bluuebunny/crossref_metadata_2025 huggingface dataset:
Hardening Treatments Increase Survival of Synthetically-coated Asexual Embryos of Carrot
Authors: Kitto S. L. , Janick Jules
Published: August 2022

Asexual embryos of carrot (Daucus carota L.) were initiated from cell suspensions and hardened by treatments with high sucrose (12% as compared to 2%), high inoculum density (0.8 as compared to 0.4 g/25 ml), or chilling (4°C the last 3 days of a 2-week embryo induction phase otherwise carried out at 29°), individually or in combination with 10−6 m abscisic acid (ABA). Carrot embryos either were encapsulated with a water-soluble resin (Polyox WSR-N 750) or nonencapsulated before drying to constant weight. Nonencapsulated embryos did not survive drying. All hardening treatments increased survival of encapsulated embryos. However, survival of embryos treated with ABA plus each of the other 3 hardening treatments was less than expected, assuming additivity. Encapsulated embryos pretreated with ABA and chilling survived 16 days of storage in darkness at 4°.
Ice Nucleation in Tomato Plants
Authors: Anderson J. A. , Ashworth E. N.
Published: August 2022

Tomato plants (Lycopersicon esculentum Mill. ‘US 28’) and plant parts ranging in fresh weight from 6 mg to 180 g were frozen in the presence and absence of epiphytic ice nucleation active (INA) bacteria. As weight increased, freezing temperatures rose from —10.5° to — 2°C in the absence of INA bacteria but varied from —3° to —2° in inoculated samples. The freezing behavior of entire plants could only be estimated using small plant parts when INA bacteria were present. INA bacteria were detected by a plate harvesting method. The fraction of tomato stem sections frozen increased with increasing exposure duration at constant temperature.
Nondestructive Spectrophotometric Determination of Dry Matter in Onions
Authors: Birth G. S. , Dull G. G. , Renfroe W. T. , Kays S. J.
Published: August 2022

The techniques used in near infrared spectrophotometry for nondestructive analysis of agricultural products were applied to determine the percentage of dry matter (% DM) of intact onions (Allium cepa L). Transmittance data were recorded for the 700 nm to 1000 nm spectral region. Second derivative data processing was used with a stepwise multiple regression analysis to develop an equation to predict the % DM of individual onions. The correlation between optical data and % DM was 0.996. In a 2nd and completely independent experiment, we obtained equivalent results demonstrating the repeatability of the method. This repeatability was demonstrated even further through the satisfactory field testing of a portable instrument.
Ice Formation in Prunus persica under Field Conditions
Authors: Ashworth E.N. , Anderson J.A. , Davis G.A. , Lightner G.W.
Published: August 2022

Ice formation was initiated between –0.6° and –2.6°C in mature Prunus persica (L.) Batsch trees growing in the field. Trees supercooled very little. Ice formation was initiated at several locations in the tree and subsequently spread throughout. The release of the latent heat of fusion following ice formation in the tissue maintained tissue temperatures 1° to 3° above air temperature for several hours and mitigated the tissue's response to ambient temperatures.
Changes in Phenolic Acids and Internal Ethylene during Long-term Cold Storage of Pears
Authors: Blankenship Sylvia M. , Richardson Daryl G.
Published: August 2022

High performance liquid chromatography of mature ‘Beurre d'Anjou’ and ‘Beurre Bosc’ pear (Pyrus communis L.) fruit flesh showed that the major phenolics at harvest were chlorogenic acid, catechin, and arbutin. Neither cultivar contained epicatechin nor p-coumaroyl quinate. During 160 days at –1°C the chlorogenic acid content of d'Anjou increased significantly. In ‘Bosc’, chlorogenic acid levels decreased during storage. Catechin content increased linearly while arbutin levels remained nearly constant in both cultivars. Coincident with the completion of the cold requirement for initiation of ripening and endogenous ethylene production, i.e., 20 days for ‘Bosc’ and 50 days for ‘d'Anjou’, there was an appearance of low levels of a p-coumaric acid derivative and trace amounts of epicatechin/p-coumaroyl quinate. At 120 days epicatechin/p-coumaroyl quinate increased in ‘d'Anjou’ but not in ‘Bosc’. There is a coincidence, and perhaps relationship, between ethylene production and the quantity as well as the composition of phenolics present during storage. Bruising pear fruit after 120 days of storage caused a 30% increase in chlorogenic acid and a 50% increase in catechin, but no increase in p-coumaric acid derivatives.
Fruit Age and Growth Regulator Effects on the Quantity and Structure of the Epicuticular Wax of ‘Washington’ Navel Orange Fruit
Authors: El-Otmani Mohamed , Coggins Charles W.
Published: August 2022

