bluuebunny/crossref_metadata_2025 huggingface dataset:
Alternative Methods to Control Western Flower Thrips (Frankliniella occidentalis) in Greenhouse Crops
Authors: Hopper Douglas A. , McIntyre Julie A.
Published: February 2019

Research focused on alternative methods to control Western flower thrips (Frankliniella occidentalis Pergande), encompassing chemicals from varying classes, parasitic nematodes, microbial insecticides, and physical/mechanical deterrents. Chemical spray applications were applied weekly for 4 to 6 weeks. Experiment 1 made comparisons between fenoxycarb (Precision), bifenthrin (Talstar), and entomopathogenic nematodes (Biosafe). Experiment 2 compared abamectin (Avid), spinosyn A and D (Spinosad), azadirachtin (neem extract: Margosan-O), and diatomaceous earth (a physical control aimed at deterring pupation). Experiment 3 compared Spinosad, fipronil, and two microbial insecticides (Naturalis-O and Mycotrol). The number of thrips counted in flowers after treatments had been applied indicated that the strict chemical treatments (Avid, Spinosad, fipronil) provided quick knockdown and overall longer-term population control. Microbial insecticides, diatomaceous earth, and nematodes maintained populations at a lower level than the control, but were not as effective as strict chemical controls. Margosan-O, Precision, and Talstar controlled populations at medium levels. For periods when populations may cycle upward, more potent chemicals could be used (Spinosad, fipronil, and Avid) while still avoiding problems associated with more toxic chemicals.
Use of Paclobutrazol to Control Height of Impatiens Grown in Media Containing Compost
Authors: Klock Kimberly A.
Published: February 2019

Ornamental horticulture industries have the opportunity to utilize compost products as components in growing media, but heterogeneity among compost products can cause unpredictability in the activity of some growth regulators when applied as a drenches to the growing medium. These experiments evaluated the effect of 0%, 30%, 60%, or 100% compost (by volume) in the medium on the efficacy of paclobutrazol applied as a drench on Impatiens wallerana Hook. In experiment 1, paclobutrazol was applied at active ingredient (a.i.) drench rates of 0, 0.016, 0.032, 0.06, or 0.125 mg/pot 16 days after transplanting impatiens `Accent Red'. In experiment 2, paclobutrazol was applied at a.i. drench rates of 0, 0.25, 0.50, 1.0, or 2.0 mg/pot 14 days after transplanting impatiens `Dazzler Punch'. In both experiments, final height and size were reduced by paclobutrazol treatments compared to untreated plants. In experiment 1, shoot dry mass of treated plants was on the average of 0.92 g less than untreated plants, while shoot dry mass, in experiment 2, did not show a significant difference between treated and untreated plants. In both experiments, final height, size and shoot dry mass were significantly different among the media, with the greatest growth in 100% compost.
Influence of Methanol, Ethanol, and Nitrogen on the Yield of Lettuce (Lactuca sativa)
Authors: Morales-Payan J.P.
Published: February 2019

Greenhouse experiments were conducted in the Dominican Republic to determine the effect of methanol and nitrogen (N) on the yield of `Black Seeded Simpson' lettuce. Plants were individually grown in plastic containers filled with loamy soil and treated with combinations of methanol, folcysteine. N rates (70, 105, 140, and 175 kg/ha) were applied at planting, and aqueous solutions of either ethanol or methanol (0%, 5%, 10%, 15%, and 20%) were applied as a foliar spray when the plants had five true leaves. Plants were harvested 50 days after planting. There were no significant effects of ethanol or methanol on lettuce yield. Lettuce yield was significantly influenced by N rates, with yield increasing as N rates were higher.
Effect of Humic Acid Substrate Drenches on Growth and Development of Seedlings
Authors: Hartwigsen Jack A. , Evans Michael R.
Published: February 2019

Cucumis sativus (cucumber), Pelargonium × hortorum (geranium), Tagetes patula (marigold), and Cucurbita pepo (squash) seed were sown into plug cells (5 ml volume) filled with a germination substrate containing peat, vermiculite, and perlite. After the seed were sown, the substrate was saturated with solution containing 0 (deionized water) 2500, or 5000 mg/L humic acid (HA). Additional treatments included seed which were sown into the substrate and saturated with nutrient solutions corresponding to the nutrient concentration of each humic acid solution. Seed were placed in a growth chamber and maintained at 22°C and under a 12-h photoperiod with a PPF of 275 μmol·m–2·s–1. After 10 d for cucumber and squash and 14 d for marigold and geranium, plants were harvested and root and shoot fresh mass recorded. Shoot fresh mass was not significantly affected by treatment for any of the species tested. Except for squash, root fresh mass was significantly increased by humic acid treatments. For cucumber, root fresh mass ranged from 0.24 g in deionized water to 0.34 g in 2500 and 5000 mg/L HA. Geranium root fresh mass ranged from 0.03 g in deionized water and 5000 mg/L HA to 0.05 g in 2500 mg/L HA. Marigold root fresh mass ranged from 0.02 g in deionized water to 0.03 g in 2500 and 5000 mg/L HA. Root fresh mass for nutrient controls were similar to those for deionized water.
Adaptation of ELISA Test for the Diagnostication of Apple Chlorotic Leaf Spot Virus (CLSV) in Apple Trees
Authors: Lessa Antonio O. , de Castro Luis A.S. , de L. Fortes Gerson R.
Published: February 2019

