bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Photosynthetic Rate Maximization on Chrysanthemum Growth and Development
Authors: Heins Royal D. , Karlsson Meriam G. , Flore J. A. , Carlson William H.
Published: August 2022

A 2nd order equation relating net photosynthesis (Pn) to photosynthetic photon flux density (PPFD), temperature, and CO2 was determined from single leaf CO2 depletion measurements made with an open gas analysis system. From this information, a photosynthetic optimization equation was used as the basis for computer regulation of greenhouse environment control using 2 strategies. In strategy 1, both temperature and CO2 setpoints were reset every 15 min based on the PPFD in the greenhouse. In strategy 2, only the temperature setpoint was reset, CO2 was ambient. The calculated setpoints represented temperature and/or CO2 values, where predicted Pn was maximized at the particular PPFD. Both strategies were compared to a typical commercial chrysanthemum environment of 16/20/24°C (night/day/vent) with ambient CO2. Chrysanthemum morifolium Ramat. (‘Bright Golden Anne’) grown in the temperature and CO2 optimized environment had significantly greater leaf, stem, and total dry weight at flowering compared to the other 2 environmental strategies. The percentage of stem dry weight and the stem length also were increased. For all 3 planting dates the percentage of flower dry weight was reduced but statistically significant on 1 date only. Flowering date was not affected. No consistent statistical differences in plant development were observed between the temperature optimized environment and the traditional environment.
Net Photosynthesis, Dark Respiration, Stomatal Conductance, Specific Leaf Weight, and Chlorophyll Content of Strawberry Plants as Influenced by Fruiting
Authors: Schaffer B. , Barden J. A. , Williams J. M.
Published: August 2022

In an initial experiment, ‘Tribute’ (day-neutral) and ‘Allstar’ (June bearing) strawberry [Fragaria × ananassa (Duch.)] plants were grouped into fruiting, partially deblossomed, and deblossomed treatments. Net photosynthesis (Pn), dark respiration (Rd), and stomatal conductance for CO2 (gs) were measured at 14-day intervals during the 1st fruiting cycle of both cultivars and at 7-day intervals during the 2nd fruiting cycle of ‘Tribute’. Pn of recently expanded leaves of fruiting plants was greater than that of deblossomed plants only during the 2nd week of the first fruiting cycle and the 2nd and 3rd weeks of the 2nd fruiting cycle. There were no differences in Rd or gs among treatments. At the end of the fruiting cycles, leaves, crowns, and roots of deblossomed plants of both cultivars had greater dry weights than those of fruiting plants. At the end of the first fruiting cycle, roots of deblossomed ‘Tribute’ had a higher percentage of total nonstructural carbohydrates (TNSC) than roots of fruiting plants. In Expt. 2, ‘Tribute’ plants were grouped into fruiting and deblossomed treatments. At 7-day intervals throughout the fruiting cycle, Pn, specific leaf weight (SLW), and chlorophyll content were determined for a leaf that was fully expanded at bloom (old leaf) and for the most recently expanded leaf (young leaf) of each plant. Pn of the young leaf was greater for fruiting plants than deblossomed plants only during weeks 5 and 6 of the fruiting cycle, and no treatment effect was observed for old leaf Pn. During fruit maturation, SLW was higher for deblossomed plants than fruiting plants for both leaf ages. Deblossomed plants had a higher leaf chlorophyll content than fruiting plants during the 1st, 2nd, and 4th weeks of the fruiting cycle.
Seed and Pod Set of Red Kidney Beans
Authors: Pechan Paul M. , Webster Barbara D.
Published: August 2022

Plants of Phaseolus vulgaris ‘Red Kidney’ were studied under controlled environmental conditions to determine the effect of prefertilization events on seed and pod set. These were analyzed on flowers of the terminal receme at anthesis and 7 days postanthesis. Microscopic examination of pollen indicted that less than 7 % of the grains were aborted and that a sufficient number of grains germinated on the stigma to ensure fertilization of all ovules within an ovary. All ovules observed were fertilized; the number of ovules per ovary was 4 or 5. Results indicate that the discrepancy between the number of ovules and the final seed number per pod is due to seed abortion rather than to ovule abortion. Pod abortion appears to be a consequence of postfertilization processes.
Nitrogen Redistribution from Almond Foliage and Pericarp to the Almond Embryo
Authors: Weinbaum S.A. , Muraoka T.T.
Published: August 2022

Mature almond trees [Prunus dulcis (Mill) D.A. Webb] growing on a very light-textured (Delhi sand) soil were fertilized with 15N-depleted ammonium sulfate during 1980. Although uptake of labeled N from the soil N pool had ceased by 1982, label persisted within the trees at least until 1984. This label presumably represented the residual portion of the organic pool of storage N absorbed by the trees several years before. Leaf, pericarp, and embryo (kernel) samples were collected over a 2-month period during embryo maturation, and samples were processed for mass spectrometric analysis. Total leaf N did not decrease during embryo maturation, but labeled N in leaves decreased by 25%. These data are consistent with the concept of N turnover and flux through mature leaves and transport of N from leaves to fruit. These data indicate also that the N stored overwinter in perennial tissues of almond trees is redistributed within the trees throughout the growing season to support the development and function of annual plant organs such as leaves and fruit.
Growth and Incidence of Bract Necrosis in ‘Gutbier V-14 Glory’ Poinsettia
Authors: Nell Terril A. , Barrett James E.
Published: August 2022

