bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Magnesium Concentrations in Nutrient Solution on Growth, Tissue Concentration, and Nutrient Uptake of Peach Seedlings1
Authors: Edwards J. H. , Horton B. D.
Published: August 2022

Seedlings of ‘Babygold 5’ peach [Prunus persica (L.) Batsch] were grown for 50 days in nutrient solutions with 0.4, 21, 42, 125, 250, 500 μm Mg. Magnesium deficiency symptoms were observed 19 days after initiation of the Mg treatments in the seedlings in 0.4 μm Mg solutions. The relative growth rate was significantly increased for the first increment of Mg concentration with no further increases at higher Mg concentrations. Increasing Mg in the nutrient solution significantly increased Mg concentration in the leaves, stems, and roots, but Mg tissue concentration decreased at all levels of Mg in the nutrient solution as physiological age increased. Visible Mg deficiency symptoms were observed on mature leaves at the 125 μm Mg treatment, but when the Mg concentration exceeded 250 μm, Mg concentration in mature leaves was increased above the threshold for appearance of Mg deficiency symptoms. No Mg deficiencies were observed on ‘Babygold 5’ seedlings when the Mg concentrations in the leaves exceeded 2000 μg/g dry weight and Mg uptake rate was 2.5 μmoles/g fresh wt./day.
Resistance of Red Raspberry Fruit and Canes to Botrytis1
Authors: Daubeny Hugh A. , Pepin H. S.
Published: August 2022

Red raspberry (Rubus idaeus L.) cultivars and selections with resistance to preharvest fruit rot, caused by Botrytis cinerea Pers. ex. Fr., were identified in a year in which its incidence was much higher than usual in British Columbia. Cultivars and selections with postharvest resistance were also identified. The correlation coefficients between preharvest and postharvest reactions were not particularly strong. Neither cane reactions to the organism nor fruit firmness were associated with fruit reactions.
Effects of Storage Temperatures on Endogenous Growth Substances and Shoot Emergence in Freesia hybrida corms1
Authors: Gilbertson-Ferriss T. L. , Brenner M. L. , Wilkins H. F.
Published: August 2022

Corms of Freesia hybrida Bailey ‘Moya’ and F. hybrida ‘Maria’ were stored at 2°, 13°, or 30°C immediately after harvest and sampled at 0, 6, or 13 weeks for fresh weight, sprouting ability, free indoleacetic acid (IAA), free abscisic acid (ABA) and conjugated ABA (conj-ABA). High performance liquid and gas-liquid chromatography methods were used for identification and quantification of the extractable IAA, ABA, and conj-ABA. Shoots from corms planted immediately after harvest emerged in 33 to 57 days. It is suggested that freshly harvested F. hybrida corms exhibit physiological dormancy for not more than 4 to 6 weeks and subsequently enter a state of imposed dormancy in storage at 30° or 2°. Physiological dormancy was released more rapidly and corm shoots emerged more rapidly during imposed dormancy when stored at 30° versus 2°. The 30° treatment did not appear to be mandatory for shoot emergence since corms stored at 2° or 13° for 6 weeks emerged within 5 or 20 days, respectively. Extended storage at 13° promoted pupation whereas storage at 30° and 2° prevented pupation. Pupated corms did not emerge when planted. The IAA, ABA, and conj-ABA levels in the corms during storage did not correspond with growth inhibition but rather appeared to relate to the formation of the new corm during pupation.
Genetic System for the Reaction of Field Beans to Beta, Gamma, and Delta Races of Colletotrichum Iindemuthianum1
Authors: Muhalet C. S. , Adams M. W. , Saettler A. W. , Ghaderi A.
Published: August 2022

Five cultivars and one breeding line of field bean (Phaseolus vulgaris L.) were evaluated for their differential reactions to beta, gamma, and delta races of anthraenose (Collectotrichum lindemuthianum [Sacc. and Magn.] Scrib.). Parental, F1 and F2 plants from 10 crosses involving anthraenose resistant and susceptible parents were inoculated with the 3 races. Inoculated plants were maintained in a mist chamber for 8 to 10 days until plants could be classified into resistant and susceptible groups on the basis of their reactions to the pathogen. The F2 segregation patterns suggested that independent and complementary gene action at 1 or 2 different loci produced a resistant reaction to all races of the pathogen. In addition, an allelomorphic series of three alleles was assumed to be controlling resistance to the beta race. A breeding scheme, involving alternate generations of back-crossing to the recurrent parent and selfing is an effective method to develop resistant cultivars.
Determination of Flowering Time and Vegetative Habit of Tagetes patula through Response Surface Techniques1
Authors: Armitage A. M. , Carlson W. H. , Cress C. E.
Published: August 2022

Flowering time, dry weight, total leaf area, and vegetative height of Tagetes patula L. were predicted on the basis of day temperature, night temperature, and quantum flux density (QFD). High temperatures (30°C) decrease flowering time regardless of QFD and greatest leaf surface area was caused by high QFD. As night temperatures increased, maximum leaf area occurred at lower day temperatures than those necessary for fastest flowering time. Each response was characterized by response surface technique.
Carbohydrate Changes in Various Organs of Bearing and Nonbearing Pecan Trees1
Authors: Wood B. W. , McMeans J. L.
Published: August 2022

Starch and sugars were generally higher in bearing than in nonbearing shoots (wood and bark) of pecan (Carya illinoensis (Wang.) Koch). Decreases in shoot starch were reflected by generally simultaneous increases in either shoot or kernel sugars. Shoot starch fell to its lowest level during the liquid stage of ovule development. Leaf starch generally declined as the growing season progressed. Total sugar levels rose in the kernel, shuck, and shell during fruit enlargement and declined during kernel growth. Mature kernels had less sugar than mature shucks. Ovule sugar was highest during the liquid stage and decreased to very low levels at maturity. Ovule starch generally increased as kernels matured.
Testing Methods, Variation, Morphological and Genetic Studies of Seed-coat Cracking in Dry Beans (Phaseolus vulgaris L.)1
Authors: Korban Safi S. , Coyne Dermot P. , Weihing John L. , Hanna Milford A.
Published: August 2022