The purpose of this study was to adapt an ELISA test for diagnosing of “Apple Chlorotic Leaf Spot Virus” (CLSV) in apple trees. This work was carried out at Centro de Pesquisa Agropecuária de Clima Temperado–CPACT/EMBRAPA, Pelotas–RS, Brazil, during the 1996 spring season. The application of ADGEN Diagnostic Systems protocol does not give some positive results from diseased apple trees. The procedure modified by FLEGG & CLARK (1979) gives an unsatisfactory result for color reaction in the positive samples. It means it is necessary to adapt this methodology. When the antigen was obtained from leaves grown from the base to the intermediate position in the stem and grounded with extracting buffer—0.02 M, pH 7.4 (1 g tissue: 3 ml extracting buffer) and polyclonal antisera and antibody alkaline phosphatase conjugate was diluted in coating buffer—0.05 M, pH 9.6 (1 μg antisera or antibody: 500 μl coating buffer) the reaction become more intensive and the test was able to diagnosticate the presence of the pathogen in infected leaves of apple trees.
Isozyme Analyses of Musa Clones Maintained at in Vitro Conditions
Authors: Reyes Luz Marina , Martinez Orlando , Beltran Margarita
Published: February 2019

Fifteen clones of banana and plantain of different ploidies, belonging to the Colombian Collection of Musaceas (CCM), maintained at in vitro conditions were characterized. Twenty-three isozyme systems were analyzed using young leaves of micropropagated clones. Eleven systems presented electrophoretic activity: diaphorase (DIA), esterase (EST), glutamate dehydrogenase (GDH), malate dehydrogenase (MDH), malic enzyme (ME), peroxidase (PRX), phosphoglucoisomerase (PGI), phosphogluconate dehydrogenase (PGDH), phosphoglucomutase (PGM), ribulose biphosphate carboxilase (RUB), and shikimate dehydrogenase (SKDH). DIA and RUB isozymes are reported the first time for the genus Musa, and ME, GDH, PGDH, and PGI are not reported previously in acrilamide support. A total of 24 loci were identified that encoded at least 50 alleles. The enzymes with greater genetic variability were EST and DIA, with 14 and 10 alleles, respectively—these represent 48% of the polymorphism detected in this study. The systems PGM, SKDH, PGDH, and ME allowed to differentiate clones of M. acuminata (bananas AA and AAA) from hybrid clones derived of M. acuminata × M. balbisiana (plantains AAB and ABB). Otherwise, it was found that materials maintained under in vitro conditions for more than 10 subcultures presented evidence of variation at the protein level. The isozymes that allowed us to observe these changes were: DIA, EST, ME, PGDH, PGM, and SKDH.
Flower and Fruit Load Influence Blueberry Plant Development and CO2 Exchange Rate
Authors: Maust B.E. , Williamson J.G. , Darnell R.L.
Published: February 2019

Two southern highbush blueberry cultivars, `Sharpblue' and `Misty', were used to investigate the influence of varying flower bud density and fruit load on vegetative development, whole-plant canopy CO2 exchange rate (CER), and leaf CER. Plants were grown in pots and flower buds were removed so that initial flower bud density (fl ower bud number/total cane length) on a whole-plant basis ranged from 0.05–0.35 flower buds/cm. Vegetative budbreak number, leaf area, and leaf area: fruit ratio decreased with increasing flower bud density. In `Sharpblue', whole-plant canopy CER measured at fruit ripening decreased with increasing flower and fruit load and decreasing leaf area:fruit ratio, while leaf CER increased with increasing fruit load and decreasing leaf area:fruit ratio. In `Misty', whole-plant canopy CER measured 4 weeks after full bloom decreased with increasing flower and fruit load, but whole-plant canopy and leaf CER at fruit ripening were similar among the different fruit loads. Average fruit fresh and dry weights increased and the fruit development period decreased with increased leaf area:fruit ratio in both cultivars. These data suggest that carbohydrate source limitations from reduced leaf area development and whole-plant canopy CER lead to decreased fruit fresh and dry weights and delayed ripening in some southern highbush blueberry cultivars.
`Himrod' Grape Responses to Rowcover Microclimate
Authors: Gatherum Dawn M. , Anderson J.L. , Seeley S.D. , Frisby J.L.
Published: February 2019

Rowcovers were placed over `Himrod' grapes during the 1992 and 1993 growing seasons to test the feasibility of manipulating the microclimate temperature sufficiently to bring the covered grapes into full bloom and harvest earlier. The rowcovers were removed from the grapes after fruit set each year. In 1992, the covered grapes bloomed 18 May, 6 days earlier than the open blocks. In 1993, full bloom in the covered grapes occurred on 29 May, 9 days earlier than the controls. However, the advanced bloom of the covered grapes did not result in the expected earlier maturity when compared to the uncovered grapes. Covered grapes did attain a soluble solids maturity index of 18 two to three days earlier than uncovered grapes.
Soil Quality Factors Affecting Garlic Production
Authors: Rosen Carl J. , Birong David E.
Published: February 2019

Recent demand for high-quality garlic (Allium sativum L.) has prompted an interest in growing garlic as an alternative crop in the Upper Midwest. The overall objective of this study was to determine the effects of various amendments on garlic growth and selected soil quality indices in two contrasting soils. Garlic (Rocambole type) was planted in the fall of 1995 on a Kandota sandy loam (5% organic matter) and a Spartan loamy sand (1.5% organic matter). Three treatments replicated three times were tested: 1) a nonamended control, 2) manure compost, and 3) fertilizer application based on a soil test. Scapes were removed on half the plants in each plot and allowed to grow until harvest on the other half. Soil microbial biomass nitrogen (N) and carbon (C) were determined before planting and about 4 weeks after emergence. Within each site, the effect of soil amendments on garlic yield depended on scape removal. Garlic yield in nonamended soil was lowest when scapes were not removed. The effect of scape removal tended to diminish when compost or fertilizer was applied. Overall yields were 35% higher in the sandy loam soil compared to the loamy sand soil. Drought stress occurred during bulbing at both locations. Higher yields in the sandy loam soil were likely due to its higher water-holding capacity. Soil amendments did not consistently affect microbial biomass N and C; however, the sandy loam soil had 2 to 6 times higher biomass N and 3 to 4 times higher biomass C than the loamy sand soil and reflected the higher organic matter content of the sandy loam.
Desert Lettuce Responds to N Rate but Not N Source
Authors: Sanchez C.A. , Obeker N.
Published: February 2019

