bluuebunny/crossref_metadata_2025 huggingface dataset:
Tomato Polygalacturonase Elicits Ethylene Production in Tomato Fruit
Authors: Baldwin E.A. , Pressey R.
Published: August 2022

Fungal cell-wall lysing enzymes have been shown to induce ethylene production in different plant systems. The effect of endogenous plant cell-wall lysing enzymes on ethylene synthesis in fruit has received only limited attention. Therefore, tomato fruit (Lycopersicon esculentum, Mill.) were vacuum–infiltrated with the tomato cell-wall enzymes, polygalacturonase I and II (PG I, PG II) and pectinmethylesterase (PME). Fruit ethylene levels were observed to increase relative to either salt, buffer, or boiled enzyme controls. This increase in ethylene production occurred in green ‘Cherry’ tomato fruit as well as in the mutants rin, nor, and Cornell 111. Enzyme-induced ethylene synthesis generally peaked at or before 17 to 20 hr and decreased to lower or basal levels in most immature normal cultivars by 42 hr after treatment. Ethylene was maintained at high levels, however, in some (possibly more mature) green fruit, as well as in all mutant lines. PG II was more effective than PG I in inducing ethylene production and PME seemed to enhance the ethylene-inducing activity of PG II.
Plant Production from Longitudinally Halved Storage Roots of Two Sweet Potato Cultivars
Authors: Hall Melvin R.
Published: August 2022

Initiation of sweet potato [Ipomoea batatas (L.)] plant harvests from the propagating bed was later from the sparse plant producer ‘Georgia Jet’ than from the profuse plant producer ‘Georgia Red’. Also, the initiation of plant harvests from storage roots cut into longitudinal halves for inspection of internal quality before bedding was later than from whole roots. These differences were reflected in lower cumulative percentages of total plants harvested from ‘Georgia Jet’ than from ‘Georgia Red’ within 2 weeks and from longitudinal halves within 2 and 4 weeks after initiation of plant harvests. Total plant production was greater from whole than from halved ‘Georgia Jet’ roots. Total plant production was greater from halved roots immersed in Botran 75W compared to those immersed in calcium hypochlorite. Cutting and immersion treatments did not influence total plant production from ‘Georgia Red’, a profuse plant producer. ‘Georgia Jet’ roots deteriorated more than ‘Georgia Red’ in the propagating bed, and deterioration was increased by cutting and immersion in calcium hypochlorite. Presprouting did not reduce deterioration of roots in the propagating bed, but did reduce the number of days from bedding until first plant harvest. It also increased the cumulative percentage of the total plants harvested within 2 and 4 weeks after harvests were initiated and increased total number of plants produced from both small and large ‘Georgia Jet’ roots and from large ‘Georgia Red’ roots. Large roots of each cultivar produced more plants than were produced by small roots when presprouted. Large roots of ‘Georgia Jet’ also produced more plants than were produced by small roots when not presprouted, but root size did not influence total plant production from ‘Georgia Red’ roots that were not presprouted. Chemical name used: 2,6-dichloro-4-nitroaniline (Botran 75W).
Internal Ethylene Concentration of ‘McIntosh’, ‘Northern Spy’, ‘Empire’, ‘Mutsu’, and ‘Idared’ Apples During the Harvest Season
Authors: Chu C.L.
Published: August 2022

Five cultivars of apples (Malus domesticus Borkh.) were sampled weekly during the harvest season for 3 consecutive years. The ethylene concentrations in the atmosphere from the apple core cavities were measured using a gas chromatograph. Each cultivar exhibited an individual range of internal ethylene concentration over the harvest season. Depending on the cultivar, the rate of increase in internal ethylene concentration varied from year to year. A single ethylene concentration cannot be used to estimate harvest maturity. Cultivar characteristics of internal ethylene concentrations and their yearly variation are two significant factors in interpreting ethylene measurements used for maturity estimations.
Stomatal and Cuticular Water Loss from Apple, Cherry, and Sweetgum Plants After Removal from in Vitro Culture
Authors: Sutter Ellen
Published: August 2022

The relative contributions of stomatal and cuticular water loss to desiccation of tissue-cultured apple (Malus domestica Borkh), cherry (Prunus avium × P. pseudocerasus), and sweetgum (Liquidambar styraciflua L.) leaves after removal from culture were studied. Conductance from both abaxial and adaxial leaf surfaces was measured on plants immediately after removal from culture, after acclimatization, and after being subjected to water stress. In all species, stomatal conductance decreased significantly after acclimatization. Cuticular conductance was significant under some conditions and may have been due to damage resulting from tissue dehydration. The three species had quite different responses to imposed water stress. Responses appeared to be related to differences in stomatal functioning, cuticular integrity, and degree of acclimatization.
Nature of the Semihard Seed Characteristic in Snap Beans
Authors: Holubowicz R. , Taylor A.G. , Goffinet M.C. , Dickson M.H.
Published: August 2022

During imbibition, water always follows the same pattern when entering the seed testa in semihard seeds (SHS) of snap bean (Phaseolus vulgaris L.). Water first enters the raphe and the chalazal region of the testa (R-CT), then migrates circumferentially along the midline of the seed, leaving the lateral faces the last to be fully imbibed. The R-CT region is the main site of primary uptake of both water vapor and liquid water by SHS. The hilum, micropyle, and strophiole play only a minor role in water uptake in SHS. In comparison to the readily permeable seeds of ‘Bush Blue Lake 47’, SHS have more total phenols in the osteosclereid cells and more pectic substances in the palisade cells of the CT. The presence of these compounds may account for the impermeable nature of SHS. Measurements made of palisade cell length and width in the R-CT region revealed that cell length increased and width decreased in the chalazal testa region (CT) as seed moisture content increased from 6% to 12%. It is proposed that semihardening of bean seeds is mainly a result of the reversible physical changes in the length and width of the palisade cells in the R-CT region. Seeds imbibe at high moisture content (12%) because the palisade cells have stretched, which allows water uptake. Seeds are impermeable at low moisture content (6%) because the palisade cells change in size and form a physical barrier to water movement.
Factors Affecting in Vitro Shoot Proliferation of French Tarragon
Authors: Mackay W.A. , Kitto S.L.
Published: August 2022