Seed-coat cracking injury was determined in Great Northern (GN) dry bean lines in 1977, 1978 (also Pintos in 1978) using 3 methods as follows: Vogel small plot thresher (field), seed dropping, and a controlled rotating impact disk machine. Differences in susceptibility for seed-coat cracking were observed within each testing method. Overall, ‘GN Emerson’, near-isogenic determinate ‘GN Nebraska #1’ and ‘Pinto UI 111’ had the best resistance to seed-coat cracking. A genotype × year interaction for seed injury occurred with the Vogel thresher but not with the other 2 methods. The other 2 methods gave consistent results but the rotating disk machine method was preferred because of ease, rapidity of operation and standardization of the rotation speed. The early and late maturing determinate near-isogenic lines of ‘GN Nebraska #1’ had less seed-coat injury than the early and late indeterminate lines using the Vogel and rotating impact disk method. The early determinate line had the least amount of seed-coat injury for all three methods. ‘Pinto UI 111’, ‘Bulgarian White’, and ‘GN D-88’, which exhibited the best resistance to seed-coat cracking in the 7 parent diallel crossing study, had the most uniform seed-coat thickness as well as having thick seed coats. The cultivars which had thin or thick but non-uniformly thick seed coats were susceptible to seed-coat cracking. Differences in thickness in macrosclerid, os-teosclerid and parenchyma cell layers of the seed coat were observed between cultivars, but no relationship between these cell layers and the seed-coat cracking response was established. Seed-coat cracking was quantitatively inherited. ‘Bulgarian White’, ‘Pinto UI 111’ and ‘GN D-88’ showed high combining ability for resistance to seed-coat cracking. The estimates of the genetic effects indicated that additive effects were mainly involved.
Breeding Methods for Improving Southern Tetraploid Blueberries1
Authors: Draper A. D. , Galletta G. J. , Ballington J. R.
Published: August 2022

Fifty seedlings each of 8 tetraploid interspecific populations involving 6 Vaccinium species were examined for date of flowering, date of fruit ripening, fruit yield, color, firmness, and size. The 8 progenies contained from 25 to 75% highbush blueberry (V. corvmbosum L.) germplasm. There were significant differences among the 8 populations for all fruit characters and for the number of days from bloom to ripe fruit. Only 2 backcross progeny populations (75% high-bush blueberry) produced significant numbers of seedlings that met the selection criteria for 4 fruit characters.
Two Bioassay Techniques for Determining Abscisic Acid Concentrations1
Authors: Bakken T. J. , Boe A. A.
Published: August 2022

Two bioassay techniques for determining abscisic acid (ABA) concentrations are reported. One used bean (Phaseolus vulgaris) embryos while the other used lettuce (Lactuca sativa) hypocotyls. The bean embryo assay requires that seeds first be soaked over night, then the embryos excised and placed in known concentrations of (RS)-ABA for 24 hours, and finally measured. The lettuce hypocotyl assay utilizes seeds incubated for 48 hours, then placed in known concentrations of (RS)-ABA for 72 hours and finally measured. A dose-response curve of each bioassay may then be used to determine unknown concentrations of ABA. The bean embryo test was more rapid, but the lettuce hypocotyl assay was simpler and more sensitive. Elongation of bean embryos and lettuce hypocotyls was inversely correlated to the log concentration of (RS)-ABA within the range of 0.01 to 100 and 0.001 to 100 μg/ml, respectively.
Diphenyl Absorption and Decay in ‘Dancy’ and ‘Sunburst’ Tangerine Fruit1
Authors: Nagy S. , Wardowski W. F. , Hearn C. J.
Published: August 2022

Effects of storage time, temperature, fruit preparation, time of harvest and number of diphenyl pads per carton with ‘Dancy’ (Citrus reticulata Blanco) and ‘Sunburst’ a seedling from ‘Robinson’ × ‘Osceola’, each C. reticulata × (C. paradisi Macf. × C. reticulata) tangerines were studied to determine the amount of diphenyl absorbed and extent of decay. Storage of ‘Dancy’ and ‘Sunburst’ at 4°C for up to 4 weeks with 1 or 2 diphenyl pads resulted in diphenyl residues less than the U.S. legal tolerance of 110 ppm. However, storage of both cultivars for 2 weeks at 21°C with 2 diphenyl pads resulted in residues exceeding this tolerance limit. Decay and diphenyl residues both tended to be higher for ‘Dancy’ than for ‘Sunburst’. ‘Dancy’ tangerines stored for 4 weeks at 21°C all decayed. Statistical examination of 2 harvests of ‘Sunburst’ showed that early harvested fruit were less susceptible to decay but prone to absorb higher amounts of diphenyl.
Internal Ethylene Concentrations of ‘McIntosh’ Apples After Harvest1
Authors: Blanpied G. D. , Samaan Latif G.
Published: August 2022

In a low ethylene environment (< 1 ppm) at 19°C, the rate of ethylene evolution was positively related to the concentration of ethylene in the cores of ‘McIntosh’ apples (Malus domestica, Borkh.). Maximum retention of flesh firmness at 1° was associated with fruit internal ethylene concentrations below I ppm, which were obtained by ethylene removal from the storage atmosphere in combination with 3 treatments to suppress ethylene biosynthesis: orchard-applied daminozide, early harvest, and low O2 tension in storage.
Germination Behavior of Sand-coated Sweet Pepper Seed1
Authors: Sachs M. , Cantliffe D. J. , Nell T. A.
Published: August 2022