Approximately 30,000 ha of iceberg lettuce (Lactuca sativa L.) are produced in the low desert region of the southwestern United States during the fall–winter–spring period each year. During this period, soil temperatures in lettuce beds range from 10 to 30°C. During the cooler part of the growing season, growers typically use nitrate-N sources because they believe they are generally more available for plant uptake. However, limited experimental evidence exists to support this practice. Three field studies were conducted during the 1994–1995 growing season to evaluate the response of iceberg lettuce to N rate and N source. The N sources urea, ammonium sulfate, ammonium nitrate, and calcium nitrate were applied at rates ranging from 0 to 300 kg N/ha. Although lettuce growth, N accumulation, and marketable yield significantly increased by N rate, there were generally no differences due to N source.
Use of Citric Industry Waste on Saline Soil
Authors: Lopez-Aguirre J.G. , Molina-Ochoa J. , Farias-Larios J. , Guzman-Gonzalez S. , Michel-Rosales A.
Published: February 2019

Amelioration and/or reclamation of saline and non-saline soils is based on the application of high quantities of agrochemical products or high volumes of water, which causes an injury in soil or downward displacement of nutrients to the lower layers in soils. Research was conducted to evaluate the effect of application of citric industry waste on saline and non-saline soil. The waste has an electrical conductivity (EC) of 2.7 dS/m and pH of 3–4.2, 35% is organic material that is readily decomposed. This experiment was carried out on field conditions using applications of three different volumes, T1 = 3200, T2 = 6400, and T3 = 9600 m3·ha–1·m–1 and a control, no-waste, (T0), using just irrigation water (EC = 2.5 dS·m–1). The same treatments were added to non-saline soil. Effect of citric industry waste application in both saline and non-saline soils was similar. In all the treatments, EC was decreased with respect to T0 and soil before application (BA), the largest decrease was found in T3. pH decreased in the top soil layer much more than in the bottom layers. Ions were decreased in all soil profile. Organic matter (OM) was increased in the profile in treatment T1 with respect to treatment T0, as well as in the top soil layers in T2 and T3, but no changes were detected in the remainder of the layers in treatments T2 and T3. We can suggest that the waste studied can be used in the amelioration of saline and non-saline soils.
Seasonal Water Use of a Kiwifruit Vine: Measurements and a Model
Authors: Green S.R. , Mills T.M. , Clothier B.E.
Published: February 2019

We recorded canopy development and stomatal function of a kiwifruit vine for the purpose of calculating the seasonal water use by the crop. Canopy development was described using an empirical “S-shaped” curve fitted to weekly measurements of the vine's leaf area. Stomatal conductance was described using a semi-empirical model based on the incident radiation, and the ambient vapor pressure deficit of the air. These two descriptors, leaf area and stomatal conductance, were combined with meteorological data to calculate vine transpiration via the Penman–Monteith model. Transpiration rates calculated at 30-min intervals were in good agreement with the instantaneous rates of sap flow measured by heat-pulse sensors located in the vine stem. The measured and calculated transpiration remained in concert throughout the experiment, thereby confirming the Penman-Monteith model as a robust and suitable model to describe the seasonal water use by kiwifruit vines. The model validation enables confident predictions of crop water use and thus aids irrigation allocation for kiwifruit crops.
Cold Stratification Improves Germination of Katsura Tree
Authors: Dosmann Michael Sean , Iles Jeffery K.
Published: February 2019

Katsura tree (Cercidiphyllum japonicum Sieb. & Zucc.), an ornamental tree native to Japan and China, is valued for its broad pyramidal form and apricot-yellow fall leaf color. Another species, Cercidiphyllum magnificum (Nakai) Nakai, exists, but is rarely encountered outside of wild populations, except in a pendulous form. Propagation of katsura is by seed germination and softwood cuttings, although little information exists in the scientific literature regarding either method of propagation. To determine conditions for optimal seed germination, we subjected C. japonicum seed to a factorial combination of moist stratification and exposure to light. Two seed lots were obtained from the Arnold Arboretum of Harvard Univ., accessions 1150-67 and 882. Half of the seeds in each lot were moist stratified in petri dishes on filter paper for 8 days at 3.5°C. All seeds then were germinated at 25°C with either a daily photoperiod of 15 hr or complete darkness. Those samples not exposed to light were placed in a light-tight container. Germination was defined as the average percentage of seeds per treatment combination that showed the emergence of a radicle. Unstratified seeds germinated at 44.7% over both seed lots. Moist stratification increased germination to 92.0% and 56.7% for 1150-67 and 882, respectively. Light did not affect germination for either seed lot. Optimal seed germination conditions for C. magnificum will be determined in future studies. We have shown that moist stratification of katsura seeds improves germination and recommend this method as a means of promoting seed germination.
Temperature and Light Effects on Germination of Burnet, Sanguisorba spp.
Authors: Holloway Patricia S. , Matheke Grant E.M.
Published: February 2019