Optimum proliferation of French tarragon (Artemisia dracunculus L. var. sativa) shoot tips was obtained on Murashige and Skoog salts and vitamins supplemented with 1.8 μM BA, 0.3 μM NAA, and 3% sucrose. Proliferation was maximal after 4 weeks of culture. Proliferation was increased with unpinched shoot tips placed horizontally on the medium. Significantly greater proliferation of shoot tips occurred on medium gelled with Gelrite than with washed Difco Bacto-agar. Medium was gelled with Gelrite (0.5, 1.0, 1.5, 2.0, 2.5, or 3.0 g·liter−1) or washed Difco Bacto-agar (2.0, 4.0, 6.0, 8.0, 10.0, or 12.0 g·liter−1). Increasing concentrations of both gelling agents decreased proliferation. Stock plant pretreatment (natural daylength or 24-hr supplemental light) did not increase proliferation in vitro. Container size had an effect on shoot proliferation, with shoots in 55 × 70 mm jars having significantly greater axillary shoot length than those in 25 × 150 mm culture tubes or 90 × 95 mm jars and significantly greater number of axillary shoots than those in 25 × 150 mm culture tubes. Long-term subculture of shoots on agar-gelled medium (4 g·liter−1) resulted in greater proliferation than those cultured on medium gelled with Gelrite (1.5 g·liter−1). Rooting was maximized by placing cuttings >10 mm in length, derived from shoots proliferated on agar-gelled medium, in clear plastic containers in the laboratory. A 5-sec dip of the basal portion of the cuttings in either NAA (537, 2685, or 5370 μM) or IBA (490, 2450, or 4990 μM) increased rooting percentage and root numbers. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA); 1-naphthaleneacetic acid (NAA); l-H-indole-3-butyric acid (IBA).
Response of American Ginseng to Foliar Applications of 2,4-D
Authors: Konsler T.R. , Monaco T.J. , Sheets T.J. , Leidy R.B.
Published: August 2022

Single and multiple applications of 2,4-D to American ginseng (Panax quinquefolium L.) with fully expanded leaves during a 3-year period caused no visible injury to foliage or roots. During the final 2 years of the study, percent plant survival was greater with two applications per year than with one, and percent gain in root weight decreased with increased rate of application of the herbicide. Also, terminal weight of roots decreased with increased number of years of herbicide application. Treated plants did not differ from nontreated plants in percent survival, final root weight, or percent gain in root weight. Herbicide residue was not detected (<0.02 ppm) in roots from plants that received multiple applications of the three highest 2,4-D dosages: 0.56, 1.12, or 2.24 kg·ha−1 a.i. Foliar residues were detected in plants treated once or twice per year for 3 years with 0.56 or 1.12 kg·ha−1 a.i. 2,4-D. Chemical name used: (2,4-dichlorophenoxy)acetic acid (2,4-D).
Evaluation of Nutrient Deficiency and Micronutrient Toxicity Symptoms in Florists’ Hydrangea
Authors: Bailey Douglas A. , Hammer P. Allen
Published: August 2022

Nutrient imbalances were investigated to a) document nutrient deficiency and micronutrient toxicity symptoms in florists’ hydrangea (Hydrangea macrophylla Thunb.) and b) examine the possible relationship of single-element deficiencies and toxicities with a foliar malformation prevelant on hydrangeas grown at >30°C. Plants subjected to N, P, K, Ca, Mg, S, B, Fe, and Zn deficiency and B and Mn toxicity treatments produced visual symptoms of the corresponding nutrient imbalance. Visual symptoms did not develop in +Fe, +Cu, +Zn, +Mo, −Mn, −Cu, and −Mo treatments. None of the symptoms induced were similar to the foliar malformations observed on hydrangeas grown at >30°. Hydrangea leaf malformation does not appear to be correlated with any single nutrient imbalance within hydrangea leaves. Results of the nutrient deficiency and toxicity experiments offer a diagnostic tool for interpretation of nutrient analysis of hydrangea.
Electrolyte Leakage, Firmness, and Scanning Electron Microscopic Studies of Watermelon Fruit Treated with Ethylene
Authors: Elkashif Mohamed E. , Huber Donald J.
Published: August 2022

Studies were conducted to investigate the influence of 50 μl·liter−1 ethylene on the cell wall, polygalacturonase (PG) activity, and electrolyte leakage of harvested watermelon [Citrullus lanatus (thunb) Matsum and Nakai] fruit. Electrolyte leakage was significantly increased in tissues from ethylene-treated fruit. The highest leakage occurred in distilled water, although the net effect of ethylene was less dramatic due to high leakage from control fruit. Leakage was greatly reduced but the ethylene effect more apparent compared to the control when tissues were incubated in an isotonic medium of mannitol or in isotonic medium containing CaCl2. Polygalacturonase activity increased markedly in ethylene-treated fruit, showing a > 10-fold rise during the first 6 days of treatment. Little change in PG activity occurred in melons stored in air, even in fruit stored for as long as 120 days. Cell walls of fruit exposed to ethylene exhibited acute ultrastructural damage. The decline in placental tissue firmness and the development of watersoaking symptoms observed by the third day of 50 μl·liter−1 ethylene treatment were apparently due, in part, to the PG-mediated cell wall breakdown resulting in cell rupture. Additionally, ethylene appeared to enhance membrane permeability.
Ranking Tissue Mineral Analyses to Identify Mineral Limitations on Quality in Fruit
Authors: Fallahi Esmaeil , Righetti Timothy L. , Raese J. Thomas
Published: August 2022

