bluuebunny/crossref_metadata_2025 huggingface dataset:
Color Sorting of Coated Brassica Seeds by Fluorescent Sinapine Leakage to Improve Germination
Authors: Taylor A.G. , Churchill D.B. , Lee S.S. , Bilsland D.M. , Cooper T.M.
Published: January 2019

Color sorting was performed to upgrade seed quality by removal of fluorescent coated seeds. The fluorescent coating was attributed to sinapine leakage from nonviable seeds. Nine seedlots, three seedlots each of cabbage (Brassica oleracea L. Capitata group), broccoli, and cauliflower (B. oleracea L. Botrytis group) were custom coated. Seed samples were pretreated before coating with or without 1.0% NaOCl for 10 minutes to enhance leakage. All samples revealed a percentage of seeds with fluorescence. The light emission from selected fluorescent and nonfluorescent coated seeds was quantified by fiber-optic spectrophotometry. Fluorescence was expressed from 400 to 560 nm, with peak emission being from 430 to 450 nm. These data confirmed our visual interpretation of blue-green fluorescence. The ratio of light emission from fluorescent compared to nonfluorescent coated seeds ranged from 4.5 to 7.0 for all samples and averaged 5.7. An ultraviolet (UV) color sorter was employed to separate fluorescent (reject) from nonfluorescent (accept) coated seeds. The percentage of nonfluorescent coated seeds (averaged over seedlot and NaOCl pretreatment) before and after sorting was 89.5% and 95.9%, respectively. Therefore, color sorting was able to remove a high percentage of fluorescent coated seeds with an average loss (rejection of nonfluorescent coated seeds) of 6%. An increase in the percent germination was recorded in eight of the nine seedlots following color sorting, and the greatest improvement was obtained with seedlots of medium quality. Germination of three medium quality lots was increased by 10 to 15 percentage points. The average increase in germination with or without NaOCl pretreatment was 8.2 and 5.5 percentage points, respectively. In conclusion, the germination of Brassica seedlots could be improved by separating (removing) fluorescent from nonfluorescent coated seeds. UV color sorting technology was employed to demonstrate that seed conditioning could be conducted on a commercial basis to upgrade seed quality.
Postharvest Infiltration of Polyamines and Calcium Influences Ethylene Production and Texture Changes in `Golden Delicious' Apples
Authors: Wang Chien Yi , Conway William S. , Abbott Judith A. , Kramer George F. , Sams Carl E.
Published: January 2019

Prestorage infiltration of `Golden Delicious' apples (Malus domestica Borkh.) with calcium (Ca) retarded texture changes during storage at 0C and inhibited ethylene production of the fruit at 20C. Infiltration of the fruit with the polyamines (PA) putrescine (PUT) or spermidine (SPD) also altered texture changes, but did not inhibit ethylene production. When the fruit were treated with Ca first and then with PA, cell wall-hound Ca concentrations increased 4-fold, but PA levels in the cell wall increased only slightly. When the fruit were treated with PA first and then with Ca, PA levels in the cell wall increased 3-fold, but Ca concentration increased only 2-fold. These results indicate that Ca and PA may he competing for the same binding sites in the cell wall and that the improvement of fruit quality during storage by these cations could involve strengthening of the cell wall.
Heat Tolerance, Cold Hardiness, and Bud Dormancy Relationships in Seedlings of Selected Conifers
Authors: Burr Karen E. , Wallner Stephen J. , Tinus Richard W.
Published: January 2019

Greenhouse-cultured, container-grown seedlings of interior Douglas fir [Pseudotsuga menziesii var. glauca (Beissn.) France], Engelmann spruce [Picea engelmannii (Parry) Engelm.], and ponderosa pine (Pinus ponderosa var. scopulorum Engelm.) were acclimated and deacclimated to cold in growth chambers over 19 weeks. Heat tolerance and cold hardiness of needles, and bud dormancy, were measured weekly. Heat tolerance of Douglas fir and Engelmann spruce needles increased with development through the first complete annual cycle: new needles on actively growing plants; mature needles, not cold-hardy, on dormant plants; cold-hardy needles on dormant and quiescent plants; and mature, needles, not cold-hardy, on actively growing plants. Heat tolerance of ponderosa pine needles differed in two respects. New needles had an intermediate tolerance level to heat, and fully cold-hardy needles were the least tolerant. Thus, the physiological changes that conferred cold hardiness were not associated with greater heat tolerance in all the conifers tested. In none of these species did the timing of changes in heat tolerance coincide consistently with changes in cold hardiness or bud dormancy.
Changes in Susceptibility to Brown Rot with Ripening in Three Clingstone Peach Genotypes
Authors: Gradziel T.M.
Published: January 2019

Susceptibility to brown rot, caused by Monilinia fructicola (Wint.) Honey, changed with fruit ripening in the susceptible clingstone peach [Prunus persica (L.) Batsch] cultivar Corona and two moderately resistant genotypes. Nonwounded fruit were more resistant before epidermis color break from green to yellow. Susceptibility increased from color break to the period when the epidermis had acquired a uniformly yellow ground color. With continued ripening, susceptibility remained constant or decreased, depending on genotype. A ripeness index based on fruit color permitted objective within and between genotype comparisons of susceptibility. The genetic selection for precociously developing high yellow-orange flesh color has resulted in a clingstone peach selection possessing a flesh quality suitable for processing and with high levels of brown-rot resistance at the mature-green fruit development stage.
Inheritance; Low Correlations of Leaf, Pod, and Seed Reactions to Common Blight Disease in Common Beans; and Implications for Selection
Authors: Arnaud-Santana Eladio , Coyne D.P. , Eskridge K.M. , Vidaver A.K.
Published: January 2019