Germination rate of sand-coated pepper (Capsicum annum L.) seed (sand grain size < 75μm for an inner coat and 75–105 μm for an outer coat layer) was faster than clay-coated seed but was slower than raw seed. Part of the germination reduction in sand-coated seeds was caused by the water-soluble Gelvatol binder used. High oxygen (O2) levels promoted the germination of sand-coated seed to a rate comparable to that of raw seed. This suggests that even with a porous sand-coating material, O2 may be limiting for the germinating seed. When inorganic O2-releasing compounds (BaO2 or NaBO3) were incorporated into the sand material, the germination of pepper seed was further inhibited.
A Rapid Method to Estimate Fruit Water Status with Special Reference to Rain Cracking of Sweet Cherries
Authors: Andersen P. C. , Richardson D. G.
Published: August 2022

A technique is described whereby osmotic potential, turgor potential and total fruit water potential can be determined quickly in the field with the aid of a pressure bomb, a hand held refractometer, and a percent soluble solids to osmotic potential conversion chart. A unique inverse linear relationship between percent soluble solids and osmotic potential was found for each fruit species. Application of this technique to rain cracking of ‘Napoleon’ sweet cherries (Prunus avium L.) shows that cracking is not strictly related to percent soluble solids, osmotic, turgor, or fruit water potential. This suggests that the degree of cuticular permeability, cuticular strength, cell wall strength or other factors may be of greater importance in determining cracking susceptibility than water potential parameters.
Changes in Hormone Content of Pear Receptacles from Anthesis to Shortly after Fertilization as Affected by Pollination or GA3 Treatment1
Authors: Martin George C. , Horgan R. , Nishijima C.
Published: August 2022

Concentration of abscisic acid (ABA), abscisic acid-glucose ester (ABA-GE), indoleacetic acid (IAA), zeatin (Z), zeatin riboside (ZR) and gibberellic acid (GA) were measured in ‘Winter Nebs’ pear (Pyrus communis L.) receptacles from anthesis to 12 days thereafter. Concentration of GA or IAA may signal subsequent growth rate for GA3-treated and pollinated receptacles. No correlations with growth were evident for Z or ZR. ABA-GE began massive accumulation prior to the senescence and abscission of control receptacles.
Breeding for Resistance to Verticillium dahliae Race 2 of Tomato in North Carolina1
Authors: Okie W. R. , Gardner R. G.
Published: August 2022

Parental, F1, F2, and backcross generations of tomato (Lycopersicon esculentum Mill.) lines Morden MEL2668170G (MEL) and ‘Walter’ (WA) were screened as seedlings for resistance to verticillium wilt (Verticillium dahliae Kleb.) race 2. Disease reaction means, based on the number of leaves and cotyledons with symptoms 5.5 weeks after inoculation, were 2.7 for MEL and 4.6 for WA. Resistance in MEL appeared to be recessive with narrow sense heritability estimated at 0.25 or less. Disease severity was sometimes inadequate to avoid the selection of escapes in advanced generations. Analysis of F3 progenies, however, indicated 3 genes or less might be involved. Results suggest race-2 resistance can be maintained in advanced generations by the elimination of highly susceptible plants and by progeny testing to insure recovery of the most resistant individuals rather than escapes.
The Effects of Leaf Age on Photosynthesis in Rose1
Authors: Bozarth Connie S. , Kennedy Robert A. , Schekel Kurt A.
Published: August 2022

For all leaf ages of Rosa hybrida L. cv. Samantha, maximum photosynthetic rates were reached at irradiances of 450 to 500 μE m−2sec−1. The magnitude of this response decreased from 20.6 mg CO2 dm−2hr−1 in the youngest leaves studied to 15.4 mg CO2 dm−2hr−1 in the oldest. Maximum photosynthetic rates were reached before full leaf expansion. Mesophyll resistance, however, increased with age from 7.8 to 12.5 cm sec−1. CO2 compensation points and dark respiration decreased throughout most of leaf development, but increased slightly at the most advanced developmental ages studied. Photosynthetic enhancement, the percent increase in net photosynthesis at 2% O2 compared to 21% O2, averaged 33% for all leaves. There was no change in the amount of photosynthetic enhancement as leaves aged, indicating that changes in photorespiration were not a major factor in photosynthetic trends over the range of leaf ages examined.
Predicting Leaf Expansion of ‘Montmorency’ Sour Cherry from Degree-day Accumulations1
Authors: Eisensmith S. P. , Jones A. L. , Goodman E. D. , Flore J. A.
Published: August 2022

Second-order rectangular hyperbolic and asymptotic models which predict spur and terminal leaf expansion of ‘Montmorency’ sour cherry (Prunus cerasus L.) were developed from leaf area observations and temperature records made in orchards near East Lansing, Mich. Average leaf area per leaf was more highly correlated with degree-day accumulation at a base of 4°C starting April 19, than with day of the year. Leaf area per leaf increased linearly with degree-day accumulation until full leaf expansion. Final spur or terminal leaf size was not constant between years.
Mineral Composition of Radish in Response to Nitrapyrin and Nitrogen Sources
Authors: Torrey D. C. , Stratton M. L. , Barker A. V.
Published: August 2022

The relationship between nitrapyrin [2-chloro-6-trichloromethyl)pyridine, a nitrification inhibitor], and the growth and the mineral composition of ‘Cherry Belle’ radish (Raphanus sativus L.) was determined with sewage sludge as the N carrier in a greenhouse study. Plant growth fell sharply as nitrapyrin was increased in concentration from 1 to 10 ppm. The concentrations of Ca, Mg, and NO3− in the plants fell with this range of treatment, whereas that of K rose. The mineral composition of shoots was altered much more than that of roots. Increasing nitrapyrin concentrations to 50 ppm had little added effects on growth or composition relative to the 10-ppm level. Some of the phytotoxicity due to nitrapyrin addition appeared to be ammonium toxicity imparted by the accumulation of ammonium-N from the mineralization of the sewage. Another greenhouse study with nitrapyrin at 10 ppm, but with KNO3, (NH4)2SO4, and sewage sludge as the N carriers, showed that a depression in growth was correlated with the accumulation or retention of ammonium-N in the medium.
Postharvest Decay, Respiration, Ethylene Production, and Quality of Peaches Held in Controlled Atmospheres with Added Carbon Monoxide1
Authors: Kader Adel A. , El-Goorani Mohamed A. , Sommer Noel F.
Published: August 2022

