bluuebunny/crossref_metadata_2025 huggingface dataset:
Factors Affecting in Vitro Embryogenesis from Undeveloped Ovules of Mature Citrus Fruit
Authors: Moore G. A.
Published: August 2022

The effects of genotype and growth additives on the induction of embryogenesis from undeveloped ovules from mature fruit of Citrus were examined. Embryos were produced in cultures of 15 of the 17 representative polyembryonic cultivars examined. Cultured ovules of 5 monoembryonic cultivars did not become embryogenic. Percentages of ovules producing embryos in the responsive polyembryonic cultivars ranged from 5 to 20 after 56 days in culture. Mean numbers of embryos per responsive ovule ranged from 1.9 to 13.2. Effects of growth additives on the production of embryos from undeveloped ovules from mature fruit of ‘Marsh’ grapefruit were tested. A low concentration (0.01 mg/liter) of butanedioic acid mono (2, 2-dimethylhydrazide) (daminozide) was most effective at increasing the induction of somatic embryogenesis over the control treatment of 500 mg/liter malt extract. The presence of abscisic acid or a higher concentration of malt extract (100 mg/liter) in the medium also increased embryo induction, but germination of embryos obtained on the malt extract medium was poor. The use of undeveloped ovules from mature fruits allows the initiation of embryogenic cultures from a wide range of Citrus species.
Relationship between Resistance to Severe and Type Strains of Bean Yellow Mosaic Virus
Authors: Tatchell S. P. , Baggett J. R. , Hampton R. O.
Published: August 2022

The inheritance of resistance in beans (Phaseolus vulgaris L.) to typical bean yellow mosaic virus (BYMV) was compared to the severe strain (BYMV-S). When F3 families of BYMV resistant ‘Great Northern UI 31’ (GN31) × susceptible ‘Dwarf Horticultural’ were tested for resistance to each virus strain, occurrence of homozygous resistant families was conditioned by 3 recessive genes for BYMV and 2 recessive genes for BYMV-S. Of the 132 families tested, 122 were susceptible to both BYMV and BYMV-S, 6 were resistant to BYMV-S and susceptible to BYMV, 4 were susceptible to BYMV-S and resistant to BYMV, and none were resistant to both. This ratio closely fits a theoretical 945:63:15:1, indicating that resistance to BYMV and to BYMV-S are inheritied independently. When GN31 was crossed with breeding line Sl-5, also resistant to both virus strains, F3 progenies included families susceptible to one or both virus strains, possibly through the complimentary interaction of modifiers. Chi square tests indicated independent inheritance of resistances to BYMV and BYMV-S in GN31 × S1-5 progenies.
Photoperiod and Soil Temperature Effects on Crop Productivity Efficiency and Growth of Seedling Geraniums in the Greenhouse
Authors: Merritt Richard H. , Kohl Harry C.
Published: August 2022

Geranium seedlings (Pelargonium × hortorum L.H. Bailey, ‘Mustang’) grown in 13 hr photoperiods were 23% taller due to stem and petiole elongation, had larger leaves, and prior to canopy closure had a higher crop productivity efficiency (CPE) than seedlings grown under 9 hr photoperiods. In general, the tallest plants were produced when grown with soil temperatures of 18°C. The highest weekly CPE attained was 3.8%.
Studies of de Novo Flower Initiation from Thin Cell Layers of Tobacco
Authors: Bridgen Mark P. , Veilleux Richard E.
Published: August 2022

The potential for in vitro floral photoinduction of epidermal and subepidermal thin cell layers (TCLs) taken from the short-day plant Nicotiana tabacum L. ‘Maryland Mammoth’, the long-day plant Nicotiana sylvestris L., and the day-neutral plant Nicotiana tabacum L. ‘Samsun’, in both the floral and vegetative states, was examined. Whether cultured under long days (16 hr) or short (8 hr), only TCLs from the flowering day-neutral species flowered in vitro. These were termed responsive TCLs. TCLs from photoperiodic plants yielded only vegetative buds; these were termed nonresponsive. Vegetative bud formation in nonflowering TCLs generally was greater than in flowering TCLs but did not approach the number of flower buds on flowering TCLs. In vitro grafts of responsive TCLs to nonresponsive TCLs resulted in flowering only in the responsive portion, regardless of the position of the graft. Just as the nonresponsive TCLs were not induced to flower by some graft-transmissible substance, responsive TCLS were not inhibited from flowering when grafted to nonresponsive TCLs.
Influence of Various Rates of Ca(NO3)2 Fertilizer and Soil Management on Young Apple Trees
Authors: Miller Stephen S. , Glenn D. Michael
Published: August 2022

Calcium nitrate applied annually at rates ranging from 22.5 g actual N per tree (0.5 N, one-half the recommended rate) to 363 g/tree (8 N) and adjusted according to tree age did not influence the growth of 4 apple (Malus domestica Borkh) cultivars (‘Golden Delicious’, ‘Triple Red Delicious’, ‘Red Yorking’, and ‘Stayman 201’) on EM 7a rootstock. There was a significant soil management (herbicide, clean cultivation, or mowed sod) × rate interaction; trees in mowed sod responded to additional N with growth and leaf N levels comparable to the vegetation-free management systems at 4 times (4 N) the recommended rate (45 g N/tree/year age). Soil management and rate of fertilization influenced leaf N levels but not leaf Ca. Leaf N and Ca differed significantly among the 4 cultivars. Cumulative yield after 4 growing seasons was influenced by tree size and soil management, but not rate of fertilization. Soil pH was significantly higher under sod than under cultivated or herbicide strip culture. Soil Ca levels were not affected in the 0 to 30 cm profile. Residual soil NO3-N did not accumulate in the surface 30 cm for any of the management systems except at the highest rate (8 N) under the cultivated and herbicide systems. Data for residual NO3-N in the 0 to 120 cm soil profile indicated that the tree demand and leaching potential for NO3-N was met at the 0.5 N rate when competition was eliminated and between the 2 N and 4 N level in mowed sod.
Influence of Spacing on Fruit Yields and Quality of Grape Cultivars Differing in Vine Vigor
Authors: Hunter D.M. , Wiebe J. , Bradt O.A.
Published: August 2022