The heritability of leaf, pod, and seed reactions; stem color and abaxial leaf pubescence; and the association of these traits were studied in advanced dry bean recombinant inbred lines derived from the Phaseolus vulgaris crosses `PC-SO' × XAN-159, `PC-50' × BAC-6, and `Venezuela 44' × BAC-6. The reaction to Xcp was quantitatively inherited in all three plant organs. Qualitative inheritance was found for stem color and leaf pubescence. Low to intermediate heritability values were obtained for the leaf and seed reactions to Xcp. Heritability estimates were consistently low for the pod reaction to Xcp. Low nonsignificant Pearson correlations were detected between leaf and pod reactions, leaf and seed reactions, and pod and seed reactions, except for the latter two correlations, which were low and significant in lines from the cross `PC-50' × XAN-154. Genetic correlations between leaf and pod reactions and leaf and seed reactions were low and significant in lines from all crosses, except for Venezuela 44 × BAC-6 in the latter case. Genetic correlations between pod and seed reactions were low and nonsignificant, except in the cross `PC-50' × XAN-159, for which a low significant correlation was observed. No significant association was found between Xcp leaf reaction and stem color or leaf pubescence. A breeding strategy for improving resistance to Xcp in P. vulgaris is discussed.
Linkage Analysis of Ten Isozyme Genes in F1 Segregating Almond Progenies
Authors: Arús Pere , Olarte Carmen , Romero Miguel , Vargas Francisco
Published: January 2019

Ten isozyme genes were studied after analyzing the variability of eight enzyme systems—glucose phosphate isomerase (GPI), phosphoglucomutase (PGM), aspartate aminotransferase (AAT), leucine aminopeptidase (LAP), 6-phosphogluconate dehydrogenase (6PGD), isocitrate dehydrogenase (IDH), shikimate dehydrogenase (SDH), and aconitase (ACO)—in the progeny of five crosses among almond [Prunus amygdalus Batsch, syn. P. dulcis (Miller) D. A. Webb] cultivars. Six of these loci were found to be located in two linkage groups, one containing four loci (Pgm-2, Gpi-2, Aat-2, and Lap-1) and two more in the other (Idh-2 and Aat-1). Genetic configurations of pairs of loci specific to segregating F1 progeny of crosses between heterozygous parents were found in our data, for which we derived the estimate of the recombination fraction and its variance. Linkage data for the gene pairs that could be estimated in various crosses were used to obtain a joint estimation of the recombination fraction.
Tree Structure and Pruning Response of Six Peach Growth Forms
Authors: Bassi D. , Dima A. , Scorza R.
Published: January 2019

The response of young, nonbearing peach [Prunus persica (L.) Batsch] trees to pruning was studied in six distinct growth forms including semidwarf, spur-type, upright, columnar or pillar, weeping, and standard. Two years after field planting, pillar and upright trees were trained to slender spindle. Semidwarf, spur-type, and standard trees were trained to the open or delayed vase form. Weeping trees were pruned in a manner similar to the Lepage hedge for pear. Branch density before pruning was highest in semidwarf, spur-type, and upright trees and lowest in pillar trees. Standard, semidwarf, and spur-type trees reacted similarly to pruning, but semidwarf trees produced as much wood in the following season as had been pruned off, and produced large numbers of fruiting branches. The small size of semidwarf trees suggested their use for medium-density plantings (MDPs). Pillar trees needed only light pruning. No major cuts were necessary and many fruiting branches were produced even on nonpruned trees. The pillar canopy was 60% thinner and required 50% fewer pruning cuts than the standard canopy and may be particularly suited to high-density plantings (HDPs). The upper canopy of weeping trees grew more than most other forms. They were intermediate in branch density and required an intermediate amount of pruning. Most striking was the unique canopy form of weeping trees, which may be used in developing new training systems. The results of this study suggest that new growth forms have the potential to reduce pruning and training requirements for peach, particularly in MDPs and HDPs. This potential suggests further investigation and exploitation of alternate peach tree growth forms.
Modified-atmosphere Packaging of `Heritage' Red Raspberry Fruit: Respiratory Response to Reduced Oxygen, Enhanced Carbon Dioxide, and Temperature
Authors: Joles Dennis W. , Cameron Arthur C. , Shirazi Ahmad , Petracek Peter D. , Beaudry Randolph M.
Published: January 2019

`Heritage' raspberries (Rubus idaeus L.) were sealed in low-density polyethylene packages and stored at 0, 10, and 20C during Fall 1990 and 1991 to study respiratory responses under modified atmospheres. A range of steady-state O2 and CO2 partial pressures were achieved by varying fruit weight in packages of a specific surface area and film thickness. Film permeability to O2 and CO2 was measured and combined with surface area and film thickness to estimate total package permeability. Rates of O2 uptake and CO2 production and respiratory quotient (RQ) were calculated using steady-state O2 and CO2 partial pressures, total package permeability, and fruit weight. The O2 uptake rate decreased with decreasing O2 partial pressure over the range of partial pressure studied. The Michaelis-Menten equation was used to model O2 uptake as a function of O2 partial pressure and temperature. The apparent Km(K½) remained constant (5.6 kPa O2 with temperature, while Q10 was estimated to be 1.9. RQ was modeled as a function of O2 partial pressure and temperature. Headspace ethanol increased at RQs >1.3 to 1.5. Based on RQ, ethanol production, and flavor, we recommend that raspberries be stored at O2 levels above 4 kPa at 0C, 6 kPa at 10C, and 8 kPa at 20C. Steady-state CO2 partial pressures of 3 to 17 kPa had little or no effect on O2 uptake or headspace ethanol partial pressures at 20C.
A Volatile Ethylene Inhibitor Improves the Postharvest Life of Potted Roses
Authors: Serek Margrethe , Reid Michael S. , Sisler Edward C.
Published: January 2019

