 12-, 14-, and 16-h photoperiods. Photoperiods were provided by delivering 8 h of sunlight, then pulling black cloth and providing daylength extension with incandescent bulbs. Air temperatures were monitored under each black cloth. Data collected included time to flower, number of flowers, and vegetative characteristics. Diascia, Sutera `Mauve Mist' and `Snowflake', Tabernamontana, and Tibouchina were day neutral with regard to flowering; i.e., no difference in days to visible bud or days to anthesis in response to photoperiod was observed. Portulaca and Scaevola increased in bud and flower number as photoperiod increased from 8 to 16 h, performing similar to quantitative long-day plants. There was no difference in time to flower for Portulaca; however, 70% more flowers were produced under the 16-h photoperiod, compared to the 8-h photoperiod. Scaevola had 26% more flowers under the 16-h than 8-h photoperiod. Abutilon, Evolvulus,and Orthosiphon performed as quantitative short-day plants. Days to visible bud and days to anthesis increased as photoperiod increased for Evolvulus and Orthosiphon, and Abutilon had decreased flower number as photoperiod increased. Although Abutilon had no difference in time to flower, there was a 43% increase in flowers on plants under the 8-h photoperiod vs. 16-h photoperiod. Evolvulus set visible bud and reached anthesis 10 days earlier under 8-h photoperiod than 16-h. Orthosiphon reached visible bud 32 days earlier under an 8-h photoperiod than a 16-h photoperiod.
Vegetable Variety Trial Programs: Opportunities and Challenges at Auburn University
Authors: Kemble J.M. , Simonne E.
Published: February 2019

In 1996, more than 72,000 acres of vegetables were produced in Alabama. This number has been steadily increasing since the mid-1980s. Growers and county agents requested information on which vegetable varieties performed well in Alabama. To support a growing vegetable industry, Auburn Univ. committed itself to developing an extensive vegetable variety trial (VVT) program focusing on rapid dissemination of results. Presently, replicated trials are held at nine experiment stations, each representing a unique growing environment. The VVTs are divided into a spring and fall section. The spring trials evaluate spring/summer planted crops such as tomato, peppers, watermelon, sweetpotato, eggplant, southernpea, lettuce, melons, cucumber, summer squash, and others. Fall trials examine cole crops, winter squash, pumpkin, and other late-summer/fall-planted crops. Turn around time from final harvest of the final crop to placing the report in the county agent's or grower's hands is 2 to 3 months. Good support is received from industry through financial contributions and/or materials. More than 3000 copies of the spring and fall VVT reports are distributed annually at field days, statewide and county meetings, and in direct mailings. Other research projects, such as projects on nutritional composition of vegetables, postharvest quality, and consumer acceptance, have been supported by materials from the VVT program. Without overwhelming support and commitment from the State of Alabama, Auburn Univ., grower organizations, and industry, the VVT program would not be the success that it is today providing timely and needed information to strengthen the growing vegetable industry in Alabama.
Is Strawberry Clipper (Anthonomus signatus) an Economically Important Pest?
Authors: Pritts Marvin P. , English-Loeb Greg
Published: February 2019

Strawberry clipper is considered to be a major pest on matted-row strawberries in the northern U.S. and Canada. This pest is thought to be so threatening that even a single clipped bud indicates the potential for serious and rapid damage. Conventional wisdom states that fields should be treated for clipper during warm weather if they have a history of clipper damage—even if fields have not been scouted. Thresholds (fi ve clipped buds per meter) are based on the assumption that one clipped bud is equivalent to the loss of one average-sized berry. However, our data show no correlation between clipper damage and yield in field surveys, and our artificial clipping studies have found that strawberry plants have the ability to compensate for flower bud loss by increasing allocation to other fruits. For example, in plots of cv. Jewel, no significant difference was found in total yields between plots with no flower bud removal and plots with all primary flower buds removed (an average of 100 clipped buds per meter)—so long as the clipping happened early in the season. An increase in the size of secondary and tertiary fruit balanced the reduced fruit numbers. Similar trends were found with Kent. The ability to compensate for early flower bud loss also was assessed in a separate study with 10 strawberry cultivars. These studies suggest that our current threshold for clipper may be nearly two orders of magnitude too low, and that clipper may not be a true economic pest of strawberry.
Shading and Leaf Age Effects on Total Phenolic Content and Specific Leaf Weight of Apple
Authors: Garcia M.E. , Rom C.R. , Murphy J.B.
Published: February 2019

