bluuebunny/crossref_metadata_2025 huggingface dataset:
Activities of Free-radical Scavenging Enzymes during Apple Fruit Maturity, Ripening, and Senescence
Authors: Abbasi Nadeem A. , Kushad Mosbah M. , Endress Anton G.
Published: February 2019

Superoxide dismutase (SOD: EC 1.1.15.1.1) and peroxidase (POD: EC 1.11.1.7) activities were evaluated during maturity, ripening, and senescence of `Red Spur Delicious' (Malus domestica Borkh.) apple fruits. SOD and POD activities did not exhibit uniform changes during fruit maturity; however, during fruit ripening, activities of both enzymes increased significantly. During fruit senescence, SOD activity continued to increase, while POD activity declined by 24% to 50%. Fruit maturity at harvest significantly affected SOD and POD activities during the progression of ripening and senescence. SOD activity was significantly higher during ripening and senescence of fruits that were harvested at full and over-mature stages than in fruits harvested at early mature stage. In contrast, POD activity was lower in fruits that were harvested at full and over-mature stages than in fruits harvested at early mature stage. Increase in SOD and POD activities during fruit ripening suggest that these enzymes are actively involved in scavenging free-radicals generated during this developmental stage. However, the decline in POD activity during fruit senescence suggest a possible disruption of the breakdown of H2O2 free-radicals. This disruption may have contributed to tissue senescence and the induction of a physiological disorder called senescence scald.
Number of Open Florets on a Flowering Stem Influences Postharvest Life of Antirrhinum majus L.
Authors: Schroeder Kenneth R. , Stimart Dennis P.
Published: February 2019

Flowering stems from three commercial inbreds and their F1 hybrids of Antirrhinum majus L. were cut when the first eight basal florets opened. Tops of the stems were removed above the eighth floret and florets were removed leaving two, four, six, or eight open florets on a stem. A completely random design with 10 replications was used. Flowering stems were placed in plastic storage containers 35 × 23 × 14 cm (L × W × H) with 2.5 L deionized water for postharvest evaluation. Evaluation took place under continuous cool-white fluorescent light (9 μmol·m–2·s–1) at 24°C Postharvest life was determined as the number of days from cutting to discard when 50% of the open florets on a flowering stem wilted, turned brown, or dried. Results showed postharvest life increased as the number of open florets on a stem decreased. Mean postharvest life increased as much as 4.7 days when only two florets remained on a stem. These results indicate a direct relationship between number of florets on a cut flower stem and postharvest life.
Anatomy of Neck Tissue of Cut Roses as Affected by Bent-neck and Preservative Solution
Authors: Kim Young A. , Lee Jong Suk
Published: February 2019

To investigate the differences of anatomical structure of neck tissue between bent-neck and strong-neck flowers, scanning electron microscopy of neck tissue during senescence of cut rose flowers held in deionized water or preservative solution (3% sucrose + 200 ppm HQS + 0.1 mM ethionine) was observed. Lignins in xylem, phloem, and interfascicular cambium of neck were stained to red by phloroglucine. More lignin was formed in the phloem of neck in rose flowers held in preservative solution than deionized water. Neck strength of cut rose could be increased by increase of lignin content, and this would prevent bent-neck and extend vase life. Parenchyma cells in neck part of rose flowers held in deionized water had thinner cell wall and less starch grains at senescence than those of flowers held in preservative solution at day 7. These starch grains would be used as energy source of rose flowers and extend vase life. Globular crystals were observed in the inner part of cells and had shape of large thorny. These crystals were cumulated in cell walls, then would prevent the activity of cell wall decomposition or increase cell wall permeability.
Changes in Bent-neck, Neck Strength, and Water Balance According to Cultivars and Preservative Solutions of Cut Rose Flowers
Authors: Lee Jong Suk , Kim Young A.
Published: February 2019

Rose (Rosa hybrida) cvs. Red Velvet, First Red, Sonia, and Saphir stems harvested at bud stage were kept in deionized water or preservative solution (3% sucrose + 200 ppm HQS + 0.1 mM ethionine) at 21°C under continuous light (1200 lux). Vase life of `First Red' and `Saphir' was much longer than those of `Red Velvet' and `Sonia' held in deionized water. Severe bent-neck was observed in `Red Velvet' flowers held in deionized water in 8 days after harvest. Rose flowers held in preservative solution resulted in extended vase life and inhibited senescence and bent-neck in four cultivars. Neck strength of `First Red' and `Saphir' rose flowers having no bent-neck and long vase life was stronger than `Red Velvet' and `Sonia' having frequent bent-neck and short vase life. Neck strength was also increased by preservative solution. Faster changes of water balance to minus value were detected in the rose flowers held in deionized water than those held in preservative solution. `Red Velvet' flowers having much absorption of water but more transpiration caused a fast change to a minus value in water balance and early bent-neck. Cell sap pH gradually increased in petal and stem of rose cultivars during senescence. Cell sap pH of flowers held in distilled water were higher than those held in preservative solution. Increased cell sap pH of rose flowers caused rapid change to blueing and yellowing of petals.
Effect of Prestorage Treatments on the Vaselife of Fresh-cut Peony Flowers Held under Long-term Cold Storage
Authors: Gast Karen L.B. , McMillan Melinda
Published: February 2019