A diagnostic procedure was developed to identify mineral limitations on pome fruit quality. Fruit mineral levels were useful only when developed on a ranked or percentile (0 to 100) basis. Therefore, procedures were developed using percentile values for both leaf and fruit mineral concentration. An individual can decide which quality parameters are important and whether minimum, maximum, or intermediate values for these quality parameters are most desirable. Multiple regression is used to predict relative rankings for each qualify parameter. A simple sorting program allows the operator to use these rankings to choose which categories of fruit are undesirable. It is then possible to select from among remaining lots those likely to contain fruit having the poststorage quality factors the operator considers most important. The approach is demonstrated with 2 years of data from a high-density ‘Starkspur Golden Delicious’ apple orchard. Selections of fruit with the best poststorage quality were based on mineral content, assuming that maximum firmness, soluble solids, titratable acidity, and yellow color were considered as most desirable. Further ranking evaluations were obtained by evaluating 6 years of data relating quality in ‘d’Anjou’ pears with fruit mineral concentrations. A ranking approach allows meaningful interpretation despite large differences in fruit mineral concentrations reported for different locations and years by a range of analytical laboratories. The procedure is flexible, and fruit could be categorized successfully according to several definitions of optimum quality.
Relationships of Plant Density and Harvest Index to Seed Yield and Quality in Carrot
Authors: Oliva Ruben N. , Tissaoui Tahar , Bradford Kent J.
Published: August 2022

Carrot (Daucus carota L. cv. Danvers) seed were produced at plant spacings of 0.05, 0.10, 0.20, and 0.30 m in 0.80-m rows to give populations of 25, 13, 6, and 4 plants/m2. Samples from the adjacent commercial carrot seed field provided an additional density of 36 plants/m2. Seed yield, harvest index, and seed quality were evaluated with respect to umbel order and plant density. Phenological development was unaffected by plant density, but plant height increased significantly as density increased. The number of umbels per plant and the number of seeds per umbel decreased with increasing plant density, while seed weight was unaffected. The proportion of the seed contributed by primary umbels increased from 20% at the lowest to 60% at the highest density. Seed yield per plant declined continuously as population increased, but seed yield per unit area increased to a maximum at 12 plants/m2, then declined. Total biological yield (above-ground biomass) rose to a plateau level with increasing plant population. Ceiling biological yield coincided with maximum seed yield. Seed quality within each umbel order, assessed by germination percentage and rate, seedling growth, embryo length, and abnormal or embryoless seeds, was unaffected by plant density, but consistently decreased from primary to tertiary umbel orders. Harvest index (seed yield/biological yield) was highly correlated with seed quality. The relationship between harvest index and plant density in carrot seed production may be useful in optimizing plant populations for maximum seed yield and quality.
Tomato Response to Trickle Irrigation and Black Polyethylene Mulch
Authors: Bhella H.S.
Published: August 2022

A 2-year field study was conducted on a fine sandy loam soil near Vincennes, Ind., to evaluate tomato (Lycopersicon esculentum Mill. cv. Sunny) response to trickle irrigation and black polyethylene mulch. Use of trickle irrigation resulted in higher petiole P and B and lower Zn concentrations than using no irrigation. Trickle-irrigated soils had lower soil NH4-N, NO3-N, and K and higher Mg concentrations than non-irrigated soils. Soil NH4-N, NO3-N, and Mg concentrations were higher in soils mulched with polyethylene than in soils without mulch. The use of trickle irrigation increased plant height, whereas polyethylene mulch increased plant spread and dry matter production. Early, late, and total yields were improved with all trickle irrigation and polyethylene mulch treatments. Total yields were 66%, 70%, and 123% greater for plants grown with polyethylene mulch, trickle irrigation, and polyethylene mulch plus trickle irrigation, respectively, than control plants.
Improvement of Plant Establishment in Bell Pepper with a Gel Mix Planting Medium
Authors: Schultheis Jonathan R. , Cantliffe Daniel J. , Bryan Herbert H. , Stoffella Peter J.
Published: August 2022

Germinated pepper (Capsicum annuum L.) seeds were combined with plug-mix, or plug-mix and Liquagel or Laponite 445 gel at various concentrations and volumes of solution to determine their effects on plant stands and seedling growth. Treatments with pregerminated seed led to earlier, more uniform seedling emergence and larger seedlings than those with non-pregerminated seeds. Final plant stands were similar for both treatments. Plant stands and seedling growth were greater and more uniform with Liqua-gel gel mix formulations than Laponite. Seeds in planting mixes with high concentrations of Laponite (2.0% by volume) and large volumes of gel solution (1.75 liter per liter of plug-mix) in dry and moist soils emerged slower and resulted in lower and less uniform stands than the plug-mix treatments. The optimum gel mix medium for plant establishment (rate and total emergence, stand uniformity, and early seedling growth) consisted of 1.0 liter of plug-mix per 1.25 liters of gel solution at a Liqua-gel concentration of 1.0%.
Inhibition of Ethylene Synthesis and Action in Ripening Tomato Fruit by Ethanol Vapors
Authors: Saltveit Mikal E. , Mencarelli Fabio
Published: August 2022