Changes in ‘Washington’ navel orange [Citrus sinensis (L.). Osbeck] fruit epicuticular wax quantity and structure were followed during fruit development, maturation, and senescence. Whole-tree sprays of 10 ppm GA3, 16 ppm 2,4-D, and a combination of GA3 (10 ppm) plus 2,4-D (16 ppm) were made at fruit color-break, and effects on wax were examined at 4-week intervals. The total epicuticular wax produced per fruit and per unit of fruit surface area increased with time on control and on treated fruit. GA3-treated fruit produced significantly lower amounts of wax per unit of surface area than did control or fruit treated with 2,4-D alone. Total epicuticular wax per unit of fruit surface area of the control was similar to that of the 2,4-D-treated fruit until late in the season, when that of the control significantly exceeded that of the 2,4-D treatment. Wax per unit of fruit area of the GA3-treated fruit was not significantly different from that of the GA3 plus 2,4-D-treated fruit until late in the season, when GA3 plus 2,4-D treatment resulted in significantly higher values. Scanning electron microscopy revealed significant changes in surface morphology and ultrastructure of the epicuticular wax during fruit development, maturation, and senescence. Control fruit and 2,4-D-treated fruit were similar, but GA3 delayed ultrastructural changes that were seen in the control fruit. The incidence of ‘sticky’ rinds was reduced significantly by GA3 treatment, and ‘sticky’ rind surface wax had a structure similar to that of senescing surfaces. Chemical names used: (2,4-dichlorophenoxy)acetic acid (2,4-D); gibberellic acid (GA3).
Feeding Influence of Three Pecan Aphid Species on Carbon Exchange and Phloem Integrity of Seedling Pecan Foliage
Authors: Wood B.W. , Tedders W.L. , Thompson J.M.
Published: August 2022

Feeding injury by pecan aphids on fully expanded pecan [Carya illinoensis (Wangenh) K. Koch] seedling foliage reduced net CO2 exchange within 2 weeks of infestation and was dependent upon aphid density and species. Increasing aphid population levels resulted in increasing reductions in net photosynthesis. Carbon exchange rates after a buildup and subsequent rapid decline of either Monellia caryella (Fitch) or Monelliopsis pecanis (Bissell) populations resulted in a 50% reduction in net photosynthesis and 25% reduction in dark respiration. This effect can persist at least 12 weeks after the cessation of aphid infestation. Such leaves exhibit aphid-induced clogging of the phloem with callose and other substances. Such clogging may be associated with the commonly observed aphid population decline in pecan orchards. Observations indicate that the influence of aphid feeding on leaf photosynthetic physiology may impair pecan productivity.
Effects of Stempiece and Rootstock Combinations on Growth, Leaf Mineral Concentrations, Yield, and Fruit Quality of ‘Empire’ Apple Trees
Authors: Lord William J. , Greene D.W. , Damon R.A. , Baker J.H.
Published: August 2022