Pretreating `Victory Parade' potted miniature roses (Rosa hybrida L.) with photolyzed diazocyclopentadiene (DACP) inhibited the effects of exogenous ethylene (acceleration of leaf and bud drop). In an ethylene-free simulated interior environment, display life of the treated plants was also greater than that of the controls and similar to that of plants pretreated with the anionic silver thiosulfate complex (STS). DACP caused an increase in the binding constant for ethylene in petals and leaves of `Victory Parade' and `Cara Mia' (a cut-flower rose cultivar). Competitive kinetics for the effects of increasing ethylene concentrations on control and DACP-treated plants are consistent with the hypothesis that the effects of DACP are due to irreversible binding to the ethylene-binding site.
Germination of Osmotically Primed Asparagus and Tomato Seeds after Storage up to Three Months
Authors: Owen Paul L. , Pill Wallace G.
Published: January 2019

The influence of two drying regimes and two storage temperatures of primed asparagus (Asparagus officinalis L.) and tomato (Lycopersicon esculentum Mill.) seeds on germination after storage up to 3 months was examined. Seeds of `Mary Washington' asparagus and `Ace 55' tomato primed in synthetic seawater (-1.0 MPa, 20C, 1 week, dark) were surface-dried at 20C and 50% relative humidity (RH) for 2 h (42% to 49% moisture) or dried-back at 20C and 32.5% RH for 48 h (moisture = 13% tomato and 22% asparagus). These and nonprimed seeds were stored in tight-lidded metal cans and heat-sealed plastic pouches at 4 or 20C for up to 3 months before germination at 20C. After 3-month storage, primed surface-dried asparagus seeds stored at 4C had greater germination percentage and rate than nonprimed seeds, surface-dried seeds stored at 20C, or primed dried-back seeds. Dried-back primed tomato seeds had higher germination percentage than surface-dried primed seeds after 2 or 3 months of storage, with storage temperature having no effect on germination perecentage or rate. In a further study, primed surface-dried and primed dried-back seeds stored at 4 or 20C for 1.5 months in sealed containers were germinated at 15, 25, or 35C under low (-0.05 MPa) or high osmotic stress (-0.4 MPa). Primed surface-dried asparagus seeds stored at 4C, compared to nonprimed seeds, surface-dried seed stored at 20C, or primed dried-back seeds, had greater germination percentage at 15 and 35C and low osmotic stress, and higher germination rate at 15 or 25C. Primed tomato seeds had greater germination percentage than nonprimed seeds only at 35C and low osmotic stress, and higher germination rate at 15 or 25C. Storage of primed tomato seeds at 4C rather than 20C increased germination rate at 15 or 25C, and increased germination percentage at 35C and low osmotic stress. For maximal seed viability and germination rate after 1.5 to 3 months of storage, primed asparagus and tomato seeds should be stored at 4C rather than 20C; however, asparagus seeds should be surface-dried, and tomato seeds should be dried-back.
Inheritance of A and B Glandular Trichome Density and Polyphenol Oxidase Activity in Diploid Potatoes
Authors: Vallejo Roger L. , Collins Wanda W. , Moll Robert H.
Published: January 2019

Glandular trichomes from some Solanum species have suppressed infestation by insects including green peach aphid, which is a main vector of potato virus Y (PVY) and potato leaf roll virus (PLRV), both of which contribute to a serious loss in potato production. Eight Solanum phureja Juz. et Buk.-S. stenotomum Juz. (Phu-Stn), three S. berthaultii Hawkes (Ber), nine F1 [(Phu-Stn) × Ber], fifteen backcross (BC) [(Phu-Stn) × F1], and seventeen reciprocal BC (BCR) [F1 × (Phu-Stn)] families were evaluated to determine the genetic variability and heritability of A and B glandular trichome density and polyphenol oxidase (PPO) activity. Experiments were carried out in completely randomized and randomized complete-block designs in the greenhouse. Genetic analysis was done using half-sib family and parent-offspring regression analysis. Phu-Stn showed a higher density of A trichomes than Ber and F1, while the BC and BCR had densities of A trichomes similar to Phu-Stn. B trichomes were not observed in Phu-Stn. Ber showed a high B trichome density, which was transmitted to the F1. In the BC, B trichomes were almost absent, but, in the BCR, the density of B trichomes was higher than that of BC. Ber and F1 had similar or higher PPO activity than Phu-Stn. PPO activity decreased in the BC, but, in the BCR, it was high and similar to Ber and F1. Broad-sense heritability estimates for A and B trichome density and PPO activity were from medium to high (0.48 to 0.77) in Phu-Stn, Ber, and F1. Narrow-sense heritability estimates for A and B trichome density and PPO activity were very low (0.04 to 0.24) in BC and BCR. In the BC families, additive genetic variance was very low for A and B trichome density and PPO activity. Half-sib family selection based on progeny testing and combined with BCs to Phu-Stn in subsequent generations would be a suggested breeding procedure to improve these traits. Phenotypic correlations between A and B trichome densities were 0.26 (F1) and 0.44 (BCR), between A trichome density and PPO activity 0.20 (F1) and 0.31 (BCR), and between B trichome density and PPO activity 0.04 (F1) and 0.27(BCR. Positive associations found between traits might facilitate simultaneous improvement for high levels of A and B trichome density and PPO activity.
Genetic Relationships and Characterization of Persian Walnut (Juglans regia L.) Cultivars Using Restriction Fragment Length Polymorphisms (RFLPs)
Authors: Fjellstrom R.G. , Parfitt D.E. , McGranahan G.H.
Published: January 2019

