bluuebunny/crossref_metadata_2025 huggingface dataset:
(245) Oryzalin Use on Buddleja to Facilitate Interspecific Hybridization
Authors: Dunn Bruce L. , Lindstrom Jon T.
Published: February 2019

Ploidy level and fertility status are often the two biggest barriers a breeder must overcome when trying to incorporate novel characteristics among related taxa. This study was aimed at developing an efficient chromosome doubling method for Buddleja L., commonly known as butterfly bush, with the goal of equalizing the ploidy level and restoring the fertility of a diploid (2n=38) F1 interspecific hybrid that has a unique orange color but happens to be sterile. This method would ease the crossing of the hybrid to the tetraploid (2n=76) B. davidii Franch. cultivars commonly found in the industry. An antimitotic treatment of oryzalin was tested on 02-25-142 (B. madagascarensis Lam. × B. crispa Benth.) in vitro using nodal sections. A factorial of varying concentrations [3, 5, and 7 μM (micromolar)] by different exposure times (1, 2, and 3 day) plus controls was set up. Oryzalin appeared to be an efficient agent for chromosome doubling in Buddleja. Significant differences in the number of polyploids were not seen between chemical concentrations and exposure times. However, higher chemical concentrations and exposure times did have a significant effect on the number of nodes that survived tissue culture. Increased leaf size and color, stem thickness, shortened internode length, and upright growth habit were all good early phenotypic indicators of polyploidy induction as later confirmed by flow cytometry. Significant increases in pollen viability accompanied chromosome doubling as crosses between 02-25-142 × B. davidii cultivars produced viable seedlings.
(57) Growth and Phenology of Lagerstroemia Hybrids in South Mississippi
Authors: Knight Patricia R. , Anderson John M. , McLaurin Wayne , Coker Christine
Published: February 2019

Lagerstroemia indica ×fauriei `Tonto' and `Sioux' were planted in Mar. 1995. All other cultivars were planted in Oct. 1985. Plants were planted into a Ruston sandy loam on a 12 × 12 ft (3.7 × 3.7 m) spacing. Trees were pruned to develop multiple trunks. Trees are pruned annually in winter to remove any limbs smaller than 0.6 cm in diameter. Pruning cuts are made 6–8 in (15.2–20.3 cm) above prior cuts. Severe pruning is performed every 5 years. Trees were evaluated at 2-week intervals during the flowering season to determine total length of flowering and duration of good to superior flowering. Growth indices (height + width + perpendicular width)/3 were recorded after plants were dormant. Total days of flowering and floral display (0–5 with 0 representing no flowers and 5 representing superior flowering) were rated. `Muskogee' had the greatest growth index after the 2004 growing season. `Seminole' had the least. However, `Seminole' had the greatest number of flowering days. `Biloxi' had the fewest flowering days. `Tonto' had the most good to superior flowering days, while `Tuskegee' and `Muskogee' had the fewest. In 2005, `Muskogee' again had the greatest growth index, while `Sioux' had the least. `Yuma' and `Seminole' had the greatest number of flowering days, and `Biloxi' again had the fewest. `Tonto' again had the most good to superior flowering days, while `Biloxi' and `Acoma' had the fewest.
(60) Establishment and Growth of Ginger Lilies Under a Sustainable Agroforestry Production System with Moringa in the U.S. Virgin Islands
Authors: Arancibia Ramon , Palada Manuel , Thetford Mack , Jose Shibu
Published: February 2019

Specialty cut flowers may be suited to sustainable production system in the tropics and an agroforestry approach was developed to add a commercial value to unused forest areas. Ginger lily (Alpinia purpurata), a specialty tropical cut flower, was planted under a sustainable alley cropping system with moringa (Moringa oleifera), to evaluate the biophysical interactions between system components. Moringa trees were planted in rows 5 m apart and were 5 years old at the time ginger lilies were planted on 1 June 2005. Two rows of ginger lilies spaced 0.6 m in row and 1.7 m between rows were planted on a 1-foot-high bed between moringa rows when trees were about 6 m tall. Alley plot length was 10 m. After a month, plant establishment was 96%. In July, the moringa trees were pruned down to 1.5 m and the biomass (foliage) was used as green manure. Ginger lilies were also mulched with straw. Plots were gradually shaded as moringa shoots developed reducing the photosynthetic photon flux to 40% of direct sun light in September and to 15% four months later. Six months after planting, height and number of shoots in shaded ginger lilies were 58% and 30% of plants in full sun, respectively. Ginger lilies began to flower 5 months after planting in the sunny plots, but no flowers were produced after 7 months in the shady plots. Since soil and tissue nitrate-N was the same between treatments, moringa biomass appears to be insufficient to increase the nutrient status of the crop. In addition, the low light intensity in the alley appears to be suboptimal for growth and production of ginger lilies.
(316) Simulation Study of the Competitive Ability of Erect, Semi-erect, and Prostrate Cowpea Genotypes
Authors: Wang Guangyao , McGiffen Milton E. , Lindquist John L. , Ehlers Jeff D. , Sartorato Ivan
Published: February 2019