Five grape cultivars (Vitis spp.) varying in vine vigor were planted at 4 spacings (1.8 m × 1.8 m, 1.8 m × 2.7 m, 2.7 m × 1.8 m, 2.7 m × 2.7 m) on a Trafalgar silty clay loam soil in Ontario. In each of the first 5 harvest years (years 3 through 7 following planting), lowest yields per vine were obtained from the closest spacing (1.8 m × 1.8 m) but the increased plant number at this spacing resulted in highest yields/ha. Fruit quality, as evidenced by soluble solids and titratable acidity, was not adversely affected by close spacing. There was a greater reduction in fruit yields per vine and vegetative growth at the closer within-row spacing than at the closer between-row spacing; this effect of within-row competition was especially pronounced for the vigorous cultivars. Results obtained in this study indicate that increasing the planting density (by reducing the between-row distance) of grapevines on clay loam soils in Ontario may lead to economical increases in production.
Inheritance of Resistance in Muskmelon to Fusarium Wilt
Authors: Zink F. W. , Gubler W. D.
Published: August 2022

The mode of inheritance of resistance to Fusarium wilt (Fusarium oxysporum f. sp. melonis) races 0 and 2 in muskmelon (Cucumis melo L.) cv Perlita FR and race 2 in ‘Doublon’ was determined by analyzing segregation of F1, F2, F3, and BC1 populations of crosses with susceptible ‘PMR 45’. The ratios obtained indicate that resistance to both races 0 and 2 in ‘Perlita FR’ is conferred by a dominant gene. The segregation data indicate that resistance to race 2 in ‘Doublon’ also is conferred by a dominant gene. Allelism tests indicated that gene Fom-1, which controls resistance to race 0 in ‘Doublon’, is different from the gene controlling resistance to race 0 in ‘Perlita FR’ and that 2 different genes confer resistance to race 2 in ‘Doublon’ and ‘Perlita FR’. The reaction of ‘Perlita FR’ and ‘Doublon’ backcross progenies of (resistant × susceptible) × susceptible, inoculated simultaneously or sequentially with race 0 and race 2, suggest that gene Fom-1 confers resistance to races 0 and 2 in ‘Doublon’ and that a single gene confers resistance to both races 0 and 2 in ‘Perlita FR’. The resistant dominant gene in ‘Perlita FR’ is designated F. oxysporum f. sp. melonis 3 (Fom-3). The source of Fusarium wilt resistance in ‘Perlita FR’ is discussed. ‘Perlita FR’ was found susceptible to race 1 and race 1, 2.
Foliar N-uptake by Eight Turfgrasses Grown in Controlled Environment
Authors: Wesely R. W. , Shearman R. C. , Kinbacher E. J.
Published: August 2022

Urea frequently is applied to turfs in liquid formulation at low water application rates which enhance potential foliar N uptake. This study was conducted to evaluate foliar N uptake by several cool-season turfgrasses treated with urea applied at low water volume (35 ml · m−2). Urea was applied foliarly to 8 turfgrasses at 2.5 g N m−2 in 35 ml m−2 of water. Verdure was harvested prior to treatment and after treatment at 24, 48, and 72 hr. Total N-uptake increases were primarily a response to increased the percentage of N, since dry matter production was stable for each turfgrass throughout the 72 hr. Maximum N-uptake occurred 24 hr after treatment. Any significant decrease in N-uptake over time suggested N-movement out of the sampling zone. Turfgrass species and cultivars showed differences in total N-uptake which resulted from initial variations in dry matter, percentage of tissue N, and variations in N-uptake rate. The percentage of N recoveries ranged from 31% to 61% for ‘Park’ Kentucky bluegrass and ‘Highlight’ chewings fescue, respectively. Cultivar differences indicated that ‘Baron’ Kentucky bluegrass was more efficient in relation to foliar N-uptake than ‘Park’ Kentucky bluegrass.
Selection and Inheritance of Heat Tolerance in the Common Bean by Use of Conductivity
Authors: Marsh L. E. , Davis D. W. , Li P. H.
Published: August 2022

Inheritance and selection of heat tolerance were investigated in common bean (Phaseolus vulgaris L.). Parental, F1, backcross, and F2 populations from the crosses PI 271998 × BBL 47, PI 271998 × 80 BP-6 and 5BP-7 × BBL 47 were used in the inheritance study. Parental, F2, F3 and backcross populations of the cross PI 271998 × BBL 47 were used to estimate selection gain. Plants were evaluated for heat tolerance by the conductivity method after 32 days in the growth chamber at 20°/15°C (day/night) and acclimation at 37° for 24 hr. The joint scaling test indicated that the additive-dominance model was adequate to explain heat tolerance in crosses PI 271998 × BBL 47 and 5BP-7 × BBL 47. The major variation for tolerance for these 2 crosses may be controlled by a small number of genes. The additive-dominance model was inadequate for PI 271998 × 80BP-6, however, and epistasis was present. Narrow sense heritability estimates ranged from 2.9% to 24.0%, indicating relatively small additive effects. Broad sense heritability estimates ranged from 0.0% to 21.6%, suggesting sizable environmental effects. Realized heritability from selection for tolerant F2 plants was 7.9%. These estimates perhaps represent the lower limit of heritability for heat tolerance. The conductivity method could be considered for evaluating heat tolerance in a breeding program but should be more effective in screening F3 families than individual F2 plants.
Seasonal Variation on the Influence of Low Temperature, Photoperiod, Light Source, and GA in Floral Development of the Evergreen Azalea
Authors: Pemberton H. Brent , Wilkins Harold F.
Published: August 2022