Bract necrosis of Euphorbia pulcherrima Willd. ‘Gutbier V-14 Glory’ was most frequently observed on transitional bracts (red leaf-shaped organs attached to the stem in the same alternate phyllotaxy as leaves and subtending the inflorescence). Transitional bracts lacked a palisade layer and their stomatal density was lower than on leaves. Necrosis was prevalent at the transitional bract tips in areas with a brochidodidmous-semicraspedodromous veination pattern. Plant growth was not affected when either fertilization was terminated at bract coloration or when plants were watered at wilt during the period from bract color to anthesis. Necrosis was greatest, however, on plants grown with high fertilizer and water levels. Necrosis may be associated with a toxicity of elements transported through pitted vein endings at the tip of the bract.
Genotype–Environment Interactions in Processing Tomatoes in Ontario
Authors: Poysa V.W. , Garton R. , Courtney W.H. , Metcalf J.G. , Muehmer J.
Published: August 2022

Improved methods of breeding, selection, and testing for yield can be developed with information on the magnitude and nature of genotype–environment interactions. Cultivar trials of processing tomatoes (Lycopersicon esculentum Mill.) grown in Ontario for 2 years at 5 locations each year were studied for genotype–environment interactions. Cultivars were evaluated for phenotypic stability and desirability using regression coefficients, mean square deviations from linear regression, and t test comparisons of genotype means with environment means. Genotype-environment interactions were significant for yield of marketable fruit each year and in a combined analysis across years. Regression analysis indicated that low-yielding genotypes had above-average yield stability across environments, while several high-yielding genotypes were unstable. Several cultivars were found to be desirable because they had a high mean yield and did not have lower yields than the test mean in any of the 5 environments. Regression analysis alone could result in misleading conclusions about the performance of high-yielding tomato genotypes. Large genotype-environment interaction variances relative to genotype variances were detected. The interaction variance components involving year were large relative to the genotype-location interaction variance, indicating the need for multiyear evaluation and selection for stability even when breeding for a limited geographic region.
Nitrogen Form Ratio Influence on Muskmelon Growth, Composition, and Manganese Toxicity
Authors: Elamin Osman M. , Wilcox Gerald E.
Published: August 2022

Muskmelon (Cucumis melo L.) ‘Harvest Queen’ was grown in sand culture to investigate the effects of NH4:NO3 ratios on melon growth and elemental composition. Plants grown at NH4:NO3 ratios of 98:14, 84:28, and 56:56 developed NH4 toxicity symptoms, whereas plants grown with 20 ppm Mn and NH4:NO3 ratios of 0:112, 14:98, 28:84, and 56:56 developed Mn toxicity symptoms. Increasing the proportion of NH4 in nutrient solution up to 1:1 with NO3 decreased Mn concentrations in plant tissues and alleviated Mn toxicity symptoms, whereas at NH4:NO3 ratios of 84:28 and 98:14 uptake of Mn was inhibited and never reached a concentration in the tissue that developed toxicity symptoms. Shoot and root growth was greatest when grown at the 14:98 NH4:NO3 ratio. Increasing NH4 in the solution beyond 14 ppm in the 112-ppm N mixture resulted in increasing limitation of growth. Increasing Mn concentration in the nutrient solution to 20 ppm restricted growth at NH4:NO3 ratios ≤1. However, Mn treatment did not influence the growth of plants grown at NH4:NO3 ratios >1 at 84:28 and 98:14.
Flower Position, Growth Regulators, and Fruit Set of Rabbiteye Blueberries
Authors: Davies Frederick S.
Published: August 2022

Seasonal patterns of fruit drop and the influence of flower position and bloom date on fruit set were studied for ‘Woodard’, ‘Bluegem’, and ‘Tifblue’ rabbiteye blueberries (Vaccinium ashei Reade). The pattern of fruit drop was similar for the 3 cultivars, with most the drop occurring within 3 to 4 weeks of full bloom. Fruit drop was most severe for ‘Tifblue’, which set only 21% to 27% of its flowers, compared with 46% to 60% for ‘Woodard’ and 53.5% to 55% for ‘Bluegem’. Position of flowering shoots in the bush and time of flower opening had no consistent effect on the percentage set, although flowers in a terminal position on the shoot generally set a higher percentage of fruit than those in a lateral position for ‘Woodard’. Spray application of gibberellic acid (GA) or (2,4-dichlorophenoxy)-acetic acid (2,4–D) at various times during bloom did not affect yields. The percentage of fruit set was poorly correlated with yields within a season for ‘Woodard’ and ‘Bluegem’, indicating that flower number is also an important determinant of yields. However, poor fruit set for ‘Tifblue’ was associated with low yields.
Acclimation and Winterhardiness Patterns in the Eastern Thornless Blackberry
Authors: Kraut Joseph L. , Walsh Christopher S. , Ashworth Edward N.
Published: August 2022

An attempt was made to alter the late-season growth habit of eastern thornless blackberry plants (Rubus sp.) with foliar sprays of growth regulators and plant nutrients. While fall applications of ethephon hastened leaf abscission, they did not affect shoot dieback or yield. Cultivar effects were very strong. ‘Dirksen’ plants had the least cane dieback and highest yield, ‘Hull’ plants were intermediate, and ‘Smoothstem’ plants were the least hardy and had the lowest yield. A significant negative correlation was found between the number of leaves retained throughout November and the subsequent yield of these 3 cultivars. Artificial freezing tests throughout the winter demonstrated that buds were less hardy than bark tissue. Bark and pith tissue from plants defoliated 30 Sept, were injured more than those tissues from plants defoliated later in the fall. No apparent relationship between fall defoliation and bud hardiness was observed. ‘Dirksen’ buds were 0.2° to 5.9°C hardier than were ‘Smoothstem’ buds. Differential thermal analysis showed that a freezing event occurred in both stems and buds at about −5°. A 2nd exotherm occurred in buds at about the LT50.
The Influence of Fruiting and Shading of Spurs and Shoots on Spur Performance
Authors: Rom Curt R. , Ferree David C.
Published: August 2022