Exposure of whole fruit, slices, or pericarp disks of tomato (Lycopersicon esculentum Mill.) to 0.5 to 3.0 ml absolute ethanol vaporized in a 4-Iiter container for 3 hr significantly reduced the climacteric rise in CO2 and C2H4 production, lycopene synthesis, and chlorophyll loss. Inhibition of ripening occurred whether fruit were at the mature-green or breaker-turning stage. Whole fruit recovered and ripened normally after a delay that was related to the tissue ethanol concentration. Treated slices did not ripen normally, and exposure to 16 μl C2H4/liter did not promote ripening. The level of ACC was 14-fold higher in treated slices, while C2H4 production was reduced 70%. Treatments with AVG and ACC indicated that ethanol inhibited ACC conversion to C2H4. Chemical names used: 1-aminocyclopropane-1-carboxylic acid (ACC); [S-(E)]-2-amino-4-(2-aminoethoxy)-3-butyric acid (AVG).
Field Studies with Crops Treated with Colloidally Dispersed Triacontanol
Authors: Biernbaum John A. , Houtz Robert L. , Ries Stanley K.
Published: August 2022

The yield response of crops to triacontanol (TRIA) applied as a colloidal dispersion was tested with 13 crop species in 45 field experiments over a 3-year period. Foliar application of TRIA resulted in treatment effects with 11 of the 13 crops and in 30 of the 45 experiments. The average yield increase was 14% with the optimum TRIA concentration in tests where yield was significantly increased, and was 5% over all 45 experiments. In seven experiments, significant yield decreases averaging 10% were measured with TRIA concentrations that increased crop yield of the same species in other tests. The most effective TRIA concentrations generally were 0.1 to 1.0 μg·liter−1. No particular stage of crop development for treatment was optimal for all crops. Based on the results of these studies, TRIA cannot be recommended for commercial application to crops in Michigan or similar environments. Chemical names used: 1-triacontanol (triacontanol).
Rabbiteye Blueberry Storage Life and Fruit Quality in Controlled Atmospheres and Air Storage
Authors: Smittle Doyle A. , Miller William R.
Published: August 2022

Fruits of rabbiteye blueberries (Vaccinium ashei Read cvs. Climax and Woodard) harvested by hand in 1984 and machine in 1985 were stored in air, 100% N2, and in 10%, 15%, or 20% CO2 with 5% O2. Storage of either blueberry cultivars in high-CO2 atmospheres resulted in greater percentages of marketable and firm fruit, and better sensory ratings, than did storage in air. Fruit of ‘Climax’ lost less weight, were firmer, and developed less decay after 21 or 42 days of storage than ‘Woodard’ fruit. Fruit quality characteristics of hand-harvested ‘Climax’ stored for 42 days and machine-harvested ‘Climax’ stored for 21 days in 20% CO2 with 5% O2 were similar to those of freshly harvested fruit.
Leaf Water Relations, Soil-to-leaf Resistance, and Drought Stress in Pecan Seedlings
Authors: Rieger Mark , Daniell Jeff W.
Published: August 2022

Leaf water relations and soil-to-leaf resistance were studied in 3-month-old pecan [Carya illinoenis (Wangenh.) C. Koch] seedlings as soil dried progressively to minimum water potentials of −0.3, −0.6, and −1.1 MPa in three separate tests. Leaf conductance, transpiration, and predawn leaf water potential declined with increasing soil water deficits, and only predawn leaf water potential fully returned to pre-stress levels after rewatering. Reduced levels of leaf conductance following water stress were apparently caused by internal factors other than leaf water potential. Leaf conductance of well-watered seedlings decreased logarithmically and with increasing leaf-to-air vapor pressure gradient. Soil-to-leaf resistance to water flow varied diurnally and generally increased following water stress at minimum soil water potentials of −0.6 and −1.1 MPa. Osmotic adjustment and changes in the distribution of water between the apoplast and symplast in leaves did not occur in response to soil water potentials of −0.6 MPa.
Grapefruit Storage Decay and Fruit Quality after High-temperature Prestorage Conditioning at High or Low Humidity
Authors: Chun David , Miller William R. , Risse Lawrence A.
Published: August 2022

Individually plastic-film-wrapped or waxed ‘Marsh’ grapefruit (Citrus paradisi Macf.) were conditioned (34.5°C, 3 days) at low (30% ± 5% RH) or high (95% ± 5% RH) humidity before cold storage (10° ± 1°; 90% ± 5% RH). Predisposition to storage decay by conditioning was investigated by examining fruit inoculated with penicillium spores either before or after conditioning. Penicillium rot in fruit that was inoculated after conditioning was reduced in plastic-film-wrapped fruit (37%) relative to waxed fruit (74%) only after 2 weeks at 10° ± 1° + 1 week at 21° ± 1° storage. Of the fruit inoculated prior to conditioning, the incidence of decay was lower in fruit conditioned at high RH than in fruit not conditioned or conditioned at low RH. No coating effect of wax or plastic-film was observed. Fruit quality tended to be adversely affected by conditioning, but this effect became less obvious with storage. Fruit coated with plastic film had a better general appearance than waxed grapefruit.
Growth Analysis of Field-grown Strawberry Genotypes Differing in Yield: II. The Hill System
Authors: Strik Bernadine C. , Proctor John T.A.
Published: August 2022

Twelve field-grown strawberry genotypes (Fragaria × ananassa Duch.) were studied. Plants were grown in a hill system and harvested weekly from early spring until the end of harvest. Genotypes differed in the progression of the natural log (In) of leaf area over time, leaf area ratio, and unit leaf rate. In all genotypes, In plant dry weight increased linearly over time, the relative growth rate was constant, and the absolute growth rate increased throughout the season. There were differences among genotypes in the number of crowns, crown dry weight, number of leaves, leaf dry weight, leaf area, specific leaf weight, number of inflorescences, and inflorescence dry weight during the fruit-filling and fruiting periods. Only crown dry weight during the fruit-filling period was correlated with yield among genotypes.
Inheritance and Stability of a Small Pustule Reaction of Snap Beans to Uromyces appendiculatus
Authors: Webster David M. , Ainsworth Peggy M.
Published: August 2022