Peony flowers are among the few fresh-cut flowers that can be stored dry at cold temperatures for weeks and still produce a viable product for the marketplace. Devising new ways to extend that storage period could open new markets for peony growers. In the northern hemisphere, more peonies could be available for summer weddings, and in the southern hemisphere, red peonies could be used for Valentine's Day. Being able to control and extend the vaselife of peony flowers could also be useful for companies that freeze-dry peonies. Their production is limited by the length of their processing cycle and the size of their freeze dryer. Being able to extend their production season could make them more profitable. Three treatments were applied to peony flowers harvested in the colored bud stage before flowers where placed in cold storage, 2°C. An untreated control was included. Flowers were removed from storage every 2 weeks for 14 weeks. Vaselife and fresh weights were evaluated. Total nonstructural carbohydrate levels of the petals, leaves, and stems of the flowers are to be analyzed. Preliminary analysis of the data shows some treatment differences.
Effects of Silver Thiosulfate, Sucrose, and Calcium Nitrate on Vaselife of Ebenus cretica L.
Authors: Paralikas Apostolos A. , Vlahos J.C. , Papadimitriou M. , Loulakakis K.A.
Published: February 2019

Ebenus cretica, Leguminosae, an endemic perennial bush of Crete, is being studied as a potential new cut flower crop. Forty-centimeter-long spikes with two to three inflorescences and six to eight compound leaves were harvested from 5-year-old plants grown from seed at the farm of the TEI, when 1/3 of the florets had opened, and were treated with various preservatives. Flower quality was evaluated morphologically combined with measurements of chlorophyll content in leaves and anthocyanin in petals. Without any postharvest treatments, inflorescences held in a solution of 100 ppm 8-hydroxyquinone sulfate (HQS) in DI water had an average vaselife of 6.8 days. Pulsing with 0.6 mM silver thiosulfate (STS) for 2 h extended vaselife up to 8.4 days. However, when ethephon was added in the solution, vaselife was significantly reduced, causing leaf yellowing and flower senescence, which suggests sensitivity to exogenous ethylene. A solution of 0.2% Ca(NO3)2 prolonged vaselife by 2.7 days, whereas higher concentrations resulted in flower discoloration and decreased flower quality. Sucrose solutions of 0.5%, 1%, 2%, and 4% had no positive effect on flower longevity. Furthermore, the higher concentrations caused leaf yellowing and petal discoloration decreasing vaselife and quality of flowers compared to control. Samples of inflorescences were taken every second day for chlorophyll (a and b) and anthocyanin measurements. The concentrations recorded were highest in the 0.2% Ca(NO3)2 treatment and were significantly correlated to flower longevity. Results indicate that Ebenus cretica may be used as a cut flower crop; however, due to the genetic variability of the Ebenus plants, a breeding line should be developed before the crop reaches the floricultural market.
Organogenesis and Cormel Production from Callus Culture of Gladiolus cv. `Balady'
Authors: Al-Juboory Karim H. , Al-Naimi J. , Al-Amiry L.K. , Shibli R. , Skirvin R.M.
Published: February 2019

Callus was initiated from leaves of Gladiolus cv. `Balady' on MS medium containing 1.0 mg/L NAA, 0.1 mg/L 2,4-D, and 0.5 mg/L kinetin. Organogenesis from callus was induced on medium containing 0.5, 1.0, 1.5, or 2.0 mg/L of either BA, kinetin, or TDZ. TDZ was more effective and resulted in a higher percentage regeneration and regenerant number. The microshoots produced were then propagated in vitro and cormel production was studied. Maximum shoot number (25.1) was obtained on medium containing 1.0 mg/L TDZ without auxin supplements in liquid shaking culture. In vitro cormel formation was significantly enhanced by B-9 and paclobutrazol. Increased sucrose concentration (4% to 5%) proved the most effective for cormel formation. Optimal dormancy break was obtained by storing cormels at 5°C for 1 month or by soaking them for 5 sec with 50 mg/L GA3. In-vitro rooting was achieved on solid medium containing NAA, IAA, or IBA, with higher root number recorded on NAA-treated cultures. Rooted microshoots were successfully acclimatized for ex vitro conditions and grown in the greenhouse. Plants produced from in-vitro propagation showed similar morphological characteristics of plants propagated by direct corm planting in the greenhouse.
In Vitro Multiple Shoot Production of Medicago sativa
Authors: Yang Guochen , Kamp-Glass Marihelen
Published: February 2019

Multiple shoots were produced directly from each explant. BA, zeatin, or TDZ were evaluated on callus initiation, development, and shoot organogenesis. Callus production was promoted when BA or zeatin was added in culture medium. However, no shoots were produced from such calli. Multiple shoots were produced directly through shoot organogenesis from each seed explant when TDZ was added to culture medium. As many as 30 to 40 shoots were produced per seed explant in about 7 weeks from culture initiation. Different alfalfa cultivars were also tested. The established multiple shoot production protocol provides an efficient way to produce transgenic alfalfa plants, thus could significantly advance alfalfa genetic transformation.
Plant Regeneration from Cell Suspension Culture of Ulmus americana L.
Authors: Ling Jing-Tian , Sauve Roger J.
Published: February 2019

Leaf segments of greenhouse-grown Ulmus americana L. plants cultured on a Murashige and Skoog basal salts medium supplemented with 0.22 mg/L thidiazuron formed friable type of callus and regenerated shoots. This friable callus readily formed a cell suspension when the callus was placed in a liquid MS medium containing 2 mg/L 1-naphthaleneacetic acid and 1 mg/L 6-benzylaminopurine. Shoots were regenerated from 3-month-old suspension cell cultures after the suspension cells had been cultured on solid medium. Shoots developed roots on MS medium containing 0.1 mg/L indole-3-butyric acid. Intact plants were successfully established in soil.
Plant Regeneration from Hypocotyl of `King's Choice' Elm
Authors: Ling Jing-Tian , Zerit Henock , Sauve Roger J.
Published: February 2019