Leaves of spurs and/or shoots of small fruiting ‘Starkrimson Delicious’ apple trees were exposed to light or shade treatments from 60 days after petal fall until fruit maturity. Shading spurs reduced spur leaf photosynthesis (Pn) and transpiration (Tr), but shading shoots had no effect on spur leaf Pn. There was no difference between fruiting and nonfruiting spur Pn and Tr. Shading shoots reduced fruit growth and delayed maturity, but shading spurs had no effect on either. Fruiting reduced—but did not eliminate—spur flowering the following year. Light conditions late in the season had no effect on flowering or spur leaf development the following spring.
The Development and Control of Husk Scald on ‘Wonderful’ Pomegranate Fruit during Storage
Authors: Ben-Arie Ruth , Or Esther
Published: August 2022

A superficial browning disorder (scald) develops on the husk of ‘Wonderful’ pomegranate (Punica granatum L.) fruit during storage. The severity of this disorder could be diminished by delaying the harvest time and by reducing storage temperature, but these 2 measures were insufficiently effective for storage periods exceeding 6 weeks, and at temperatures of 6°C or lower, chilling injury also occurred. Scald incidence was correlated with the amount of o-dihydroxyphenols extractable from the husk, and was significantly controlled by measures that inhibited their oxidation by polyphenol oxidase. Such postharvest measures included dipping the fruit in boiling water for 2 minutes and in anti-oxidant solutions, in bisdithiocarbamate-containing maneb for 30 seconds, or storing the fruit in a low-O2 atmosphere. The most effective control of husk scald was obtained by storing late-harvested fruit in 2% O2 at 2°. However, this treatment resulted in accumulation of ethanol, which caused off-flavor development. When the fruit were transferred to air at 20°, ethanol and off-flavors dissipated.
Responses of Daminozide-sprayed ‘McIntosh’ Apples to Various Concentrations of Oxygen and Ethylene in Simulated CA Storage
Authors: Liu F.W. , Ci Long-Jun
Published: August 2022

Daminozide-sprayed ‘McIntosh’ apples (Malus domestica Borkh.) were stored for 7.5 to 8 months in 19-liter jars with flow-through controlled atmosphere (CA) at 3.3°C. Various combinations of gases were tested in 2 years: 1%, 1.5%, 2%, 2.5%, and 3% O2; 0%, 3%, and 3→5% (3% for one month and then 5%) CO2; and <1 and 500 μl·liter−1 ethylene. High ethylene caused significant softening of apples in 3% O2 + 3% CO2 or 3% O2 + 3→5% CO2 (3 + 3 or 3 + 3→5), but its effect diminished by lowering O2 concentrations. In 1 + 3, the 2 concentrations of ethylene made only a slight difference in fruit firmness in one year and no difference in another year. In <1 μl·liter−1 ethylene, lowering O2 concentrations from 3% to 2% and 1% did not increase fruit firmness, but did reduce rates of ethylene production. A small percentage of apples developed skin injury in 1 + 3 and 1.5 + 3 in one year, and apples of one of 3 jars stored in 1 + 3 developed slight off-flavors in another year. A storage atmosphere of 2 + 3 and <1 μl·liter−1 ethylene, which kept apples firm without injury or off-flavor and with very low rates of ethylene production, may be ideal for low-ethylene CA storage of daminozide-sprayed ‘McIntosh’ apples. Chemical names: butanedioic acid mono (2,2-dimethylhydrazide) (daminozide).
Whole Plant Photosynthesis and Dry-matter Partitioning in Fruiting and Deblossomed Day-neutral Strawberry Plants
Authors: Schaffer B. , Bar den J.A. , Williams J.M.
Published: August 2022

On a whole-plant basis, deblossomed ‘Tribute’ strawberry plants had higher rates of net photosynthesis (Pn) and greater leaf area than fruiting plants during the last 3 weeks of a 6-week fruiting cycle. Leaves of both fruiting and deblossomed plants had a greater dry weight and total nonstructural carbohydrate (TNSC) content than the roots, crown, or fruit. At the end of the fruiting cycle, dry weight and TNSC content of leaves were higher for deblossomed plants than fruiting plants. There was no difference in crown or root dry weights between treatments. Pn was highly correlated with plant dry weight and TNSC during the 3rd, 5th, and 6th weeks of the fruiting cycle.
Growth and Photosynthesis of Easter Lily in Response to Flower Bud Removal
Authors: Wang Yin-Tung , Breen Patrick J.
Published: August 2022

Buds or open flowers are often removed in the production of Easter lily (Lilium longiflorum Thunb.) bulbs. To determine if time of flower removal affects bulb size or plant growth, flower buds of container-grown ‘Nellie White’ plants were removed when the length of the largest flower bud was 1.0 cm (early) or 3.5 cm (late). Net photosynthesis of the 5th (upper) and 25th (mid-shoot) leaves was monitored and plants were harvested 2 months after full bloom of intact controls. Early disbudding stopped pedicel growth, inhibited stem elongation, and reduced total leaf area 12%, but did not affect bulb weight. Stem elongation was inhibited less by late disbudding; leaf area and plant weight were unaffected. Both fresh and dry bulb weights of late disbudded plants increased by 15%. Early disbudding reduced the rate of net photosynthesis of leaf 5 (particularly during the 3 weeks following full bloom), whereas late disbudding had less effect. Treatments did not affect photosynthesis of leaf 25. Reduced stem growth under late disbudding, without a severe reduction in photosynthesis, may have increased the availability of assimilate for bulb growth. Early disbudding caused 81% of the daughter bulbs to sprout prematurely, compared to 27% for late disbudding and 9% for controls. In a field study, removing flower buds at 1.5 cm or 4.0 cm in length increased bulb fresh weight over intact controls by 12% and 30%, respectively. Disbudding did not increase sprouting of field-grown plants. Delaying removal until the first flower bud is 3.5–4.0 cm long reduces deleterious effects on shoot growth while significantly improving bulb size.
Response of Beans to Simulated Ambient and Uniform Ozone Distributions with Equal Peak Concentration
Authors: Musselman R.C. , Huerta A.J. , McCool P.M. , Oshima R.J.
Published: August 2022