Ecophysiological simulation models provide a quantitative method to predict the effects of management practices, plant characteristics, and environmental factors on crop and weed growth and competition. The INTERCOM interplant competition model was parameterized, calibrated by monoculture data for three cowpea (Vigna unguiculata) genotypes that differed in growth habit, common sunflower (Helianthus annuus), and common purslane (Portulaca oleracea), and used to simulate competition of cowpea cover crops with sunflower or purslane. The simulation results were compared with observations from field competition experiments in 2003 and 2004. INTERCOM did not simulate biomass production and leaf area index (LAI) of cowpea and purslane well, probably due to a lack of published data on purslane physiology. INTERCOM simulated the competition of cowpea genotypes and sunflower accurately. The simulation model of cowpea and sunflower at two densities was used to study the effects of cowpea growth habits on final biomass production of cowpea and sunflower. The model suggested that the erect growth habit was more competitive than the semi-erect and prostrate growth habits when cowpea genotypes were grown with sunflower. Cowpea leaf area distribution was important to higher cowpea biomass production, while cowpea height growth was important to reduce sunflower biomass.
(318) The Flat Bed Scanner as a Close-up Digital Camera
Authors: McConnell James
Published: February 2019

A flat bed scanner can be used as a high-resolution digital camera with close-up capabitlities for photographing plant material such as leaves, flowers, and plant pests. The scanner is very useful as a diagnostic and instructional tool that is more portable and less expensive than a camera and dissecting microscope. The quality of the images can be very good and can be enhanced in post-production using image editing software. The main disadvantage is the shallow depth of field, which requires the object be on a single plane.
(322) Development of a Web-accessible Germplasm Collection Database Using Public Domain Software Tools
Authors: Villordon Arthur , Njuguna Wambui , Gichuki Simon , Ndolo Philip , Kulembeka Heneriko , Jeremiah Simon , LaBonte Don , Yada Bernard , Tukamuhabwa Phinehas , Mwanga Robert
Published: February 2019

Web-based information delivers real-time or near-real-time data to clientele and other stakeholders. Although proprietary methods are available for interactively searching and updating databases through web interfaces, these methods generally require varying costs to maintain licensing agreements. The availability of publicly available software that require minimal or flexible licensing costs provide a cost-effective alternative to institutions that are considering access to databases via a web-accessible interface. For example, if a current web server is already configured to support hypertext preprocessor (PHP) scripts and MySQL databases, all that needs to be installed is a form script to allow the searching, inserting, and deleting of records. We describe procedures, software, and other applications that we used to develop a publicly accessible web interface to an experimental database of representative sweetpotato accessions in Kenya. The web address of this database is http://www.viazivitamu.org. This site also contains links to sweetpotato collection sites in Kenya, Tanzania, and Uganda graphically shown using a public domain GIS viewer. This demonstrates that public domain web-based tools can be configured not only to support collaborative activities among researchers in various locations, but also to provide relevant data to clients and other stakeholders.
(0) A Website of Horticulturally Important Plants on the University of Hawaii Campus
Authors: Kobayashi Kent D. , Kaufman Andrew J. , Ohama Allison A.
Published: February 2019

The University of Hawaii at Manoa campus offers a rich diversity of plants for students, university personnel, and the public. Although providing botanical facts, a current university web site and an arboretum brochure about campus plants lack horticulturally related information. By highlighting the unique horticultural plants on campus, a web site would provide valuable information on the uses, care, and propagation of these plants. The purpose of this project was to develop a web site featuring horticulturally important plants on campus. The home page explains why plants are beneficial in interior spaces. Other sections of the web site include basic plant care, plant selection, plant names, and plant pictures. Basic plant care covers planting media, containers, watering, lighting, fertilizing, pruning, propagation, and pest control. Users can select plants using two criteria—lighting in the plant's desired location (low, medium, and high) and low plant maintenance. Information on a specific plant is accessed by common name, scientific name, or a plant's picture. Each plant's web page provides details on its background, care, and propagation. By emphasizing the important horticultural plants on campus, this web site helps students, university personnel, and the public select and grow plants for their dormitories, apartments, offices, and homes. In addition, users gain knowledge about the lush landscape environment on campus. Lastly, the web site enhances the learning experience of students in horticulture and botany courses, serves as a resource for K–12 students for their visits to the campus to learn about tropical plants, and aids tourists in planning a more informative visit to campus to see the plants they learned about on the web site.
(247) Identification of Molecular Markers Associated with Carotenoid and Tocopherol Variability in Broccoli
Authors: Kobira Kanta , Ibrahim Khalid , Jefferey Elizabeth , Juvik John
Published: February 2019

Considerable epidemiological evidence exists on the association between consumption of antioxidant-rich vegetables and incidence of chronic diseases, including cancer and cardiovascular disease. Broccoli (Brassica oleracea L. sp. italica) florets are relatively abundant sources of antioxidants, and potentially amenable to genetic manipulation to enhance this vegetable's health-promoting properties. This investigation focuses on the identification of chromosomal segments in the nuclear genome of broccoli associated with antioxidant carotenoid and tocopherol variability. A broccoli F2:3 population consisting of 163 families derived from a cross between two parents (VI-158 and BNC) and previously mapped with 62 polymorphic SSR and SRAP marker loci was evaluated for carotenoid and tocopherol concentration in floret tissue over two growing seasons. Significant differences were observed among F2:3 family means for concentrations of lutein (10-fold difference between the lowest and highest family), beta-carotene 17-fold), alpha-tocopherol (8-fold) and gamma-tocopherol (6-fold). On a concentration basis, beta-carotene, lutein, alpha-tocopherol, and gamma-tocopherol were the most abundant antioxidant forms in broccoli. Heritability estimates of primary phytochemicals ranged from 0.35 to 0.38, 0.40, and 0.44 for beta-carotene, alpha-tocopherol, gamma-tocopherol, and lutein, respectively. Composite interval mapping (CIM) identified two quantitative trait loci (QTL) associated with carotenoid variability on two linkage groups and five QTL associated with tocopherol variability on four linkage groups. The QTL identified in this study have potential for use in marker-assisted crop improvement programs to develop elite germplasm designed to promote health among the consuming public.
(248) Does Harvesting Stage Affect Bulb Quality in Spring-sown Onions?
Authors: Kamal Neel , Cramer Christopher S.
Published: February 2019