Seeds of Chinese elm cultivar King's Choice were collected from field-grown plants and germinated aseptically. Hypocotyl segments were excised from 2-week-old seedlings and cultured on Murashige and Skoog (MS) medium supplemented with TDZ alone or in combination with 0.05 mg/L NAA. At least 50% of explants produced shoots 4 weeks after culture initiation. At thidiazuron (TDZ) from 0.05 to 5.0 mg/L, the number of shoots/explant increased as concentration increased. Addition of 0.05 mg/L NAA stimulated shoot regeneration when TDZ concentration was 0.5 mg/L or less, but suppressed it if TDZ concentration was higher than 0.5 mg/L. Regenerated shoots elongated quickly on MS medium supplemented with 1 mg/L gibberellic acid and initiated rooting on MS medium containing 0.1 mg/L indole-3-butyric acid.
Somatic Embryogenesis of the Cedars of Lebanon (Cedrus libani)
Authors: Talhouk S.N. , Shmoury M. , Baalbaki R. , Khuri S.
Published: February 2019

Somatic embryogenesis offers a great potential for large-scale production of Cedrus libani, which is important not only as a forest tree, but also for the development of a timber industry. In an attempt to optimize conditions for embryogenic callus induction, we used zygotic embryos at different developmental stages as explants, compared different media, and used several hormone levels and combinations. Results indicated that post-cotyledonary immature embryos had highest induction efficiency. Four different media namely 1/2 MS, Durzan, Litvay's, and Von Arnold supplemented with similar hormone levels showed no significant difference in efficiency of callus induction. Induction frequencies of embryogenic callus from explants subjected to different hormone levels and combinations were dependent on the developmental stage of the explant.
Effect of Planting Dates and Variety on Maturity and Yield of Southernpea
Authors: Becker C.H. , Morelock T.E.
Published: February 2019

Southernpea (Vigna unguiculata) is a popular home garden, fresh-market, and processing vegetable in the southeastern United States. Processing schedules are normally controlled by planting the same variety at different dates. Difference in genetic maturity would allow growers to stagger harvest dates by planting different maturity peas on the same day and allow genotype to alter harvest dates. This procedure would allow growers to better utilize available soil moisture and optimum planting dates. Ten southernpea varieties and breeding lines representing early, medium, and late maturity were planted in Kibler, Ark., during the summers of 1994 and 1995. Five different planting dates were used. Flowering dates and days to maturity were recorded and plots were harvested for yield. Results indicate that relative days to maturity can be significantly shortened or lengthened by the time of planting. Varieties planted in early June or early August took longer to mature then when they were planted in late June or early July.
Specialty Potato Varieties in Pennsylvania
Authors: Orzolek Michael D. , Simpson Terry W.
Published: February 2019

Acreage of white potato production in Pennsylvania has steadily declined in the past 20 years, from ≈25,000 acres in 1976 to 18,000 acres in 1996. This decline in acreage has occurred mainly with potatoes used for chips, with a much smaller acreage loss for tablestock potatoes. The most common tablestock varieties on the market are round white or long russet varieties, which have been around for 30 to 50 years. However, the 90's consumer is more perceptive and creative with food choices, such that color, texture, and taste have become important characteristics in choosing new food items. Specialty new potatoes represent a relatively unexplored market with excellent potential for sales expansion in the fresh market and tablestock industry. Today's consumers are demanding more variety with respect to virtually all produce commodities and potatoes are no exception. Consumers demand different size, color, and taste of fresh vegetables, including potatoes. New specialty potato varieties (Yukon Gold is an example) are currently in demand by restaurants and some retail markets, and it appears that relatively high returns are possible with these specialty potatoes. Twenty-nine red, buff, or blue-skinned and white-, yellow-, purple-, or red-fl eshed potato varieties were planted in a replicated study at the Hort Research Farm, Rock Springs, Pa., in 1996. Yield and quality characteristics of these varieties will be presented along with some consumer acceptance/evaluation data collected from a local supermarket.
Effects of Plant Density, Row Arrangement and Cultivar on Fruit Size and Yield in Honeydew Melons
Authors: Brandenberger L.P. , Wiedenfeld R.P.
Published: February 2019

Melon growers in the Lower Rio Grande Valley of Texas have observed in the past that particular sizes of melons and the earliness of melons had a direct effect upon economic returns. A replicated study was carried out during two seasons to determine what specific effects plant density, row arrangement, and cultivar would have on fruit size and yield. The study combined six spacing treatments with three cultivars in a randomized design utilizing five replications on top of raised beds on 80-inch centers. Work was initiated by direct seeding and then thinning to the desired spacing interval in plots located in a commercial field. Plots were harvested by commercial harvesting crews. Results indicate that different plant spacings and honeydew cultivars can result in differences in fruit size, earliness, and returns/acre over different seasons and environments although spacing and cultivar acted independent of one another. Lower plant populations resulted in the production of larger fruit and higher plant populations resulted in the production of smaller fruit. Cultivar did affect the size of fruit produced, with some cultivars resulting in larger melons and others producing more small melons. In both seasons, the double-row 24-inch spacing resulted in an earlier harvest and exhibited a higher percent harvest for the first harvest in both years. Cultivar Sure 7050 was significantly later than either `Honeybrew' or `Morning Ice'. Returns/acre were significantly different between spacing treatments for a majority of harvests. The double-row 24-inch spacing resulted in the highest returns/acre. Both `Morning Ice' and `Sure7050' had significantly higher returns when compared to `Honeybrew'.
Yield and Plant Characteristics of Mint Germplasm in Virginia
Authors: Rangappa M. , Bhardwaj H.L. , Hamama A.A.
Published: February 2019