The effects of shading and leaf age on the production of foliar phenolics of two apple (Malus domestica Borkh.) cultivars, `Liberty' and `Red Rome Beauty', were studied. Potted trees were grown outdoors and their leaves tagged weekly when they reached 20 mm in length. This process continued for the duration of the experiment. At 3 weeks from budbreak, the trees were placed in three shade treatments: 0% shade (control), 60% shade, and 90% shade. After 5 weeks, the leaves were collected for phenolic assay. Specific leaf weight (SLW) was determined from the leaf below the tagged leaf. Shade significantly affected the total phenolic content. Leaves in 0% shade had the highest levels of total phenolics. The phenolic content decreased with increasing shade, with trees in 90% shade having a 72% reduction in total phenolics. There was a significant shade by leaf age interaction. There was a decrease in total phenolic content with increasing leaf age except for those leaves whose development occurred before the experiment was started. The 1-week-old leaf had the highest phenolic content, while 4-week-old leaf had the lowest amount. The 5- and 6-week-old leaves that had been tagged prior to the onset of the shade treatments has similar phenolic content in all treatment. SLW significantly decreased with increasing shade and increased with leaf age. Results of this study indicate that light and leaf developmental stage are important factors in the total foliar phenolic content, but, once phenolics are synthesized, shading does not affect their content.
Cutting Production of Poinsettia Cultigens Grown in Central Florida
Authors: Wilfret Gary J.
Published: February 2019

Production of stock plants is essential for the asexual propagation of poinsettia, but variability exists among cultigens in the development of axillary shoots under high day/night temperatures of central Florida. Thirty-eight and 44 cultigens were grown during 1995 and 1996, respectively, and were evaluated for cutting production and subsequent growth of harvested cuttings. Plants were pruned twice prior to cutting harvest, with a projected cutting number of 21 in 1995 and 27 in 1996. Cuttings were graded into three groups based upon stem caliper and overall quality: #1, #2, and cull. Number of #1 cuttings/plant in 1995 ranged from 3.4 to 18.6, represented by `Cortez' and `Ball 838', respectively; a majority of the cultigens produced between 14 and 16 cuttings in the top grade. Number of usable (#1 and #2) cuttings ranged from 4.9 to 30.0, represented by `Cortez' and `Jolly Red', respectively, with a mean of 20.2. Stem caliper of cuttings measured 7 cm from terminal apex ranged from 0.55 cm of `Mikkel 520' to 0.91 cm of `Ball 838'. Cuttings of `Cortez' and `Red Splendor' had poor lateral development. During 1996, number of #1 cuttings ranged from 9.8 (`Picacho') to 22.2 (`Freedom'), with a mean of 16.6. Number of usable cuttings ranged from 14.2 to 31.9, represented by `Cortez' and `Spotlight Dark Red', with a mean of 25.3. Stem caliper ranged from 0.55 cm (`Ball 865') to 0.79 cm (`Supjibi'). Cuttings taken from plants of the `Cortez' series produced few, if any, laterals, while `Marblestar' and `Jolly Red' had up to 50% aborted axillary buds.
Introducing Tomcast and Action Thresholds for Processing Tomatoes in Western Kentucky
Authors: Rowell Brent , Nokes Sue , Meyer Annete , Bessin Ric , Nesmith William
Published: February 2019

Farmers' field trials conducted in western Kentucky counties in 1995 and 1996 showed that dramatic reductions in insecticide usage are possible using scouting and action thresholds. Five-acre plots were scouted and treated according to action thresholds while adjacent 5-acre plots were treated weekly with insecticides. Seven out of 10 insecticide sprays were eliminated, saving $65/acre for the 1995 season. There were no differences in yield, insect damage, or fruit quality between the scouted plots and the plots that were treated weekly. Assuming similar low pest populations in all 885 acres of the company's contracted fields, savings could have amounted to nearly $31,000 for 1995 after deducting scouting costs. There were no yield or quality differences from three test plots treated according to regularly scheduled applications and three plots treated according to action thresholds for insect pests and according to Tomcast predictions for fungal disease control in 1996. We have demonstrated the value of using Tomcast as an aid in making fungicide spray scheduling decisions for processing tomatoes in Kentucky. Although we were able to greatly simplify the Tomcast-CR10 datalogger interface program in 1996, there were still difficulties in getting information from the university-based computer to the company making spray applications. The company will be able to access the datalogger and obtain the information directly in 1997. The further analyses of “Skybit” satellite data collected in 1996 should also tell us whether this type of information might be used instead of a remote datalogger thus simplifying the process even further. We plan to build on the quick adoption of the Tomcast system and to make it sustainable by transferring “ownership” to the growers and processing company in 1997.
Effect of Buckwheat as a Flowering Border on Populations of Cucumber Beetles and Their Natural Enemies in Cucumber and Squash
Authors: Platt Jason , Caldwell John S. , Kok L.T.
Published: February 2019