Response of Phaseolus vulgaris L. cv. California Dark Red Kidney to 2 different ozone concentration distributions was examined at 2 dose levels in controlled fumigations. When peak ozone concentrations were equal and total doses equivalent, there was no difference in injury, growth, or yield between a simulated ambient distribution with normal diurnal ozone fluctuations and a uniform distribution typical of laboratory fumigation at constant concentration. Plants fumigated with either ambient or uniform ozone distribution had oxidant stipple leaf necrosis and reduced growth and yield. There was significantly increased injury and reduced growth and yield at a high ozone dose for both types of distribution. The data indicate that with equal peak concentration and equivalent total dose, the constant square-wave, ozone concentration distributions in laboratory fumigations are adequate to describe mode of action and magnitude of response to ambient exposures.
Response of Vegetable Crops to Nitrogen Rates in Tillage Systems With and Without Vetch and Ryegrass
Authors: Knavel Dean E. , Herron J.W.
Published: August 2022

Direct-seeded bush beans, sweet corn, summer squash, and transplanted tomato and cabbage were grown under varying tillage and cropping systems in 1982 and 1983. Cultural treatments were conventional tillage (CT), no-tillage without cover crop (NT–CC), and no-tillage with a cover crop (NT + CC) of hairy vetch (Vicia villosa) in 1982 and perennial ryegrass (Lolium multiflorum) in 1983. Split applications of N were 56 and 112 kg·ha−1 in CT plots and 0, 56, and 112 kg·ha−1 in NT plots. Plant stand and yields of bush beans and sweet corn were highest in CT plots in both years. Plant stand of squash was less for CT in 1982, but greater for CT than for NT + CC in 1983. Yields of squash were similar, but plant dry weight was greater in CT than in NT + CC. Plant stand of tomato and cabbage for NT + CC was similar to CT in 1982, but cabbage stand was greatest for CT in 1983. Total tomato yields were greater for NT – CC in 1982 and similar to those for CT in 1983, but yields were greatly reduced for NT + CC in 1983. Only in 1982 were cabbage heads of certain treatments marketable and they were greatest for CT. Sidedressing bush bean, sweet corn, cabbage, and summer squash plants with N in NT – CC plots increased yields linearly in 1982. Of the crops grown by NT + CC, only yields of bush beans and cabbage in 1982 and green fruit of tomato in 1982 showed a linear increase by sidedressing with N. Sidedressing with N increased N contents of all crops linearly in 1982, but not in 1983. Weed control was excellent in CT sweet corn and satisfactory in CT and NT – CC plots of the other crops. For the other crops in NT + CC plots, most of the weed and/or cover crop growth was the regrowth of vetch in 1982 and perennial ryegrass in 1983 after weed control chemicals were applied.
Effects of Oxygen and Temperature During Imbibition on Seeds of Two Bean Lines at Two Moisture Levels
Authors: Ladror Uri , Dyck Ray L. , Silbernagel Matt J.
Published: August 2022

Low temperature and oxygen stresses were imposed during the first 48 hr of germination on 2 lines of snap bean (Phaseolus vulgaris L.), stress tolerant (PI-165426-BS) and stress-sensitive (‘Goldcrop’). At 22°C, O2 concentrations of 0%, 1%, and 2% increased leakage from the seeds, delayed emergence, and reduced growth, compared to 5% and 21% O2. These effects were aggravated by reducing the initial seed moisture from 12% to 8% in ‘Goldcrop’, but not in PI-165426-BS. At 10°, the effect of oxygen deficiency was minimized. Low temperatures inhibited growth of ‘Goldcrop’, but not of PI-165426-BS, and increased leakage from seeds of both lines. The survival of seeds exposed to the low temperature decreased when initial seed moisture was reduced from 12% to 8%. Flooding the seeds for 24 hr increased leakage and reduced emergence and growth much more than 24 hr of complete anoxia. Since the effects of anoxia are different than flooding injury, a mechanism of flooding injury not related to oxygen deficiency is discussed.
Effect of Magnesium and Manganese Nutrition on Muskmelon Growth and Manganese Toxicity
Authors: Elamin Osman M. , Wilcox Gerald E.
Published: August 2022

Muskmelons (Cucumis melo L.) ‘Harvest Queen’ were grown in sand culture to evaluate the response to Mn toxicity as affected by solution concentration of Mn and Mg. Manganese toxicity symptoms were developed as water-soaked spots, necrotic spots, and necrotic lesions, which were most severe on the lower mature leaves. Leaves developed toxicity symptoms when they contained ≥900 μ-g·g-1 Mn. Increased levels of Mg in the nutrient solution alleviated symptoms of Mn toxicity, decreased Mn concentration in shoot and root tissues, and increased growth of muskmelon plants. The reduction in Mn toxicity was brought about by reduced root absorption of Mn at high Mg supply.
Yield Component Interactions in Cultivars of the Highbush Blueberry
Authors: Siefker J.H. , Hancock J.F.
Published: August 2022

Yield component analysis of 9 Vaccinium corymbosum L. blueberry cultivars indicated that yield was more strongly determined by canes per bush and berries per cane than by berry weight. High numbers of berries per cane were associated with low berry weights in all cultivars. Component interactions ranged from slightly additive in ‘Bluecrop’ and ‘Spartan’ to highly compensatory in ‘Rubel’ and ‘Berkeley’. The consideration of component interactions in cultivar trials may enhance the accuracy in identification of desirable genotypes.
Breeding Strategies for Increasing the Anthocyanin Content of Cranberries
Authors: Sapers Gerald M. , Jones Susan B. , Kelley Michael J. , Phillips John G. , Stone Eric G.
Published: August 2022