Seeds of three Sanguisorba species native to Alaska were germinated in growth chambers with constant air temperatures of 5°, 10°, 15°, 20°, 25°, or 30°C and an irradiance of 150 μM·m–1·s–2 for an 18-hr photoperiod to identify optimum germination in relation to temperature and light. Four replicates of 100 seeds each were sown onto filter paper in petri dishes in each temperature treatment. At 20°C, four additional dishes per species were enclosed in foil to exclude light. Dishes were arranged at random by species in large clear plastic bags, and daily counts of radicle emergence were recorded. Germination of all three species was fitted to third-order polynomial equations by regression analysis. The predicted optimum germination temperature for Sanguisorba officinalis was 25°C; S. menziesii was 24°C; and S. stipulata was 25°C. Germination was most rapid (days to 50% germination) for each species in the 25°C treatment. S. stipulata did not germinate at 5°C, and both S. stipulata and S. menziesii showed less than 50% germination at 30°C. Seeds of all species germinated as well in darkness as in light.
Randomly Amplified Polymorphic DNA (RAPD) Variation Among Commercial Cultivars and Hybrids of Cabbage (Brassica oleracea var. capitata L.)
Authors: Cansian R.L. , Echeverrigaray S.
Published: February 2019

Randomly amplified polymorphisms (RAPD) were used to assess genetic diversity among five cultivars and 10 hybrids of cabbage (Brassica oleracea var. capitata L.). One-hundred-forty bands were scored from 15 oligonucleotide decamer primers selected from Operon Techn. kits B, W, X, and Y. The similarity indices between cabbage entries were computed from RAPD data, and these ranged from 0.53 to 0.95. The RAPD data allowed us to identify all the genotypes, even some of those characterized only by few bands. The cluster analysis formed five groups. One of these groups was formed by a single entry characterized by their precocity. The traditional cultivars Chato de Quintal and Chato de Brunswick were included in the same group, together with the Brazilian hybrid `Astrus'. Four of the six Japanese hybrids, imported and commercialized in Brazil, showed low variability between themselves.
Clonal Propagation of Cauliflower, Brassica oleracea botrytis for Hybrid Seed Production
Authors: Smith Nicole , Bhalla Prem L.
Published: February 2019

Brassica oleracea is an important vegetable crop, which includes fully cross-fertile cultivars such as broccoli, Brussels sprouts, cabbage, cauliflower, collard, kohlrabi, and kale. F1 hybrids are desirable, as plants grown from hybrid seeds benefit from the heterotic effect of crossing genetically distinct pure lines. But, there is no practical and reliable method to create male sterility for hybrid seed production that is suitable for Brassica vegetables. We have been working to induce nuclear male sterility in cauliflower (Brassica oleracea var. botrytis) by antisense inhibition of Bcp1, a unique anther-specific gene of Brassica. The production of nuclear male-sterile lines will enable male lines with superior agronomic traits to be converted to female parents. Thus, vegetative propagation of parent plants for hybrid seed production by tissue culture is desirable. To achieve this objective, we compared various plant tissues, including stem, petiole, leaf, leaf rib, flower stem, pedicel, flower bud, and petal as explants for tissue culture propagation of an Australian cultivar (B-4) of cauliflower, Brassica oleracea var. botrytis. Four different MS based media containing different amounts of BAP, NAA, GA3, and silver nitrate were used. The cultures were incubated at 25°C with a 16-hr photoperiod. Initial response was visible within 10 days, but percentage callus, root, and shoot formation was scored after 3 weeks of culturing. Of all the explants tested, pedicel explants showed maximum shoot initiation and leaf explant did not respond to regeneration under the conditions tested. The results from these on going experiments will be presented and discussed.
Construction of a Genetic Linkage Map and Locations of Halo Blight and Brown Spot Resistance Loci in Common Bean (Phaseolus vulgaris L.) using RAPD Markers
Authors: Ariyarathne H.M. , Coyne Dermot P. , Jung Geunhwa
Published: February 2019

Halo blight (HB), brown spot (BS), and rust incited by the bacterial pathogens Pseudomonas syringae pv. phaseolicola (Psp), Pseudomonas syringae pv. syringae (Pss) and the fungal pathogen Uromyces appendiculatus, respectively, are important diseases of common beans. The objectives were to construct a RAPD linkage map, and to locate HB and BS resistance genes and genes for some other traits. One-hundred-seventy RAPD markers were mapped in 78 RI lines of the cross BelNeb 1 and A 55. Eleven main and nine minor linkage groups were identified. MAPMAKER/QTL, interval mapping, was used to identify genomic regions involved in the genetic control of the traits. One region was found to control HB leaf reactions to strain HB16 while three regions controlled reactions to strain HB 83. These regions accounted for 22% and 18%, 17%, and 17% of phenotypic variation of resistance, respectively. Four putative QTLs were identified for resistance to BS, and accounted for 37%, 26%, 23%, and 19% of the phenotypic variation. Rust resistance was determined by a single major gene to both rust strains US85NP 5-1 and D82vc74fh. However, linked markers were not identified. The V gene controlling flower and stem color was tightly linked with the Operon marker O10.620.
Affinity Grouping of Lentil Accessions through Comparative Electrophoresis of Seed Proteins
Authors: Echeverrigaray S. , Oliveira A.C. , Carvalho M.T.V. , Derbyshire E.
Published: February 2019

The comparison of the electrophoretic patterns of seed polypeptides and basic proteins of 40 lentil germplasm accessions revealed a wide qualitative and quantitative variation that allowed the individual characterization of all the genotypes. The statistical analysis of the variation and the clustering of the samples by multivariate methods allowed the construction of five affinity groups that were consistent with the origin and genetic relationships among the accessions. These results indicate the reliability of this simple and inexpensive biochemical analysis in lentil germplasm bank management, cultivar identification and monitoring, and the construction of affinity groups that can help breeding programs.
Genetic Variation among Garlic Cultivars as Determined by Randomly Amplified Polymorphic DNA Markers
Authors: Echeverrigaray S. , Cansian R.L. , Delamare A.P.L. , Silveira R.P. , Barni V.
Published: February 2019