Cucumber beetles Acalymma vittatum (Fab.) and Diabrotica undecimpunctata howardi (Barber) (Coleoptera: Chrysomelidae) are major pests of cucurbits, and biological methods are needed for their control. A floral border of buckwheat Fagopyrum esculentum (Moench) was planted perpendicular to Cucumis sativa L. `Arkansas Littleleaf' and Cucurbita pepo L. `Seneca' rows to assess effects on populations of cucumber beetles and the presence of natural enemies. Numbers of Diptera were used as an indicator of potential border attractiveness to natural enemies Celatoria diabroticae (Shimer) and Celatoria setosa (Coquillett) (Diptera: Tachinidae). Sticky traps and modified Malaise traps at increments from the border were used to monitor insect numbers. There was a quadratic decline from 19.5 Diptera in the border to 2.8 Diptera at 20 m from the border in June 1995 and linear declines from 14.8 and 14.2 Diptera in the border to 9.8 and 6.8 Diptera at 36 m in June and Aug. 1996, respectively. Numbers of striped cucumber beetles were variable, with a non-significant (P = 0.08) linear increase from 13.0 insects in the border to 17.5 insects at 36 m in June 1995, but quadratic decreases to 27 m in June, July, and Sept. 1996. Similar declines as distance from the border increased were found in numbers of tachinid flies (Diptera: Tachinidae) and Hymenoptera wasps and Pennsylvania leatherwings, Chauliognathus pennsylvanicus (Deg.) (Coleoptera: Cantharidae) and lady beetles (Coleoptera: Coccinellidae) in 1996. No meaningful effects on cucumber (1995) or squash (1995 and 1996) yield were found. Although the natural populations of Celatoria spp. were not high enough to achieve control, these results suggest that flowering borders may be useful as habitats for releasing natural enemies of cucumber beetles. Numbers of Pennsylvania leatherwings, Chauliognathus pennsylvanicus (Deg.) (Coleoptera: Cantharidae) showed a significant linear decline from 2.1 insects in the border to 0.2 insects at 36 m in June 1996, but no significant relationship was found in 1995 or in Aug. 1996.
Use of Genomic in Situ Hybridization (GISH) to Track Genetic Introgression in Onion
Authors: Hou Anfu , Peffley Ellen B.
Published: February 2019

Introgression of genes in species crosses can be observed morphologically in backcrossed or selfed progenies, but the phenotype does not give information about the movement of DNAs. Cytogenetic markers allow for visualization of specific DNAs in a genome. Few cytogenetic markers are available in onion to monitor the introgression of DNA in species crosses. Genomic in situ hybridization (GISH) provides a way to locate unique DNA sequences contributed by parents. We are using GISH to monitor the movement of DNAs from A. fistulosum into A. cepa. Results of experiments using A. fistulosum as probe DNA, and A. cepa as blocking DNA will be reported. Also presented are hybridization sites observed in F1BC3 progeny of the GISH.
Sprouting Characteristics of Microtubers, Minitubers and Field-grown Tubers of Three Micropropagated Potato Cultivars
Authors: Alsadon Abdullah A. , Knutson Kenneth W.
Published: February 2019

Tubers of three potato cultivars (Norland, Desiree, and Russet Burbank) produced on field-grown plants, greenhouse plants (minitubers), and in-vitro plantlets (microtubers) were kept at 5, 10, and 20°C. Sprouting was recorded throughout a 14- to 22-week storage period. The effect of cultivar, temperature, and tuber size closely followed previous research for field- and greenhouse-produced tubers. For in-vitro produced microtubers, the temperature effect followed an expected pattern, but the cultivar effect was different from that observed for field and greenhouse tubers. Two sprouting indices were developed (sprouting rate index and sprouting ratio index) to quantitatively describe the sprouting characteristics. Correlation coefficients suggest that the “sprouting ratio” method can be an acceptable alternative to the “sprouting rate” method.
Mineral Nutrient Content of Selected Turfgrass Species and Cultivars
Authors: McCrimmon James N.
Published: February 2019