Pustule size following inoculation with race 38 of the rust fungus [Uromyces appendiculatus (Pers.) Unger var. appendiculatus] was measured on primary leaves of snap bean (Phaseolus vulgaris L.). Data from parental lines ‘Strike’, ‘Cape’, and ‘Resisto’ and F1, BC1, and F2 populations from crosses among these lines indicate that small-pustule resistance of ‘Cape’ and ‘Resisto’ is conditioned by the same dominant allele. Tests to detect race specificity of this allele were inconclusive.
Berry Thinning and Cluster Thinning Influence Vegetative Growth, Yield, Fruit Composition, and Net Photosynthesis of ‘Seyval blanc’ Grapes
Authors: Kaps Martin L. , Cahoon Garth A.
Published: August 2022

Crop reduction on single-shoot ‘Seyval blanc’ grapevines by either berry or cluster thinning resulted in a decrease in total fruit weight and an accompanying increase in berry weight, °Brix, and vegetative growth. Titratable acidity and pH of the juice were not consistently affected by either berry or cluster thinning. Net leaf photosynthesis at 43 days past full bloom increased with higher cluster number per plant. Berry weight was greatest when the crop of berries were borne in three clusters per shoot rather than in a single cluster. Berry thinning appears to be an acceptable substitute to cluster thinning for crop reduction of ‘Seyval blanc’ grapes.
Respiration and Ethylene Production in Harvested Watermelon Fruit: Evidence for Nonclimacteric Respiratory Behavior
Authors: Elkashif Mohamed E. , Huber Donald J. , Brecht Jeffrey K.
Published: August 2022

The postharvest behavior of watermelon [Citrullus lanatus (Thunb.) Matsum and Nakai] fruit harvested at selected stages of development and stored in air or exposed to 50 μl ethylene/liter or 6500 μl propylene/liter was investigated. Characteristics measured included the effects of ethylene or propylene on ripening, respiration, ethylene production, and fruit firmness. Ethylene treatment induced a rapid deterioration of fruit at all maturation stages, as evidenced by the acute placental tissue softening and watersoaking. Melons of all maturation stages held in air showed little textural change throughout storage and produced only trace quantities of ethylene. Respiratory activity of fruit at each maturation stage was enhanced in the presence of ethylene or propylene and returned to normal rates upon removal of the gases. Ethylene production was not initiated by exposure of fruit to propylene, and was detected only in fruit exhibiting symptoms of decay. The results support the conclusion that watermelon fruit exhibit a nonclimacteric pattern of ripening.
Effects of Irrigation Regimes on Yield and Water Use of Summer Squash
Authors: Stansell J. R. , Smittle D. A.
Published: August 2022

Summer squash (Cucurbita pepo L. cv. Dixie hybrid) were grown in drainage lysimeters under closely controlled and monitored soil water regimes. Variables included three irrigation treatments, three growing seasons, and two soil types. Marketable fruit yield was greatest and production cost per kilogram of marketable fruit was least when squash was irrigated at 25 kPa of soil water tension. Yields were greatest for the spring season of production and least for the fall season. Regression equations are provided to describe the relationships of water use to plant age and to compute daily evapotranspiration : pan evaporation ratios (crop factors) for squash irrigated at 25, 50, and 75 kPa of soil water tension during the spring, summer, or fall production season.
Rapid Depletion of Nitrogen Applied to Kentucky Bluegrass Turf
Authors: Bowman D. C. , Paul J. L. , Davis W. B. , Nelson S. H.
Published: August 2022

The depletion of N applied to a moderately N-deficient Kentucky bluegrass (Poa pratensis L.) turf was measured using a soil sampling procedure. Nitrogen as either Ca(NO3)2 or (NH4)2SO4 was applied in solution at 5 g N/m2 and washed into the thatch and soil with an additional 0.3 cm of water. Both N forms were located primarily in the thatch and upper 1 cm of soil. The was present in the soil solution, while the was mainly exchangeable (86%). The concentrations of and in the soil solution were 452 and 56 μg N/ml, respectively, in the upper 1 cm of soil. Depletion of both and from the turf was very rapid, with 70% to 80% of the applied N disappearing during the first 24 hr. Essentially all of the applied N was depleted by 48 hr. Results using (l5NH4)2SO4 indicate that ≈75% of the depletion is attributable to absorption by the turf. Similar results were obtained following fertilization of perennial ryegrass (Lolium perenne L.), tall fescue (Festuca arundinaceae Schreb.), and creeping bentgrass (Agrostis palustris Huds.).
Nutrition and Yield of Young Apple Trees Irrigated with Municipal Waste Water
Authors: Neilsen G. H. , Stevenson D. S. , Fitzpatrick J. J. , Brownlee C. H.
Published: August 2022

‘Macspur McIntosh’ and ‘Red Chief Delicious’ apple (Malus domestica Borkh.) on M.7a rootstock were subjected to treatments involving all combinations of two types of irrigation water (well-water or municipal effluent) from 1983, the year of planting, through 1987 and three rates of N fertilization (0, 200, 400 g NH4NO3/tree per year), from 1984 through 1987. The zero N treatment was increased to 100 g NH4NO3/tree per year in 1986 due to low vigor of these trees. Effluent irrigation increased leaf N, P, and K concentration in 4 of 5 years for ‘McIntosh’, while leaf N, P, and K increased in 1, 4, and 2 years, respectively, for ‘Delicious’. Effluent irrigation increased trunk diameter increment in all years and fruit number and yield in 1985-86 for both cultivars. No major horticultural limitations to the use of effluent irrigation were observed. Nitrogen fertilization increased leaf N in 3 years for ‘McIntosh’ and 2 years for ‘Delicious’, while leaf P and K were decreased at the highest N rate in 2 years for each cultivar. Nitrogen fertilization did not increase trunk diameter and increased fruit number and yield only in 1986 after 3 years of a zero N treatment. The results implied a role for P in the establishment and early growth and yield of young apple trees.
Phytophthora Root Rot and Irrigation Schedule Influence Growth and Phenology of Processing Tomatoes
Authors: Ristaino J. B. , Duniway J. M. , Marois J. J.
Published: August 2022