A collection of 35 mint (Mentha spp.) lines was evaluated during 1996 for fresh and dry yield, percentage of leaves, leaf moisture, and stem moisture to study suitability for fresh markets. These lines were categorized based on geographic origin (domestic vs. foreign), ploidy level (diploid vs. polyploid), mint type (peppermint vs. spearmint), and genetic makeup (pure lines vs. hybrids), and statistical comparisons were made between these categories. Fresh yield and proportion of fresh leaves in the total harvest were affected by type and genetic makeup of mint accessions. Spearmint had significantly greater yield than peppermint (4.1 vs. 2.5 kg/m2) and higher proportion of leaves (69% vs. 63%). Species had higher fresh yield than hybrids (4.1 vs. 2.7 kg/m2) and higher proportion of leaves (69% vs 65%). Domestic accessions, peppermint, and hybrids had significantly higher leaf moisture than foreign accessions, spearmint, and species (26% vs. 22%, 28% vs. 23%, and 27% vs. 24%, respectively). None of the categories affected moisture content in the total plant harvest or stems. Further details of these data will be presented and discussed.
Chemical Characterization of Basil (Ocimum spp.) Germplasm from Brazil
Authors: Vieira Roberto F. , Simon James E.
Published: February 2019

Ocimum species are largely used in Brazil both as a condiment and in traditional medicine against bronchitis, cough, and sorethroat in the form of tea or syrup. As little research has examined the natural products from Brazilian basil, 14 accessions of Ocimum, including O. basilicum (4), O. campechianum (3), O. gratissimum (6), and O. kilimandsharicum (1), collected in Brazil were grown in the Purdue Univ. greenhouse and upon maturity harvested, the volatile oil extracted and analyzed by GC/MS. Thirty-one constituents were identified. Three accessions of O. gratissimum showed high content of eugenol (40% to 66%), while the other accessions contained either high thymol (33%) or p-cymene (28% to 42%). The constituents of the single O. kilimandscharicum included 1,8-cineole (39%), methyl-chavicol (21%), and ß-bisabolene (23%). O. campechianum accessions contained either high 1,8-cineole (62%) or high ß-caryophyllene (79%). O. basilicum could also be separated chemically: a linalool:methyl chavicol type (47:28%); one methyl chavicol type (72%), and a third, methyl cinnamate (61%). One accession was identified containing >90% trans-methyl cinnamate, which crystallized during extraction. Plants rich in targeted compounds, such as the one with 90% trans-methyl cinnamate, can be used as source of germplasm for breeding and potential commercialization
Identification and Characterization of Basil Anthocyanins
Authors: Phippen Winthrop B. , Simon James E.
Published: February 2019

The importance of anthocyanins as a food coloring, UV protectant, inhibitor of pathogens, and medicinal compound has been well-documented, with more than 300 anthocyanin compounds being reported in plants. The Lamiaceae family, including sage, thyme, and basil, has long been recognized as a rich source of diverse and unique anthocyanins. Because purple basil varieties have become more popular in the ornamental and herb trade, we conducted a study to identify and characterize the anthocyanins present in eight varieties of purple basils (Ocimum basilicum) utilizing high-pressure liquid chromatography, spectral data and plasma-desorption mass spectronomy. Nine different anthocyanins were identified. Seven of the pigments were cyanidin-based, with cyanidin-3-(6”-p-coumarylglucoside)-5-(6”'-malonylglucoside) as the major pigment. Two minor pigments based on peonidin were also identified. Total anthocyanin content was also determined and comparisons made to other anthocyanin sources.
“Black Spot,” a Physiological Disorder of Seed Development in Watermelon
Authors: Nerson Haim
Published: February 2019

Production of watermelons for seed consumption is popular in many regions of the world. In the Mediterranean area, large white seeds are preferred. Six breeding lines were selected for investigating the nature of black spot, an undesirable feature reducing the commercial value of the seeds. Black spot is expressed as blackened areas of the seed coat, mostly near the margin in mild cases, but extending over much of the seed coat in severe cases. Sowing date had a significant effect on expression of black spot. Seeds that developed in early summer (June) had low frequency and severity of black spot expression, whereas seeds that developed later in the summer (July–August) had markedly increased expression. Large differences were also observed among the breeding lines. There was a significant negative correlation between severity of black spot and seed weight, suggesting that black spot is a stress-related phenomenon.
Stand, Growth, and Yield of Snap Beans in Conventional Tillage and No-till Hairy Vetch Mulch
Authors: Abdul-Baki Aref A. , Teasdale John R.
Published: February 2019

Stand, plant growth, and yield were determined on `Matador' and `Carlos' snap beans (Phaseolus vulgaris L.) that were planted as a summer crop in a 3-year study using conventional tillage (CT) and no-till hairy vetch (Vicia villosa L. Roth) mulch (HV) systems. The CT plots received (kg·ha–1) 67 N as ammonium nitrate at preplanting and both CT and HV plots received (kg·ha–1) 17N–34P–17K with the planter. Stand differences between CT and HV were not significant. Average yields in CT and HV over a 3-year period were 13.3 and 19.8 t·ha–1, respectively. Average plant dry mass 2 days before harvest was not significantly different between CT and HV. Leaf area per plant 2 days before harvest was 1992 and 3092 cm2 in CT and HV, respectively. Higher yield in the HV mulch system, as compared to CT, can be attributed to larger leaf area per plant, higher soil organic matter and water-holding capacity, and less soil compaction in the HV plots.
Effects of Seed Treatments on Germination of Seed Collected from Native Populations of Oenothera
Authors: Balch Sandra A. , McKenney Cynthia B. , Auld Dick L.
Published: February 2019