Limited information is available concerning the mineral nutrient content of different turfgrass species. There is a need to develop sufficiency ranges for turfgrasses under various management programs. The nutrient concentration of a turfgrass provides an indication of the nutrient status and quality of the turf. A study was conducted to assess the mineral nutrient composition of selected turfgrass species and cultivars. Plant tissue samples of the following turfgrasses were collected: creeping bentgrass, Agrostis palustris Huds. `Penncross'; bermudagrass, Cynodon dactylon (L.) Pers. `NuMex Sahara', `Santa Ana', `Texturf 10', and Cynodon dactylon (L.) Pers. × Cynodon transvaalensis Burtt-Davy `Tifgreen', `Tifway'; perennial ryegrass, Lolium perenne L. `Medalist × Blend'; St. Augustinegrass Stenotaphrum secundatum (Walt.) Kuntze `Seville'; and zoysiagrass, Zoysia japonica Steud. `El Toro' and Zoysia japonica × Zoysia tenuifolia Willd. ex Trin. `Emerald'. Three samples of each cultivar were collected, washed with deionized water for 30 s, and dried in a forced-air oven at 70°C for 72 hr. Plant samples were analyzed for both macronutrient and micronutrient concentration. For the bermudagrass cultivars, the concentrations of potassium (K) and magnesium (Mg) were less than 20.0 g·kg-1 and 2.0 g·kg–1, respectively, and less than known sufficiency levels. `Tifway' and `Texturf 10' had lower nitrogen (N) concentrations than other bermudagrasses. `Penncross' and `Medalist X' had the highest N concentrations. Zoysiagrass had low concentrations of N, phosphorus (P), calcium (Ca), K, and Mg. The concentration of copper (Cu) was low for zoysiagrass and three bermudagrass cultivars (`Texturf 10', `Tifgreen', and `Tifway'). There were differences among the turfgrasses for manganese (Mn) and zinc (Zn) concentrations.
Combining Osmopriming and Biopriming
Authors: Warren J.E. , Bennett M.A.
Published: February 2019

Osmopriming has been shown to enhance seed performance by increasing germination rates and uniformity. Furthermore, these enhancements persist under less-than-optimum conditions, such as salinity, reduced water availability, and excessively high or low temperatures. Additional benefits include resistance to soil pathogens due to lower leachate levels and more rapid emergence. To augment these existing qualities, it would be advantageous to incorporate beneficial organisms that antagonize soil-borne diseases, combining the benefits of both systems into a single procedure. To accomplish this, processing tomato seeds (Lycopersicon esculentum Mill. OH8245) were bioprimed in aerated –0.8 Mpa NaNO3 at 20°C for 4 days, at which time a mixture of nutrient broth, a defoaming agent, and beneficial bacteria that has been adjusted to the same osmotic potential is added. The bacteria used, Pseudomonas aureofaciens AB254, has been proved to control Pythium ultimum on a variety of crop seeds. After 7 days the seeds are removed having been primed and colonized with 105 colony forming units (cfu)/seed. In the absence of pathogen pressure, osmoprimed and bio-osmoprimed seeds performed similarly improving overall germination by 40% after 3 days, as well as low temperature (10–15°C) germination. However, when these seeds were sown in soilless media inoculated with P. ultimum, osmoprimed and bio-osmoprimed emergence was 57% and 74%, respectively, showing the improvements that these biologicals can provide. Thermogradient table results, storage tests, cfu/seed, and pathogen control will be discussed.
Development of a Software Prototype to Teach Students Landscape Estimation
Authors: Henry Paul H. , Midden Karen , Thibeault Thomas
Published: February 2019

Development of this software was initiated after receipt of a USDA Higher Education Challenge Grant. The visually realistic software, which uses digital photography as a software base, will serve as an effective and cost-efficient means through which students in landscape horticulture programs can improve their skills in estimating job costs prior to entering the job market. The software will allow students, while in a classroom setting, to visualize a job site from various perspectives, determine the tasks (landscape installation/landscape maintenance) that must be accomplished, and calculate an estimate taking into account direct costs (materials, labor, equipment), indirect costs (overhead), and profit. The interactive nature of the software will allow students to compare their estimates with one of known accuracy generated simultaneously by the computer. Incorporation of this software into academic curricula should increase prospects of long-term success for the many students who plan to start their own landscape horticulture businesses soon after graduating from college and university programs.
The Effect of Four Composts on the Establishment of Vesicular–Arbuscular Mycorrhizae in Soilless Media
Authors: Miller Michelle , Linderman Robert , Fuchigami Leslie
Published: February 2019