The effects of 11% CO added to air or to 4% O2 ± 5% CO2 on brown rot development, respiration, ethylene production, firmness, color, composition, and internal breakdown of peaches [Prunus persica (L.) Batsch cv. Fay Elberta] were evaluated during holding at 5°C for 14 days followed by 3 days at 20° in air. The addition of 11% CO to 4% O2 ± 5% CO2 atmospheres completely inhibited growth of Monilinia fructicola (Wint.) Honey in vitro and in vivo. However, the normal rate of rot development resumed once inoculated plates and fruits were transferred to air at 20°. CO added to air stimulated CO2 and C2H4 production and enhanced softening, but its effects were insignificant when added to 4% O2, 5% CO2, or their combination. CA treatments without CO decreased respiration and C2H4 production rates and delayed softening. Differences among treatments in composition were small. Internal breakdown incidence and severity were slightly reduced by CO and increased by CO2.
Autotoxicity of Asparagus officinalis L.1
Authors: Yang Hsu-Jen
Published: August 2022

Crude aqueous extracts from dead stems, crowns, and roots from both field-grown and tissue-cultured asparagus plants delayed, but did not prevent, germination of asparagus seed. Root extract inhibited root and shoot development of asparagus seedlings grown in growth pouches. Stem and crown extracts reduced root growth but not shoot growth. The extracts of all 3 tissues caused more secondary root formation and root branching. The highest concentration of extract from crown-plus-root tissues, 5 g of tissue/100 ml water, inhibited radicle growth and killed seedlings. Toxicity of the crown-root extract was not reduced by adding activated charcoal to the extract or by autoclaving the extract. These results suggest that toxic substances in dead asparagus tissue are water-soluble and stable and may persist in old asparagus fields.
Effect of Post-plant Nematicides and Trickle Irrigation on Newly Planted Peach Trees1
Authors: Funt R. C. , Krusberg L. R. , Ross D. S. , Goulart B. L.
Published: August 2022

Carbofuran (2,3-dihydro-2,2-dimethyl-7 benzofuranyl methylcarbamate) at 5.7 and 11.1 kg/ha reduced soil populations of lesion (Paratylenchus penetrans, Filipjev & Shuurmans Stekhoven), pin (Paratylenchus sp. Cobb), and lance (Hoplolaimus galeatus, Cobb, Filipjeu & Schuurmans Stekhoven) nematodes. The highest rates of granular and flowable carbofuran were phytotoxic on peach [Prunus persica (L.) Batsch] planted just prior to treatment. In a subsequent experiment in soil previously planted to peach (old soil) or not previously planted to peach (new soil), trickle irrigation alone reduced dagger (Xiphinema americanum, Cobb) and lesion nematode populations. Carbofuran plus trickle irrigation reduced the dagger and lesion nematode populations and had the highest rate of tree growth in the old soil. Granular phenamiphos (ethyl-3-methyl-4-(methylthio) phenyl (1-methylethyl) phosphoridate) either alone or in combination with trickle irrigation reduced the stunt (Tylenchorhynchus claytoni, Steiner) nematode population. However, when phenamiphos was applied alone, tree growth was equal to the control in old soil but less than the control in new soil.
A Dwarfing Gene that Reduces Seed Weight and Pod Length in Common Bean1
Authors: Bassett Mark J.
Published: August 2022

Common bean (Phaseolus vulgaris L.) genotype, MITA 10597, has small seeds (x = 122 mg, s = 31) and short, narrow pods (x = 44 mm, s = 13.2) with tight constrictions between seeds. A bean breeding line, 7-1404, has longer pods (x = 99 mm, s = 18.4) and larger seeds (x = 269 mg, s = 32). The inheritance of the dwarf seed and pod type of MITA 10597 was studied in the F2 and backcross populations from the cross MITA 10597 × 7-1404 and also from F2 populations from backcrosses of 7-1404 to an F3 plant (from 7-1404 × MITA 10597) selected for the dwarf seed (DS) character. The DS character was found to be controlled by a single, recessive gene that restricts development in seeds with the ds//ds genotype. The apparent phenotypic segregation for seed size in the pods of heterozygous (+//ds) F1 plants was found to be under genetic control.
Physiological Mechanisms of Host-plant Resistance in the Genus Lycopersicon to Heliothis zea and Spodoptera exigua, Two Insect Pests of the Cultivated Tomato1
Authors: Juvik J. A. , Stevens M. A.
Published: August 2022

When larvae of Heliothis zea (Boddie) were caged on fruits of varying developmental ages from 3 accessions of Lycopersicon, the length of the larval stage and mortality were positively correlated with fruit α-tomatine content. Larval growth rates and adult weights of H. zea were found to be inversely correlated with fruit alkaloid content. Growth and survival of caged Spodoptera exigua (Hubner) were not related to the levels of tomatine in the fruit. However, a highly significant correlation exists between fruit cuticular toughness and S. exigua mortality. Compared to the processing tomato line VF145B-7879, lower H. zea and S. exigua survival rates were observed when the larvae were reared on the tougher, higher-alkaloid fruits of L. esculentum var. cerasiforme and L. pimpinellifolium accessions. These results indicate a possibility of enhancing cultivar resistance to these insect pests through the development of tough-fruited, high-α-tomatine genotypes.
Reduction in Yield and Market Quality of Celery Caused by Soil Salinity1
Authors: Francois L. E. , West D. W.
Published: August 2022