The influence of Mailing (M)26, M9, M27 rootstocks and stempiece/rootstock combinations M9/Malling-Merton (MM)106, M9/MM111, M27/MM106, and M27/MM111 on growth, leaf nutrition, and fruit quality of ‘Empire’ apples (Malus domestica Borkh.) was evaluated. After 8 growing seasons, height and spread of trees on M26, M9/MM106, M9/MM11, M27/MM106, and M27/MM111 were similiar and were greater than those of trees on M9 and M27. Mn concentration in leaves from trees on M27 was higher than that of leaves from trees on other rootstock and stempiece/rootstock combinations. Production of trees on M26, M9/MM106, and M27/MM106 was greater than that on M9/MM111, M9, and M27. When fruitfulness was related to trunk area, trees on the various rootstock and stempiece/rootstock combinations did not differ in production efficiency. Effect of rootstock or stempiece/rootstock on fruit size was inconsistent. Fruit from trees on M27/MM111 entered in to their climacteric later than those from trees on M26 and M 27 for 2 years and from trees on M9 and M9/MM106 for 1 year, but the delay was small. No fruit flesh firmness differences were detectable. Soluble solids content of fruit from trees on M27 was higher than that of fruit on M26, M9/MM111, and M27/MM111. Senescent breakdown was more prevelant in fruit from trees on M26 than on M9, M27, M9/MM111, and M27/MM111.
Genetic Variation within and between Two Cucumber Populations Derived via the Inbred Backcross Line Method
Authors: Owens K.W. , Bliss F.A. , Peterson C.E.
Published: August 2022

Selected inbred backcross lines from 2 cucumber (Cucumis sativus L.) populations were studied to determine whether genetic variation existed within and between 2 populations for fruit length and weight. F1 hybrids from intra-population diallel and inter-population North Carolina Design II matings were evaluated in 1981 under greenhouse or field conditions. Significant genetic variability was found among selected inbred backcross lines within each population for fruit length and weight. General (GCA) and specific (SCA) combining ability estimates were significant, indicating that both additive and nonadditive effects were important for trait expression among lines from the same population. Analysis of inter-population design II F1 hybrids indicated that male and female (GCA) or additive effects accounted for most of the variation between lines for fruit length and weight. Significance of specific combinations (SCA) and the F2 data confirmed that genetic variation existed between populations. Therefore, selection and intercrossing of specific inbred backcross lines from both populations may lead to maximum fruit size and recovery of the desired horticultural characterisics of the recurrent parent. The inbred backcross line method is well suited for the transfer of genes controlling a quantitative trait from an unadapted or exotic source into a commercially acceptable type.
Growth Capacity of ‘Valencia’ Orange Buds on Different Rootstocks during Cold-hardening Temperatures
Authors: Yelenosky G. , Wutscher H.K.
Published: August 2022

In the article “Growth Capacity of ‘Valencia’ Orange Buds on Different Rootstocks during Cold-hardening Temperatures” by G. Yelenosky and H.K. Wutscher [J. Amer. Soc. Hort. Sci. 110(1):78–83. 1985.], the figure captions for Figures 2 and 3 were reversed.
Effect of Cyanogenic Glycosides on Growth of Callus from Almond and Plum
Authors: Heuser Charles W.
Published: August 2022

The effects of the cyanogenic glycosides, amygdalin and prunasin, and their breakdown products, cyanide and benzaldehyde, on callus derived from ‘Marianna 2624’ plum (Prunus cerasifera Ehrh. × P. munsoniana Wight & Hedr.) and on that from 2 almond cultivars (P. amygdalus Batsch ‘Nonpareil’ and ‘Texas’) were compared. Prunasin (D-Mandelonitrile-β-D-glucoside) inhibited the growth of ‘Marianna 2624’ plum and ‘Nonpareil’ almond callus but not ‘Texas’ almond. Amygdalin (D-Mandelonitrile-β-D-gentiobioside) inhibited ‘Marianna 2624’ plum callus growth but promoted growth of both almond cultivars. All 3 cultivars were inhibited to the same extent by sodium cyanide, indicating that cyanide was not the differentiating inhibitory breakdown product of the cyanogenic glycosides. Benzaldehyde, another catabolite of prunasin and amygdalin, was strongly inhibitory to ‘Marianna 2624’ plum callus growth at 0.05 mm, but a concentration of 5 mm was required to inhibit similarly growth of either almond callus. The greater sensitivity of ‘Marianna 2624’ plum callus, compared to almond callus, to the cyanogenic glycosides and benzaldehyde, but not cyanide, suggests that benzaldehyde is an important factor in the almond/plum incompatibility.
Identification of Apple Cultivars by Isozyme Phenotypes
Authors: Weeden N.F. , Lamb R.C.
Published: August 2022