The beneficial use of vesicular–arbuscular mycorrhizae (VAM) in mineral soils is well-documented, but little is known about the effect of soilless mixes on mycorrhizal colonization of roots. Previous research indicates that mycorrhizal colonization is affected by pH, soluble salts, phosphorus levels, cation exchange capacity, percent organic matter, and some peats. No other research has been published, to our knowledge, on the role of commonly used horticultural composts and mycorrhizal establishment. This study examined four different composts for their effect on VAM establishment using onion roots as an indicator. The composts used in the study were vermicompost, spent mushroom compost, yard waste compost, and processed manure fiber. Plant growth parameters, phosphorus (P) levels and rate of desorption, and microbial populations were analyzed in relation to the percent of VAM colonization of the roots. Significant differences were found in percent VAM colonization between composts. The primary factors influencing VAM colonization were the initial levels of P in the blends and the rate and amount of P released. The experiment raised questions about the balance between mineralized P and organic P in composts and their effect on VAM fungal spore germination.
The Effect of Soluble and Slowly Soluble Phosphorus Supply on the Growth of Three Citrus Rootstocks in a Composted Pine Bark Substrate
Authors: Lea-Cox John D. , Smith I.E.
Published: February 2019

Pine bark and peat-based substrates have been shown to have low-phosphorus (P) fixation capacity and high leach-potential, similar to that occurring in high-organic soils lacking in inorganic colloids. A long-term greenhouse experiment was conducted where three rootstock species of varying growth rate, Citrus jambhiri Lush.(RL), Citrus reshni Hort. ex Tan. (CM), and Poncirus trifoliata L. × Citrus sinensis L. (Osbeck) (CC), were grown in 3-L containers in composted pine bark, amended with three forms of P. Two slowly soluble forms (Calmafos and MagAmp) and soluble single superphosphate were incorporated at 0 (control), 200, 400, and 800 g P/m3, in a completely randomized block design (n = six plants). A split fertigation treatment of P at 50 mg·L–1 vs. No P was superimposed on the design (n = 3). Despite significant (P > 0.01) differences in P availability in the substrate after 380 days, particularly between liquid P (μ = 65 mg·L–1) vs. no liquid P (μ = 15 mg·L–1), differences in leaf analysis of seedlings after 235 days showed little significance (2.2 vs. 2.7 mg·g–1). To avoid excessive leaching of P from pine bark substrates, it therefore appears that slow-release forms of P are adequate to maintain relatively high growth rates of citrus stock without supplemental P fertigation.
Effects of Photosynthetic Photon Flux, Photoperiod, and CO2 Enrichment on the Growth and Morphogenesis of Lettuce Plug Transplants
Authors: Kitaya Yoshiaki , Niu Genhua , Ohashi Maki , Kozai Toyoki
Published: February 2019

Artificial lighting is widely used in controlled environment plant production to enhance plant growth and quality. However, high light intensity with artificial lighting is costly, and often causes increase of leaf temperature and, thus, leaf burn. We investigated the effects of photosynthetic photon flux (PPF) and photoperiod on the growth and morphogenesis of lettuce plug transplants under ambient and enriched CO2 levels. Three days after seeding, the plants were cultured under four PPF levels (100, 150, 200, and 300 μmol·m–2·s–1), two photoperiods (16 and 24 hr), and two CO2 levels (400 and 800 μmol·mol–1) for 18 days in growth chambers. Light source was fluorescent lamps. The air temperature around the plants was kept at 20°C. The results showed that dry weight of the plants increased linearly as PPF and daily integrated PPF (product of PPF and photoperiod) increased under both CO2 levels. At the same daily integrated PPF, higher CO2 level and longer photoperiod led to higher dry weight of the plants. CO2 enrichment increased significantly dry weight of the plants. The ratio of T/R and specific leaf area of the plants decreased quadratically as daily integrated PPF increased under both CO2 levels. The ratio of leaf length to leaf width of the plants decreased quadratically as PPF increased under the two photoperiods and CO2 levels.
Influence of Ambient UV Radiation on Growth and Flavonoid Concentration of `New Red Fire' Lettuce
Authors: Krizek Donald T. , Britz Steven J. , Mirecki Roman M.
Published: February 2019