Florida-produced ‘Prize’ azalea plants were shipped to Minnesota with apical floral buds whose individual flowers had styles which had commenced elongating. These plants were ready for rapid forcing if given the traditional 6 weeks at 9°C. However, a single 2000 ppm GA (Pro Gibb3) spray treatment resulted in plants which flowered more rapidly without a traditional cold treatment when forced in a glasshouse under natural daylength (ND) in Minnesota during the spring and summer. Length of the ND in these experiments was considered critical, as plants forced in the spring and summer under an 8-hr short day (SD) treatment did not flower in a uniform manner, or floral abortion occurred in GA treated, uncooled plants forced during the autumn. Under ND conditions, extended to 20-hr by high pressure sodium, cool-white fluorescent or incandescent lamps, plants flowered more rapidly than those plants cooled at 9° for 6 weeks and forced under ND. Uniformity of flowering was enhanced and GA treatment had no effect when 3 weeks of 9° cooling preceded supplemental lighting treatments during autumn forcing. During winter, 20-hr of high pressure sodium + GA treatment or a SD treatment of noncooled plants resulted in more rapid, but similarly uniform flowering, when compared to plants with 6 weeks of cold treatment. These data provide evidence indicating that ‘Prize’ azalea floral buds may not exhibit a physiological dormancy.
Resistance of Various Classes of Grapes to the Bunch and Muscadine Grape Forms of Black Rot
Authors: Jabco Jeffrey P. , Nesbitt William B. , Werner Dennis J.
Published: August 2022

Eight or 9 commercial cultivars from each of 4 grape classes were inoculated with the black rot fungus (Guignardia bidwellii f. sp. euvitis and f. sp. muscadinii) of bunch and muscadine grapes, respectively. The 4 classes consisted of 3 bunch grape classes (Vitis vinifera L., American hybrids, and French hybrids) and 1 muscadine class (V. rotundifolia Michx). Resistance was determined by leaf and petiole infection ratings (0−4) and average leaf and petiole lesion size (mm). Inoculation with Guignardia bidwellii f. sp. euvitis resulted in significantly larger average leaf lesion size on Vitis vinifera than on American and French hybrids (4.3 vs. 3.5). American hybrids had significantly higher (3.3 vs 2.3) leaf disease rating than French hybrids. Vitis rotundifolia received significantly lower disease rating then the 3 bunch grapes classes (0.4 vs. 2.9). A hypersensitive reaction was observed on leaves of most V. rotundifolia cultivars. Inoculation with Guignardia bidwellii f. sp. muscadinii resulted in significant differences in leaf infection ratings between French and American hybrids (0.8 vs. 1.6) and between V. rotundifolia and the 3 bunch grape classes (3.1 vs. 1.2). There were significant pathogen form × grape class and pathogen form × cultivar within grape class interactions.
Comparisons of Calcium Chloride, Calcium Phosphate, and a Calcium Chelate as Foliar Sprays for ‘McIntosh’ Apple Trees
Authors: Bramlage W. J. , Drake Mack , Weis S. A.
Published: August 2022

A 4-year study compared CaCl2, Ca(H2PO4)2, and a polyphenolic acid chelate of Ca, applied as foliar sprays, for improving apple (Malus domestica Borkh.) fruit quality. Technical grade 77% to 80% flake CaCl2 consistently increased fruit Ca concentrations and reduced senescent breakdown after storage and occasionally reduced superficial scald after air storage. When materials other than Ca(H2P04)2 were applied at concentrations providing soluble Ca concentrations equal to that of technical grade CaCl2, equal benefits were achieved. Treatments that increased Ca also usually reduced Mg concentrations in outer cortex tissue. Ca(H2PO4)2 increased fruit P but not fruit Ca concentration, and a reduction in superficial scald was the only accompanying benefit to the fruit.
Net Economic Values of Eight Soil Management Practices Used in Stake Tomato Production
Authors: Estes E. A. , Skroch W. A. , Konsler T. R. , Shoemaker P. B. , Sorensen K. A.
Published: August 2022

Staked tomatoes (Lycopersicon esculentum Mill) grown in 8 soil management systems are compared for differences in marketable yields, gross revenues, treatment costs, and net economic values. Maximum marketable yields were obtained using a fumigant and straw mulch combinatory practice, but the highest net economic value (gross revenues less treatment costs) was realized by a fumigant and herbicide ground management practice. These data suggest that the use of mulch materials and/or herbicides increased yields and net returns over standard cultivation practices.
Carbon Balance Model of a Growing Apple Shoot: II. Simulated Effects of Light and Temperature on Long and Short Shoots
Authors: Johnson R.S. , Lakso A.N.
Published: August 2022

A computer model of a growing apple (Malus domestica Borkh.) shoot was used to estimate the effects of light and temperature on the C balance of a shoot. Long-term average solar radiation (langley/day) and maximum and minimum temperatures from Geneva, N.Y., were used as weather inputs. To simulate other weather conditions, solar radiation was increased or decreased by 150 langley/day, and maximum and minimum temperatures increased or decreased by 5.6°C. Both a short shoot of 2 cm and a long shoot of 50 cm final length were simulated. The model output indicated that increased light reduced carbohydrate import and caused earlier and greater export. Increased temperature increased carbohydrate import and the subsequent rate of carbohydrate export. The short shoot had a greater initial rate of C export and continued to export more total carbohydrates than the long shoot for about 30 to 50 days after budbreak. Slow leaf area development at a given temperature had little effect on carbohydrate import but delayed the beginning of export.
Effect of Paclobutrazol and Analogs on Growth, Yield, Fruit Quality, and Storage Potential of ‘Delicious’ Apples
Authors: Greene Duane W.
Published: August 2022