Fifty-four apple (Malus domestica Borkh.) cultivars were characterized electrophoretically using 6 isozyme systems. Intracultivar variation in isozyme phenotype was not observed, whereas intercultivar polymorphism was sufficient to permit reliable and unambiguous identification of nearly every cultivar. The most useful isozyme systems for distinguishing among the cultivars were 6-phosphogluconate dehydrogenase and aspartate aminotransferase. Sports could not be distinguished from the original cultivar. The genetic basic of several polymorphisms was known, enabling the comparison of the isozyme genotype observed in a hybrid with that predicted on the basis of parental genotypes. The 6-phosphogluconate dehydrogenase genotype of ‘Spartan’ indicated that ‘Yellow Newtown’ may not have been the paternal parent.
Predictions of Quality by Preharvest Fruit and Leaf Mineral Analyses in ‘Starkspur Golden Delicious’ Apple
Authors: Fallahi Esmaeil , Righetti Timothy L. , Richardson D.G.
Published: August 2022

Forward stepwise multiple regression equations were developed from seasonal leaf and fruit mineral analyses to predict quality parameters for ‘Starkspur Golden Delicious’ apple (Malus domestica Borkh.) during 1980–82. Quality parameters were evaluated both at harvest and after 6 months of 0°C storage. Soluble solids, skin ground color, and titratable acidity were strongly predictable as early as June or July. However, an August analysis was most predictive. For titratable acidity, a combination of both leaf and fruit minerals produced stronger predictions than leaf or fruit minerals alone in each individual year. Soluble solids, skin ground color, and bitterpit were more accurately predicted by fruit analyses. Fruit size was important in regression equations for firmness, but was not essential for other parameters. Although between-year predictions were not as good as within-year predictions, regression equations could successfully place fruit in high or low categories for most quality parameters.
Growth and Productivity of ‘Grand Rapids’ Lettuce in Diurnally Fluctuating Temperatures and Day/night Average Temperatures
Authors: Miller William B. , Langhans R.W.
Published: August 2022

The feasibility of utilizing different patterns of air temperature changes over the light and dark periods was investigated to provide a basis for greenhouse energy conservation. ‘Grand Rapids’ lettuce was grown hydroponically in microprocessor controlled growth chambers, under a light level of 325 µmol s-1m-2 PPF. Air temperatures were: a) increased from 15° to 35°C (late-peak), b) decreased from 35° to 15° (early-peak), and c) increased to 35°, then back to 25° (mid-peak) during the 16-hr light period. The late and mid-peak patterns had a gradual decrease in night air temperature, whereas the early peak pattern had a gradual increase in night air temperature. Each of these patterns averaged 25° during the light period, and 20° during the dark period. “Early-peak” plants grew poorly, whereas plants grown under the mid- and late-peak regimes grew well. Early morning diffusive resistance was similar for early- and mid-peak plants. Transpiration rates followed the air temperature changes.
Xylem Differentiation and Boron Accumulation in ‘Italian’ Prune Flower Buds
Authors: Hanson E.J. , Breen P.J.
Published: August 2022