RFLP markers were used to investigate genetic diversity among California walnut (Juglans regia) cultivars and germplasm collected worldwide. Sixteen of 21 RFLP markers were polymorphic in the 48 walnut accessions tested. RFLP markers were useful for identifying walnut cultivars. All genotypes were heterozygous at ≈20% of the loci for both California and worldwide germplasm. California walnut germplasm contained 60% of the worldwide allelic diversity. Cluster analysis of genetic distance between accessions and principal component analysis of allelic genotypes showed two major groups of walnut domestication. California germplasm was associated with germplasm from France, central Europe, and Iran and had less genotypic similarity with germplasm from Nepal, China, Korea, and Japan.
Environmental Effects on Blueberry Flower Size and Shape Are Minor
Authors: Lyrene Paul M.
Published: January 2019

The effects of environmental factors, including chilling duration during dormancy and temperature during flower bud expansion, were studied on the following blueberry flower parameters: corolla length, corolla aperture diameter, stigma location relative to the apex of the corolla tube, position of the anthers relative to the stigma and to the apex of the corolla, and style length. Flowers on plants that were chilled over 1400 hours differed little from those that received only 310 chill units. Flowers that developed under warmer temperatures had significantly wider corolla apertures. In one experiment but not the other, corolla length and style length increased under warmer temperatures. For nearly every parameter in each of three experiments, there were significant environment × clone interactions. Overall, however, it appeared that neither lack of chill units during dormancy nor warm temperatures during flower development changed flower morphology enough to affect fruit set.
Resistance to Fusarium oxysporum at Different Developmental Stages of Asiatic Hybrid Lilies
Authors: Straathof Th.P. , Löffler H.J.M.
Published: January 2019

Tests for determining resistance to Fusarium oxysporum f.sp. lilii in different developmental stages of Lilium were developed. Under standardized conditions, commercial bulbs, yearling bulbs, scale bulblets, and scales of 16 Asiatic lily cultivars were tested for Fusarium resistance. Disease ratings were analyzed statistically using a threshold model for ordered categorical data. For each cultivar in each stage the resistance level was calculated as the disease severity score (DSS). Disease severity score values of cultivars in the four stages were reproducible between experiments, although some variation in cultivars was found. This variation may be attributed to the origin of plant material. Disease severity score values among cultivars in each developmental stage were correlated with the average DSS over all four stages, although some specific cultivar-stage deviations were found. The scale test is recommended for early selection while the scale bulblet test is recommended as a final check.
Apical Dominance in Apple (Malus domestica Borkh): The Possible Role of Indole-3-Acetic Acid (IAA)
Authors: Wang Shiow Y. , Faust Miklos , Line Michael J.
Published: January 2019

The effect of IAA on apical dominance in apple buds was examined in relation to changes in proton density (free water) and membrane lipid composition in lateral buds. Decapitation induced budbreak and enhanced lateral bud growth. IAA replaced apical control of lateral buds and maintained paradormancy. Maximal inhibition was obtained when IAA was applied immediately after the apical bud was removed; delaying application reduced the effect of IAA. An increase in proton density in lateral buds was observed 2 days after decapitation, whereas the change in membrane lipid composition occurred 4 days later. Removing the terminal bud increased membrane galacto- and phospholipids and the ratio of unsaturated to corresponding saturated fatty acids. Decapitation also decreased the ratio of free sterols to phospholipids in lateral buds. Applying thidiazuron to lateral buds of decapitated shoots enhanced these effects, whereas applying IAA to the terminal end of decapitated shoots inhibited the increase of proton density and prevented changes in membrane lipid composition in lateral buds. These results suggest that change in water movement alters membrane lipid composition and then induces lateral bud growth. IAA, presumably produced by the terminal bud, restricts the movement of water to lateral buds and inhibits their growth in apple.
Effect of Potassium, Magnesium, and Calcium Deficiencies on Carbohydrate Pools and Metabolism in Citrus Leaves
Authors: Lavon Ruth , Goldschmidt Eliezer E. , Salomon Rafael , Frank Andre
Published: January 2019

Carbohydrate content and related enzyme activities were determined in leaves of rough-lemon (Citrus volkameriana Ten. & Pasq) plants grown under K, Mg, and Ca deficiencies. Starch content was lower and soluble sugar significantly higher in K-deficient than in control leaves. Magnesium- and Ca-deficient leaves, on the other hand, accumulated large amounts of starch. Electron micrographs also showed a reduction in the number and size of starch grains in chloroplasts of K-deficient leaves, while those of Mg- and Ca-deficient leaves were filled with large starch grains. Total amylase activity increased 3- to 7-fold in K-deficient leaves, with maltose as the major product and small amounts of maltotriose. Electrophoretic separation of amylase isozymes on native gels containing starch or amylopectin showed higher band intensities in K-deficient leaves. Examination of the capacity of leaf extracts to use amylopectin vs. β-limit dextrin indicated that mainly 8-amylase was involved. Acid invertase activity increased 7-fold in K-deficient leaves, while alkaline invertase showed little change.
Gas Exchange, Water Relations, and Dry Weight Partitioning during Root Initiation and Development of Poinsettia Cuttings
Authors: Svenson Sven E. , Davies Fred T. , Duray Sharon A.
Published: January 2019