The effect of cultivar on cranberry (Vaccinium macrocarpon Ait.) fruit size and composition was investigated. ‘Ben Lear’, ‘Crowley’, ‘Early Black’, and ‘Franklin’ berries contained about twice the anthocyanin of the other clones. Based on projections of analytical data, potential gain could be enhanced by increasing the proportion of berries that attain high anthocyanin content, seen in individual fruits within samples, as compared to the alternative strategies of breeding for improved anthocyanin content, for small berries, or for synchronous ripening.
Carbon Dioxide Enrichment for Stimulation of Growth of in Vitro-propagated Grapevines After Transfer from Culture
Authors: Lakso A.N. , Reisch B.I. , Mortensen J. , Roberts M.H.
Published: August 2022

The hypothesis was tested that the growth of in vitro-propagated, nonrooted grape shoots (Vitis L. hybrid) directly after transfer from culture (ex vitro) is limited by photosynthetic C supply and that growth would be stimulated by CO2 enrichment (CDE). Plantlets were grown for 30 days in air with 350 or 1200 ppm (v/v) CO2 in humidified, flow-through chambers at 26°C. Destructive growth analyses were made at 0, 10, 20, and 30 days after transfer from culture to soil. CDE had no significant effect on total plant dry weight increase in the first 10 days. By 20 and 30 days, CDE-treated plants were 2 and 4 times greater in dry weight, respectively, than controls. Root growth was most improved by CDE, being almost 6 times greater than controls by 30 days. Leaf area per plant and root : shoot ratio were both doubled by CDE at 20 and 30 days. Since these results were under nonstress conditions, the use of CDE for growth stimulation needs to be evaluated under stress-hardening regimes.
Development and Prevention of Chilling Injury in Papaya Fruit
Authors: Chen Nein-Ming , Paull Robert E.
Published: August 2022

Papaya (Carica papaya L.), a climacteric fruit, became progressively less susceptible to chilling injury as it ripened. Symptoms of chilling injury included skin scald, hard areas in the pulp around the vascular bundles, and water soaking of tissue. Mature green fruit were most sensitive to chilling and began showing injury after 10 days of storage at 2°C. Chilling injury symptoms began to occur after 20 days at 7.5°. Fruit that showed 60% yellowing could be kept at 2° for 17 days without developing injury. Preconditioning papaya fruit for 4 days at 12.5° before storage for 12 or 14 days at 20° reduced chilling sensitivity. The decrease in chilling sensitivity with preconditioning was associated with partial fruit ripening. Waxing and wrapping papaya with polyethylene reduced chilling injury, but the fruit had an off-flavor. Controlled atmospheres of low oxygen (1.5% to 5%) with or without high C 02 (2% or 10%) delayed ripening, but did not reduce chilling injury symptom development. Calcium treatment led to increased chilling injury of papaya fruit. Delaying storage until the fruit ripened decreased chilling susceptibility and increased storage life at chilling temperatures. Shipping 60% yellow fruit at 2° could provide a procedure for achieving fruit fly disinfestation. Differences in cultivar response to chilling injury were noted.
Cytokinins and Flower Development in Leucospermum
Authors: Napier D.R. , Jacobs G. , Van Staden J. , Forsyth C.
Published: August 2022

Flower quality in Leucospermum can be improved by increasing the diameter and length of the reproductive shoot and by increasing floret initiation and capitulum size. During flower induction, endogenous cytokinin levels were low, with mainly “storage” forms of cytokinins being present. However, during flower differentiation, endogenous cytokinin levels increased and most of the activity was in the form of “free” cytokinins. One application of benzyladenine, if applied during the flower induction phase, increased both reproductive shoot diameter and the number of florets per capitulum.
Carotenoid and Starch Content of Near-isogenic B+B+ and BB Genotypes of Cucurbita
Authors: Schaffer Arthur A. , Paris Harry S. , Ascarelli Immanuel M.
Published: August 2022

The starch and carotenoid contents of the flesh of mature fruits were compared in 10 B+B+ Cucurbita accessions and their near-isogenic BB counterparts. There were significant differences among the accessions with respect to starch, total carotenoid, carotene, and xanthophyll contents. The accessions also responded differently to the substitution of B for B+. The B allele reduced the starch content only in those accessions possessing a high starch content with B+B+. B increased total carotenoids in most of the accessions. Those having the lowest carotenoid content in the presence of B+B+ were least affected by substitution of B. C. pepo cv. Fordhook Zucchini, and a breeding line derived from it, showed the greatest increase in carotenoid content after allelic substitution. The possible role of the B allele in plastid development and its use in breeding for increased carotene content in Cucurbita are discussed.
Comparison of Six Methods of Multiple-trait Selection for Fruit Yield and Quality Traits in Three Fresh-market Cucumber Populations
Authors: Strefeler Mark S. , Wehner Todd C.
Published: August 2022