Processing tomatoes (Lycopersicon esculentum Mill.) grown in field plots with soil infested or not infested with Phytophthora parasitica Dastur. were furrow-irrigated for 4 to 8 hr every 14 days (normal) or 28 days (less frequent) or with alternating 4- to 8-hr and 24-hr irrigations every 14 days (prolonged). Disease developed more rapidly and symptom severity was significantly greater on shoots and roots of plants that received prolonged irrigations. Disease symptoms on roots progressed more rapidly and were observed earlier than those on shoots in plants given prolonged or normal irrigation. Severe disease during early vegetative and reproductive growth caused significant reductions in total plant, leaf, and fruit dry matter and in the numbers of flowers and fruit in plants receiving either prolonged or normal irrigation. Diseased plants given prolonged irrigation also partitioned less total dry matter into leaves and fruit and more into stems than noninoculated plants. Less frequent irrigation of infested plots caused a delay in disease onset and reduced the impact of disease on numbers of flowers, fruit, and dry matter accumulation. Phytophthora-induced water stress during critical stages of crop development apparently can have major impacts on plant growth, phenology, and yield in processing tomato.
Density Separation of Imbibed and Primed Vegetable Seeds
Authors: Hill H. J. , Taylor A. G. , Min T.-G.
Published: August 2022

The objective of this study was to determine the relationship between seed density and seed quality of vegetable seeds hydrated by imbibing or priming procedures. Species studied were: lettuce (Lactuca sativa L.), tomato (Lycopersicon esculentum Mill.), onion (Allium cepa L.), cabbage (Brassica oleracea var. capitata L.), and carrot (Daucus carota L.). Seeds of each crop were soaked in either aerated distilled water at 25C (imbibed seeds) or polyethylene glycol (PEG) 8000 at 15C (primed seeds). After soaking, seeds were separated into density classes with a float-sink procedure using aqueous solutions of Maltrin 600 (Maltrin 500 for lettuce) with 0.02 g·cm−3 density increments. Significant (P > 0.01) positive relationships were determined between seed density classes and germination percentages for lettuce, tomato, and onion seeds, whether separated after imbibition (R2 = 0.93, 0.83, and 0.66, respectively) or after priming (R2 = 0.95, 0.94, and 0.91, respectively). High-density classes of hydrated lettuce, tomato, and onion seeds in either the imbibed or primed treatment usually exhibited faster and more uniform rates of radicle emergence and, after 6 days, had longer hypocotyls (cotyledon for onions) than low-density classes. The significant quality differences exhibited among the density classes of lettuce, tomato, and onion seeds after priming will enable seedlots of these species to be upgraded by discarding the low-density, poor-quality seeds.
Yield and Tree Size of Four Citrus Cultivars on 21 Rootstocks in California
Authors: Roose M. L. , Cole D. A. , Atkin D. , Kupper R. S.
Published: August 2022

Fruit production and tree size were measured and yield efficiency was computed for 11-year-old trees of ‘Washington’ navel and ‘Olinda Valencia’ oranges [Citrus sinensis (L.) Osbeck], ‘Minneola’ tangelo (C. paradisi Macf. × C. reticulata Blanco), and ‘Lisbon’ lemon (C. limon Burm. f.) on 21 rootstocks in the San Joaquin Valley of California. Performance of most rootstocks was similar over all scions, and several rootstocks produced trees with higher yields than ‘Troyer’ and ‘Carrizo’ citranges [C. sinensis × Poncirus trifoliata (L.) Raf.], the current standard rootstocks. ‘Yuma Ponderosa’ lemon (× C. limon) had the highest yields, but several trees on this rootstock died or were declining. Trees on ‘C-32’ citrange (C. sinensis × P. trifoliata) were largest, and yielded nearly as much as those on ‘Yuma Ponderosa’ lemon. ‘C-35’ citrange (C. sinensis × P. trifoliata) produced smaller trees with excellent yield efficiencies, and should be suitable for higher-density plantings with most scions, except perhaps navel orange, because this combination yielded poorly at other locations. ‘Rangpur’ lime (C. limonia Osbeck) was promising only with lemon scion, and ‘Swingle’ citrumelo (C. paradisi × P. trifoliata) only with ‘Minneola’.
Photoperiodic Control of Flowering of Salvia leucantha
Authors: Armitage A. M. , Laushman J. M.
Published: August 2022

Plants of Salvia leucantha were subjected to 8, 10, 12, or 14 hr of light under controlled environmental conditions. Salvia leucantha is a short-day plant with a critical photoperiod of 12 hr for macrobud development, but 10 hr for subsequent flower development. About 14 photoperiodic cycles are necessary for flower initiation, but at least 42 cycles are required for normal anthesis and raceme elongation. Apices that had initiated under < 6 weeks of short days failed to develop when placed under long days. Flower initiation did not occur when night break lighting of 1.3 μmol·s−1·m−2 was provided by incandescent lamps.
Susceptibility of Blackberry Tissues to Freezing Injury after Exposure to 16C
Authors: Warmund M. R. , George M. F. , Ellersieck M. R. , Slater J. V.
Published: August 2022