The influence of ambient UV radiation on growth and flavonoid concentration of Lactuca sativa L. (`New Red Fire' lettuce) was examined. Plants were grown outdoors for 31 days from seed in window boxes covered with one of three different UV filters—UV transparent tefzel (10%T, 245 nm), UV-B-absorbing polyester (10%T, 319 nm), or UV-Aand UV-B-absorbing Llumar (10%T, 399 nm). Plants were grown in plastic pots filled with vermiculite and subirrigated with nutrient solution. Lettuce plants grown in the absence of solar UV-A and UV-B radiation showed a significant increase in leaf number and biomass of tops and roots as compared to those grown under ambient UV-A and UV-B. They also had a lower concentration of flavonoids and other UV-absorbing substances at 270, 300, and 330 nm (on both an area and on a dry-weight basis). These findings should be of interest to researchers involved in protected cultivation because the transmission of UV-B radiation is greatly attenuated by standard greenhouse glass. Our results also have implications for human nutrition, since bioflavonoids are important as antioxidants.
Studies on in Vitro Culture of the Australian Fan Flower, Scaevola
Authors: Bhalla Prem L. , Tozer Katherine
Published: February 2019

Plants of genus Scaevola (family, Goodeniaceae), commonly known as “fan flowers,” are mostly endemic to Australia. Commercially popular species are Scaevola aemula, S. albida, S. striata, and S. phlebopetala. These plants are used as ground covers in Australia and as hanging baskets, window boxes, and garden bed plants in Europe and America. Two aspects of in vitro culture of Scaevola are reported here; micropropagation and direct shoot regeneration. A number of commercially available cultivars of S. aemula, S. phlebopetala, S. striata and wild-collected S. phlebopetala, S. glandulifera, S. hookeri, and S. ramonissima were used for micropropagation experiments. Micropropagation medium contained salts, vitamins, L-cysteine, sucrose, and agar. Tissue-cultured shoots were rooted in hormone-free medium. A high survival percentage (>95%) was obtained when plants were transferred to soil under glasshouse conditions. Results on in vitro shoot induction and regeneration response of leaf, stem, root, node, and flower explants of two horticulturally important species of the Australian fan flower, Scaevola aemula and Scaevola striata arealso presented. Of all the explants tested, node explants of these species were the first to respond in tissue culture. Maximum number of shoot induction and regeneration was achieved from node explants of Scaevola aemula and node and stem explants of Scaevola striata. More than 95% of the regenerated shoots were rooted on the medium supplemented with 4 mg/L of IBA. The significance of above findings in assisting breeding program for new horticultural desirable cultivars of Australian fan flowers will be discussed.
Growth Response to Orchard Replant Disorders in Some New Malus Rootstocks
Authors: Isutsa Dorcas K. , Merwin Ian A. , Brodie Bill B.
Published: February 2019

Orchard replant disorder (ORD) is a widespread soilborne disease complex that causes stunting and poor establishment of replanted fruit trees. Chemical and cultural control of ORD provide effective, but short-term, control. More-sustainable strategies would involve ORD-resistant rootstocks not yet identified in apple. We tested `Bemali', G11, G13, G30, G65, G189, G210, and G707 clones from the apple rootstock breeding program at Geneva, N.Y., for their response to ORD in a composite soil collected from New York orchards with known replant problems. Clones were tested in the greenhouse in steam-pasteurized (PS), or naturally infested field soils (FS) with about 900 Pratylenchus penetrans and 150 Xiphinema americanum per pot. Plant dry mass, height, root necrosis, and nematode populations were determined after 60 days under optimal growing conditions. Stunting, reduced plant dry mass, and root necrosis were more severe in FS than in PS for most of the clones (P ≤ 5%), but G30 and G210 were substantially more tolerant to replant disorder than smaller ones, but this toleratnce might not be sustained in fields with greater or more prolonged nematode infestations. There is sufficient variation in apple rootstock resistance or tolerance to ORD to suggest that genetic resistance may be identified and developed for better management of orchard replant problems.
Colchiploidy Identification of Sections of Shoot Apices in Apple in Vitro
Authors: Shi Yinping , Wang Qiangsheng , Zhou Guangfang , Sui Congyi
Published: February 2019