Since B levels in prune (Prunus domestica L.) flowers may affect fruit set, the accumulation of B in buds was studied for 2 months prior to bloom to determine when B enters buds and the importance of the xylem as the supply route. Bud anatomy and the distribution of azosulfamide dye in excised prune twigs indicated that xylem in the axes of flower buds differentiated and became functional only when buds begin to swell, 5 weeks before bloom. Discontinuous xylem connections prior to bloom may impede B movement into dormant buds. In intact trees, B accumulated in buds slowly before bud swelling, but rapidly as buds accumulated dry matter from swelling until bloom. The concentration of B in xylem exudate was unchanged from 19 Jan. until bloom on 1 Apr., whereas marked increases in the concentrations of P, K, Ca, and S began 5 weeks before bloom. These changes suggest that the remobilization of B in the xylem of branches prior to bloom is more limited than that of other elements. Transpiration from buds was calculated from the rate of Ca accumulation in buds and Ca concentrations in xylem exudate, by assuming all Ca entered buds via the xylem. Using calculated daily transpiration rates and concentrations in xylem exudate, it was estimated that only 26% of the B entering buds was supplied by the xylem.
Expression of Mature Characteristics by Tissue Culture Plantlets Derived from Embryos of Loblolly Pine
Authors: McKeand Steven E.
Published: August 2022

In a field study comparing seedlings and tissue culture plantlets of loblolly pine (Pinus taeda L.) after two growing seasons, the plantlets had numerous growth and morphological characteristics of mature trees. The appearance of mature traits was surprising, since the plantlets originated from juvenile, embryonic tissues. Evidence from other studies with tissue culture propagation of pine species suggests that plantlets often express mature characteristics. Some of the characteristics of the loblolly pine plantlets, such as lower incidence of fusiform rust [Cronartium quercuum Berk. Miyabe ex Shirai f. sp. fusiforme (Cumm.) Burds. et Snow], fewer branches, and less taper, would be of great economic advantage if the growth rates remain similar to comparison seedlings.
Citrus Nematode Alters Carbohydrate Partitioning in the ‘Washington’ Navel Orange
Authors: Hamid Gamaleldin A. , Van Gundy Seymour D. , Lovatt Carol J.
Published: August 2022

Root infection by the citrus nematode (Tylenchulus semipenetrans Cobb) at population densities above the economic threshold caused altered patterns of root and shoot growth of 20-year-old ‘Washington’ Navel orange trees (Citrus sinensis L. Osbeck) budded on Troyer citrange rootstock (Poncirus trifoliata L. Raf. × C. sinensis), compared with control trees protected from nematode infection by oxamyl (1.1 kg/ha/3 weeks) and permitted to recover from prior nematode infection. Nematode-infected trees initiated new roots every 4–6 weeks, beginning as early as midMarch through as late as mid-January. Each root flush was equal to or greater in magnitude (number of new roots per gram roots) than those observed from oxamyl-treated trees. Oxamyl significantly reduced the population of female nematodes. Oxamyl-treated trees produced 4 relatively small root flushes, typical of healthy trees and exhibited a net increase in root biomass; nematode-infected trees failed to increase root biomass despite repeated root initiation. Oxamyl-treated trees also produced more new shoots and exhibited a greater increase in length per shoot and mean number of leaves per unit shoot length than untreated trees. Measurements of the levels of available glucose, sucrose, and starch provided evidence that nematode-infected trees were carbohydrate depleted. Starch levels were typically 70% higher in the canopy and 96% higher in the roots of oxamyl-treated trees compared to untreated. Root initiation appears to be the first response of the trees penetrated by citrus nematode larvae; repeated root initiation in response to the many generations of larvae that hatch each year is probably a key factor contributing to the depletion of carbohydrate in nematode-infected trees.
Relationship Between GA Application and Phyllomorph Length in Streptocarpus
Authors: Lyons R. E. , Veilleux R. E. , Booze-Daniels J. N.
Published: August 2022

Three cultivars and 3 selfed lines of Streptocarpus × hybridus Voss plants proved to be highly variable via cluster analysis. Yet 5 of the 6 populations examined showed a significant, negative, linear correlation between flowering and phyllomorph length at the time of treatment with 25 μg GA4+7. There was no treatment effect on peduncle length or the time span separating flowering of the first and 2nd, 2nd and 3rd, or first and 3rd inflorescences.
Effect of Chemicals and Photoperiod on the Growth and Flowering of Thanksgiving Cactus
Authors: Ho Yunn-Shy , Sanderson Kenneth C. , Williams J. C.
Published: August 2022