Six selection indices (Smith-Hazel, desired gain, simple-weighted, rank summation, Elston's weight-free, and Baker's standard deviation) were compared to determine the effectiveness of each in identifying superior families for improving 8 fruit yield and quality traits in 3 fresh-market cucumber populations differing in genetic diversity (elite, medium-base, and wide-base). The rank summation, Elston's weight-free, and Baker's standard deviation indices were constructed with 5 traits as well as with the full 8 traits to determine whether measurement of fewer traits would suffice. The Smith-Hazel and desired gain indices were constructed using 5 traits only, since the 8-trait indices had problems with trait colinearity. The effectiveness of the indices was measured by calculating selection differentials for each index. In the elite population, the Smith-Hazel index produced negative selection differentials for all 8 traits studied. In the medium-base and wide-base populations, the Smith-Hazel index had positive differentials, but the desired gain index had negative differentials for the 8 traits studied. The simple-weighted, rank-summation, Elston's weight-free, and Baker's standard deviation indices all had positive selection differentials for the traits of interest in all 3 populations. The best index was the rank summation for 5 traits, since it had the highest overall selection differential of those measured and was easiest to calculate.
Influence of Adjuvants on Foliar Absorption of Nitrogen and Phosphorus by Soybeans
Authors: Stein Larry A. , Storey J. Benton
Published: August 2022

Adjuvants at various concentrations were evaluated for phytotoxicity and capacity to enhance foliar absorption of N and P. Some adjuvants among the following classes were phytotoxic to soybean (Glycine max Merr.) leaves at concentrations of 0.25% and 0.5% active ingredient on a volume or weight/volume basis: sulfonates, alcohols, ethyoxylated hydrocarbons, esters, sulfates, and amines. Many adjuvants in the following classes: alcohols, sulfonates, ethoxylated hydrocarbons, polyethylene glycols, carbohydrates, proteins, and phosphates were not phytotoxic at concentrations as high as 1.0%. Sometimes increasing phytotoxicity occurred at increasing concentrations, but the humectants, such as glycerol and propylene glycol, were not phytotoxic at concentrations of 10.0%. Selected adjuvants were mixed with a foliar fertilizer (12.0N–1.7P–3.3K–0.5S) and evaluated for enhancement of foliar absorption of N and P. The average increases in percentage of N and P for the glycerol, lecithin, and Pluronic L-121 (an ethyoxylated hydrocarbon), and foliar fertilizer combinations, respectively, were 8.9%, 2.2%, and 2.5% for N and 34.2%, 27.6%, and 20.8% for P over the foliar fertilizer control, respectively, for the 3 adjuvants.
Field Evaluation of Establishment Methods and Intensive Management Practices for Strawberries
Authors: Handley David T. , Pollard James E.
Published: August 2022

Field experiments were conducted to determine differences in vegetative development and fruit production of Fragaria × ananassa Duch. in response to high-density planting vs. spaced-runner bed establishment, fruiting of high-density plantings in the establishment year, spring vs. summer planting of dormant crowns, and removal of stolons in excess of those required for a specific plant density. Yields did not differ significantly between spring-planted plots established exclusively with densely planted dormant crowns (11 plants per m2) and those established under a spaced-runner system using 4 stolons per mother plant to achieve the same final plant density. In spring-set, high-planting-density plots, fruit production in the planting year was low and had no effect on vegetative development or 2nd-year yields. Summer planting resulted in high mortality rates for 2 of 3 cultivars. By October, surviving summer-planted crowns had numbers of leaves and branch crowns per plant equivalent to those planted in spring. Reduced stolon production in summer plantings resulted in poor establishment of spaced-runner beds, but had no effect on dense-planted beds. Summer planting reduced yields in both high-density and spaced-runner beds compared to spring planting. Successful bed establishment in the summer is dependent on cultivar and planting density. Removal of stolons increased yields and promoted further stolon initiation in spring plantings, but had no effect on summer plantings.
Urea Hydrolysis in Potting Media
Authors: Elliott George C.
Published: August 2022

Urea hydrolysis and the fate of ammonium produced were evaluated in bark : peat : sand, peat : vermiculite, and 14 commercial potting media, in cropped and uncropped samples. Urea hydrolysis was much more rapid in pine bark : peat : sand than in peat : vermiculite. Significant variation in urea hydrolysis was observed among the commercial media. Urea hydrolysis was more rapid in cropped than in uncropped media. Substantial net N immobilization was observed in most media. Although nitrification was evident, there was generally very little net nitrate accumulation. Differences in urea hydrolysis and ammonium accumulation were of sufficient magnitude to warrant consideration in fertilizer management.
Competition Among Berries on the Cranberry Upright
Authors: Baumann T.E. , Eaton G.W.
Published: August 2022

One hundred fruiting uprights were sampled for each of 3 cranberry (Vaccinium macrocarpon Ait.) cultivars, ‘Ben Lear’, ‘Bergman’, and ‘McFarlin’. Length of the upright, flowers per upright, berries per upright, seeds per berry, and weight of the berries were recorded. Two-dimensional partitioning using analysis of variance and multiple regression were combined for yield component analysis on a per-upright basis. In decreasing order, fruit set, berry enlargement, and number of flowers per centimeter of the upright were the most important components. Linear trends accounted for most of the differences due to position with lower positions having more flowers, fruit set, seeds per berry, and larger fruit than upper positions on the upright. More berries were set in ‘Ben Lear’ than in ‘McFarlin’ and ‘Bergman’.
Root Distribution of ‘Tifblue’ Rabbiteye Blueberry as Influenced by Irrigation, Incorporated Peatmoss, and Mulch
Authors: Spiers James M.
Published: August 2022

A field study was conducted to evaluate individual and collective influences of 3 soil moisture-supplementing practices (irrigation, incorporated peatmoss, and mulching) on root system development in ‘Tifblue’ rabbiteye blueberries (Vaccinium ashei Reade). Plants that received no water-supplementing treatments died within 3 years. Root growth was least in plants receiving only one of the 3 treatments and greatest in plants receiving all 3. Ranking of individual treatments on root dry weight production was mulch > incorporated peatmoss > irrigation. Mulching resulted in uniform root distribution from the plant crown outward, while peatmoss tended to concentrate the root system near the crown area. Incorporating peatmoss concentrated roots at the 30- to 45-cm depth, while mulching tended to concentrate the roots in the upper 15 cm of soil. In a sandy, well-aerated soil, the major factor influencing root distribution appears to be soil moisture.
Fruit Anthocyanin Content of Some Euvitis × Vitis rotundifolia Hybrids
Authors: Goldy R.G. , Ballinger W.E. , Maness E.P.
Published: August 2022