Experiments were performed on ‘Cherokee’ blackberry (Rubus sp.) floral buds and cane tissue collected from field plantings on 12 Jan. and 18 Feb. 1987 to determine the susceptibility of floral primordia, phloem, and xylem to freezing injury after exposure to 16C for 0, 4, 12, 24, or 48 hr. Before rest completion in January, floral primordia, phloem, and xylem subjected to 16C were hardier than those tissues tested in February when rest was completed. Floral primordia and cane tissues dehardened slowly with time at 16C before rest completion. After rest was completed, the rate of deacclimation of floral primordia and xylem increased. Some blackberry canes were subjected to two thawing episodes at 16C for 4 hr. In January, phloem and xylem of canes thawed twice were as hardy or hardier than those tissues in samples thawed once. Conversely, two thawing episodes in February resulted in greater xylem injury than a single episode, but two episodes did not affect the hardiness of the phloem. The number of thawing episodes did not affect floral bud hardiness at either sampling date.
Genetic Parameters Estimated for an Advanced-cycle Strawberry Breeding Population at Two Locations
Authors: Shaw D. V. , Bringhurst R. S. , Voth V.
Published: August 2022

Strawberry (Fragaria × ananassa) seedlings were evaluated for yield, fruit weight, and commercial appearance in two field trials established in 1985 and 1986. Genetic analyses for unbalanced diallels were performed to quantify genetic, environmental, and interaction variance for each trial separately, and for crosses common to two locations in a single year. When data from crosses common to two test locations were analyzed simultaneously, narrow-sense heritabilities (h2) averaged 0.35 (±0.11), 0.21 (±0.07), and 0.08 (±0.06) for yield, fruit weight, and appearance score. Broad-sense heritabilities (H2) were 0.35 (±0.11), 0.27 (±0.12), and 0.21 (±0.11) for the same traits, respectively. These estimates do not differ significantly from heritabilities estimated from the ancestral breeding population 20 years ago. Estimates of H2 for single-location analyses were biased upwards by dominance × location interactions for all traits. Additive × location interactions were detected for appearance score and contributed a small bias to single-location estimates of h2. Use of biased estimates in predicting genetic gain could lead to errors in choice of appropriate selection strategy.
Transmission of the Common Blight Pathogen in Bean Seed
Authors: Aggour Ahmed R. , Coyne Dermot P. , Vidaver Anne K. , Eskridge Kent M.
Published: August 2022

Common blight in beans (Phaseolus vulgaris L.), incited by Xanthomonas campestris pv. phaseoli (Smith) Dye, is a serious seedborne disease in various parts of the world. We tried to detect possible differences in seed infection and transmission of bacteria in selected bean cultivars/lines. Dry seeds, flower buds (24 to 36 hr before anthesis), small pods (2 to 3 days old), and green seeds of individual plants of Bac-6, ‘Venezuela 44% ‘Pompadour Checà’ dry beans, and of dry seed of Great Northern (GN) ‘Tara’ were examined for possible internal infection after inoculating the seeds, seedlings, and plants with common blight bacterium at various sites. Inoculation of the pedicels of the flower buds and small pods resulted in transmission of the bacteria through the vascular tissue of the pod to the seeds, causing internal infection without any external symptoms shown either by the pods or seeds. Bac-6 was resistant to seed infection, and ‘Venezuela 44’ was most susceptible, followed by ‘Pompadour Checà’ and GN ‘Tara’. Planting infected seeds did not result in a systemic transmission of the bacteria in the vascular tissue of the plants to the seeds. Infected leaves were likely to be the main source for the external infection of pods, which could lead to internal and/or external seed infection. Breeding for resistance to seed infection and transmission of bacteria should aid the control of this disease. A useful technique for assessing internal infection of seeds with the bacteria was developed.
Fall Ethephon Delays Bloom in ‘Redhaven’ Peach by Delaying Flower Differentiation and Development during Dormancy
Authors: Crisosto C.H. , Lombard P.B. , Fuchigami L.H.
Published: August 2022

Ethephon at 120 mg·liter−1 applied to hand-defoliated or nondefoliated trees in late Oct. 1984 delayed ‘Redhaven’ [Prunus persica (L.) Batsch.] full bloom by ≈5 days in 1985. The same treatment applied on 1 Nov. 1985 delayed full bloom by 9 days in 1986. Hand-defoliation alone was ineffective in delaying bloom in either season. Ethephon treatments increased abscisic acid (ABA) and ethylene levels in dormant buds collected throughout the 1985–86 dormant season. Starch and reducing sugar contents and total chilling requirement were not affected by the ethephon and hand-defoliation. Flower primordia were delayed in differentiation and growth during late fall following a 1986 spray of ethephon. A delay in flower development and growth may be caused by increased levels of ethylene and ABA. Chemical names used: (2-chloroethyl) phosphonic acid (ethephon); aminoethoxyvinylglycine (AVG).
Pinching Technique Influences Lateral Shoot Development in Poinsettia
Authors: Berghage Robert D. , Heins Royal D. , Karlsson Meriam , Erwin John , Carlson William
Published: August 2022

Lateral shoot growth and plant morphology of poinsettia (Euphorbia pulcherrima Willd.) were influenced by the pinching technique used for apical meristem removal. Plants were pinched in one of four ways: 1) soft (removal of the apical meristem plus stem and leaf tissue associated with leaves ≤2 cm long); 2) medium (removal of the apical meristem plus stem and leaf tissue associated with leaves up to 7 cm long); 3) hard (removal of the apical meristem plus stem and leaf tissue associated with all immature leaves); and 4) leaf removal (LR; soft pinch as defined above plus removal of all immature leaves but not the associated stem tissue). Initial growth of lateral shoots on soft and some medium-pinched plants was less than initial growth of lateral shoots on hard- or LR-pinched plants. Shorter lateral shoots and longer primary stems at anthesis on soft-pinched plants resulted in vertical plant architecture. Hard- and LR-pinched plants had a more horizontal plant architecture. The average height : width ratio of soft-, hard-, and LR-pinched plants at anthesis was 0.77, 0.68, and 0.63, respectively. Of 10 commercial cultivars tested in 1987, 48% of the inflorescences of soft-pinched plants developed below the bract canopy, compared with 27% and 31% for hard- and LR-pinched plants, respectively. These results show that the use of a soft pinch to increase inflorescence number in the bract canopy is not productive if immature leaves are left on the plant when pinching.
Implications of Year × Season × Genotype Interactions in Mungbean Yield Trials
Authors: Fernandez George C.J. , Chen H.K.
Published: August 2022