A postbloom foliar application of 1500 and 3000 ppm paclobutrazol (PB) increased flesh firmness of ‘Delicious’ apple (Malus domestica Borkh.) but reduced seed number and fruit size at harvest. The following year, flowering was not affected, but fruit set was increased. A decrease in terminal growth, leaf size, fruit L/D ratio, fruit size, pedicel length, and fruit soluble solids were also observed with the high rate of PB. PB increased fruit flesh calcium and total yield, and retarded fruit ripening. Dichlorobutrazol (DCB) did not affect final terminal growth but reduced L/D ratio, pedicel length, and fruit size the year after application. Following storage, flesh firmness of PBtreated fruit was not influenced, but senescent breakdown was dramatically reduced. Retarded ripening and reduced senescent breakdown were attributed to increased calcium in fruit flesh. Variability in terminal growth was increased as the inhibitory effects of PB dissipated. Three years after application, fruit L/D ratio and pedicel length were decreased, even though there was no longer a reduction in terminal growth. Chemical names used: (2RS, 3RS)-1-(2,2-dichlorophenyl-4-4-dimethyl-2-(1H,1,2,4-triazol-lyl)pentan-3-ol (paclobutrazol); (2 RS, 3 RS)-1-2,2-dichlorophenyl-4,4-dimethyl-2-(1H1,2,4-triazol-lyl)pentan-3-ol (dichlorobutrazol).
Temperature, Supplemental Lighting, and Chloromequat Chloride Effects on Flowering of Geranium Seedlings
Authors: Quatchak D.J. , White J.W. , Holcomb E.J.
Published: August 2022

The time between sowing and flowering (crop cycle) of geranium Pelargonium × hortorum Bailey was affected by light, temperature, chloromequat chloride (CCC), and cultivar. A minimum daily light integral of 17 mol·d−1·m−2, provided by high-pressure sodium lamps (HPS) prior to transplanting, accelerated flower initiation. HPS, low pressure sodium (LPS), and metal halide (MH) lamps, used as supplemental light after transplanting, reduced the crop cycle significantly compared to incandescent (INC) or natural light only. Crop cycles were similar among the HPS, LPS, and MH lamp treatments when equal-input lamp wattage was used per unit growing area, even though PPF values at the plant canopy varied. Plants grown at 21° and 27°C had a 5- to 15-day-shorter crop cycle than plants grown at 18° and 21°. Generally CCC reduced the crop cycle, but not consistently for all cultivar and lighting combinations. Chemical names used: 2-chloro-N,N,N-trimethylethanaminium chloride [chloromequat chloride (CCC)].
Forcing Herbaceous Peonies
Authors: Byrne Thomas G. , Halevy Abraham H.
Published: August 2022

Flower bud initiation of herbaceous peony (Paeonia L.) may start soon after the current year’s flower anthesis in June; buds continue to develop until the onset of dormancy in the fall. Flower formation, days to harvest, foliage senescence, and dormancy are unaffected by photoperiod. Flower bud dormancy can be broken by storage of dormant plants for a minimum of 4 weeks at 5.6°C after which they may bloom in the greenhouse in 8 to 10 weeks. Increasing storage time to 6 weeks or reducing the temperature to 1° increases the total number of shoots that grow after forcing.
Estimates of Heritabilities and Genetic Variances of Three Yield and Five Quality Traits in Three Fresh-market Cucumber Populations
Authors: Strefeler Mark S. , Wehner Todd C.
Published: August 2022

Variance components for 3 fruit yield and 5 fruit quality traits in 3 cucumber (Cucumis sativus L.) populations were estimated using a North Carolina Design I analysis. Three populations were studied (elite, medium base, and wide base), having been formed by intercrossing lines to produce 3 levels of genetic diversity. Families were evaluated in 1.5 × 1.5 m plots using once-over harvest at the stage of 15% oversized fruits. Heritabilities based on full-sib family selection for fruit yield ranged from 0.03 to 0.25, and for the fruit quality traits 0.00 to 0.30. The wide base population would be best for long-term selection for the traits studied, because it had the highest predicted means for all traits except percentage of culls, fruit shape, and overall performance after 15 cycles of full-sib family selection.
Effects of Oxyfluorfen as a Pretransplant Treatment on Weed Control and Cabbage Yield
Authors: Bhowmik Prasanta C. , McGlew Edwin N.
Published: August 2022

Treatments of oxyfluorfen at 0.43 kg·ha−1 as a pretransplant (PT) treatment, followed by several sequential postemergence grass herbicides as post-over-the-top (POT) treatments, provided excellent broadleaf and grass control in transplanted cabbage (Brassica oleracia var capitata L.). These herbicides included sethoxydim, fluazifop-butyl, and haloxyfop-methyl. Oxyfluorfen treatments alone gave 86% to 89% control of grass species. Broadleaf weeds were controlled effectively with oxyfluorfen treatments. Cabbage had acceptable tolerance to oxyfluorfen at 0.43 and 0.56 kg·ha−1 when applied as a PT treatment either alone or with grass herbicides. Increased injury to cabbage was noted with the high rate of oxyfluorfen. Yield and quality of cabbages were not reduced by oxyfluorfen applied pretransplant. Yields of marketable cabbage obtained with the treatments of oxyfluorfen as PT treatment followed by sequential grass herbicides as POT treatment, ranged from 24.3 to 27.1t·ha−1 in 1983 and 35.7 to 39.0 t·ha−1 in 1985. Chemical names used: 2-chloro-l-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene (oxyfluorfen); 2-[l-(ethoxyi-mino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-l-one (sethoxydim); (±)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy]propanoic acid (fluazifop-butyl); and 2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy] propanoic acid (haloxyfop-methyl).
Effect of Liming Rate on Nitrification in a Pine Bark Medium
Authors: Niemiera Alexander X. , Wright Robert D.
Published: August 2022