The anthocyanin (Acy) content of 12 Euvitis × Vitis rotundifolia hybrids, 3 V. vinifera L., one V. × labruscana, and one V. rotundifolia Michx. clone were analyzed by high performance liquid chromatography (HPLC) techniques. All intersubgeneric hybrids contained mono- and diglucoside Acy, and all but one produced acylated Acy. A total of 40 pigments was separated, with ‘Concord’ having the most at 31. An additional unidentified pigment was detected in ‘Noble’. Sufficient variation was present in the hybrids for selection of genotypes that would improve color of wines. Relative Acy content (percentage of total) in the hybrids ranged from 2.3% to 44.3% for malvidins, 0.7% to 30.3% for petunidins, 0.8% to 69.2% for peonidins, 0.0% to 17.2% for cyanidins, and 0.5% to 52.3% for delphinidins. Relative content of acylated Acy forms in the hybrids ranged from 0.0% to 51.1%. Total Euvitis-type pigmentation (monoglucoside plus acylated Acy) in the hybrids ranged from 19.5% to 55.0%.
Anatomy of Fertile and Male-sterile Carrot Flowers from Different Genetic Sources
Authors: Struckmeyer B. Esther , Simon Philipp
Published: August 2022

An anatomical comparison of florets from fertile, brown anther partially fertile, petaloid male-sterile, and 3 brown anther male-sterile carrot (Daucus carota L.) lines indicated that most pollen was well-developed and deeply stained in fertile lines. Partially fertile plants contained fertile and sterile anthers in which meiosis had occurred. The 3 lines of brown anther steriles examined failed to enter meiosis. In early development of the fine foliage brown anther sterile, all cells of the anther, including sporogenous cells, hypertrophied. Later, sporogenous tissue collapsed. The anatomical structure of the stamens in petaloid florets was leaf-like and similar to petals.
A Comparison of Carbon and Water Vapor Gas Exchange Characteristics Between a Diploid and Highbush Blueberry
Authors: Moon J.W. , Flore J.A. , Hancock J.F.
Published: August 2022

CO2 assimilation (A), leaf conductance to water vapor (gl), mesophyll conductance (gm), and water use efficiency (WUE) were compared for two cultivars of highbush (Vaccinium corymbosum L.) and a wild diploid lowbush blueberry species (Vaccinium darrowii Camp.) in response to PPF, CO2, temperature, and vapor pressure deficit (VPD) to determine if apparent tolerance of V. darrowii to high temperature and drought conditions resulted from differences in gas exchange characteristics. Cultivar differences between ‘Bluecrop’ and ‘Jersey’ in A were not significant when expressed on a leaf area, leaf dry weight, or total chlorophyll basis. Maximum CO2 assimilation rates for V. darrowii were about 35%, 50%, or 40% lower than highbush cultivars when expressed on a leaf area, leaf dry weight, or total chlorophyll basis, respectively. Differences between ‘Bluecrop’ and ‘Jersey’ were also non-significant for mesophyll conductance, transpiration, CO2 compensation points, and water use efficiency. CO2 assimilation maximized between 600-800 µmol·s–1·m–2 photosynthetic photon flux (PPF) for all three genotypes and the temperature optima ranged between 18° and 26°C for ‘Jersey’, 14° and 22° for ‘Bluecrop’, and 25° and 30° for V. darrowii. As temperature was increased from 20° to 30°, leaf conductance (gl) to water vapor was lower and water use efficiency was higher for V. darrowii, compared to ‘Bluecrop’ but not ‘Jersey’. There was a 50-65% reduction in gl as VPD was increased, but only 10–20% reduction was observed in A. Leaf conductance to water vapor was reduced for V. darrowii, which restricted intercellular CO2. Since crosses are possible between highbush and V. darrowii, it is possible that heat tolerance and/or drought resistance could be improved in Highbush blueberry through the incorporation of genes from V. darrowii.
Photosynthesis of Olive Leaves: Effect of Light Flux Density, Leaf Age, Temperature, Peltates, and H2O Vapor Pressure Deficit on Gas Exchange
Authors: Bongi G. , Mencuccini M. , Fontanazza G.
Published: August 2022

Clonal plants of four olive (Olea europaea L.) cultivars that originated in cool, moderately hot, and hot climates were examined for their photosynthetic potentials. Within 3 to 4 weeks, plants had fully expanded leaves; by 3 months the apparent photosynthesis, A, increased to a maximum of 5.4 µmol CO2/m2 per sec, while the water use efficiency (WUE) was 2.6 mmol CO2/mol H2O. The mean chloropohyll content was 0.564 mmol/chlorophyll (a + b)/m2. Mean assimilation rate was negatively correlated to leaf area. The values of A were three to four times less than those reported for apple and almond, whereas WUE was 22% greater. A values were proportional to stomatal conductance. Mesophyll resistance was higher than several C3 plants and the optimum temperature for photosynthesis varied among cultivars, seemingly according to the climate where they originated. Stomata opened and closed within 10 min in response to changes in humidity. Gas exchange properties were not affected by peltate removal.
Flowering, Fruit Set, and Fruit Development in Birdsnest-type Muskmelons
Authors: McCollum T.G. , Cantliffe D.J. , Paris H.S.
Published: August 2022