Onions grown in New Mexico are currently harvested manually at 80% tops down (TD). Mechanical harvesting is a matter of urgency for growers in order to remain competitive and to reduce their cost and time. The objective of this study was to find the effect of different harvest stages on bulb quality. Twelve different onion cultivars were sown in Feb. 2004 in Las Cruces, N.M. The experiment was laid out in split-plot design with four harvest treatments based on physiological maturity—20% TD, 80% TD, 1 week after 80% TD, and 2 weeks after 80% TD as whole plots, with cultivars as sub-plots. After curing, data on harvest date, bulb diameter, height, firmness, number of growing points, average center diameter, fleshy scale number, and scale thickness were collected. Maximum number of scales was observed when bulbs were harvested 2 weeks after 80% TD, while average scale thickness was greatest when bulbs were harvested 1 week after 80% TD. Significant treatment by cultivar interaction was observed for bulb firmness. Cultivars Cimarron, Sierra Blanca and NMSU 04-52-2 produced firmer bulbs in all treatments, while NuMex Casper, NuMex Jose Fernandez and NuMex Centric produced firmer bulbs than others, only at 20% TD. Maximum bulb firmness was observed in NMSU 04-28 and NMSU 03-52-1 than others, when harvested 1 or 2 weeks after 80% TD. Overall, bulbs harvested 1 to 2 weeks after 80% TD exhibited firmer bulbs with more scales and greater scale thickness.
(249) Partition Variability in Sweet Corn and Broccoli Carotenoid and Tocopherol Content
Authors: Ibrahim Khalid , Juvik John
Published: February 2019

Vegetables are a rich source of dietary carotenoids and tocopherols, powerful antioxidants that have the capacity to protect cells against oxidative damage caused by free radical reactions. There is evidence for a negative correlation between the incidence of certain types of cancer, age-related macular degeneration, cataract development, and cardiovascular disease with increased carotenoid and tocopherol intake. Development of elite vegetable germplasm with enhanced levels of these phytochemicals will potentially promote health among the consuming public. To assess the feasibility for genetic improvement in phytochemical content, it is necessary to partition the phenotypic variability into its component sources (genotype, environment, and genotype by environment interaction). To provide data for comparison and partition of phenotypic variation, 41 sweet corn and 13 broccoli genotypes were grown and harvested in one location for 3 years and analyzed for phytochemical content by HPLC. The most abundant form of carotenoids and tocopherols were lutein and gamma-tocopherol in sweet corn and beta-carotene and alpha-tocopherol in broccoli. Analysis of variance showed that, in sweet corn, the differences among genotypes described most of the phenotypic variation (76% for lutein, and 78% for gamma-tocopherol). Genotype by year interaction was a second significant factor, while variation affiliated with the year was found to be a minor component. In contrast, in broccoli, the three sources of variability contributed equally to describe the total phenotypic variation for beta-carotene and alpha-tocopherol. These results suggest that elite sweet corn and broccoli germplasm with improved carotenoid and tocopherol levels can be developed using conventional breeding protocols.
(260) Analysis of Fruit Shape Using Digital Photography
Authors: Wycislo Andrew P. , Karcher Douglas E. , Clark John R.
Published: February 2019

Quantifying fruit shape is challenging, particularly when measurements are made on segregating populations of plants that vary greatly in shape. Objective manual measurements can be performed on small samples of fruit, but this method is not feasible when dealing with larger samples or when shape variations are slight and continuous. Also, subjective rating scales can be utilized, but they are less effective when done by multiple raters due to varying descriptive standards among individuals. Therefore, we have developed a method to analyze digital images containing multiple fruits to characterize fruit shapes. Each segregant of a population of table grapes with parents of significant varying shapes was photographed and analyzed. Image pixels representing fruit were selected and evaluated for area and perimeter, which were subsequently used to calculate a shape factor and compactness value. This was a reasonably simple and quick method for quantifying grape berry shape, giving the researcher valuable phenotypic data in numerical form. This technology should be useful for shape characterizations of other fruits as well.
(261) The Use of Stem Cuttings to Determine Chilling Requirement in Blackberries
Authors: Carter P. Manjula , Clark John R.
Published: February 2019