The effect of soil salinity on yield and market quality parameters of celery [Apium graveolens L. var. dulce (Mill.) Pers.] was determined in field plots. Saline treatments were imposed by irrigating with water that contained NaCl and CaCl2 in equal concentrations. Celery was found to be moderately sensitive to salinity. Relative yield was reduced 6.2% for each unit increase in soil salinity beyond 1.8 dS/m (dS/m = mmho/cm, referenced at 25°C). Petiole length, width, and thickness were also significantly reduced with increasing salinity. Salinity had no effect on pith development.
Effect of Irrigation Frequency during Greenhouse Production on the Postproduction Quality of Petunia hybrida Vilm.1,2
Authors: Armitage A. M. , Kowalski T.
Published: August 2022

‘Coral Sea’ petunia plants were irrigated at “low” frequency (surface media dry, soil moisture = −4 to −10 bars), “normal” frequency (surface media moist, soil moisture = −0.8 to −3 bars) or “high” frequency (surface media wet, soil moisture > −0.6 bars) during production. Postproduction quality was evaluated under cool (10°C day, 10° night), moderate (20° day, 20° night), or hot (30° day, 20° night) temperature postproduction environments. Frequency of irrigation was not significant when plants were placed in cool postproduction environments. In moderate or hot postproduction conditions, plants irrigated with high frequency declined in quality most rapidly. Low moisture-treated plants had slower flower development and senescence, greater dry weight, and better overall visual quality than plants with other moisture treatments.
Evidence for Simple Genetic Control of Sugar Type in Carrot (Daucus carota L.)1
Authors: Freeman Roger E. , Simon P. W.
Published: August 2022

Reducing sugar (glucose and fructose) and sucrose are the major free sugars (total sugars) in the carrot root. Striking genetic variation exists for the reducing sugar/total sugar ratio (percentage of reducing sugar). Inbred carrot lines with high and low percentages of reducing sugar were used as parents in establishing various F1, F2, F3 and backcross populations to study the inheritance of root sugars. It was determined that a single major gene regulates the reducing sugar to sucrose balance in carrot roots with dominance for high percentage of reducing sugar. We propose that this gene be designated Reducing sugar, symbolized Rs. This relationship is of interest since sugars in the carrot root are a major storage carbohydrate and a primary component of carrot flavor.
Effects of “Rapid CA”, High CO2, and CaCl2 Treatments on Storage Behavior of ‘Golden Delicious’ Apples1
Authors: Lau O. L. , Meheriuk M. , Olsen K. L.
Published: August 2022

Excellent firmness retention in ‘Golden Delicious’ apples was achieved in a “rapid CA” (rapid reduction of O2 by use of N2 flushing) storage procedure. Pretreatment of the fruit with high levels of CO2 prior to rapid CA had little or no effect on firmness. Higher flesh calcium content was beneficial in firmness retention when fruit was stored in air, in “slow CA” (O2 reduced by fruit respiration), or held in air for 10 days prior to rapid CA. Rapid CA provides an effective means to control softening in ‘Golden Delicious’ apples and to avoid injury caused by calcium and high CO2 treatments.
Environmental Factors Influencing Leaf Water Potential of Chrysanthemum1
Authors: Stanley C. D. , Harbaugh B. K. , Price J. F.
Published: August 2022

A study was conducted to investigate environmental factors which affect leaf water potential (LWP) response of chrysanthemums (Chrysanthemum × morifolium Ramat). Meteorological parameters, including air temperature (TEMP), relative humidity (HUM), total solar radiation (RAD), and photosynthetically active radiation (PAR) were measured simultaneously as LWP determinations were made diurnally for plants grown with 5 different irrigation rates. Stepwise multiple regression analyses using the meteorological parameters as independent variables and LWP as the dependent variable showed that models developed for each irrigation rate included TEMP, HUM, and PAR as statistically significant (P = 5%) independent variables. Coefficients of determination (R2) for the models ranged from 0.83–0.87. A combined model, including irrigation rate (R) as an independent variable along with the meteorological parameters, revealed that TEMP, PAR, HUM, and R were statistically significant at P = 1% and had an R2 = 0.84. Results reveal environmental factors which must be considered in studies involving LWP measurements for chrysanthemums in order to avoid misinterpretation of data.
The Freezing of Water in Woody Tissues of Apricot and Peach and the Relationship to Freezing Injury1
Authors: Ashworth E. N. , Rowse D. J. , Billmyer L. A.
Published: August 2022

The freezing of water within the woody tissues of apricot (Prunus armeniaca L.) and peach [Prunus persica (L.) Batsch] was characterized and the relationship to freezing injury established. Bark and xylem tissues exhibited contrasting freezing patterns and mechanisms of freezing resistance. Water in xylem parenchyma cells deep-supercooled. Tissue injury appeared to result from the freezing of this supercooled water. In contrast, water within bark tissues underwent equilibrium freezing. Bark injury resulted from the stresses which accompany extracellular ice formation and cellular dehydration.
Embryogenesis and Plantlet Regeneration from Callus of Hibiscus acetosella1
Authors: Reynolds B. D. , Blackmon W. J.
Published: August 2022