A 100% pine bark medium was amended with dolomitic lime at 0, 3, or 6 kg·m−3 and periodically fertilized with 210 ml of a nutrient solution containing 100 ppm N as (NH4)2S04. At the 3- and 6-kg lime treatments, medium solution NH4-N concentrations decreased rapidly while N03-N concentrations increased. At 0 kg lime, the NH4-N decrease was slower than at the 3- and 6-kg lime treatments and N03-N was not found. Similarly treated bark without plants was used to determine a N03-N accumulation rate (NAR). NAR was greatest at 6 kg of lime, except at the last 2 sampling dates, when NAR did not differ between 3 and 6 kg of lime. This lack of difference was attributed to a limiting NH4-N supply at 6 kg of lime. In a 2nd experiment, NAR of bark treated with 6 kg of lime per m3 and fertilized with 300 ppm NH4-N was 3 times greater than with bark treated with 100 ppm NH4-N, thus supporting the contention that, over time, the NH4-N supply of the 100-ppm treatment limited nitrification. These results indicate that the stimulative influence of lime on nitrification is subject to medium pH and NH4-N status that changes over time.
Carbohydrate Composition and Sensory Quality of Fresh and Stored Sweet Corn
Authors: Evensen K.B. , Boyer C.D.
Published: August 2022

Sweet corn (Zea mays L.) was evaluated for sensory quality and carbohydrate composition at harvest and after storage at 0° or 10°C for 2 weeks. Total sugar (reducing sugar plus sucrose) declined more quickly during storage at 10° than at 0° in all cultivars, but the relative changes in sucrose and reducing sugars during storage were often complex. Hedonic (like/dislike) and sweetness scores awarded by taste panelists were significantly correlated with each other and with reducing sugar, sucrose, and total sugar concentrations only after storage. The highest correlations were between sucrose concentration and hedonic taste scores (r = 0.76, P < 0.01) and between sucrose concentration and sensory sweetness scores (r = 0.73, P < 0.01). Starch concentration varied with cultivar, but was not correlated with sensory quality. Water-soluble polysaccharide concentration varied with cultivar, storage time, and storage temperature, but did not correlate with sensory quality.
Effect of Osmotic Stress on Somatic Embryogenesis in Carica Suspension Cultures
Authors: Litz Richard E.
Published: August 2022

Suspension cultures derived from Carica papaya L. ovular callus were subcultured on modified Murashige and Skoog medium containing 60 g·liter−1 sucrose, 400 mg·liter−1 glutamine, 9 μm 2,4-D, and either 0–0.45 m sodium chloride (NaCl) or the osmotically equivalent concentrations of mannitol. After 4 successive subcultures (120 days), the suspensions from each NaCl treatment were inoculated into the entire range of salt-containing media, and were subcultured on the same media formulations for 4 months. Cultures grown in the presence of mannitol were treated in the same manner. Sodium chloride generally inhibited somatic enbryogenesis; however, somatic embryogenesis was stimulated greatly following subculture from media with 0.18 m NaCl into media containing lower concentrations of salt. Enhancement of somatic embryogenesis also occurred following preconditioning with 0.30 m and 0.45 m mannitol. The increased rate of somatic embryogenesis was lost after 2 to 3 subcultures in media having lower osmolarities. Chemical names used: (2,4-dichlorophenoxy)acetic acid (2,4-D).
Chilling Exposures and Ethylene Treatment Change the Level of ACC in ‘Honey Dew’ Melons
Authors: Lipton Werner J. , Yi Wang Chien
Published: August 2022

‘Honey Dew’ melons (Cucumis melo L.) accumulated substantial amounts of ACC during a 2½-week chilling exposure at 2.5°C. The final concentration in chilled skin tissue was 15 nmol·g–1, which was about 70 times that in nonchilled skin tissue. The level of ACC in the underlying flesh also was increased by chilling, but to a lesser extent. The concentration of ACC decreased continuously during subsequent warming of the melons at 20° and had returned almost to the at-harvest level (<1 nmol·g–1) after 24 hr. Ethylene and CO2 production were low at 2.5° but rose rapidly during warming. A pre-chilling ethylene treatment (1000 µl·liter–1) for 18 hr at 20°) reduced chilling injury and ACC accumulation. ACC accumulation in the skin was negatively correlated with the presence of solar yellowing. Chemical names used: 1-aminocyclopropane-1-carboxylic acid (ACC).
Photomorphogenic Responses of Strawberry to Photoperiodic and Photosynthetic Radiation
Authors: Maas John L. , Cathey Henry M.
Published: August 2022

The effects of supplemental light provided by high- and low-pressure sodium (HPS and LPS), metal halide (MH), and incandescent filament (INC) lamps were determined on the photomorphogenic responses of strawberry (Fragaria × ananassa Duch.) plants. Supplemental light was provided in the greenhouse under normal winter conditions of 9–12 hr of daylight in Beltsville, Md. Growth responses of representative Junebearer (‘Badgerbelle’), everbearer (‘Our Own’), and day-neutral (‘Tribute’) plants propagated by tissue culture (TC) and conventional means (RP) were recorded under supplemental lighting compared to natural day length (ND) conditions and with long days simulated by ND supplemented with a daily 4-hr night interruption (NI) with 0.9 W·m–2 (400–850 nm) INC exposure (ND and NI) at 2200–0200 hr. Vegetative and reproductive responses to supplemental lighting varied with the photoperiod class of the cultivar and with its mode of propagation. Vegetative growth (stolon and daughter plant development) of Junebearer RP and both Junebearer and everbearer TC plants was promoted by all supplemental light treatments. Supplemental light did not promote growth of everbearer RP plants or day-neutral TC or RP plants. Crown branching of day-neutral TC plants was promoted by several treatments, but the number of crowns on RP plants was increased only under LPS at 12 W·m–2 for 24 hr. Flower truss initiation of Junebearer plants was not stimulated by supplemental light treatments compared to ND. Everbearer RP plants produced more flower trusses under supplemental light treatments compared to ND, but TC plants were stimulated only by LPS at 12 and 24 W·m-2 for 24 hr. Day-neutral RP plants produced more flowers per truss under most treatments compared to ND, but TC plants produced the greatest number of flowers per truss under MH at 12 W·m-2 for 24 hr.
Recurrent Selection for Resistance to White Mold in Phaseolus Species
Authors: Lyons M.E. , Dickson M.H. , Hunter J.E.
Published: August 2022