Gas exchange, water relations, and dry weight partitioning of shoot tip cuttings of `Eckespoint Lilo Red' (`Lilo') and `Gutbier V-10 Amy Red' (`Amy') poinsettia (Euphorbia pulcherrima Wind. ex Klotzsch) were studied during the initiation and development of adventitious roots. Net photosynthesis (A) and stomatal conductance (g) of cuttings were initially low and remained low until root primordia formation. Foliar relative water content (RWC) and osmotic potential (ψπ) increased upon formation of root primordia. Following formation of root primordia (2 days before visible root emergence) and concurrent with increasing RWC and ψπ, g increased. As roots initially emerged, A and g increased rapidly and continued to increase with further root primordia development and subsequent emergence of adventitious roots. Cutting stem and leaf dry mass and leaf area increased during the first few days after sticking cuttings. During primordium development and initial root emergence, the highest percent increase in dry weight was accounted for by basal stem sections. AU cuttings of both cultivars rooted and had similar root numbers after 23 days, but `Lilo' cuttings had 15% better rooting and 44% more roots than `Amy' after 15 days. This research supports the hypothesis that formation and elongation of root primordia coincides with increased gas exchange in poinsettia cuttings, and that gas exchange can be used as a nondestructive indicator of adventitious root development.
The Use of Molecular Markers to Analyze the Inheritance of Morphological and Developmental Traits in Apple
Authors: Lawson Darlene M. , Hemmat Minou , Weeden Norman F.
Published: January 2019

Five morphological and developmental traits (branching habit, vegetative budbreak, reproductive budbreak, bloom time, and root suckering) were analyzed in a family obtained from the apple (Malus domestica Borkh) cross `Rome Beauty' × `White Angel'. The phenotypic variation in these traits was compared with a selected set of marker loci covering the known genome of each of the parents to locate genes with major effects on the traits. The contrasting branching habits of the two parents appeared to be controlled by at least two loci. One of these, Tb, governed the presence or absence of lateral branches, particularly on the lower half of shoots. The locus was heterozygous in `White Angel' and was mapped to a 5 CM interval on linkage group 6. At least one other locus conditioning spur-type branching appeared to be segregating, but the locus or loci could not be linked to segregating markers. The timing of initial vegetative growth was tightly associated with the chromosomal region in which the Tb gene is located and maybe a pleiotropic effect of this gene. Time of reproductive budbreak correlated with segregation at the isozyme marker, Prx-c, on linkage group 5. Variation in time of bloom and later stages in flower development appeared to be controlled by different genes not linked to Prx-c. The tendency to produce root suckers cosegregated with a marker on `White Angel' linkage group 1, suggesting control by a single locus, Rs. Data from a `Rome Beauty' x `Robusta 5' family provided additional information on the inheritance of these traits.
Characterizing NAD- and NADP-dependent Alcohol Dehydrogenase Enzymes of Strawberries
Authors: Mitchell William C. , Jelenkovic Gojko
Published: January 2019

The NAD-dependent and NADP-dependent alcohol dehydrogenase activities of strawberries (Fragaria xananassa Duch.) were found to have broad substrate specificities including those alcohols and aldehydes responsible for strawberry aroma and flavor either directly or through their ester products. NAD-dependent activities were greatest against short-chained alcohols, whereas the NADP-dependent activities were most active against aromatic and terpene alcohols. Differences were seen in substrate specificity between receptacle and achene alcohol dehydrogenase activities. Alcohol dehydrogenase activities were found to be developmentally regulated in receptacle tissue and increased during the period of fruit maturation and ripening. Isoelectric focusing of NAD-dependent ADH activities showed that several isozymes of this enzyme exist, that they differ between receptacle and achene tissues, and that they vary among specific genotypes. Our results suggest that NAD- and NADP-dependent ADH activities are integral components of flavor and fragrance volatile production in ripening strawberries.
Monitoring Prunus Necrotic Ringspot Virus Infection by Hybridization with a cRNA Probe after in vitro Micrografting
Authors: Heuss-LaRosa Kathleen , Hammond Rosemarie , Crosslin James M. , Hazel' Christine , Hammerschlag Freddi A.
Published: January 2019

In vitro micrografting was tested as a technique for inoculating peach [Prunus persica (L.) Batsch] shoot cultures with Prunus necrotic ringspot virus (PNRSV). Cultured `Suncrest' shoots derived from a naturally infected tree (as indicated by ELISA testing) maintained virus in vitro, with virus concentrations in growing tips and folded leaves being several times those of fully expanded leaves. Infected shoots served as graft bases and source of the virus. Grafted tips were derived from `Suncrest' trees that had tested negative for the virus. Leaf samples were collected from the tips following grafting and analyzed for the presence of virus by slot-blot hybridization with a (DIG)-labeled cRNA probe derived from PNRSV RNA 3. Rates of successful grafting ranged from 55% to 73% in three trials and PNRSV was found in all tips analyzed. Virus concentrations approximated those found in source shoots, suggesting that in vitro micrografting should be useful for screening transformed peach shoots for coat protein-mediated resistance to PNRSV. Chemical name used: digoxigenin (DIG).
Growth and Yield Sensitivity of Four Vegetable Crops to Soil Compaction
Authors: Wolfe David W. , Topoleski Daniel T. , Gundersheim Norman A. , Ingall Betsy A.
Published: January 2019