The birdsnest plant type in muskmelon (Cucumis melo L. var. reticulatus Naud.) is characterized by short internodes, weak apical dominance, and concentrated yield. Flowering, fruit set, and fruit development in a birdsnest-type were examined and compared with those characters in a vine-type muskmelon to understand how the concentration of yield is achieved. A muskmelon breeding line with the birdsnest habit, D26, was compared with ‘Noy Yizre'el (NY), a vine-type cultivar. Results of a greenhouse and field study indicated that the two genotypes had similar patterns of perfect flowering; however, D26 set a greater number of fruit than NY. The pattern of fruit set and fruit maturity (yield) was more concentrated in D26 than in NY. First-set fruit had an inhibitory effect on the development of later-set fruit in NY, but this effect was not apparent with D26. NY fruit were larger in size and had higher soluble solids than D26 fruit. The concentrated fruit set and yield of birdsnest-type plants suggests a more equal partitioning of assimilates to young, developing fruit than in vine-type plants.
Glucosinolates in Turnip Tops and Roots: Cultivars Grown for Greens and/or Roots
Authors: Carlson Diana G. , Daxenbichler M.E. , Tookey H.L. , Kwolek W.F. , Hill C.B. , Williams P.H.
Published: August 2022

Fourteen cultivars of turnip [Brassica rapa, rapifera group, also B. campestris L. ssp. rapifera (Metzg.) Sinsk.] recommended for human consumption of either tops or tops and roots and five cultivars recommended for consumption of roots were selected to compare glucosinolate (GS) levels in tops and roots. Also, two cultivars used for animal feed were included. The study revealed significantly lower levels of 1-methylpropyl-GS and 2-hydroxy-3-butenyl-GS in tops and roots of cultivars grown for greens, compared to those used for animal feed. Contents of 1-methylpropyl-, 3-butenyl-, and 4-pentenyl-GSs were higher in turnip tops than in roots, while 2-hydroxy-3-butenyl-, 4-(methylthio)butyl-, 4-(methylsulfinyl)butyl-, 2-hydroxy-4-pentenyl-, 5-(methylthio)pentyl-, 2-phenylethyl-, 3-indolylmethyl-GSs and total GS were all higher in the roots. GS patterns for seeds tended to correlate with those of the tops.
Salt Stress, Mechanical Stress, or Chlormequat Chloride Effects on Morphology and Growth Recovery of Hydroponic Tomato Transplants
Authors: Adler Paul R. , Wilcox Gerald E.
Published: August 2022

Growth retardants have been used to control stem elongation of hydroponic tomato (Lycopersicon esculentum Mill.) transplants. However, the residual effect of chlormequat chloride on vegetative growth reduces yield. Therefore, the recovery rate of transplant growth was compared between treatments that reduce stem elongation (salt stress, thigmic stress, and chlormequat chloride) to determine which treatments had the best combination of a fast growth recovery rate and control of stem elongation. Tomato plants were grown hydroponically during treatment and recovery periods in a recirculating nutrient solution. Although all treatments except thigmic stress initially decreased shoot dry weight, 24 days after treatment (DAT) termination night-salt stress and thigmic stress produced plants with shoot dry weight comparable to controls. Day and 24-hr salt stress and chlormequat chloride-treated plants had shoot dry weights of 40% to 60% of control 24 DAT termination. Plants treated with chlormequat chloride were still growing slower than controls 24 DAT termination. Both night-salt stress and thigmic stress are suitable prospects for use in control of hydroponic tomato transplant vegetative growth. Oscillatory wind stress applied by the sweeping motion of a leaf blower or by brushing plants with a foam rubber mat are potential commercially feasible ways to apply mechanical stress. Chemical names used: 2-chloro-N,N,N-trimethyIethanaminum chloride (chlormequat chloride).
Effect of Foliar- and Soil Surface-applied Paclobutrazol on Vegetative Growth and Fruit Quality of Sweet Cherries
Authors: Looney Norman E. , McKellar J.E.
Published: August 2022

The length of the lag phase following treatment and the persistence of the eventual growth suppression effect of 1.15 g paclobutrazol (PBZ) per tree declined as the area of treated soil surface beneath the tree increased. Treating one side of the tree row was as effective as treating both sides, but immediately adjacent “control” trees were largely unaffected by these soil-surface treatments. In a 2nd experiment, single, or multiple sprays applying the same amount of chemical in total gave equal growth control in the season of application, but residual growth control was slightly superior on trees sprayed four or 10 times. All PBZ treatments advanced anthesis but failed to improve flower number or fruit set. The weight of individual cherries was increased in each of the three years following the soil-surface application of PBZ, but, except for a reduction in soluble solids, fruit quality was unaffected. Foliar sprays of PBZ in 1984 led to larger fruit size in 1985, but fruit coloring was delayed and soluble solids were reduced. A preharvest spray of 20 ppm gibberellic acid (GA3) substantially enhanced the PBZ effect on fruit size and color but also increased fruit firmness, juice acidity, stem length, and fruit removal force and reduced the incidence and severity of pitting following 2 weeks of cold storage. Chemical names used: β-[(4-chlorophenyl)methyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol).
Efficacy of Rodenticides for Control of Orchard Voles
Authors: Byers R.E. , Carbaugh D.H.
Published: August 2022

Efficacy of several rodenticides was evaluated in laboratory and field tests. ZP Rodent Bait AG pellets gave greater mortality of pine (Microtus pinetorum) and meadow (Microtus pennsylvanicus) voles in field and laboratory trials than a similar-looking commercially available zinc phosphide (ZnP) pelleted formulation and a whole wheat and cracked corn formulation. Laboratory comparison of six new pelleted formulations (zinc phosphide, ZnP) revealed one that gave similar mortality as ZP Rodent Bait AG. Quintox (vitamin D3) gave average to excellent mortality of voles in laboratory trials, but very poor to fair control of voles in field trials.