Schlumbergera truncata (Haw.) Moran ‘Christmas Charm’, ‘Lavender Doll’, and ‘White Christmas’ were grown under an 8 hr natural photoperiod or an 8 hr natural photoperiod plus 4 hr of incandescent light from 10:00 pm to 2:00 am and treated with single sprays of BA at 100 and 200 ppm, GA at 25, 50, and 100 ppm, BA at 100 and 200 ppm plus GA at 25 or 100 ppm, calcium carbide at 2910 ppm, ethephon at 100 and 1000 ppm, daminozide at 5000 ppm, ancymidol at 132 ppm, and chlormequat at 1000 ppm in 2 experiments. No flower buds were initiated from any plants grown under the 8 + 4 hr photoperiod. BA applied at 100 and 200 ppm increased the number of phylloclades on ‘Christmas Charm’ plants grown under the 8 + 4 hr. BA at 200 ppm applied to plants grown under the 8 hr photoperiod caused an increase in flower bud number and earlier flowering in all cultivars tested. BA + 100 or 200 ppm 100 ppm GA applied to plants grown under the 8 hr + 4 hr photoperiod stimulated the growth and elongation of phylloclades. Applied to plants grown under the 8 hr photoperiod, BA plus GA caused the growth and elongation of phylloclades, initiation of lower buds, and induced the development of lateral phylloclades and flower buds. Ancymidol at 132 ppm and 1000 ppm chlormequat sprays produced earlier flower bud initiation and increased flower number to flower bud ratios on ‘Christmas Charm’ plants. Chemical names used: N-(phenylmethyl)-H-purin-6-amine (BA); gibberellic acid (GA); (2-chloroethyl)phosphonic acid (ethephon); butanedioic acid mono(2,2-dimethylhydrazide) (daminozide); α-cycloproply-α-4-methoxyphenyl)-5-pyrimidinemethanol) (ancymidol).
Rootstock and Scion Effects on the Seasonal Distribution of Dry Weight and Carbohydrates in Young Apple Trees
Authors: Brown Christopher S. , Young Eric , Pharr David M.
Published: August 2022

Carbohydrates were measured in young apple (Malus domestica Borkh.) trees throughout the period of 28 Mar. 1983 to 16 Apr. 1984. Two rootstocks, M.9 (full dwarf) and MMIII (vigorous) and 2 scion cultivars, ‘Redchief and ‘Northern Spy’ were used in the 4 possible combinations. Trees were separated into 5 classes of vegetative tissue and analyzed for starch, sorbitol, and soluble sugars. Dry weights also were measured. Trees of MMIII had a greater dry weight in the above and below ground portions than trees on M.9. Carbohydrate contents followed a similar pattern. ‘Northern Spy’ scions had greater dry weight and carbohydrate content in the above ground portion than ‘Redchief. ‘Redchief had greater dry weight and carbohydrate content in the below ground portion than ‘Northern Spy’. Above ground starch content and below ground sorbitol and soluble sugar content did not follow this pattern.
Regulation of in Vitro Shoot and Root Regeneration in ‘Macspur’ Apple by Sorbitol (D-Glucitol) and Related Carbon Sources
Authors: Pua Eng-Chong , Chong Calvin
Published: August 2022

In vitro shoot proliferation and rooting of the apple scion cultivar ‘Macspur’ (mature culture) and of open-pollinated seedlings of ‘Macspur’ (seedling culture) were studied in response to the carbon sources, sorbitol, sucrose, glucose, and fructose, each supplied at 10, 30, 50, and 70 g/liter, or to the presence of varying proportions of sorbitol between 25% and 100% in conjunction with sucrose (30 g/liter total). Although the highest shoot number and shoot fresh weight of both cultures occurred with 30 g/liter sorbitol and sucrose, respectively, a medium with 25% sorbitol and 75% sucrose was best for shoot production. There was a decreasing trend in leaf/stem (fresh weight) ratio of shoots as the percentage of sorbitol increased in the medium. On rooting media supplied with 10–70 g/liter of each c source, rooting was best with 30 g/liter sucrose. In the mature culture (initially sucrose-grown), enhance shoot proliferation and rooting occurred on sorbitol medium after this source was subcultured 3 times on sorbitol medium.
Trickle Irrigation Requirements for Strawberries in Coastal California
Authors: McNiesh C. M. , Welch N. C. , Nelson R. D.
Published: August 2022