Oenothera biennis, common evening primrose, is grown commercially for its seed, which contains high levels of gamma-linolenic acid (GLA), a fatty acid with pharmaceutical and dietary importance. Other native species of Oenothera are being evaluated for the presence of GLA in their seed and their potential as a commercial source of GLA. Native evening primrose species have shown slow emergence and low germination percentages. Studies were conducted to determine the effects of chilling, scarification, and priming on germination of seed for six species of native evening primrose. Overall, seed germination was improved by seed treatments. However, responses to the various treatments differed among species.
Lupine (Lupinus polyphyllus) Flower in Response to Long-day Photoperiod by Day Extension
Authors: Hopper Douglas A.
Published: February 2019

Ninety-six uniform plants of each `Russell hybrid' and `Gallery' mix lupines sown 9 June 1995 were randomly assigned to 32 unique treatment combinations. On 14 Dec 1995, plants were either placed in a 17/13°C day/night temperature (DT/NT) greenhouse (COOL) or 22/18°C DT/NT greenhouse (WARM) as controls, or in a constant 4.5°C cooler in the dark for 6, 8 10, or 12 weeks. After cooling, plants were transplanted to #1 nursery cans (2.75 liter) using Sunshine mix #2 and were assigned randomly to the COOL or WARM greenhouse. Greenhouse control plants under natural days were transplanted at intervals similar to cooled plants. Days until visible bud and flowering were analyzed using SAS PROC GLM. Plants receiving long day (LD) flowered 7 to 10 weeks (46 to 70 days) after the start of LD forcing. Buds were visible in 30 to 35 days. Plants receiving natural days (ND) did not flower uniformly unless they were cooled for 12 weeks, yet flowering took longer (8 to 12 weeks) when compared with LD. Unfortunately, LD lighting for the entire forcing period caused excess stretching, so plants finished too tall for quality potted plants. Forcing in a COOL greenhouse delayed flowering about a week compared to the WARM greenhouse.
Growth of Cyclamen as Affected by Day and Night Temperatures
Authors: Karlsson Meriam , Werner Jeffrey
Published: February 2019

The growth of Cyclamen persicum Mill. `Laser Scarlet' and `Sierra Scarlet' was evaluated for plants grown at day/night temperature differences of +9, +3, 0, –3 or –9°C. The day temperature was maintained for the duration of the 16-hr photoperiod and the day and night temperatures were selected to provide an average daily temperature of 16°C. The plants were grown at the specific temperatures starting 15 weeks from seeding until flowering. Total daily irradiance was 10 mol/day per m2. There was no significant difference in time to flower for plants of `Laser' (115 10.3 days from transplant). Flower buds appeared earlier above the foliage for `Sierra' plants grown at negative differences of 3 or 9°C (113 11.4 days) compared to plants grown at constant 16C (124 9.7 days). At flowering, plants grown with a positive difference of 9°C were significantly taller (22 1.9 cm for `Laser' and 24 2.0 cm for `Sierra') than the plants at 16C (19 1.9 cm for `Laser' and 21 2.1 cm for `Sierra'). Plants of `Laser' grown at +3C difference were also taller (21 2.1 cm) than the control plants at 16°C. Plant dry weight was larger for plants of both `Laser' and `Sierra' grown with +9°C. There were no differences in flower number or flower size among plants within each cultivar grown at the different temperature conditions.
Factors Affecting Flowering of Asclepias spp.
Authors: Nordwig G. , Erwin J.E.
Published: February 2019

Asclepias sp. seed were germinated and placed under different photoperiod treatments at constant 15, 20, or 25 ± 2°C. Photoperiod treatments were 8 hr, 8 hr plus night interruption lighting (2200–0200 hr, 2 μmol·m–2·s–1 from incandescent lamps), day extension lighting 1700–2000 HR (100 μmol·m–2·s–1 from highpressure sodium lamps), or daylight plus continuous light (100 μmol·m–2·s–1 light from high-pressure sodium lamps) treatments. Treatments were terminated at anthesis or after 15 weeks. Variation in plant habit and flowering were documented. Also, temperature/photoperiod effects/interactions on plant development are discussed. Lastly, species were classified into appropriate photoperiodic groups and evaluated for potential use as new floriculture crops.
Hydrophobic Particles for Pest Control in Deciduous Tree Fruit Production
Authors: Glenn D.M. , Puterka G. , van der Zwet T. , Byers R.
Published: February 2019

Fruit production requires extensive use of pesticides to control pest damage and maintain high product quality. Hydrophobic particles alter the leaf surface due to the hydrophobic and reflective nature of the particles and impart characteristics that make the plant surface incompatible, and/or unrecognizable to the pest. Hydrophobic particles were applied to apple and pear in field and greenhouse studies. Specific diseases, insect pests, plant growth, and yield were monitored and evaluated on treated plants in comparison to untreated and chemically treated controls. Powdery mildew in apple and Fabrea leaf spot in pear were controlled by the hydrophobic particles. Aphids, mites, and psylla were controlled in apple and pear. Hydrophobic clays have the potential of cross-protection for several disease and insect pests while imparting beneficial horticultural effects that would increase long-term productivity and sustainability of fruit production systems.
Protection of Long English Cucumber against Powdery Mildew through Induced Resistance using Milsana (Leaf Extracts)
Authors: Daayf F. , Ongena M. , Bélanger R.R.
Published: February 2019