A collection of garlic (Allium sativum L.) germplasm, including 11 cultivars currently used in South Brazil, was evaluated using randomly amplified polymorphic DNA (RAPD) markers. Objectives were to assess genetic variations and relationships among cultivars and determine the potential of RAPD markers for the identification of garlic cultivars. One-hundred-twenty-two RAPD bands were scored from 12 oligonucleotide decamer primers selected from Operon Techn. kits B, X, and Y. Of these, 46 bands (37.6%) were polymorphic. Similarity indices between garlic entries were computed from RAPD data, and these range from 0.69 to 1.00. UPGMA cluster analysis of genetic distances showed three groups: one formed by nine cultivars and two formed by single entries. The nine cultivars that form group I had common origin, which explains the high similarity observed between them.
Using Cupric Hydroxide to Reduce the Rooting-out of B&B Stock During Storage
Authors: Maynard Brian K. , Johnson William A.
Published: February 2019

Cupric hydroxide formulated as Spin Out™ [7% Cu(OH)2 in a latex carrier] was used to prevent the rooting-out of Taxus × media Rehd. `Densiformis' root balls into surrounding mulch or soil during storage over a 4-month period. Treatments evaluated in one study included: painting the bottom of the root ball with copper-paint, setting the root ball on copper-treated burlap or ordinary copper-treated burlap; rewrapping the root ball with copper-treated burlap before mulching or burlapping with copper-treated burlap, with appropriate controls. All treatments provided good control of rooting-out after 12 to 16 weeks storage. The most effective treatments were setting the root ball on copper-treated burlap (unmulched; 92% reduction in root count after 16 weeks) and rewrapping or burlapping into copper-treated burlap (mulched; 90% and 86% reduction in root count after 16 weeks). A second study used TexR® Agroliner (Spin Out™-treated non-woven fabric), on which root balls were set (unmulched treatments), rewrapped or burlapped (mulched treatments). TexR® Agroliner stopped rooting-out completely without adversely affecting plant quality. Using copper-treated burlap to prevent rooting-out during storage can reduce the incidence of re-balling and root removal prior to shipping and planting B&B nursery stock.
Vegetable Crops Research and Information Center World Wide Web Site
Authors: Schrader Wayne L. , Voss Ronald E. , Bradford Kent J. , O'Neil Carol
Published: February 2019

The Univ. of California's Vegetable Crops Research and Information Center (VRIC) has developed a new World Wide Web site that allows the rapid development and peer review of multi-discipline, research-based information. The VRIC website (http://vrichome.ucdavis.edu) disseminates peer-reviewed fact sheets, research results, updated publications, and multi-media educational resources relating to critical issues, best management practices, postharvest handling, and marketing of vegetable crops. The website disseminates multi-discipline information originating from the Univ. of California, the USDA, and cooperating agencies and universities. The VRIC website proactively sends peer-reviewed critical-issue fact sheets to selected news media, government, industry, and academic contacts. These fact sheets help personnel frequently contacted by the media during crises to answer questions effectively. The website directs visitors to additional agricultural information resources and contains information on careers and educational opportunities available in the field of vegetable crops.
Production of Dihaploids in Carnation (Dianthus caryophyllus L.)
Authors: Dolcet-Sanjuan Ramon , Clavería Elisabet , Rodríguez Alfonso J. , Llaurado Marta
Published: February 2019

Callus and shoot organogenesis were obtained from anthers of Dianthus caryophyllus L. `Manon', `Amapola', `Elsy', and `IB212', harboring mid-uninucleated microspores. Significant differences between genotypes were observed on number of responsive anthers (10.4% to 72.1%) and rescued plants per responsive anthers (1.2% to 4.8%). A modified H medium (Nitsch and Nitsch, 1969) with 20 g/L maltose and 0.25% Gelrite, supplemented with 10 μM 2,4-D and 1 μM TDZ, was most appropriate for callus induction. Plants were regenerated after subsequent subculture to the same medium, but amended with 0.1 μM TDZ. Zymogram types for aminopeptidase (AAP) in polyacrilamide gel electrophoresis proved that all 40 plants regenerated from `Amapola', `Elsy', or `IB212' where heterozygous, and consequently not originated from the microspores but from somatic tissue. Alternatively, in situ-induced parthenogenesis through pollination with gamma-irradiated pollen and in vitro embryo rescue was tested. A total of 92 embryos, including normal and no cotyledonary embryos, were rescued from 38 fruits harvested out of 70 crosses between `Scania' and `Amapola'. Embryos were rescued 21 to 28 days after pollination by culture in a modified E20A (Sauton and Vaulx, 1987) medium. Phosphogluco isomerase (PGI) and Shikimic dehydrogenase (SDH) zymograms in starch gel electrophoresis, and AAP in polyacrilamide gel electrophoresis, indicated the parthenogenic origin of three of the regenerated plants. Flow cytometry of nuclei proved the early diploidization, during in-vitro micropropagation, of the parthenogenic carnation haploid plantlets.
Growth and Productivity of Tropical Leaf Vegetables in the Virgin Islands
Authors: Palada M.C. , Crossman S.M.A. , Kowalski J.A.
Published: February 2019