Controlled trickle irrigation applications in commercial strawberry [Fragaria xananassa Duch. ‘Heidi’] plantings in coastal California were used to estimate crop coefficients (Kc) relating applied water requirements to reference evapotranspiration (ETo) and Class A pan evaporation (Epan). The value of Kc increased with foliar growth during spring and leveled off at a relatively constant maximum through summer and early autumn. Since rates of ETo averaged 13% higher than Epan, lower Kc values were recommended for irrigation schedules based on ETo than for schedules based on Epan. The value of maximum Kc for ETo scheduling was fixed between 0.45 ≤ Kc ≤ 0.7, whereas the limits for Epan scheduling were 0.55 ≤ Kc ≤ 0.8. Upper Kc limits were established by scheduling small volume irrigations only as necessary to maintain favorable soil moisture conditions. Harvest results and soil matric potential measurements indicated that irrigations scheduled at the lower Kc limits could lead to production loss. An evaluation of grower irrigation practices showed that current applied water rates could be reduced significantly by scheduling irrigations with recommended Kc values.
Response of Seed of Seven Deciduous Fruits to Stratification Temperatures and Implications for Modeling
Authors: Seeley S. D. , Damavandy Hossein
Published: August 2022

Chilling-temperature response curves were obtained by testing seed germinability at 25°C after 0 to 2880 hr (120-hr intervals) of stratification at temperatures from −4° to 16°. The curves of the species tested were bellshaped with a definite skew to the cold side in some species. Some activity was detected at −2° and at 16°, the approximate limiting temperatures of the process. Dormancy was broken most rapidly at 4° in seeds of P. persica, P. communis (cold climate source), P. avium, P. mahaleb and M. domestica, whereas 6° was more effective in P. armeniaca, C. oblonga, and P. communis (warm climate source). The data were used to define a stratification degree hour and develop a stratification model for the seed of these species.
Response of Kentucky Bluegrass to Four Growth Retardants
Authors: Christians Nick E.
Published: August 2022

A turfgrass blend of ‘Parade’, ‘Adelphi’, ‘Glade’, and ‘Rugby’ Kentucky bluegrasses (Poa pratensis L.) was treated with N-[2,4-dimethyl-5-[[(trifluromethyl) sulfonyl] phenyl] acetamide (mefluidide) at 0.28 and 0.56 kg ha−1; (2-chloroethyl) phosphonic acid (ethephon) at 2.24, 4.48, and 6.72 kg ha−1; 5-(4-chlorophenyl)-3,4,5,9,10-pentaaza-tetracyclo [5,4,1,02,6,08,11]dodeca-3,9-diene (BAS 106 00 W) at 1.68, 3.36, and 5.04 kg ha−1, and α-(1-methylethyl)-α-[4-(trifluromethoxy) phenyl]-5-pyrimidinemethanol (EL-500) at 0.84, 1.21, and 1.40 kg ha−1 in field and greenhouse studies. Each of the materials investigated was effective in retarding Kentucky bluegrass growth in field studies. However, effects on growth inhibition and turfgrass quality varied between years. Ethephon was the only material not effective in reducing clipping yield in the greenhouse, whereas none of the growth retardants inhibited root organic matter production or rhizome weight in the greenhouse study.
Response of Ilex Cultivars to Media and pH on the Incidence of Black Root Rot Caused by Thielaviopsis basicola (Berk. & Br.) Ferraris
Authors: Merrill Lorie E. , Sanderson Kenneth C. , Williams John C. , Reed R. Bruce
Published: August 2022