Application of Milsana, a commercial formulation of leaf extracts fromReynoutria sachalinensis, has been shown to reduce the incidence of cucumber powdery mildew (Sphaerotheca fuliginea Schlecht, ex Fr. Poll.) under both smalland large-scale conditions.This treatment could therefore have a potential in a scheme of integrated control of powdery mildew. Increased chlorophyll values due to the treatment were recorded, but could not explain the prophylactic properties of the extracts. Also peroxidases, polyphenoloxidases, and PAL were shown to be activated, but no phytoalexins could be detected before in cucumber. In this work, phenolic compounds extracted from cucumber leaves were separated and analyzed for their differential presence and fungitoxicity in relation to the Milsana protection against powdery mildew. Six compounds were shown to display a significant increase in concentration as a result of the elicitation, this being particularly evident when the plant was stressed with the pathogen. These compounds were the first evidenced phytoalexins in cucumber. The major compound was identified as the methyl ester of p-coumaric acid.
Field Applications of Fungicides Improve Postharvest Quality and Storage Life of Some Pumpkin Cultivars
Authors: McClurg Charles A.
Published: February 2019

Commercial producers of pumpkin (Cucurbita pepo) in the Mid-Atlantic region frequently experience losses from the fungal diseases powdery mildew (Erysiphe cichoracearum) and black rot (Didymella bryoniae). In addition to loss of fruit size in some cultivars, the diseases can result in poor-quality handles (fruit stems) and preand postharvest decay. Since the pumpkins are grown for fresh market ornamental use, their appearance, size, and quality are important in marketing strategies. Applications of recommended fungicides during the growing season, although costly, reduce losses in fruit size and quality from fungal pathogens. Subsequent storage studies have documented reduced losses and maintenance of handle quality of pumpkins treated with fungicides during the growing season. This suggests that those who want or need to store pumpkins prior to sale can evaluate costs and benefits of the program. Producers can also choose cultivars that are better suited to storage if fungicides will not be used.
Preplant Soil Amendments influence the Incidence of Phytophthora Root Rot in `Heritage' Red Raspberry
Authors: Maloney K.E. , Pritts M.P. , Wilcox W.F. , Sorrells M.E.
Published: February 2019

Phytophthora is a severe root rot disease in most raspberry production regions throughout the world. Disease control options are limited to raised bed culture and fungicide applications. Few Phytophthora-resistant varieties are available that have commercial quality. Little is known about how soil amendments (i.e., composts, fertilizers, and limestones) influence Phytophthora control in raspberry. We evaluated the effects of preplant soil modification on the incidence of Phytophthora root rot in red raspberries. The experiment was conducted simultaneously at two sites to differentiate between the nutritional value of the amendments and the disease control value. One site has a known history of Phytophthora and a the second site is assumed to be free of the causal organism. Raspberry plant growth and fruit yield measurements were taken for all treatments. Preplant soil application of Gypsum (CaSo4) and post-plant applications of phosphorous acid sprays (H3PO3) had the greatest fruit yields compared to all other treatments in the Phytophthora-infested site. Gypsum-treated plots had greater cane diameter, cane height, and cane density compared to the control plots on the Phytophthorainfested site. A second experiment was conducted to further investigate the use of gypsum for control of Phytophthora in raspberries. Field soil was collected for use as potting medium from each of the aforementioned sites and pathogen free `Titan' plants were established in the greenhouse. After subsequent floodings, gypsum-treated soils delayed foliar disease symptoms compared to the control plots. At the end of the experiment, the control plants had 100% foliar disease symptoms and gypsum-treated pots had 33% disease symptoms. This study suggests that gypsum could be used in an integrated approach to Phytophthora management in raspberries. Future research should identify minimal effective rates of gypsum, examine other calcium sources, and determine effectiveness in other fruit crops.
Plant Regeneration from Cotyledons of Five Watermelon Cultivars
Authors: Jaworski Jason M. , Compton Michael E.
Published: February 2019

Cotyledon explants of five watermelon cultivars (`Desert King', `Mickylee', `Sangria', `Sweet Princess', and `Male Sterile') were prepared from 7-day-old in vitro-germinated seedlings. Explants were incubated on shoot regeneration medium for 6 weeks, followed by several 3-week cycles on shoot elongation medium. The five cultivars differed in their ability to form shoots within 9 weeks on the selected media. Shoot regeneration frequency was about 1.5to 2.9-fold greater for `Mickylee' (60%) than `Sangria' (47%), `Sweet Princess' (27%), `Male Sterile' (26%), and `Desert King' (24%). Rooting of elongated shoots (>2 cm) occurred within 2 weeks on medium containing 1 μM IBA and ranged from 25% (`Desert King') to 92% (`Sangria'). Plantlets were transferred to six-pack containers filled with soilless medium (1 Sunshine Mix: 1 coarse perlite) and covered with a transparent plastic lid. Plants were acclimatized to ambient conditions by gradually removing the lid over a period of 3 days after new growth was observed. The percentage of acclimatized plants ranged from 50% (`Sweet Princess' and `Mickylee') to 100% (`Male Sterile'). Acclimatized plants were transferred to the greenhouse and grown for at least 4 weeks before screening for ploidy variants. Ploidy of regenerated plants was estimated by counting the number of chloroplasts per guard cell pair. Plants with an average of 18 or more chloroplasts per guard cell pair were declared tetraploids. Plants with fewer chloroplasts per guard cell pair were declared diploids and discarded. Tetraploid plants were transferred to the field, grown to maturity, and self-pollinated for seed increase.
Seed Viability in Miscanthus Grown in Different Hardiness Zones
Authors: Tchida Courtney L. , Meyer Mary H.
Published: February 2019