Four tropical leaf vegetables commonly used as pot herbs for “kallaloo,” a local West Indian dish, were grown in replicated plots during the fall season of 1996 to determine growth and productivity. Leaf vegetables included green malabar spinach (Basella alba L.), red malabar spinach (Basella rubra L.), sweetpotato (Ipomoea batatas L.), and bush okra or jute mallow (Corchorus olitorius L.). Plants were harvested periodically and data on number of stems or vines, fresh weight of stems and leaves, leaf area, and leaf area index (LAI) were recorded. Except for leaf fresh weight, cultivars or species did not differ significantly in all parameters measured. Leaf fresh weight ranged from 27 g for jute mallow to 198 g for red malabar spinach. LAI was highest for sweetpotato (2.90) and lowest for jute mallow (0.86). Among the species, productivity (fresh weight) was highest (6.78 g/m2 per day) for green malabar spinach and lowest (3.22 g/m2 per day) for jute mallow.
Influence of Suaeda salsa as a Companion Crop with Tomato Plant in a Closed Root System
Authors: Albahou M.S. , Green J.L.
Published: February 2019

The use of the halophyte Suaeda salsa as a salt absorber in saline soils has been exploited as an attempt to increase crop productivity in marginal saline soils. The shoot and root salt contents of this halophyte has been documented to reach up to 27% and 12% of dry weights. The sodium salinity stress of the growth media [peat:vermiculite (1:1 by volume)] may be alleviated by planting the Suaeda with tomato plant in the same root pouch of a completely closed root environment, referred to as the closed insulated pallet system (CIPS). The CIPS is a continuous sub-irrigation capillary system with water moving from reservoir to rootzone in response to plant uptake. In CIPS, fertilizer reserve is placed at the top surface of the root matrix, so fertilizer ions move downward by diffusion. The objective of the present research was to utilize the Suaeda salsa as a bio-desalinator, so salinity of the growth media is reduced, thus reducing the salt uptake by the tomato cv. `Pik Red'. Two salinity levels (control and 4 g/L NaCl in the sub-irrigation water) were imposed on tomato plants or tomato grown with Suaeda in the same pouch. Sodium contents were reduced 56.4% and 37.1% in the growth media and tomato foliage, respectively, in the presence of the halophyte during a 110-day growing period. Likewise, the electrical conductivity of the growth media was reduced by 31.1% with Suaeda companionship. The Suaeda had accumulated salts up to 4.1 mg/g dry weight tissues. The results seem promising; however, growth and yield of tomato plants grown with the halophyte were significantly decreased, probably due to competition for nitrogen and/or light. Research is underway for development of the CIPS to better accomodate crop companionship.
Winter Legume Cover for Sustainable Tomato Production
Authors: Singh Bharat P. , Whitehead Wayne F.
Published: February 2019

The purpose of this study was to compare the efficacy of winter cover cropping with legumes for replacing synthetic N fertilization in tomato production. The following winter/spring fertility treatments were applied: 1) 0 N winter/ 0 N spring, 2) 0 N winter/90 kg·ha-1 N spring, 3) 0 N winter/180 kg·ha-1 N spring, 4) 0 N winter+rye/0 N spring, 5) 0 N winter+hairy vetch/0 N spring, and 6) 0 N winter+crimson clover/0 N spring. In the spring of 1996, tomato cultivar `Mountain Pride' was planted in all plots. The effects of different treatments on plant dry weight and fresh fruit yields were determined. Tomato following legumes or supplied with 90 kg·ha-1 fertilizer N produced highest plant dry weight, while 0 N winter/0 N spring and 0 N winter+rye/0 N spring produced plants with least dry weights. Treatments differed in a similar fashion also for fresh fruit yields. The results suggested that winter legumes were at par with commercial N fertilizer in supplying needed inorganic N to the succeeding tomato crop soil.
Photoperiod and Temperature Affect Lamium, Scaevola, Verbena, and Calibracoa Development and Propagation
Authors: Cutlan A. , Erwin J.E. , Huntington H. , Huntington J.
Published: February 2019

Lamium maculatum L. `White Nancy', Scaevola aemula R. `New Blue Wonder', Verbena × hybrida Groenl. & Ruempl. `Tapian Blue', and Calibracoa × hybrida `Cherry Pink' were placed under different photoperiod treatments at constant 15, 20, 25, or 30 ± 2°C air temperature. Photoperiod treatments were 9 hr, ambient daylight (≈8 hr) plus night interruption lighting (2200–0200 hr, 2 μmol·m–2·s–1 from incandescent lamps), or ambient daylight plus continuous light (100 μmol·m–2·s–1 light from high-pressure sodium lamps). Data on plant development and rootability of cuttings from each environment was collected. Days to anthesis was lowest when plants were grown under the continuous lighting treatment across species. Verbena and Calibracoa stem elongation was greatest when grown under 30°C under continuous lighting. Species were classified as to photoperiodic flower induction groups. Implications of these data with respect to propagating and finishing these crops are discussed.
Manipulation of Low Temperature and Light Quality for Storage of Broccoli in Vitro
Authors: Wilson Sandra B. , Iwabuchi Keiko , Rajapakse Nihal C. , Young Roy E.
Published: February 2019