Plantlets have been produced by germination of somatic embryos derived from callus of Hibiscus acetosella Welw. ex. Hiern. Five of the media used were based on Nitsch and Nitsch's Medium H (purchased formulated without IAA or sucrose). To this base were added, per liter: 40 g glucose for NH; 10 g sucrose for NH-1; 40 g sucrose, 1 mg 2,4-dichlorophenoxyacetic acid (2,4-D), and 1 mg 6-furfurylaminopurine (kinetin) for RM-1; 40 g glucose, 250 mg NaH2PO4·H2O, 28 mg FeC6H5O7·nH2O, 100 mg i-inositol, 30 mg adenine, 0.1 mg (2-chloroethyl)trimethylammonium chloride (chlormequat), and 4 mg 2,4-D for SEM-1; and 40 g glucose, 0.1 mg chlormequat, 0.05 mg B-napthoxyacetic acid (NOA), and 10 mg 2-isopentyladenine (2iP) for HC. The B5 medium was Gamborg's B5 without 2,4-D. All media contained 8 g agar and had the pH adjusted to 5.7 prior to autoclaving. Primary explants placed on HC produced adventitious shoots and callus. When callus explants from HC or primary explants of roots were placed on RM-1, a callus containing embryoid-like structures was produced. Torpedo stage embryos were induced by subculturing this callus from RM-1 on SEM-1 and could be proliferated by sequential transfer from SEM-1 to RM-1, then back to SEM-1. When callus containing torpedo-stage embryos was transferred to B5, the embryos germinated and produced rudimentary plantlets with elongated hypocotyls, short roots, and small cotyledons. These developed into plants when transferred to NH-1.
Root Temperature, Water Relations, and Cold Hardiness in Two Citrus Rootstocks1
Authors: Wilcox Darlene A. , Davies Frederick S. , Buchanan David W.
Published: August 2022

The influence of root temperature on whole-plant water relations and cold hardiness in seedlings of 2 citrus rootstocks—rough lemon (Citrus jambhiri Lush.) and Carrizo citrange [C. sinensis (L.) Osbeck × Poncirus trifoliata (L.) Raf.]—and ‘Valencia’ scions on both rootstocks was examined. Plants were exposed to root temperatures of 5°, 10°, or 15°C for 5–8 weeks, while shoots were exposed to a nonacclimating air temperature of 30°. Root temperatures of 5° decreased leaf xylem water potential and increased cold hardiness. Statistical differences in diffusive resistance and transpiration were observed only at the 5° root temperature. Root temperature did not significantly alter leaf relative water content in either seedlings or budded plants. A decrease in soil and root temperature alone, without a simultaneous reduction in air temperature, can provide an effective cold-acclimating environment for citrus.
Changes in Indoleacetic Acid, Abscisic Acid, Gibberellins, and Cytokinins during Budbreak in Pecan1
Authors: Wood B. W.
Published: August 2022

The dynamics of indoleacetic acid (IAA), cis-trans abscisic acid (c,t-ABA), and gibberellin (GA)- and cytokinin-like compounds were measured in pecan [Carya illinoensis (Wang) K. Koch; cv. Desirable] buds following their release from imposed dormancy. Both bound and free ABA levels in apical and basal primary buds and in secondary buds declined 27 days prior to budbreak until the time of budbreak, with the exception of a steady rise in free ABA in secondary buds. During this period IAA initially dropped sharply, remained low, and finally increased again at budbreak. Cytokinin-like substances peaked after the drop in IAA but prior to the peak in gibberellin-like substances which occurred during bud swelling. The findings raise the possibility of a key regulatory role for IAA, possibly through its influence on regulation of bud cytokinin and gibberellin levels via their metabolism in roots. Growth regulator dynamics during pecan budbreak are discussed in relation to the hormonal theory versus tissue sensitivity to growth regulators.
Effects of Anaerobic Nitrogen and Carbon Dioxide Atmospheres on Ethanol Production and Postharvest Quality of Blueberries
Authors: Saltveit Mikal E. , Ballinger Walter E.
Published: August 2022

The ethanol content of ‘Harrison’ and ‘Jersey’ highbush (Vaccinium corymbosum L.) and ‘Premier’ rabbiteye blueberries (V. ashei Reade) increased linearly with time (1 to 4 hours) and exponentially with temperature (0° to 30°C) during exposure to an atmosphere of pure N2 or CO2. CO2 production was depressed about 20% under N2 gas. Berries which were placed in air after 4 hours in CO2 lost half the CO2 they contained every 30 minutes. After 3 hours, CO2 evolution from treated and control fruit was the same. Fruit quality was unaffected by exposure at 0° to 30° to pure N2 or CO2 gas for up to 4 hours. However, 22 hours in a CO2 atmosphere at either 0° or 30° reduced fruit quality. An equation was derived to calculate ethanol accumulation under different cooling rates.
Photographic Analysis of Cucumber Fruit Elongation
Authors: Wehner Todd C. , Saltveit Mikal E.
Published: August 2022

Growth patterns of cucumbers (Cucumis sativus L.) were studied by photographing developing fruit at 2- or 3-day intervals over a 30-day period beginning with pollination (day 0). Nine cultivars were studied: ‘Chinese Long Green’, ‘Sprint 440’, ‘Marketmore 76’, and ‘Minisol’ (all fresh-market types); ‘Riesenschal’ (a schälgurken type); and ‘Marbel’, ‘Kobus’, ‘Calypso’, and ‘Wisconsin SMR-18’ (all pickling types). Analysis of the photographs showed that all sections of the fruit grew in length at a constant rate during the 30-day period. The pattern of growth was fairly uniform, except that there was slightly more growth in the center section than at the ends, and slightly more growth at the blossom end than at the peduncle end of the fruit. Fresh-market and schälgurken types had the longest fruit over the 30-day period of growth, but pickling types had the highest percent change in length. Pickling types produced shorter fruit because they stopped growing earlier than the two other types (12 vs. 14 days, respectively).
Fertilizer and Plant Density Effects on Yield Performance and Leaf Nutrient Concentration of Bush Snap Beans
Authors: Mack H.J.
Published: August 2022