Miscanthus is one of the most popular ornamental grasses. Reports of self-seeding however, have occurred in the Central Atlantic states, making it a possible weed threat. Ascertaining whether Miscanthus self-seeds or not may determine its continued use as an ornamental, decorative plant. With more than 50 named cultivars of Miscanthus sinensis and several other Miscanthus species available in the trade, wide morphological variation appears to exist within this genus. Because Miscanthus is a warm-season grass requiring a relatively long growing season, self-seeding may vary depending on the USDA Hardiness Zone in which the plant is grown. Mature inflorescences from 35 different cultivars or species of Miscanthus were collected or acquired from nurseries or arboreta in USDA Zones 4, 5, 6, and 7 in the fall or early winter of 1996. Inflorescences were examined for seed set by hand cleaning. The percentage of viability seed and seed germination was determined by germination in laboratory conditions. Results varied by cultivar or species and as well as by source. A comparison of results will presented and the implications of Miscanthus self-seeding or becoming a potential weed threat will be discussed.
The Effect of Composted Organic Wastes on Weed Control Provided by Preemergence Herbicides
Authors: Johnson Jennifer A. , Kuhns Larry , Harpster Tracey
Published: February 2019

Community waste management programs that include the composting of sewage sludge and yard wastes have become a necessity. Using these composts provides many benefits; however, increased levels of organic matter may reduce the effectiveness of preemergence herbicides. Determining how herbicide application rates may need to be adjusted when composted waste is incorporated into the soil may permit the use of these amendments without any decrease in weed control. This experiment examined the effect of two types of compost (composted sewage sludge and composted yard waste) on the weed control provided by four preemergence herbicides. The soil was a Hagerstown silt loam amended with 10%, 20%, or 30% compost by volume. Each mix was placed in half-gallon cardboard milk cartons. The cartons were seeded at 1/2 and 1/4 inches with a mixture of broadleaved weeds and grasses. Each soil mix was treated with simazine, oxyfluorfen, oryzalin, and metolachlor at two rates. Control was evaluated both visually by number and by the dry weight of the harvested weeds. Preliminary results indicate composted sewage sludge causes a greater reduction in herbicide efficacy than composted yard waste. Oryzalin and metolachlor were affected less than oxyfluorfen or simazine. The experiment was repeated using lower application rates. In one replication the soil mixes from the previous experiment were used. The second replication used a Hagerstown silty clay loam soil with fresh compost. The results of this experiment will provide preliminary information for future field studies designed to determine if the application rates of preemergence herbicides need to be adjusted when fields are amended with composted organic matter.
In Vitro Bioassays as Indicators of Salinity Tolerance in Potato
Authors: Zhang Y. , Donnelly D.
Published: February 2019

The relative salinity tolerance of three potato cultivars, including `Russet Burbank', `Kennebec', and `Norland', were compared using three in vitro bioassays (single node cuttings, root tip segments, and microtuberization) and yield data from field lysimeters irrigated with salinized water. The single-node cutting bioassay was simpler to perform than the root tip segment and microtuberization bioassays. The single-node cutting bioassay can be recommended as a substitute for more laborintensive and costly field assessments of salinity effects on yield.
Growth and Fruiting of Apple Trees on Dwarf and Semi-dwarf Rootstocks in Different High-density Orchards
Authors: Devyatov A.S.
Published: February 2019

An orchard trial was established by planting an orchard with between-row intervals of 4 m. The French Axe was trained for trees with intervals in the row of 1 and 1.5 m. The hedgerow was used for treatments of 2–2.5 and 3 m between trees in the row. Semi-dwarf rootstock of Bud54-118 and dwarf one Bud62-396 were used. The growth of of these rootstocks was analogous to MM106 and M26, respectively. The trunk cross-sectional area of 7-year trees on 54-118 rootstock was 2.3 times more than on 62-396 for cv. Antey and 1.5 times more for cv. Tellisaare. The height of tree with French Axe crown at 7 years after planting on 54-118 rootstock reached 3.5–4 m. The height of tree was 0.5 m smaller on 62-396. The crown habit of tree on 62-396 rootstock was more comfortable for high -density orchard than trees on 54-118. The sum length of twigs that were cut out during 1993–96 to attain of normal density of crown was 2-4 times more than on 62-396 rootstock. Commercial fruiting of cv. Antey started at the 3rd leaf, but it was on 4th leaf for the more-dwarf rootstock 62-396. Average yield of fruit at 3–6 years after planting of cv. Antey for treatment of distance between trees in the row of 2 or 1.5 m was 6.8 kg/tree per year-1 for 54-118 rootstock, 3.4 and 3.5, respectively, for 62-396 rootstock. Yield at the 7th year after planting reached 24 and 32 kg on 54-118 rootstock, 16 and 15 kg on 62-396, respectively. Analogous date obtained for cv. Tellisa are. cv. Spartan on both rootstocks started to fruiting at 5-6 years after planting. The fruit quality was very high in all treatments of the trial.
Apple Orchard as Twin-row Tree-belt on Dwarf and Semi-dwarf Rootstocks
Authors: Devyatov A.S.
Published: February 2019