Storage systems for tissue-cultured plants offer versatility in managing labor to meet market availability. Storage systems that minimize growth and yet sustain photosynthetic and regrowth potential require temperature, light quality, and light intensity to be manipulated for plantlet quality during and after storage. Broccoli (Brassica oleracea L. Botrytis Group `Green Duke') plantlets were cultured photoautotrophically (without sugar) or photomixotrophically (with sugar) on cellulose plugs in liquid medium in vitro for 3 weeks at 23°C and 150 μmol·m–2·s–1 photosynthetic photon flux (PPF). To determine the conditions that yield a zero carbon balance, plantlets were subsequently stored for 3 days under different temperatures (1°C, 5°C, 10°C, 15°C), different light intensities (1.6 PPF, 4.1 PPF, 8.6 PPF), and different light spectra (white, blue, red). Plantlets stored under 5 PPF and 5°C maintained a zero carbon balance. Subsequently, plantlets were stored for 4, 8, or 12 weeks at 5°C under darkness or 5 PPF of white, red or blue light. Stem elongation was observed for plantlets stored under blue light. Plantlets stored under red light were characterized by increased chlorophyll, increased specific leaf mass (leaf dry mass per unit leaf area, SLM), increased starch in leaf tissue, and increased total soluble sugars in leaf and stem tissue. Plantlets grown with sucrose were characterized by increased dry mass, regardless of light treatment. After 8 weeks, plantlets grown with or without sucrose and stored in darkness did not survive acclimatization to greenhouse.
Water Transfer in a Papaya/Corn Split-root Culture System
Authors: Marler Thomas E. , Discekici Haluk M.
Published: February 2019

`Honey Jean #3' sweet corn was planted in one-half of a split-root culture system containing `Tainung 1' or `Known You 1' papaya seedlings to determine if papaya roots could transfer water to the corn seedlings. After the corn seedlings were established, water was withheld from both compartments (2/2) or only the compartment containing the corn seedlings (1/2). Control plants were grown with both halves well-watered. Pre-dawn relative water content (RWC) of corn leaves was measured as an indicator of drought stress. Following 11 days, root competition was relieved in half of the 1/2 plants by cutting the papaya root connection between the half with corn from the rest of the papaya culture system. RWC of 1/2 corn plants was maintained above that of 2/2 plants, but below that of control plants. After relieving root competition, the 1/2 plants in competition with papaya roots maintained higher RWC than the 1/2 plants relieved of competition. Leaf tissue of all corn plants except the control plants was necrotic by 30 days. The results indicate that development of drought stress in corn using this culture system was retarded by watering a portion of the papaya roots not associated with the corn roots. Drought stress was accelerated by relief of competition with papaya, which is evidence that water was being supplied by the papaya roots within the papaya/corn system.
Heat Stress and Chilling Sensitivity of Tomato Fruit
Authors: McDonald R.E. , McCollum T.G. , Baldwin E.A.
Published: February 2019

Mature green `Sunbeam' tomato fruit (Lycopersicon esculentum Mill.) were treated in water for 1 hr at 27 (ambient), 39, 42, 45, or 48°C, and then either ripened at 20°C (nonchilled) or stored at 2°C (chilled) for 14 days before ripening at 20°C. The most-effective heat treatment was 42°C, which reduced decay 67% in chilled fruit and 53% in nonchilled fruit. Heat treatment had no effect on time required to ripen the fruit. Red-ripe tomatoes had higher respiration rates and evolved more ethylene following nonchilling storage, but heat treatment had no effect on respiration or ethylene evolution. Red color development was enhanced by heat treatment, and inhibited by chilling. At red ripe, fruit were firmer as a result of storage at the chilling temperature, while heat treatment had no effect on firmness. Heat-treated fruit were preferred in terms of taste and texture over nontreated fruit in informal taste tests, with the exception of the 45°C treatment. With increasing temperature of heat treatment, there was increased electrolyte leakage following chilling storage. Of the 15 flavor volatiles analyzed, the levels of five were decreased with increasing temperature of heat treatment. Storage at the chilling temperature reduced the levels of six flavor volatiles. Prestorage heat treatments can reduce decay with only minimal adverse effects on tomato fruit quality.
Lipid Peroxidation Products in Tomato Fruit (Lycopersicon esculentum) during Storage after Exposure to Hormic Doses of UV Light
Authors: Barka Essaid Ait , Kalantari Siamak , Arul Joseph
Published: February 2019

Fresh fruit and vegetables are highly perishable because of their active metabolism during the postharvest phase. Previous studies showed that hormic dose of UV cause a delay in the senescence of tomato fruit by about 7 days. The objective of this study was to elucidate whether UV acts on the cell membrane in producing the phenomenon of delayed senescence, since it is known that UV radiation can provoke photooxidation of membrane lipids. Membrane lipid peroxidation was studied in tomato fruit (Lycopersicon esculentum Mill cv. Trust) treated by hormic UV dose, and was followed by assaying products of lipid oxidation during the storage period. We observed the production of lipofuscin-like compounds, malondialdehyde, aldehydes, pentane, ethane, and hydrogen peroxide within few days of the treatment. An increase in the efflux of electrolytes (total, potassium, and calcium) was also observed. An immediate increase in the level of these products of oxidation supports the hypothesis that UV radiation induces membrane lipid peroxidation. However, beyond 5 to 7 days after treatment, the production of oxidation products and electrolyte leakage were lower than the control fruits. Thereafter, the level of products of lipid oxidation associated with senescence was higher in control fruits than in treated ones. Results suggest that the initial oxidation stress by the exposure to UV led to biochemical reactions inducing the production of stress compounds, such as polyamines, which are non specific antioxidants. Consequently, a delay in the senescence was observed.
Are the “Dentatun” Complex of Viburnum Species Genetically Distinct?
Authors: Shoemaker Candice A. , Barnett Michael
Published: February 2019