A 3-year field study conducted on an Eel silt loam soil (Aquic Udifluvent) compared cabbage (Brussica oleracea L. capitata group), cucumber (Cucumis sativus L.), snap bean (Phaseolus vulgaris L.), and sweet corn (Zea mays L.) for their growth and yield response to an artificially compacted soil layer beginning at about the 10-cm depth. Slower growing cabbage seedlings in compacted plots were more subject to flea beetle damage than the uncompacted controls. Prolonged flooding after heavy rainfall events in compacted areas had a more adverse effect on cabbage and snap bean than on cucumber or sweet corn. Sweet corn showed almost no growth reduction in one of the three years (1993) when relatively high fertilizer rates were applied and leaf nitrogen deficiencies in compacted plots were prevented. Maturity of cabbage, snap bean, and cucumber was delayed, and the average reduction in total marketable yield in (direct-seeded) compacted plots was 73%, 49%, 41%, and 34% for cabbage, snap bean, cucumber and sweet corn, respectively. Yield reduction in transplanted cabbage (evaluated in 1993 only) was 29%. In a controlled environment greenhouse experiment using the same soil type and similar compaction treatment as the field study, compaction caused a reduction in total biomass production of 30% and 14% in snap bean and cabbage, respectively, while cucumber and sweet corn showed no significant response. The growth reductions of snap bean and cabbage in the greenhouse could not be attributed to compaction effects on soil water status, leaf turgor, nutrient deficiency, or net CO, assimilation rate of individual leaves. Root growth of sweet corn was least restricted by the compacted soil layer. The contrast between our field and greenhouse results indicates that the magnitude of yield response to compaction in the field was often associated with species sensitivity to secondary effects of compaction, such as prolonged flooding after rainfall events, reduced nutrient availability or uptake, and prolonged or more severe pest pressure.
Shoot Growth Rate and Density Affect Bud Necrosis of `Riesling' Grapevines
Authors: Wolf Tony K. , Warren M. Kay
Published: January 2019

Examination of `Riesling' grape (Vitis vinifera L.) in Virginia suggested that a high incidence of bud necrosis (BN) in some vineyards was associated with canopy shade and rapid shoot growth. BN appeared to originate as an abortion and dehydration of the primary, and occasionally secondary, buds of the developing dormant bud. BN frequency was lowest among the basal four nodes of a given shoot or cane, and increased in frequency through node 20. Experiments were conducted in 1991 and 1992 to evaluate the specific involvement of shoot growth rate and canopy shade on `Riesling' BN. Shoot growth rate (SGR), measured in a 17-day period around bloom, had a significant, positive relationship with BN in one of two vineyards. BN was positively associated with cane diameter and average internode length. Applying the growth retardant paclobutrazol significantly reduced SGR and BN incidence up to 80% among nodes 6 to 15 in two separate vineyards. Artificial shade (64% or 92% reduction in photosynthetic photon flux), suspended over vine canopies in the 3-week period before véraison, did not affect BN. Shoots of canopies that had been thinned before bloom to 10 shoots/m of canopy expressed slightly lower BN levels than shoots sampled from canopies that had been thinned to 20 shoots per meter. `Riesling' BN appeared more influenced by shoot vigor than shade under Virginia growing conditions. Chemical name β-[(4-chlorophenyl)methyl]-α-(1,1-dimethyl-ethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol).
Potassium Fertigation Requirements of Drip-irrigated Strawberry
Authors: Albregts Earl E. , Hochnmth George J. , Chandler Craig K. , Cornell John , Harrison Jay
Published: January 2019

`Oso Grande' and `Sweet Charlie' strawberries (Fragaria × ananassa Duch.) in 1991-92 and `Oso Grande' and `Seascape' in 1992-93 were grown in a K fertilization study using polyethylene-mulched and fumigated beds. Potassium was injected weekly into the drip irrigation system at 0.28,0.56,0.84, 1.12, and 1.40 kg K/ha per day. Early, March, and total-season marketable fruit yields were not affected by K rate during either season. The average fruit weight of `Oso Grande' for the early, March, and total-season harvest periods in the 1992-93 season decreased with increased K rate. For the same harvest periods, `Seascape' average fruit weight increased, decreased, and did not change, respectively, with increased K rate. Cull fruit yield during both seasons and fruit firmness during the 1992-93 season were not affected by K rate. Petiole sap, whole leaf, and leaf blade K concentrations increased with increasing K rates on most sampling dates during both seasons. `Oso Grande' and `Sweet Charlie' produced similar total marketable fruit yields the first season, but `Oso Grande' produced higher total yields than `Seascape' during all harvest periods of the second season.
Molecular Cloning and Characterization of Genes Expressed during Early Tomato (Lycopersicon esculentum Mill.) Fruit Development by mRNA Differential Display
Authors: Tieman Denise M. , Handa Avtar K.
Published: January 2019