Chilling requirement, (the number of hours below 7 °C necessary to break dormancy) has been shown to vary with genotype in blackberry (Rubus subgenus Rubus). Previous work has demonstrated that the chilling requirement of field-grown plants could be accurately determined from stem cuttings of lateral shoots taken at 100-hour intervals of chilling up to 1000 hours, by placing them in a mist chamber maintained at 26 °C with a daylength of 16 hours, and observing budbreak over a period of 5 weeks. This technique has previously demonstrated clear differences in the chilling requirements of thorny and thornless floricane-fruiting cultivars. In the current study, a comparison of floricane-fruiting and primocane-fruiting blackberries using the stem-cutting technique illustrated a lower chilling requirement associated with the primocane-fruiting trait. The use of the stem-cutting technique can be a simple and effective tool for assessing blackberry adaptation to different hardiness zones.
(264) Progress in Developing Non-melting-flesh Peaches for Fresh-market Use
Authors: Beckman Thomas , Krewer Gerard , Chaparro Jose , Sherman Wayne
Published: February 2019

The primary purpose of the three-way cooperative regional project involving the USDA, University of Georgia, and University of Florida, is to develop improved fresh-market peach cultivars for use in the moderate-chill areas of the southeastern United States. Since 1995, this project has concentrated on the development of non-melting flesh materials as an alternative to conventional melting-type cultivars. It is our belief that the slower softening, non-melting characteristic will allow growers to pick fruit several days later at a more mature stage, thus improving eating quality without sacrificing shipping ability. To date, this program has released three non-melting peach cultivars and is poised to release several more. Through our postharvest evaluations we have been able to demonstrate that these new releases and selections have equal, if not superior, firmness compared to current commercial melting-type cultivars, in combination with higher soluble solids and soluble solids/titratable acidity ratios. Compared to current commercial melting-type cultivars, the new non-melting releases and selections display superior red skin blush, fruit shape, and cropping ability. Moreover, they are of comparable size and have a significantly reduced incidence of split and shattered pits.
(265) DNA Sequence Variation within the Promoter of VvmybA1 Associates with Flesh Pigmentation of Intensely Colored Grape Varieties
Authors: Porret Naomi , Cousins Peter , Owens Christopher
Published: February 2019

Grapevine (Vitis vinifera L.) is one of our oldest domesticated crops and economically the most important cultivated fruit crop in the world. Cultivated grapes show substantial diversity in fruit color, including: varying shades of black, red, pink, grey, white, and types with pigmented berry flesh. The majority of V. vinifera cultivars only possess anthocyanin pigmentation in the skin of the berry (also known as teinturiers). However, some cultivars possess berries with intensely pigmented flesh as well as skin, which is often also associated with greater pigmentation of vegetative tissues. The genetic control and inheritance of fruit color in grapevine is poorly understood, despite evidence that the primary determination of anthocyanin production appears to be controlled by a single dominant locus in V. vinifera with white fruit being a recessive character. Recently, it has been shown that the presence of Gret1, a Ty3-gypsy-type retro-transposon in the promoter region of a myb-like regulatory gene is present in white-fruited cultivars of V. vinifera and that allelic variation in this gene associates with several qualitative classes of grape fruit color. It has been observed that the red-flesh berry phenotype is similarly controlled by a single dominant locus. Considering the association of variation in VvmybA1 with grape berry skin color, it was hypothesized that DNA sequence variation in VvmybA1 would also be associated with genotypes showing intensely pigmented berry flesh. In this study, we show that allelic variation in VvmybA1 associates with the teinturier phenotype both in a panel of accessions possessing red-flesh as well as in a population of full-sibs segregating for the red-flesh phenotype.
(197) E-beam Irradiation Influences Grapefruit–Drug Interaction-related Furocoumarins
Authors: Girennavar Basavaraj , Simpkins Sara , Jayaprakasha G.K. , Patil Bhimanagouda
Published: February 2019

Food and drug interaction has been under discussionm and specifically grapefruit and drug interaction has been under investigation, in recent years. Irradiation of food has multiple benefits in food preservation through several processes, such as sprout inhibition, disinfection, decontamination, delayed maturation, and sterilization. When ionizing radiation is passed through food, it may affect the functional components, including organoleptic characteristics. In addition to naringin, dihydroxybergamottin, paradisin A, and bergamottin, as well as their isomers, are considered putative bioactive furocoumarins present in the grapefruit juice, which interfere with the first pass metabolism of the drugs. These compounds inhibit the activity of CYP P450 3A4 and P-glycoprotein, which, in turn, will increase bioavailability of certain medications. In order to investigate the effect of pre-and postharvest practices on furocoumarins, `Rio Red' and `Marsh White' grapefruits were irradiated with 1, 5, and 10 kGys of e-beam. The irradiated fruit juice was analyzed for qualitative and quantitative changes in furocoumarins. Fifty milliliters of grapefruit juice was extracted with ethyl acetate three times and ethyl acetate extract was dried under vacuum and analyzed by HPLC. Irradiation at 1 kGys showed a decrease in the total content of dihydroxybergamottin, paradisin A, and bergamottin compared to 5 kGys, 10 kGys, and control. This project is based upon work supported by the USDA-CSREES under Agreement USDA IFAFS # 2001 52102 02294 and USDA # 2005-34402-14401 “Designing Foods for Health” through the Vegetable & Fruit Improvement Center.
(200) Inhibition of PAL, CHS, and ERS1 Transcription by 1-MCP
Authors: MacLean Dan D. , Murr Dennis P. , DeEll Jennifer R. , Kupferman Eugene
Published: February 2019