Growth and fruiting of apple trees in twin-row tree-belts were studied during 5 years after planting the orchard. Distance between belts was 4 m, between rows in a belt was 1 m, between trees in row 3 or 1.5 m, giving tree densities of 1335 or 2670 trees/ha, respectively. Control was a single-row planting 4 × 3 or 4 × 1.5 m, producing densities of 833 or 1665 trees/ha. Trees were trained as hedgerow in treatments with a density of 1335 or 833 trees/ha. Each tree in a twin-row belt had a separate crown with narrow passage between trees. This passage was cut through every year. Fruiting of `Tellisaare' began at 2nd leaf, `Antey' at 3rd, and `Spartan' at 4th leaf after planting. Total yield for 3 years in the highest density treatment of single-row planting of `Antey' and `Tellisaare' was >50 t·ha–1 and in twin-row orchard construction from 36 to 57 t·ha–1, depending on orchard density. The two-fold increase in orchard density from 1335 to 2700 trees/ha raised yield of `Antey' by 58% and `Tellisaare' by 33%. Single-row treatment with a tree density of 1665/ha averaged 17.1–17.5 t·ha–1 without great expenditure on pruning of trees. The fruit quality was very high in all treatments.
Vegetative Growth of Coffee Cultivars under Mechanical Pruning Systems
Authors: Liu Guofan , Kobayashi Kent , Bittenbender H.C. , Gautz Loren
Published: February 2019

Pruning methods 1.5 × 1.5 m (topping and hedging) and stumping to 0.70 m were used on coffee cultivars Guatemalan, Red Catuai, Yellow Caturra, and Mokka. In the hedged treatment, `Mokka' had the longest laterals, followed by `Guatemalan', with `Red Catuai', and `Yellow Caturra' having similar lengths. `Mokka' had the most nodes/lateral. `Guatemalan' showed the fastest growth (height), followed by `Mokka', with `Red Catuai' and `Yellow Caturra' having similar growth. For 0.70-m pruning, vertical lengths of `Guatemalan' were the longest. `Mokka' had the most vertical nodes. `Guatemalan' had the longest vertical internodes, followed by `Red Catuai' and `Yellow Caturra', with `Mokka' having the shortest. `Yellow Caturra' had the most laterals/vertical, followed by `Red Catuai' and `Guatemalan'. `Mokka' had the fewest. Lateral lengths, nodes/lateral, and internode length were similar for all cultivars. Two-meter pruning height may be best for `Red Catuai' and `Yellow Caturra' because of slow growth, shorter laterals, and fewer nodes/lateral. These two cultivars grew well after being stumped due to faster regrowth and more laterals remaining on new verticals. 1.5-m pruning appears optimum for `Guatemalan', but it grew very well after stumping. It may be better to prune `Mokka' to a 2-m height with a narrow canopy remaining because of its good multiple verticals, fast lateral growth from new verticals in canopy but not in full sun, and more vertical nodes but less laterals regrowing from new verticals on main trunks exposed to full sunlight.
Bag and Liner Color Greatly Affect Apple Temperature Under Full Sunlight
Authors: Ritenour Mark , Schrader Larry , Kammereck Rudi , Donahue Raymon , Edwards Gerald
Published: February 2019

Some apple growers place specially designed bags with liners around fruit in the field to produce a unique surface color required by some premium markets. However, heat damage has been observed on `Fuji' apples that were bagged and reached high temperatures in the field. We tested different colored apple bags and their liners to determine the amount of light that is transmitted and whether bag color affected heating of the apples inside. Apple bags and liners were very effective at screening out sunlight; however, the absorbed light substantially warmed the bags and apples inside. No UV-A or B and less than 1% of photosynthetically active radiation (PAR) passed through the outer bag regardless of bag color and the inner liners transmitted ≈9% of the UV-A, 3% of the UV-B, and 30% of the PAR. When ambient air temperatures were only ≈25°C, dark green bags or red or green liners warmed the sun-facing apple surface to ≈43°C, while light green bags warmed to ≈36°C. Wrapping apple bags in aluminum foil to increase bag reflectivity greatly reduced heat buildup and maintained sun-facing fruit surface temperatures only slightly above air temperature (≈27°C). Possible design improvements for apple bags used in hot, sunny climates will be discussed.
Isolation and Characterization of the Vascular-specific 22-kDa Zn-binding Protein
Authors: Taylor Kathryn C. , Elli Danielle R.
Published: February 2019

A 22-kDa Zn-binding protein (ZBP) was isolated from the phloem tissue and evacuated xylem sap of `Valencia' sweet orange [Citrus sinensis (L.) Osbeck] on rough lemon [C. jambhiri (L.)], as well as Valencia on Rangpur lime [Citrus limonia Osbeck]. Phloem and xylem Zn was associated with the 22 kDa ZBP. The Mr value of this ZBP was estimated to be 19,500 by size exclusion chromatography and 22,800 by SDS-PAGE. This protein was isolated with an isoelectric point of 7.5. Ion exchange chromatography demonstrated that 22-kDa ZBP was highly anionic, requiring 0.43 M NaCl for elution from QAE Sepharose. The 22-kDa ZBP appears unique to citrus, having no cross reaction with protein from several tissues from a range of plant species. Accumulation decreased under Zn-deficient conditions, was enhanced by osmotic stress, and the protein completely disappeared with wounding. Amino acid composition demonstrated that the protein was rich in aspartate, and glutamate; and contained 6 cysteine, and 4 histidine residues. These amino acids may be involved in metal binding. N-terminal amino acid sequencing demonstrated that the 22-kDa ZBP had identity with sporamin A&B precursors, Kunitz-type trypsin inhibitors, and miraculin. It is suggested that the genes that encode these proteins are derived from a common ancestral gene.