The growth of tomato fruit is the result of cell division early in development followed by cell expansion until the onset of ripening. We have utilized the mRNA differential display technique to clone genes differentially expressed in 10- and 20-day-old tomato fruit, when most fruit cells are undergoing a transition to growth by cell expansion. Of 1753 total bands observed using 30 independent primer sets, 31 differential display bands were obtained only in either 10-or 20-day - old fruit RNAs. Seven differentially expressed bands from 10-day-old fruit RNAs and six from 20-day-old fruit RNAs were cloned and characterized by sequence analysis and mRNA expression patterns in developing fruit, leaf and root tissues. Two clones had sequence similarities to 3-deoxy-D-arabino-heptulosonate-7-phosphate (DAHP) synthase or threonine deaminase genes, while the remaining clones did not correspond to previously characterized genes. Steady state levels of mRNAs corresponding to seven clones were upregulated between 10 and 20 days of fruit development, while two clones were downregulated during growth and ripening. Most clones also hybridize to mRNA species present in leaf and root tissues. Collectively, these results suggest a transition in gene expression between 10- and 20-day-old fruit development.
Comparing Stability Indices for Ripening Date and Yield in Blueberry
Authors: Gupton Creighton , Clark John , Creech David , Powell Arlie , Rooks Susan
Published: January 2019

To determine if any of the available techniques for estimating stability in different environments are useful in blueberry (Vaccinium ashei Reade and V. corymbosum L.), 14 clones were evaluated in nine environments for ripening date and yield. Type 1 and 2 stability statistics, plots for each genotype mean versus its coefficient of variation (cv) across environments (genotype grouping), environmental index regression, and cluster analyses were compared. The highest yielding rabbiteye and southern highbush clones across locations were not deemed stable by Type 1 and Type 2 stability statistics, genotype grouping, or environmental regression technique. No evidence of curvilinear response was found. The nonparametric cluster analysis with known cultivars included appears to be most useful compared to other methods of estimating stability used in this study.
Salinity Influences Photosynthetic Characteristics, Water Relations, and Foliar Mineral Composition of Annona squamosa L.
Authors: Marler Thomas E. , Zozor Yasmina
Published: January 2019

Leaf gas exchange, chlorophyll fluorescence, water relations, and mineral nutrient relations responses of Annona squamosa seedlings to mild salinity were studied in sand culture in five experiments during 1990, 1991, and 1993. Trees were irrigated with a complete nutrient solution (control) or with this solution amended to 3 or 6 dS·m-1 with sea salt. Inhibition of net CO2 assimilation, stomatal conductance of CO2, and transpiration was apparent within 2 weeks of initiating salinity treatments, and gas exchange continued to decline until day 30 to 35. The diurnal pattern of leaf gas exchange was not altered by increased salinity. Salinity reduced CO2, light energy, and water-use efficiencies. Salinity sometimes reduced the ratio of variable to maximum fluorescence below that of the control, and this response was highly dependent on the ambient light conditions that preceded the measurements. Dark respiration was unaffected by salinity stress. Root zone salinity of 3 dS·m-1 administered for 52 days did not influence foliar sodium concentration or the ratio of sodium to potassium, but increased chloride concentration and decreased nitrogen concentration. The sodium response indicated that some form of exclusion or compartmentation occurred. Salinity reduced osmotic potential of root tissue but did not influence foliar osmotic or predawn xylem potential. These results indicate that A. squamosa is sensitive to salinity stress, and that the responses to salinity are consistent with other salt-sensitive woody perennial species.
Gamma Irradiation-induced Variation in Carrots (Daucus carota L.)
Authors: Al-Safadi Bassam , Simon Philipp W.
Published: January 2019

Carrot tissue cultures, germinating seed, and dry seed were exposed to gamma radiation. Irradiation accelerated germination of carrot seed in the M1 generation at low doses (0.5 and 1 krad), whereas higher doses delayed germination. A high negative correlation was observed between dose and survival of plants after seed irradiation. Plant size and root weight were 20 % to 35% greater than control plants after seeds, but not tissue cultures, were exposed to low doses of gamma irradiation. Higher doses reduced M1 plant size by >50% in germinating seed and tissue culture treatments but less for the dry seed treatment. Seed production decreased while phenotypic variation of M1 plants increased with increasing gamma ray dosage. Root weight and total dissolved solids were highly variable in M2 families. Less variation was observed in total carotene content and none was seen in sugar type (reducing vs. nonreducing sugars). Induced variation in root color and root shape was also observed. Irradiation of germinating seed and tissue cultures yielded more M2 variation than irradiation of dry seed. Putative point mutations were not observed. Unirradiated carrot tissue cultures did not yield significant M2 somaclonal variation. Average root weight of M2 plants increased with increasing gamma ray dosage, especially for the dry seed treatment.
Combining Abilities for Yield and Bulb Quality among Long- and Intermediate-day Open-pollinated Onion Populations
Authors: Havey Michael J. , Randle William M.
Published: January 2019

A factorial mating design, using three male-sterile F1 lines in testcrosses with a sample of open-pollinated (OP) onion populations, was used to estimate combining abilities and heterosis for bulb yield, size, storage ability, pungency, soluble solids content (SSC), and water loss after 3 months in storage. Samples of testcross bulbs were flowered and scored for fertility to estimate frequencies of the nuclear allele maintaining cytoplasmic male sterility. General combining ability (GCA) estimates for OP populations (males) were significant (P < 0.05) for yield, SSC, and proportion of bulbs with diameters >7.5 cm. GCA estimates for female testers were significant for storage ability and proportion of bulbs with diameters <5.0 cm. Male × female interactions (specific combining ability estimates) were significant for SSC and storage ability. Our analyses did not reveal any storage population from which inbreds would likely yield significantly better with the male-sterile tester lines. Spanish OP populations tended to produce testcrosses with larger bulbs, lower pungency and SSC, and poorer storage ability. Heterosis estimates were most often significant for yield and SSC; less often for pungency, storage ability, and bulb size; and not significant for water loss in storage. Overall, significant GCA estimates indicate that superior onion inbreds and populations may be developed using recurrent-selection strategies that increase the frequency of desirable alleles with additive effects.
Fruit Mass Development in Three Cranberry Cultivars and Five Production Regions
Authors: DeMoranville Carolyn J. , Davenport Joan R. , Patten Kim , Roper Teryl R. , Strik Bernadine C. , Vorsa Nicholi , Poole Arthur P.
Published: January 2019