Knowledge of the type and extent of the genotype × environment (G × E) interaction on a particular crop can be applied to improve the efficiency of resource allocation in long-term yield trials. Estimates of the relative magnitude of G × E, for seed yield and related traits, were obtained from mungbean [Vigna radiata (L.) Wilczek] field trials conducted at the Asian Vegetable Research and Development Center (AVRDC) in Taiwan. Ten diverse genotypes were evaluated in spring, summer, and fall during 2 years. Photoperiod, temperature, and distribution of pest and diseases vary distinctly during these seasons. The was greater than the for plant height, seeds per pod, 100-seed weight, and days to flowering; however, seed yield, first harvest percentage, pods per plant, and mean maturity were greatly influenced by was significant for all variables, except seed weight, while was significant for plant height, pods per plant, seeds per pod, and days to flowering. The second-order interactions, G × Y × S, were large and greater than the first-order interactions (G × Y, G × S) for seed yield, pods per plant, and seeds per pod. Estimates of expected error variance for genotypic mean from varying years, replications, and three seasons suggest that 3 years and three replications would be effective in selecting promising lines from three-season yield trials conducted at AVRDC.
Effect of Gypsum and Dolomite on Pythium Diseases of Seedlings1
Authors: Gill D. L.
Published: August 2022

The addition of gypsum (10, 5 or 2½ lb./yd3) or gypsum plus dolomite (each 5 lb./yd3) to soils before planting with 7 kinds of ornamental and vegetable seeds did not result in more useful seedlings in uninfested soil, but in most instances, significantly increased percent of good seedlings in soil infested with Pythium myriotylum or P. aphanidermatum over the control. In uninfested soils the addition of 5 lb./yd3 dolomite did not increase the number of useable seedlings compared with unamended, uninfested soil. The dolomite resulted in significantly more useful, healthy seedlings than the control only with tomato and calendula in P. myriotylum-infested soil and in stock with P. aphanidermatum-infested soil.
Role of Transpiration and Phloem Transport in Accumulation of 45Calcium in Leaves of Young Apple Trees1
Authors: Stebbins R. L. , Dewey D. H.
Published: August 2022

Apple (Pyrus malus L.) seedlings or rooted layers growing in nutrient solution in the greenhouse were used to determine the role of xylem and phloem in the accumulation of Ca in the leaves. 45calcium accumulation increased with increasing rates of transpiration as measured by water losses. Girdling experiments demonstrated that the phloem was the primary route of translocation. Young leaves accumulated more 45ca than old leaves even though the water losses for plants bearing only young leaves or only old leaves were similar. 45calcium accumulation in mature leaves was decreased when the shoot tips were removed. Apparently, in young apple trees Ca moves primarily in the phloem, but leaks into the xylem at increasing reates in the younger stem and near the growing apex.
Spacing of Container-Grown Trees in the Nursery1
Authors: Harris Richard W. , Leiser Andrew T. , Neel P. Lanny , Dwight Long , Stice Norman W. , Maire Richard G.
Published: August 2022

The spacing of container-grown Betula verrucosa Ehrh., Eucalyptus sideroxylon A. Cunn., Dodonaea viscosa ‘Purpurea’ Jacq., and Liquidambar styraciflua L. was studied at 2 California locations in 1967 and 1968. As area per plant increased from can-to-can spacing, trunk caliper and taper increased, as did wt of roots and branches plus leaves, but increases in height and wt of trunk were less. At the closest spacings, the lower foliage was sparse, giving the trees a leggy appearance. Adequate spacing, about twice the can-to-can area, the first season gave benefits of increased trunk caliper and fuller foliage with a minimum sacrifice in height.
Exogenous Growth-Regulator Effect on Tomato Fruit Cracking and Pericarp Morphology1
Authors: Batal K. M. , Weigle J. L. , Lersten N. R.
Published: August 2022

Growth-regulating chemicals, individually or in combinations, sprayed on tomato fruits growing in the greenhouse, significantly reduced fruit cracking in ‘Marglobe’. The amount of cracking in treated ‘Marglobe’ fruit was similar to that in crack-resistant ‘Heinz 1350’. Differences in pericarp morphology between untreated ‘Marglobe’ and ‘Heinz 1350’ were found in the shape of the epidermal cells and cell sizes in the subepidermal and mesocarp layers. Pericarp morphology of the treated ‘Marglobe’ fruits was more like that of ‘Heinz 1350’ than that of the untreated ‘Marglobe’.
Induction Period and Threshold Temperatures for Premature Ripening in ‘Bartlett’ Pears1,2
Authors: Wang C. Y. , Mellenthin W. M.
Published: August 2022

Continuous exposure of pears to 7.2°C (night) - 21.1°C (day) for 2 days or 10°C - 21.1°C for 9 days or 7.2°C - 26.7°C for 21 days induced the physiological disorder, premature ripening, during the month immediately preceding normal harvest. During the same period, premature ripening did not develop with temp exposures of 12.8°C - 21.1°C or with 7.2°C - 32.2°C. Cool temp 6 to 9 weeks prior to harvest may also cause premature ripening to occur but the fruit will recover to normal behavior if subsequent temp are above the threshold level.