The ethylene antagonist 1-methylcyclopropene (1-MCP) was investigated for its potential impact on the transcription of key flavonoid biosynthetic (PAL and CHS) and ethylene perception (ERS1) genes during the postharvest storage of pear (Pyrus × communis L.). Optimally harvested red and green `d'Anjou' fruit were treated with 1 μL·L-1 1-MCP for 24 h at 0 °C to 1 °C, and subsequently placed in cold storage (0–1 °C, 90–95% RH). Fruit were removed every 21 days for 126 days, and evaluated for firmness, TSS, and ethylene and volatile production for up to 10 days (≈21 °C). Tissue samples were collected for Northern blot analysis and determination of flavonoid and chlorogenic acid content. PAL content increased during the 1-week simulated marketing period irrespective of storage duration, which coincided with an increase in respiration and ethylene content. Although it was still detectable, total PAL content was dramatically reduced by the 1-MCP treatment. CHS was abundant immediately after harvest and after removal from storage, but declined rapidly thereafter, and was not detectable after 1 week at room temperature. The 1-MCP treatment further exacerbated this decreasing trend in CHS content. ERS1 content appears to be stable throughout storage and the simulated marketing period, with levels lower in 1-MCP-treated fruit. These results suggest that 1-MCP significantly inhibits the transcription of key flavonoid and ethylene regulatory enzymes, possibly compromising the nutraceutical content of pear fruit. The increase in PAL with the concomitant decrease of CHS after removal from storage suggests a diversion of carbon from flavonoid compounds into simple phenols, such as chlorogenic acid.
(203) Responses of `Golden Delicious' Apples to 1-MCP Applied in Air and Water
Authors: Argenta Luiz , Fan Xuetong , Mattheis James
Published: February 2019

The efficacy of the ethylene action inhibitor 1-methylcyclopropene (1-MCP) applied in water to slow ripening of `Golden Delicious' [Malus sylvestris var. domestica (Borkh.) Mansf.] apples was evaluated in comparison with 1-MCP applied as a gas in air. The material was applied by dipping fruit in 1-MCP water solutions (0, 0.03, 0.3 or 3 μM) for 4 min, or by exposing fruit to 1-MCP gas (0, 0.01, 0.1 or 1 μL·L-1) in air for 12 h. Fruit were held in air at 20 °C for 25 days after treatment or stored at 0.5 °C in air for up to 6 months followed by 7 days in air at 20 °C. Application of 1-MCP in water or air delayed the increase in respiration and ethylene production associated with fruit ripening, and reduced the amount of fruit softening, loss of acidity and change in peel color. Treatments applied in water required a concentration 700-fold higher compared to those applied in air to induce similar physiological responses. Fruit responses to 1-MCP varied with treatment concentration, and the maximum effects were obtained at concentrations of 0.1 or 1 μL·L-1 in air and 3 μM in water. Peel color change was impacted less than retention of firmness and titratable acidity for some 1-MCP treatments. Treatment with 1-MCP was less effective for slowing peel degreening when treated fruit were stored at 0.5 °C compared to storage at 20 °C. In 1 of the 3 years of this study, fruit treated with 1-MCP and stored in air at 0.5 °C developed a peel disorder typified by a gray-brown discoloration that is unlike other disorders previously reported for this cultivar.
(282) Identification of MicroRNAs in Citrus
Authors: Fang Jinggui , Chao Chih Cheng T.
Published: February 2019

MicroRNAs (miRNA) are endogenous tiny RNAs (about 22 nucleotides in length) that can play important regulatory roles in plants and animals by targeting mRNAs for cleavage or involved in translational suppression. Based on the sequence conservation of many miRNA genes in different plant genomes, it is possible to identify miRNAs in citrus. Identification of miRNA is the prerequisite for understanding the miRNA function in citrus. Citrus is an important fruit crop in the world and the publicly available citrus EST databases are increasing. Thirty known miRNAs from Arabidopsis were used to search the citrus EST databases for miRNA precursors. Nine possible citrus miRNA sequences were predicted to have fold-back structures. The Northern results indicated most of the 26 Arabidopsis miRNAs are expressed ubiquitously in the leaf, young shoot, flower, and root tissues of Nules Clementine mandarin (Citrus clementina Hort. Ex Tan.) and Trifoliate orange (Poncirus trifoliata [L.] Raf.). Some miRNAs accumulated preferentially in different tissues.
(284) Factors Influencing Somatic Embryogenesis of Proembryonic Mass Suspension Culture in `Autumn Royal Seedless' Grape
Authors: Jittayasothorn Yingyos , Lu Jiang , Xu Xia , Thipyapong Piyada , Boonkerd Nantakorn
Published: February 2019

Biotechnology has great potential for grape genetic improvement. However, successful implementations of grape biotechnologies, such as transformation and in-vitro selection, are based on a high yield productivity of synchronized somatic embryos as well as an efficient single-cell regeneration system. Suspension culture has been known as an ultimate approach to provide those requirements. We recently developed the highly repeatable protocol for PEM suspension culture of `Autumn Royal Seedless' (Vitis vinifera L.). In a following experiment, three factors, including activated charcoal (AC), darkness, and full- or half-strength MS medium were tested for their impact on grape embryogenesis of PEM suspension cells. All three factors proved to be important for grape somatic embryogenesis. Darkness was the most-influenced factor among the three. After 4 weeks on full-strength MS medium plus AC, suspension cells mostly grew friable callus and somatic embryos were rarely observed under 16-h light conditions, whereas numerous somatic embryos were fully developed in darkness. Strength of MS medium and AC also affected grape somatic embyogenesis. In every combination tested, full-strength MS media was all superior to half-strength, which was more obvious under darkness. The AC had a positive effect for promoting of somatic embryogenesis.
(43) Salinity Tolerance in Herbaceous Perennials
Authors: Cabrera Raul I. , Rahman L. , Niu Genhua , McKenney Cynthia , Mackay Wayne
Published: February 2019