Fruit mass development in `Crowley', `Pilgrim', and `Stevens' cranberry (Vaccinium macrocarpon Ait.) was compared in five states for two seasons. Comparing all locations, `Stevens' and `Pilgrim' cranberries had similar growth curves with a faster growth rate than that of `Crowley'. Regional differences in fruit development were observed. Shorter growing seasons, especially in Wisconsin, were compensated for by more rapid growth rates. Conversely, low initial mass and slower growth rates were compensated for by the longer growing season in the Pacific Northwest. Solar radiation intensity accounted for little of the variability in fruit growth. Neither growing degree days nor numbers of days were good predictors of cranberry fruit fresh mass accumulation. Instead, numbers of moderate temperature days (between 16 and 30 °C) appeared to be key, accounting for greater than 80% of the variability in cranberry fresh biomass accumulation. The most rapid growth rates occurred when temperatures were in this range. High temperatures were limiting in New Jersey while low temperatures were limiting in Oregon and Washington. In one of two seasons, low temperatures were limiting in Wisconsin: accumulation of 0.5 g fresh mass took 11 d longer. Massachusetts had the fewest periods of temperature extremes in both seasons, resulting in the shortest number of days required to accumulate 0.5 g fresh mass.
Dynamic Relationships between Field Temperatures and Broccoli Head Quality
Authors: Dufault Robert J.
Published: January 2019

Fifty-six field plantings of `Baccus', `Citation', `Packman', and `Southern Comet' broccoli were made in Charleston, S.C., at 2-week intervals from February to November from 1990 to 1992. The objective was to determine broccoli's response to growing season mean (GSM) temperatures for several important market quality characteristics, such as head shape, color, density, leafiness, and bead size. Regression analysis determined whether quality was more affected by GSM minimum (min) or maximum (max) temperature for each head quality characteristic. Head leafiness and density of `Baccus' were insensitive to GSM min (7.0 to 23.5 °C) and GSM max (17.5 to 32.5 °C) temperatures experienced during these years. `Baccus' head color was unacceptable at <20.3 °C GSM max and head shape was unacceptable at <19.8 and >26.8 °C GSM max. `Citation' head color and leafiness were unacceptable at >20.5 and >20.2 °C GSM max, respectively. Head density of `Citation' was unacceptable at <19.2 and >28.9 °C GSM max and head shape was unacceptable at <18.4 and >25.7 °C GSM max. Quality of `Packman' was unacceptable for head color at <21.0 and >27.3 °C GSM max, head leafiness at >32.0 °C GSM max, head density at <8.4 and >18.0 °C GSM min, and head shape at >22.0 °C GSM max. `Southern Comet' head quality was unacceptable for head color at <9.2 and >16.5 °C GSM min, head leafiness at >32.0 °C GSM max, head density at <8.9 and >16.2 °C GSM min, and head shape at <21.0 and >25.3 °C GSM max. GSM min or max temperatures did not affect bead size of any cultivar during any planting time studied.
Design and Analysis of a Modified-atmosphere Package for Minimally Processed Romaine Lettuce
Authors: Segall Kevin I. , Scanlon Martin G.
Published: January 2019

The first goal of this study was to determine the packaging film O2 permeability required to maintain a steady-state O2 concentration of 3% in modified-atmosphere packaging (MAP) of minimally processed romaine lettuce (Lactuca sativa L.). The second goal of the study was to determine the extent to which MAP could preserve lettuce quality and consequently extend product shelf life. Oxygen consumption rates of commercially prepared lettuce samples were determined in a closed system for each of three atmospheres (3% O2 combined with either 6%, 10%, or 14% CO2). Enzymatic, quadratic, and linear mathematical models were compared to determine which best described the respiratory data. The linear model was the most suitable and was used to predict the O2 consumption rate of the minimally processed romaine lettuce under the desired package headspace gas concentrations. The predicted O2 consumption rate was used to calculate the necessary O2 permeability for the packaging film. Packages (21.6 × 25.4 cm) were constructed from a polypropylene-polyethylene-laminate film with the appropriate O2 permeability. Packaged samples were stored under three modified atmospheres (MAs) (3% O2 combined with either 6%, 10%, or 14% CO2) for 20 days, and headspace gas concentrations, lettuce appearance, and color were evaluated every other day. Growth of pectinolytic and lactic acid bacteria was also studied. The O2 consumption rate of the lettuce decreased with increasing CO2 levels. The O2 levels in the MA packages equilibrated at 7% to 11%. Compared to a control atmosphere of air, MAP delayed the development of tissue discoloration. Preliminary results indicated no effect of MAP on microbial growth. Of the three CO2 levels, 10% was slightly more effective than 6% and 14%. Critical choice of packaging permeabilities combined with MAP maintained the quality of minimally processed romaine lettuce and thereby increased shelf life by about 50%.