There were no significant fertilizer x plant-density interactions affecting yields or leaf nutrient concentrations of snap beans (Phaseolus vulgaris L.) in 5 field experiments. Higher rates of fertilizer application produced significantly higher yields of pods than did lower rates in 2 experiments. At higher plant densities (15.2- to 30.5-cm rows, 43 to 65 plants/m2) yields were 20% to 38% higher than at lower plant densities (91.4-cm rows, 22 to 29 plants/m2). Average yield increase at higher densities was 29%. Crop economic values followed similar trends. At higher plant densities, average N, K, Ca, and Mg concentrations in leaves at early bloom were lower than at lower densities. Higher fertilizer rates tended to increase N concentration in leaves but had no consistent effects on P, K, Ca, and Mg.
Effect of Gibberellic Acid on Yield and Quality of Fall-harvested and Overwintered Spinach
Authors: Gonzalez Alfredo R. , Marx David B.
Published: August 2022

A single application of 20 ppm gibberellic acid (GA3) 2 weeks before harvest increased yields and height of fall spinach (Spinacia oleracea L.) by inducing the setting of leaves in an upright position and stimulating petiole and stem growth. Small differences were noted between GA3-treated and untreated overwintered spinach. Cultivars responded similarly to growth conditions and to GA3 application. Both GA3-treated and untreated fall spinach had better quality than overwintered spinach harvested in the spring. Spinach treated with GA3 had higher shearpress values, yellow and green color, lower titratable acidity, and no change in pH values as compared to the control. A panel graded GA3-treated spinach slightly higher in amount of petioles and stems and lower in general acceptability than the untreated control. Better utilization of GA3 was obtained in the fall-grown spinach.
Development of Flowers and Changes in Carbon Dioxide, Ethylene, and Various Sugars of Cut Zinnia elegans Jacq.
Authors: Stimart Dennis P. , Brown Dennis J. , Solomos Theophanes
Published: August 2022

Postharvest flower fresh weight of Zinnia elegans Jacq. increased when held in solutions containing 200 mg liter-1 8-hydroxyquinoline citrate (8-HQC) and sucrose and decreased when held in deionized water. Ethylene biosynthesis was enhanced by holding flowers in solutions of 8-HQC + 1, 2% or 3% sucrose compared with deionized water where ethylene release was low initially and remained low. Carbon dioxide evolution declined sharply the first 2 days postharvest and remained low for flowers held in deionized water, but remained at initial levels for those held in 200 mg liter-1 8-HQC + 3% sucrose. Glucose, fructose, and sucrose in ray florets declined to levels barely detectable if flowers were held in deionized water but increased if held in 200 mg liter-1 8-HQC + 3% sucrose. The induction of ethylene biogenesis may be an injury response caused by sucrose.
Variation in Sechium edule in Central America
Authors: Engels J.M.M.
Published: August 2022

Genetic variation for 11 fruit characteristics of Central American chayotes (Sechium edule Sw.) was similar in Costa Rica, Honduras, Guatemala, and Mexico. Costa Rica possessed many types belonging to the extremes of the total range. Fruit size descriptors were correlated strongly.
Variation in Wound Response among Cultivars of Red Maple
Authors: Gallagher Peter W. , Davis Sydnor T.
Published: August 2022

Wound closure and growth data were determined over a 2-year period for 12 cultivars of red maple (Acer rubrum L.) and branch and trunk wounds were analyzed for extent of associated discolored wood. A cultivar effect was noted in both closure and compartmentalization rates. ‘Armstrong’, ‘Doric’, ‘Gerling’, and ‘October Glory’ exhibited below average closure rates; ‘Schlesinger’, ‘Autumn Flame’, and ‘Autumn Glory’ had a more rapid closure rate in response to wounding. ‘Red Sunset’ and ‘Schlesinger’ were above average and ‘Bowhall’ and ‘Scanlon’ were below average in capacity to compartmentalize wounds. Previous years' twig extension growth was a good prediction of a plant's ability to close wounds. Higher nutrient levels of callus were associated with higher closure rates.
Sources and Nature of Resistance to Downy Mildew and Turnip Mosaic in Chinese Cabbage
Authors: Niu Xin-ke , Leung Hei , Williams Paul H.
Published: August 2022

Forty-six Chinese cabbage [Brassica campestris spp. pekinensis (Lour) Olsson] lines consisting of open-pollinated cultivars, inbreds, and F1 hybrids from China were screened for seedling resistance to downy mildew (Peronospora parasitica) (Pers.) Ex. Fr. Thirty-seven lines of this collection were screened for turnip mosaic resistance. Five lines showed dual resistance to downy mildew and turnip mosaic. Resistance to downy mildew at the cotyledon stage, expressed as a reduction in the sporulation capacity of P. parasitica, was under dominant monogenic control. Turnip mosaic resistance was expressed as a hypersensitive reaction. Genetic analysis of a cross between turnip mosaic resistant and susceptible parents suggested that resistance was conditioned by 2 dominant genes.
Mycorrhizal Infection and Growth of Onion in the Field in Relation to Phosphorus and Water Availability
Authors: Bolgiano N.C. , Safir G.R. , Warncke D.D.
Published: August 2022

Vesicular-arbuscular (VA) mycorrhizal colonization of onion (Allium cepa L.) roots was found at high levels in commercially used soils only when P concentrations were below 30 µg/cm3. Soils sampled were muck soils with varying amounts of organic matter and sand and marl soils, and the P range was 10-250 µg/cm3. Onions were also seeded in 2 fields of Houghton muck soil, at 4 P levels, with and without inoculum of Glomus etunicatus Becker & Gerdemann. High colonization occurred when soil P concentrations were below 15-20 µg/cm3. High yields and high colonization past midseason were achieved simultaneously upon the addition of 30 kg/ha P. In a separate experiment, onions were grown at 3 P levels and 2 watering regimes. The P concentrations associated with limited mycorrhizal root colonization shifted from 15 to 30 µg/cm3 with a decrease in water availability. The results demonstrate the need for control of soil water conditions, as well as P, when attempting to utilize VA mycorrhizae.
Yield Components and Pod Quality of Snap Beans Grown under Differential Irrigation
Authors: Bonanno A. Richard , Mack Harry J.
Published: August 2022