In this preliminary study, we evaluated the salinity tolerance of selected herbaceous perennials. Liners of Rudbeckia hirta `Becky Orange', Phlox paniculata `John Fanick', Coreopsis grandiflora `Early Sunrise', Lantana ×hybrida `New Gold' and Cuphea hyssopifolia `Allyson' were transplanted to 4-gal plastic containers filled with peat moss: pine bark: sand (3:1:1) medium amended with dolomite, Micromax and Osmocote 18-6-12 (at 2, 0.6, and 6 kg·m3, respectively). The plants were irrigated for 14 weeks with tap water containing 0, 1.5, 3, 6, 12, and 24 mM of NaCl: CaCl2 salt mixture (2:1 molar ratio). Increasing salt stress had differential effects on plant growth and quality, with Rudbeckia and Phlox being the most adversely affected even by the lowest salt treatment of 1.5 mM, with dry weight reductions of ∼25% compared to the controls. Conversely, Lantana and Cuphea tolerated extremely well salinity up to 12 mM, where dry weight reductions were less than 10% of the nonsalinized controls. The Lantana and Cuphea plants also presented the lowest leaf Cl accumulation with increasing salinity, whereas Coreopsis showed the highest Cl accumulations at any salinity level. Plots of leaf Cl concentration against dry weights showed steeply declining relationships for Rudbeckia and Phlox plants, confirming our observations and assessment that these species are to be considered salt-sensitive. Leaf Na accumulation is currently being analyzed.
(47) Herbicide Efficacy in Alternative Substrates for Container-grown Nursery Crops
Authors: Cochran Diana R. , Gilliam Charles H. , Fain Glenn , Wright Robert D.
Published: February 2019

This study evaluated the effects of nine alternative substrates on herbicide efficacy in container-grown nursery crops: 1) VT (pine wood chips hammer-milled to pass a 0.4-cm screen); 2) USDA (pine wood chips hammer-milled to pass a 0.64-cm screen; 3) AUC (Pinus taeda chipped including needles); 4) AUHM (AUC hammer-milled to pass a 0.48-cm screen; 5) 1 VT: 1 commercial grade pinebark (v/v); 6) 1 USDA: 1 pinebark (v/v); 7) 1 AUC: 1 pinebark (v/v); 8) 1 AUHM: 1 pinebark (v/v); and 9) 6 pinebark: 1 sand (v/v). Each substrate was amended with 6.35 kg of 17–6–12 (17N–2.6P–10K) control-release fertilizer, 2.27 kg of lime, and 0.89 kg micromax per cubic meter. Containers (8.3 cm) were filled on 15 June and three herbicides applied the next day: Rout (oxyfluorfen + oryzalin at 2.24 + 1.12 kg·ha-1), Ronstar (oxadiazon at 4.48 kg·ha-1) and a nontreated control. The next day, containers were overseeded with 25 prostrate spurge seed. Data collected included weed counts 30 and 60 days after treatment (DAT) and weed fresh weights at 60 DAT. Spurge occurred less in the two treatments of 100% pine wood chips followed by the AUC treatment. With spurge, the least weed fresh weight occurred with the USDA and AUC treatments. For example, at 30 DAT, spurge count was reduced by 33%, 40%, and 70%, respectively, when comparing VT, USDA, and AUC to pinebark: sand. Spurge fresh weight at 60 DAT followed a similar trend. With all of the substrates except AUHM, the addition of commercially used pine bark resulted in less weed control. Rout provided superior control followed by Ronstar and the nontreated control. These data show that control of prostrate spurge with commonly used preemergent applied herbicides may actually be improved with some of the alternative substrates currently being tested.
(49) Effects of Sowing Time and Tray Size for Production of Onion
Authors: Kwon Young-Seok , Cho Kwang-Soo , Im Ju-Seong , Lee Eung-Ho , Kim Won-Bae
Published: February 2019

Onions are a major vegetables in Korea. Short-day onions are grown in more than 95% in southern area of South Korea, and long-day onions are grown above 600-m altitude in the highlands. Onion cultivation in the highland areas has become difficult for farmers to obtain high income but stable production because of higher cost of seed and the intensive labor involved in production. Consequently, onion set culture by inexpensive onion seeds compared with expensive F1 seed has an advantage due to the higher proportion of marketable size bulbs. This study was conducted to find out the suitable sowing time and tray size for onion set culture in the highlands—the earlier the sowing time, the higher the number of onions set. The most appropriate sowing date and 1.6–3.5 g of onion set size was early to middle May, also with the highest distribution percentage. The highest set number (780.8 set/m2) of suitable onion set size (1.6–3.5 g) were harvested from the 288 trays, followed by 770 set from the bed (9 g/m2 of seed sowed), and (7/m2 of seed sowed) in the 406 tray.
(315) Learning Style Characteristics of On-line Horticulture Students
Authors: McKenney Cynthia
Published: February 2019