Recurrent selection was used to breed Phaseolus species for resistance to white mold disease, caused by Sclerotinia sclerotiorum. Twenty diverse genotypes selected for resistance to white mold formed the cycle 0 population. These lines were intercrossed in a partial diallel, and the F2 progeny were tested for resistance to white mold using a detached blossom/ascospore technique. Twenty single-plant selections were made, and the F3 progeny of these selections formed the cycle 1 population. A 2nd cycle of intercrossing, evaluation, and selection was completed, and genetic gain was determined by evaluating disease resistance of the selfed progeny derived from the cycle 0, 1, and 2 populations. There was a highly significant linear improvement in mean disease response from cycle 0 to cycle 2. When a subjective rating was used to assess disease response, the average gain/cycle was 0.52 rating units, and the percentage gain from cycle 0 to cycle 2 was 31%. When measurement of lesion length (centimeters) on the main stem was used to assess disease response, the average gain/cycle was 1.96 cm, and the percentage gain from cycle 0 to cycle 2 was 50%. The results of this study indicate that recurrent selection may be a useful technique for the development of resistance to white mold in Phaseolus species.
Seed Hydration Treatments For Improved Sweet Corn Germination and Stand Establishment
Authors: Bennett Mark A. , Waters Luther
Published: August 2022

This research examines the potential of seed hydration for improving sweet corn (Zea mays L.) seed performance, especially for plantings in cool (10°–15°C) soils. In addition to the effect of hydration treatments, the influence of seed quality and cultivar was evaluated using electrolyte leakage tests and seedling growth cold tests. Seed hydration treatments included seed hardening (a wetting/drying cycle), seed moisturizing (placing seed in moist vermiculite), and osmoconditioning, which were compared to a dry seed control. Hardening and moisturizing treatments improved early emergence by as much as 20%, while osmoconditioning significantly lowered field emergence. Seed moisturizing and hardening also improved uniformity of emergence, and reduced the number of days required to attain 50% or 75% emergence. Seed hydration treatments were effective with the three levels (high, medium, and low) of seed quality and the three cultivars (‘Jubilee’, ‘Midway’, and ‘Reward’) studied.
Onion Responses to Various Salinity Levels
Authors: Wannamaker Mary Jo , Pike Leonard M.
Published: August 2022

Onion growth responses to salinity levels were evaluated using five onion cultivars. In a plant growth study, eight salt levels were used with electrical conductivities (EC) ranging from 0.8 to 12.0 dS·m−1. Total area of the leaves and stem, dry weight, plant height, and leaf tip burn were measured after 45 days of growth. All five cultivars were sensitive to low salt levels, with significant reduction occurring at 1.4 dS·m−1. In a 2nd experiment germination percentage was evaluated for 8 days; a wider range of salt levels was tested (0.0–50.0 dS·m−1). Rate of germination was retarded 1–3 days with increasing salt concentrations, but germination percentage after 8 days was not significantly reduced in the 0.0–25.0 dS·m−1 salt levels. Germination was prevented at 45.0 dS·m−1 for all cultivars except ‘Texas Grano 1015Y’, which exhibited slight germination. These test results confirm that salt effects during germination are not related to later responses of the whole plant to salt. Screening onion for salt tolerance would best be done at the vegetative stage.
Seasonal Development of Highbush Blueberry Roots Under Sawdust Mulch
Authors: Abbott John D. , Gough R.E.
Published: August 2022

Annual growth of white unsuberized roots from mature ‘Earliblue’, ‘Bluecrop’, and ‘Lateblue’ blueberry (Vaccinium corymbosum L.) plants relative to soil temperatures, shoot growth, and stage of development was studied for 3 years. The growth of roots continued throughout the year, but was much reduced at soil temperatures below 8°C. Two peaks in the growth of roots occurred, the first in early June and the 2nd, higher peak in September. Both peaks in root growth occurred with soil temperatures of 14° to 18°. The growth rate declined at soil temperatures outside this range. Growth of roots was concomitant with shoot growth.
Nonbacterial Ice Nucleation in Peach Shoots
Authors: Anderson J.A. , Ashworth E.N. , Davis G.A.
Published: August 2022

Experiments were conducted to determine the relative contributions of bacterial and nonbacterial ice nuclei to freezing of peach [Prunus persica (L.) Batsch] shoots. Exposure to 33°C for 3 hr eliminated bacterial ice nuclei active at −3° on inoculated shoot pieces, but controls were not affected. In another experiment, ice nucleation temperatures and ice nucleation-active (INA) bacterial populations of field-collected shoots were determined. Mean freezing temperatures of 20 g (fresh weight) shoots were not significantly different in the presence or absence of INA bacteria (detection limit of 10 cells/g fresh weight). INA bacteria were detected on 19% of the shoots with a maximum natural population of 180 cells/g fresh weight. Inoculation studies indicated that 20 g fresh weight peach shoots contained a mean of 1.0 nonbacterial (−3°) ice nuclei, while shoots with 180 INA cells/g fresh weight averaged 1.4 (−3°) ice nuclei per 20 g. Most ice nuclei active at −3° were of nonbacterial origin.
Induction of Intumescence Injury on Leaf Disks
Authors: Morrow Robert C. , Tibbitts Theodore W.
Published: August 2022