Field experiments were conducted to evaluate the effects of differential irrigation treatments on the yield and pod quality of ‘Oregon 1604’ and ‘Galamor’ snap beans (Phaseolus vulgaris L.) in 1981 and 1982. Treatments in which various levels of positive canopy minus air temperature differences [stress-degree-days (SDD)] accumulated between irrigations were evaluated along with irrigation at 4 growth stages, a dry treatment which received only one irrigation to establish plants, and a control treatment irrigated at -0.06 MPa soil water potential (SWP). In both seasons, yield was related strongly to the average soil water potential from planting to harvest. Yields in 1982 were at least 5 MT/ha greater at a given average soil water potential than in 1981. Yields of ‘Oregon 1604’ and ‘Galamor’ were similar under adequate irrigation, but under greatest water stress, yield of ‘Oregon 1604’ was higher than for ‘Galamor’. Pod number was reduced only in the dry treatment. Percentage of set pods, pod length, and number of seeds per pod were all reduced by low irrigation, while fiber content of pods and weight per seed were increased by low irrigation.
Calcium-related Leaf Necrosis of Seedling Carrots
Authors: Tibbitts T.W. , Setiamihardja R. , Palzkill D.P. , Olszyk D.M.
Published: August 2022

Seedlings of carrot (Daucus carota L.) develop leaf necrosis when subjected to conditions which encourage rapid growth in controlled-environmental chambers. Necrosis occurred on the 4th and 9th developing leaves and was apparent as they unfolded. Injury was determined to be calcium-related, since foliar CaCl2 applications reduced injury and covering the plants during the dark period to promote translocation of Ca by root pressure flow stopped injury completely. Young unfolding leaves in covered plants had 50% greater Ca concentrations than those plants maintained in the chamber without covering. Carrot cultivars had different degrees of sensitivity to the leaf necrosis with ‘Red Core Chantenay’ > ‘Danvers’ > ‘Carousel’ > ‘Scarlet Nantes’.
Selection for Improved Low Temperature Germination in Cucumber
Authors: Nienhuis J. , Lower R.L. , Staub J.E.
Published: August 2022

Recurrent half-sib selection within a heterogeneous population of cucumber (Cucumis sativus L.) was effective in improving germination at 15°C from 34.4% in cycle 0 to 92.4% in cycle 3. The linear regression coefficient indicated an average increase of 19.8% units per cycle of selection. Correlated responses to selection resulted in increased percentage of germination at 20° and 25° and decreased days to germination at 15°, 20°, and 25°.
Yield Response of Major Pod-bearing Nodes in Bush Snap Beans to Irrigation and Plant Population
Authors: Mauk Craighton S. , Breen Patrick J. , Mack Harry J.
Published: August 2022

Yield variables of mainstem nodes 6 (terminal) and 2 (that of the first trifoliate leaf) of ‘Oregon 1604’(Phaseolus vulgaris L.) were evaluated at 2 irrigation regimes × 2 plant populations in a warm (1978) and a moderate (1979) season. A single inflorescence formed at node 6, whereas up to 4 inflorescences were borne on branches at node 2. After emergence, crops were irrigated either when the soil water potential reached −0.06 MPa (high) or −0.25 MPa (low). High and low plant populations were, respectively, 45 vs. 18 plants/m2 in 1978 and 54 vs. 33 plants/m2 in 1979. Yield per unit area was increased significantly from 38–54% by high plant population and 40–120% by high irrigation. On a per plant basis, plant population failed to have a significant effect on total yield or yield variables at node 6. At node 2, however, high plant population reduced the number of inflorescences in 1978 and decreased the number of flowers, number of pods formed and harvested, and percentage set and reduced pod yield by about 50% in both years. Per unit area yields of node 2 at high and low plant population differed by less than 13–18%. Since the productivity of node 6 was not influenced by density, per unit area yields at this node more directly reflected plant population. Nodes 2 and 6 responded similarly to the low irrigation regime, which in 1978 significantly decreased the number of pods formed, percentage set, and pod yield at both nodes. Irrigation effects on individual yield parameters at each node generally were less in the cooler 1979 season. No significant irrigation–plant population interactions occurred for any measured yield variable in either season.
Calculating Heat Units via a Sine Function
Authors: Logan Samuel H. , Boyland Patricia B.
Published: August 2022

The concept of heat units (degree days) has provided a basis for several studies to analyze the time between planting and maturity for plants. The model reported here utilizes a sine function to approximate the behavior of temperatures during the day. The available heat units for the day then are obtained by integrating the sine function given constraints of the plant growth process as reported by other authors. These constraints include: 1) a minimum temperature below which plant growth stops; 2) a high temperature above which plant growth remains unchanged for some interval up to a maximum temperature; and 3) a maximum high temperature above which plant growth is retarded. The model is developed explicitly for tomato (Lycopersicon escutentum Mill.).
Inheritance, Linkage, and Gene Interaction Studies in Lettuce
Authors: Ryder Edward J.
Published: August 2022

Two new lettuce genes are described and named: chlorophyll deficient-2 (cd-2) and Early flowering (Ef). Brown pericarp is either a pleiotropic effect of plump involucre (pl) or is caused by a closely linked gene. White pericarp (w) is epistatic to brown. Endive-like leaf (en) and white pericarp are linked, with P = 0.47. Virescent (vi) and fringe (fr) are linked, with a recombination value of p = 0.25. Genes for spininess and anthocyanin color are linked. Endive, white, virescent, fringe, and male sterile-6 (ms-6) form a linkage group. Three other double recessives have interactive relationships. Endive and fringe together are phenotypically extreme endive; virescent and golden (go) together are golden; golden and chlorophyll deficient-2 are golden and partially lethal.