Viburnum bracteatum Rehd. is a member of the “dentatum” complex represented by at least three types: V. bracteatum, V. dentatum L., and V. rafinesquianum Schult. V. bracteatum is an endangered species in Georgia and at the federal level is a candidate as an endangered species. Two populations were located in northwestern Georgia; however, there is some concern as to whether they are in fact V. bracteatum. To determine if it is possible to distinguish between the three Viburnum species, cellulose acetate electrophoresis to detect isozyme variation was done. Polymorphic enzymes resolved were alcohol dehydrogenase, malic dehydrogenase, glucose-6-phosphate dehydrogenase, malic enzyme, 6-phosphogluconate dehydrogenase, phosphoglucomutase, and phosphoglucose isomerase. Fresh bud tissue was used, and tissue samples were electrophoresed three times for each enzyme assayed. A review of 100 phylogeny trees created with Dollop analysis was done. V. rafinesquianum, the known sample of V. bracteatum, and the 12 samples of possible V. bracteatum were all equally parsimonious. V. dentatum was consistently an outgroup. In conclusion, isozyme variation can assist in Viburnum species distinction.
Assessment and Evaluation Program for the Australian Native Flower, Ixodia achillaeoides
Authors: Barth Gail E.
Published: February 2019

A research program is being conducted to support the development of superior varieties of Ixodia achillaeoides for cut flower production. This species is an everlasting daisy in the Asteraceae, which is produced on a woody perennial bush and is currently both harvested from the wild and cultivated in Southeastern and Western Australia. Ixodia shows a high degree of variation in plant form, flower characteristics, and flowering dates throughout its geographic distribution. In our assessment program, seedlings are screened for a range of morphological and flowering characteristics, and clonal selections are established under cultivation to assess suitability to row culture. The goal is the development of selections with known flowering characteristics and disease tolerance for fresh and dried flower markets and for flowering pot plants. Description is given of assessment criteria for selection of varieties for dried and fresh markets. Seventy selected varieties are currently being assessed in randomized block plantings at two sites in South Australia. Preliminary results and descriptions are presented for superior selections made for dried flower markets. The postharvest performance of selections for fresh markets will be discussed. Research on control of flowering will be presented.
Effect of Rootstock on Nitrogen and Water Use in Apple Trees
Authors: Khemira H. , Schrader L.E. , Peryea F.J. , Kammereck R. , Burrows R.
Published: February 2019

One-year-old `Fuji' apple trees on six rootstocks (Mark, M.9, M.26, M.7A, MM.106, and MM.111) were compared for N and water uptake and utilization. The trees were potted in sand and subjected to a 75-day N-deprivation period (supplied with modified Hoagland's solution lacking N) to deplete their N reserves. Thereafter, they were supplied with a complete modified Hoagland's solution. Uptake of water and N differed by rootstock. Water and N uptake were positively related to tree dry weight (r = +0.97, P = 0.001). Trees that had the highest N concentrations at planting were the last to set bud during the N-deprivation-phase. Tree size after one growing season depended largely on rootstock girth and whole-tree-Nconcentration at planting (r2 = 0.80, P = 0.0001) regardless of rootstock. Water and N uptake efficiency (liter of water or mg N absorbed per g root dry weight, respectively) differed among the rootstocks, being highest for trees on MM.111 and lowest for trees on M.7A rootstock. Nitrogen and water utilization efficiency (g dry weight gained per mg N or per liter of water absorbed, respectively) were not influenced by the rootstock.
Purification and Characterization of a Prominent Polygalacturonase Isozyme Produced by Phomopsis cucurbitae in Decayed Muskmelon Fruit
Authors: Zhang J.X. , Bruton B.D. , Biles C.L.
Published: February 2019

Phomopsis cucurbitae is a latent infecting pathogen that infects unripe muskmelon fruit, but causes decay after harvest. This fungus causes severe losses during muskmelon fruit storage and marketing in the U.S., Japan, and some Central American countries. Previous studies showed that the fungus produced the cell wall-degrading enzyme polygalacturonase (PG) in both culture and muskmelon fruit tissue. The role of P. cucurbitae PG in the fruit decay process and its relation to latent infection is not well-understood. A prominent PG isozyme produced by the fungus in decayed fruit was purified to homogeneity by a sequence of extraction, ultrafiltration, preparative isoelectric focusing, anion exchange, and gel filtration chromatography. This isozyme exhibited endo-activity, a molecular weight of 54 kDa according to SDS-PAGE, and a pI of 4.2 based on IEF-PAGE. Isozyme activity was optimal at 40–45°C and pH 5.0. It had a Km of 44.7 g/ml and a Vmax of 0.313. The purified isozyme also effectively macerated mature muskmelon fruit tissues. This isozyme was the most prominent of the PG isozymes produced by P. cucurbitae in decaying fruit, and may play an important role in postharvest decay.
Phosphogypsum (CaSO42H2O) Effects on Cantaloupe Postharvest Quality (Cucumis melo L.)
Authors: Ramirez Hugo , Torcates Mary , Perez Jose , Rodriguez Josefina , Perez Marin E.
Published: February 2019

The response of different doses of calcium sulfate or phosphogypsum (PG) on several postharvest quality parameters of `Laguna' cantaloupe hybrid were analyzed in the semi-arid San Francisco experiment station (UCLA), located in the Lara state, Venezuela. The experimental design was a completely randomized block with four treatments (0, 300, 600, and 1200 kg/ha, PG) with five replications. The PG was surface-spread on the irrigation furrows, 1 day before sowing. The fruits were harvested at maturity and stored under an average temperature of 28°C for posterior quality analysis. The PG treatments did not have any effect on the studied parameters: total soluble solids (°Brix), consistency (kg/cm2), diameter, and cavity of the fruit, pulp thickness, and dry and fresh matter. All of the parameters evaluated decreased during the 6 days of storage. These results could be because of the low doses of PG used or because the supply of calcium was not a limitation in these soils.