A procedure for inducing intumescence injury (oedema) on leaf disks was developed using a species of wild tomato, Lycopersicon hirsutum PI LA 1625. This procedure used Plexiglas vessels with which various combinations of irradiance direction and leaf disk orientation could be studied. Disks (1.4 cm in diameter) were cut from leaves and floated on distilled water in these vessels. Irradiation was provided by cool-white fluorescent lamps and was filtered through ultraviolet- (UV) absorbing Plexiglas. Disks were scored for injury after a period of 72 hr. Intumescences that developed on leaf disks using this procedure appeared similar in size, shape, and coloration to those on intact plants. Disks taken from leaves that were almost fully expanded developed injury most consistently, and the adaxial disk surface was much more sensitive to this injury than the abaxial surface. Intumescences were generally greater on the disk surface in contact with water. Besides L. hirsutum, injury was induced successfully on disks cut from eucalyptus (Eucalyptus globulus), sweet potato (Ipomoea batatas), tomato (Lycopersicon esculentum), ivy geranium (Pelargonium peltatum), European aspen (Populus tremula), and white potato (Solanum tuberosum).
Growth of ‘Thompson Seedless’ Grapevines: I. Leaf Area Development and Dry Weight Distribution
Authors: Williams Larry E.
Published: August 2022

Data were collected over 3 years to provide detailed information on growth and development of ‘Thompson Seedless’ grapevines used for raisin production. Leaf area and leaf, shoot, and cluster dry weights were measured throughout the growing season. Results were plotted against growing degree days (GDDs), using a minimum temperature threshold of 10°C, after budbreak. There was a linear increase in leaf area and vegetative dry matter from about 200 to 1000 GDDs after budbreak. Cluster dry weight increased linearly from 750 GDDs after budbreak until harvest. While shoot numbers per vine increased 70% from 1983 to 1985, there was not a similiar increase in the amount of dry matter per vine. Weight per unit leaf area (WL) increased from ≈ 40 g·m-2 early in the season to >65 g·m-2 90 days after fruit harvest. Results indicate that vines in this vineyard maintained a constant growth pattern year after year when growth was plotted vs. growing degree days.
Influence of Leaf to Fruit Ratios and Nutrient Sprays on Fruiting, Mineral Elements, and Carbohydrates of Apple Trees
Authors: Ferree David C. , Cahoon Garth A.
Published: August 2022

For 5 years, the leaf to fruit ratios of mature ‘Golden Delicious’ (Malus domestica Borkh.) apple trees on M.9 rootstock with declining leaf N levels and fruit size were adjusted to low, medium, or high levels of leaves per fruit, 2 weeks after bloom, coupled with 8 weekly foliar sprays of urea, phosphorus-potassium-sulfur (PKS), or urea plus PKS beginning at pink. No interaction occurred between the leaf : fruit ratios and foliar sprays. Mean leaf N over 5 years was slightly reduced when the crop was adjusted to high numbers of leaves: fruit and increased by urea or PKS foliar sprays. The only effect of adjustment in leaf: fruit ratio or foliar nutrients on nonstructural carbohydrate (NSC) levels was an increase in leaf NSC in 1978-1980. As the number of leaves per fruit increased, the percentage of the total harvest in the larger size classes increased with corresponding decrease in the smaller size classes. Total yield per tree, fruit firmness, and russeting were not influenced by adjusting the leaf : fruit ratio, while soluble solids were increased and fruit color decreased at the high level of leaves per fruit. Foliar urea sprays increased the percentage of fruit in the largest size class, yield per tree, fruit firmness, soluble solids, color, and the amount of russet.
Physiological and Quality Responses of Brussels Sprouts to Storage in Controlled Atmospheres
Authors: Lipton Werner J. , Mackey Bruce E.
Published: August 2022

Brussels sprouts (Brassica oleracea L., Group gemmifera) were stored 2, 3, or 4 weeks at 2.5°, 5°, or 7.5°C with 0.5%, 1%, 2%, 4%, or 21% O2, or in the following combinations of % O2/%CO2: 1/10, 2/10, or 20/10. Storage was followed by 2 or 3 days of aeration at 10°. Low O2 levels reduced the rate of CO2 production relative to that in air, but rates were similar among the low O2 levels. Ethylene production was low at 2.5° and 5° in all atmospheres, but at 7.5° it was 20% to 170% higher in air than in low O2. Ethylene production was virtually stopped during exposure to high CO2, but increased dramatically during aeration. Since low O2 levels retarded yellowing and 10% CO2 retarded decay development, the combinations of low O2/high CO2 effectively extended the storage life of the sprouts at 5° and 7.5°. The beneficial effect of CA storage was still evident after return of the samples to normal air. The sprouts retained good appearance for 4 weeks at 2.5° whether stored in CA or in air. Storage in 0.5% O2 occasionally induced a reddish-tan discoloration of the heart leaves and frequently an extremely bitter flavor in the nongreen portion of the sprouts. None of the atmosphere modifications appreciably affected either the tissue pH or texture of the sprouts.
Refreshed Delayed Light Emission and Fluorescence for Detecting Pretreatment Effects on Chilling Injury in Coleus
Authors: Abbott Judith A. , Krizek Donald T. , Semeniuk Peter , Moline Harold E. , Mirecki Roman M.
Published: August 2022