Plant mutation induced with colchicine, disturbance of chimeras has long been unsolved. Authors used embryo culture in vitro induced with colchicine for inducing genome of embryonic cells of diploid apple to be doubled, cell doubled differentiated into adventitious shoots, and then were culture into plantlets. By morphological preselection, plants induced hundreds of genotypes had been obtained. To identify ploidy variation of three histogenic layers of shoot apices, sections of shoot apices of 284 plants were identified. Two-hundred-forty-nine tetraploid plants were selected. Entire mutants accounted for 98%, chimeras 2%. This proved that induction in vitro could indeed eliminate disturbance of chimeras and was a new induction technique simply and effectively. Accurate rate of morphological preselection was confirmed by 87.7% by sections of shoot apices. The identification of ploidy of mutated plants of apple in vitro induced with colchicine, the method of combining morphological preselection with sections of shoot apices had advantages over that of chromosome count. First, the method is simple, saving time and labor, with a high success rate and reliable results. Second, whether the mutated plants were chimeras and chimera structures could be known. Main criteria of identifying ploidy by sections of shoot apices are the size of cells, nuclei, and nucleoli and numbers of nucleoli of three histogenic layers of shoot apices. Morphological characters of tetraploid were dumpy, thick, and strong stem with short internodes; small petiole angle; broad-round thick leaves with dark green color; round leaf base; thick and sharp-pointed sawteeth; protruding and clear main vein.
In Vitro Conservation of Wild Pear (Pyrus syrica) in Jordan
Authors: Shibli Rida A. , Ajlouni M. , Jaradat A. , Shatnawi M.
Published: February 2019

Some factors that affect the in vitro conservation of wild pear (Pyrus syrica) microshoot cultures were studied. Sorbitol and mannitol at 0.2 to 4.0 M reduced growth significantly and extended the subculture intervals to 5 months when cultures where kept at 15°C. Increasing sucrose to 12% in the medium was not highly effective and the subculture intervals did not exceed 3.0 months. After 2 years of maintaining cultures on slow-growth medium, cultures grew slowly when transferred to fresh control medium. Shoots started to proliferate after three subcultures (6.0 weeks apart) on medium containing 1.0 mg/L BA and 0.1 mg/L NAA. New microshoots were rooted on medium containing 2.0 mg/L IBA and rooted microshoots gave 90% survival when acclimatized ex vitro under intermittent mist.
Somatic Embryogenesis in Commercial Crops—An Overview
Authors: Thomas Joseph , Sreedhar D. , Murali S. , Jose S. , Krishnan K.Gopal , Salama P.K. , Sayee V. , Bagyalakshmi B. , Narendran M. , Lokeswari T.S.
Published: February 2019

Many researchers regard somatic embryogenesis as a system of choice for in vitro propagation of superior varieties of crops such as coffee, mango, datepalm, and rose. While there are advantages, commercialization has not been possible so far in coffee, mango, and rose. The work highlights some reasons for this and feasible alternatives. We have established somatic embryogenesis in four elite Indian arabica coffee genotypes. Plantlets (3500) of all the four varieties are now being field-evaluated. The cost of producing these propagules is 15 times the seedling cost at present. A major constraint is the long time (6 months) needed to reach the five-leaf stage in vitro prior to release for acclimatization. This period can be reduced to 2 months using exvitro development after the two leaf stage. There are many reports of somatic embryogenesis in mango. Results on establishing free-living plantlets have not been encouraging.We found a number of abnormalities in the shape of the somatic embryos in cv. Rumani. However, except for the “rod”-shaped ones (that lacked cotyledonary expansion), all embryos germinated satisfactorily (75% rooting).We have encouraging results in reducing the time required to generate suitable plantlets for field acclimatization and in standardizing the procedures for grafting. Our laboratory has developed methods for ex vitro germination of mature embryos in datepalm,which yield more numbers of free-living plantlets (50%–60%) in only 3 months with an average of four leaves per plant. This compared favorably with in vitro germination that takes 6 months and produces plantlets with one or two leaves only. A novel protocol for obtaining somatic embryogenesis in rose from petal derived calli was developed by us (Murali et al., 1996). The number of embryos induced was too low for commercial application. [Murali et al., 1996. Euphytica 91:271–275].