Learning style preferences may impact the success of on-line students in distance education courses. In this study, students from four on-line courses voluntarily completed a modified learning styles assessment instrument. Students attaining a course average of 90% or greater were considered to have excelled in their respective course. The results from these learners were compared to those of students with lower course averages. It was determined the students that excelled in these on-line courses were visual learners that preferred more images and diagrams than textual references and instructions. This was confirmed by their choice of a map rather than written instructions to a new location when compared to their peers. In addition, they were more likely to prefer a class where they used visual skills rather than auditory skills than their peers. The high-performing students were also more likely to lose points on a timed test due to not reading the written information carefully, while their peers with lower course averages were more likely to run out of time on the test. Recognizing these learning style differences may allow faculty to design courses that better suit their on-line students.
(140) Salt Tolerance Assessment of Kentucky Bluegrass Cultivars Selected for Drought Tolerance
Authors: Grieve Catherine M. , Bonos Stacy A. , Poss James A.
Published: February 2019

Six selections of Kentucky bluegrass (Poa pratensis L.) cultivars, selected based on their drought tolerance under field and growth chamber conditions in New Brunswick, N.J., were evaluated for salt tolerance based on yield and growth rates at eight soil water salinities [2 (control), 6, 8, 10, 12, 14, 18, and 22 dSm-1] from Apr. to Sept. 2005 in Riverside, Calif. Cultivars Baron and Brilliant were selected as drought sensitive and `Cabernet', `Eagleton', and `Midnight' were selected as drought tolerant. A Texas × Kentucky bluegrass (Poa arachnifera × Poa pratensis) hybrid selection (identified as A01-856) developed for improved drought and heat tolerance was also included. Vegetative clones were established in a randomized complete-block design with three replications, each containing 11 clones. Cumulative biomass and clone diameters were measured over time to evaluate relative yields and growth rates for the six cultivar selections. Based upon maximum absolute biomass production as a function of increasing EC, the order of production was `Baron' > `Brilliant' > `Eagleton' > `Cabernet' ≥ `Midnight' > A01-856. Yield relative to the non-saline control (2 dSm-1) for each cultivar was similar, except that the differences between cultivars were less pronounced, and `Baron' slightly outperformed `Brilliant'. Clone area expansion rates were analyzed with a phasic growth model and beta, the intrinsic growth rate of the exponential phase parameter, significantly varied with salinity. Ranking of cultivars, based on expansion rates, was similar to that based on cumulative biomass. Salinity tolerance in this experiment did not appear to be related to the observed ranking for drought tolerance.
(141) Leaf Abscisic Acid Accumulation in Response to Substrate Water Content: Variation Among Acer rubrum L. Genotypes
Authors: Bauerle William L. , Inman William W. , Dudley Jerry B.
Published: February 2019

Quantitative differences in leaf abscisic acid (ABAL) among four cultivars of red (Acer rubrum L.) and one Freeman maple (Acer × freemanii E. Murray) were investigated. This study tested the hypothesis that ABAL concentration can be used to compare the effects of water stress on the gas exchange response of five different maple cultivars, including four red maple genotypes, `Summer Red', `October Glory', `Autumn Flame', and `Franksred' (Red Sunset), as well as one hybridized Freeman maple genotype, `Jeffersred' (Autumn Blaze). Cloned genotypes of red and Freeman maple were subjected to two treatments: 1) irrigated daily to container capacity or 2) irrigation withheld for one drought and recovery cycle. Leaf abscisic acid concentration, gas exchange, and whole-tree sap flow measurements were conducted under both conditions. Over the course of the drought stress and recovery phase, net photosynthesis (Anet), stomatal conductance (gs), and transpiration (E) declined as ABAL and instantaneous water use efficiency (A/gs) increased. This study found that ABAL tracked gs and that stomatal responsiveness to substrate moisture deficit is likely mediated by ABA accumulation in leaf tissue. This research demonstrates a leaf-level physiological response to substrate volumetric water content that appears to depend on ABAL concentration. In addition, the evidence in this study indicates that ABAL may be used as a potential surrogate for the gs response to substrate water stress and could become part of a cultivar drought tolerance selection strategy for red and Freeman maple.
(145) Water Relations of Avocado in Response to Changes in Relative Humidity
Authors: Heath Robert L. , Mickelbart Michael V. , Arpaia Mary Lu , Fassio Claudia , Miller Ruby
Published: February 2019