Intact plants of a green-leafed strain of Coleus blumei Benth. (PI 354190) were exposed to 5°C for 48 or 72 hr after pretreatment for 48 hr at two levels of photosynthetic photon flux (PPF) (8 or 320 μmol·s−1·m‒2) at two temperatures (13° or 20°). Plants were sprayed with two abscisic acid (ABA) levels (0 or 200 g·m‒3) either 0 or 48 hr before chilling. Postchilling condition of the plants was assessed by comparing the time courses of refreshed (cyclically excited and measured) delayed light emission (RDLE) and fluorescence (FLU) from dark-equilibrated leaves. Greater suppression of RDLE and FLU indicates greater injury. Plants pretreated at 8 μmol·s−1·m‒2 PPF showed less suppression of RDLE and FLU, contained more chlorophyll, and showed less injury than did plants pretreated at 320 μmol·s−1·m‒2 PPF. Increasing the duration of chilling from 48 to 72 hr reduced the maximum RDLE and FLU slightly. Pretreatment temperatures and ABA concentration had negligible effects on RDLE and FLU levels. The maximum RDLE, the RDLE level at 7.5 sec, the maximum FLU, the FLU at 1.5 sec, and variable FLU were the measurement variables most responsive to individual and combined treatment effects. Maximum RDLE from upper leaf surfaces was the measurement most responsive to the combined effects of all treatments. Chemical name used: [S-(Z,E)]-5-(1-hydroxy-2,6,6-trimethyl-4-oxo-2-cyclohexen-1-yl)-3-methyl-2,4-pentadienoic acid [abscisic acid (ABA)].
Histogenic Instability in Tissue Culture-proliferated Strawberry Plants
Authors: Marcotrigiano Michael , Morgan Pamela A. , Swartz Harry J. , Ruth Jennifer
Published: August 2022

A phenotypic and sexual analysis of Fragaria vesca ‘Albo-Marginata’ determined that the leaf variegation was of chimeral origin. Stable periclinal chimeras were established in vitro from runner tips. Plants were transferred to proliferation media containing 0.5 μm IBA, 0.3 μm GA3, and BA at either 0, 1.3, 4.4, or 13.2 μm. Whereas the histogens of field-grown runner plants remained stable, more than 90% of the plantlets propagated in vitro varied from the original explants. Most variants were albino or were green, but some were mericlinal chimeras. Histological evidence indicated that many shoots were adventitious, arising from basal callus tissue or petioles. Chemical names used: 1H-indole-3-butanoic acid (IBA); gibberellic acid (GA3); N-(phenylmethyl)-1H-purin-6-amine (BA).
Influence of Photoperiod, Apical Meristem, and Explant Orientation on Axillary Shoot Proliferation of Apple Cultivars in Vitro
Authors: Yae Byeong Woo , Zimmerman Richard H. , Fordham Ingrid , Ko Kwang Chool
Published: August 2022

The apple (Malus domestica Borkh.) cultivars Empire, McIntosh, Delicious, Triple Red Delicious, and Vermont Spur Delicious were grown on Linsmaier and Skoog (LS) medium containing 4.4 μm BA, 0.5 μm IBA, 1.3 μm GA3, 87.6 mm sucrose, and 7 g·liter−1 Difco Bacto-agar. All cultivars produced significantly more total shoots and shoots >1 cm (usable shoots) on a 16-hr compared to a 24-hr photoperiod. Removing the apical meristem significantly increased both the total and usable shoots only for ‘Triple Red Delicious’. Placing explants horizontally on the medium significantly increased the number of total and usable shoots for all cultivars except ‘McIntosh’. Internode length was significantly reduced for ‘Delicious’, ‘Triple Red Delicious’, and ‘Vermont Spur Delicious’ and increased for ‘Empire’ on 24-hr photoperiods. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA); 1H-indole-3-butanoic acid (IBA); gibberellic acid (GA3).
Pollen Viability in Five Southeastern United States Diploid Species of Vaccinium
Authors: Megalos B.S. , Ballington J.R.
Published: August 2022

Five southeastern United States diploid Vaccinium species were examined in 1983 and 1984 for pollen viability, unreduced pollen frequency, and pollen diameter. Significant intraspecific variation occurred for all three characteristics. Pollen viability and 2n pollen frequency did not vary significantly among species or between years. The number of clones producing 2n pollen was low, 8 of 41 in 1983 and 3 of 41 in 1984. Vaccinium elliottii Chapm. accounted for at least half of the 2n clones each year and also exhibited the highest unreduced pollen frequencies in 1983 (1.9%) and 1984 (1.6%). All 1984 2n clones were diplandrous the previous year, suggesting a genetic basis for unreduced gamete production. Unreduced pollen was found in three of the five species studied. Pollen diameter was not a good criterion for distinguishing one diploid species from another. Significant pollen diameter differences from 1983 to 1984 may be attributable to differences in pollen storage procedures and not environment per se.
Temperature, Grafting Method, and Rootstock Influence on Iron-deficiency Chlorosis of Bean
Authors: Zaiter H.Z. , Coyne D.P. , Clark R.B.
Published: August 2022

Two resistant (Great Northern ‘Emerson’ and Neb-WM1-83-10) and two susceptible (PI 165078 and ‘Steuben Yellow Eye’) cultivars/lines of dry bean (Phaseolus vulgaris L.) to iron (Fe) deficiency chlorosis, and their reciprocal graft combinations (two methods) were grown in pots in Tripp sandy clay loam (coarse-silty, mixed, mesic Aridic Haplustoll) known to induce Fe deficiency chlorosis. Experiments were conducted in a growth chamber under low (24°/13°C) and high (29.5°/18.5°) air temperature regimes at 15/9 hr (light/dark) periods. The experimental plan was a split-plot with temperature regimes as main plot and treatments in a completely randomized design with two replications. When scions of entries susceptible to Fe deficiency were grafted onto rootstocks of resistant entries, the leaves of the grafted plants were greener than the ungrafted susceptible entries. In reciprocal combinations, the leaves of scions of the resistant entries became chlorotic. These data indicate that rootstocks of dry beans appear to control chlorosis resistance, presumably due to root uptake or translocation of Fe. The chlorosis was more severe on leaves of cleft-grafted-scions than with approach-grafted-scions and more severe under the low compared to high temperature regimes.