Vapor pressure deficit (VPD) is the driving force for plant water loss. However, air relative humidity (RH) can be used as a surrogate for VPD. While plants can adapt to environments with varying RH, little is known about how they respond to sudden shifts in RH. Areas of Southern California can experience drastic shifts in RH, from 60% or greater to less than 20% in just a few hours. The effect of these shifts on avocado (Persea americana Mill.) tree productivity is a major concern to growers. We studied the effect of shifts in RH on `Hass' avocado leaf stomatal conductance (gs) and branch sap flow in trees grafted on Duke 7 clonal rootstock. Under many conditions, the avocado assimilation rate is governed by gs. When gs is high in morning (>150 mmol·m-2·s-1), the water loss generally leads to some stomatal closure in the afternoon (50% or more). Conversely, low morning gs results in a higher gs rate in the afternoon (10% to 20% stomatal closure). This relationship between morning and afternoon gs is intensified by a shift from high to low RH in the afternoon. Therefore, in a drier atmosphere in the afternoon, the afternoon depression in gs is greater, leading to an impaired assimilation capacity. We hypothesize that the afternoon decrease in gs is due to low root/shoot hydraulic conductivity since soil water is readily available. While it is possible that low hydraulic conductivity on gs is exacerbated at the graft union, sap flow of grafted trees in greenhouse studies was nearly equal to trees on their own roots (ungrafted); in fact, often the depression in the afternoon was less on grafted trees. This suggests that while avocado is not suited to areas with low RH, water flow through the roots could be an additional criterion in selecting improved rootstocks.
(146) Minimal Role of Ethylene on Leaf Abscission in Water-stressed Betula papyrifera Marsh.
Authors: Gu Mengmeng , Robbins James , Rom Curt , Choi Hyun-Sug
Published: February 2019

It has been observed that paper birch (Betula papyrifera Marsh.) has significant leaf abscission under mild to severe water stress. One-year-old paper birch seedlings were exposed to water deficit, ethylene, or inhibitors of ethylene action under controlled conditions to study water-stress induced leaf abscission. Exposing well-watered and water-stressed paper birch to 20 ppm of ethylene for 96 hours resulted in more than 50% leaf abscission regardless of plant water status, while water stress alone did not cause leaf abscission. However, the application of 1 ppm ethylene did not cause leaf abscission. Exposure to 1 ppm 1-methylcyclopropene or treatment with 0.1 mM of silver thiosulfate did not affect predawn water potential, gas exchange, and chlorophyll fluorescence. The measured evolved ethylene did not significantly increase in water-stressed paper birch prior to leaf abscission. Based on these observations, ethylene would appear to play a minor role in water-stress induced leaf abscission in paper birch.
(126) Morphology and Physiology of Sugar Transport in Apple Leaves
Authors: Reidel Edwin J. , Cheng Lailiang , Turgeon Robert
Published: February 2019

Sorbitol is the predominant phloem-translocated carbohydrate in apple. The pathway—either apoplastic or symplastic—of sugar transport from photosynthetic cells to the phloem is not established. Furthermore, the presence of absence of phloem loading has not been tested. This study characterized the morphology and physiology of sugar movement to the phloem in apple leaves. An electron micrographic survey of apple leaf minor vein morphology was performed. Plasmodesmata were abundant and found at the interfaces of each cell type from mesophyll to sieve elements, indicating a symplastic sugar pathway. We also tested for a phloem loading mechanism. First, 14C-labeled sorbitol and sucrose were introduced exogenously to leaf discs to determine if they are loaded into veins from the apoplast. Although leaf discs floated on a solution containing either sugar actively accumulated label, the labeling pattern was diffuse, with no accumulation in minor veins. The addition of the sulfhydryl reagent PCMBS to the leaf disc assay inhibited sugar uptake. We also attempted plasmolysis of apple leaf sections to measure the solute concentration difference between photosynthetic mesophyll cells and cells of the minor vein phloem. Apple leaf pieces fixed in a solution containing 1.5 mol/kg osmoticum did not plasmolyze. We conclude that although active uptake of both sorbitol and sucrose takes place in apple leaves, apoplastic phloem-loading is absent. Considering the high sugar concentration and the symplastic connectivity among leaf cell types, we propose that sugars are instead enter the phloem after moving down—rather than against—a concentration gradient.
(128) Effect of 2,4-DP Concentration on Fruit Drop Control and Maturation of `Braeburn' Apples
Authors: Garriz Patricia , Colavita Graciela , Alvarez Hugo , Blackhall Valeria
Published: February 2019

Apple fruit abscission shortly before harvest is a frequent, recurring problem, thereby reducing potential yield. The synthetic auxin 2 (2,4-dichlorophenoxy) propionic acid (2,4-DP) was evaluated for its effect on reducing fruit drop and influencing ripening of `Braeburn' apples, in the High Valley region of Río Negro, Argentina (38°56'S, 67°59'W). Thirteen-year-old apple trees grafted on MM 111 rootstock were sprayed on 4 Mar. 2005, at 162 days after full bloom (DAFB) with 2,4-DP at doses of 0.05% and 0.10% (v/v), applied with an airblast sprayer, until runoff. Each tree was trained to palmette and planted in a single row from north to south with spacing of 2.3–4.0 m. The following measurements were performed: a) accumulated fruit drop, twice per week and b) maturity indices, weekly. Samples of uniform-size fruits were assessed for maturity (n = 20 per date and treatment), from 167 (commercial harvest) to 195 DAFB. On 23 Mar. (at 181 DAFB), cumulative fruit drop for control treatment was 19.9%, whereas 2,4-DP significantly reduced it to 4.90% and 2.94% at 0.05% and 0.10% (v/v), respectively. Reduction in the drop was also significant later, and 2,4-DP at both doses controlled drop comparably. The synthetic auxin did not affect fruit quality and maturation, based upon flesh firmness, starch degradation, and soluble solids concentration. We conclude that 2,4-DP is an effective drop control compound and it is useful as a management tool to increase yield by reducing fruit abscission and to extend the harvesting window of `Braeburn' apples, since it does not affect ripening. Delaying harvest may provide flexibility for scheduling of labor, fruit processing and packaging, cold storage, and marketing.