An isolate of Thielaviopsis basicola (Berk. & Br.) Ferraris from Ilex crenata Thunb. was highly pathogenic to susceptible hollies while the isolate from Pelargonium × hortorum L.H. Bailey was less pathogenic. Various ratios of pine bark and sphagnum peatmoss did not suppress T. basicola on susceptible hollies. Of the cultivars tested, I. crenata ‘Helleri’ and I. pernyi Franch were most susceptible, while I. aquifolium L. × I. cornuta Lindl. and Paxt. ‘Nellie R. Stevens’, I. cornuta ‘Burfordii’ × I. peryni ‘Lydia Morris’, and I. cornuta ‘Burfordii Nana’ were the most resistant to T. basicola. I. crenata ‘Helleri’, grown in a medium with a pH of 5.0 or 6.0, had less black root rot development than similar plants in a medium with a pH of 6.5.
Inheritance of Resistance to Phytophthora Root Rot in Highbush Blueberry
Authors: Clark John R. , Moore J. N. , Draper A. D.
Published: August 2022

Young highbush blueberry seedlings (Vaccinium corymbosum L.) from 26 crosses of a partial diallel were inoculated with Phytophthora cinnamomi Rands by dipping the roots into a mycelial slurry. The seedlings were grown 90 days in sand in the greenhouse and rated for resistance to root rot damage. Of the 2412 inoculated seedlings, 214 (8.9%) were resistant. The 2 parental clones that produced the largest percentage of resistant seedlings were US 141 and G-164; within their progenies, each produced an average of 18% resistant seedlings. Mean squares for general (GCA) and specific combining ability (SCA) were significant at the 1% and 5% levels, respectively. The mean square estimate for GCA was about 5 times higher than that for SCA, While both additive and nonadditive effects are important, rapid improvement can be made by phenotypic selection. Resistance to P. cinnamomi in blueberry progenies studied appears to be partially recessive and quantitatively inherited. Inoculation of young seedlings by root dipping in a mycelial slurry of P. cinnamomi and growing the seedlings in sand provided rapid identification of resistant plants.
Predicting Harvesting Date of Processing Tomatoes by a Simulation Model
Authors: Wolf S. , Rudich J. , Marani A. , Rekah Y.
Published: August 2022

A computer program was developed for predicting the times of emergence, flowering, turning stage, and harvesting of processing tomatoes. The program was validated and calibrated by using 1972-1980 tomato data from 44 fields at 2 locations in Israel. Predictions are based on accumulation of heat units defined in terms of “physiological days”, where 1 physiological day is equivalent to a calendar day with a constant temperature of 26°C. The growing season was divided into 4 stages: from sowing to emergence, from emergence to flowering, from flowering to turning stage, and from turning stage to harvesting. Accumulation of physiological days during the first 2 stages is based on a linear function. During the last 2 stages, a quadratic function is used to calculate daytime heat units wherever the daily average temperature is above 20°. The maximum rate of development is at 26°. In the last stage, soil stress index also is taken into account. Use of the model makes it possible to predict the day of harvest with a precision of ±3 days, as compared with ±9 days when a daily mean systems is employed.
Role of Seed Mineral Content in the Occurrence of Transverse Cotyledon Cracking of Snap Bean
Authors: Eisinger Barbara A. , Bradford Kent J.
Published: August 2022

Seed calcium, magnesium, and potassium contents of 4 snap bean cultivars (Phaseolus vulgaris L. ‘Spartan Arrow’, ‘Astro’, ‘Avalanche’, and ‘Early Gallatin’) were studied in relation to degree of susceptibility to transverse cotyledon cracking (TVC). TVC index numbers ranged from a minimum of 13 (resistant) to a maximum of 111 (extremely susceptible). To determine whether seed Ca is related causally to TVC, seed Ca content was altered through foliar application of calcium polycarboxylate. Without supplemental Ca sprays, the seed Ca contents of the 4 cultivars varied from 17.3 to 24.7 μ eq/g. Calcium sprays increased seed Ca contents by up to 18%. In some instances, changes in the amounts of seed Ca were as great as the initial varietal differences in seed Ca content. The TVC indices of the cultivars remained unchanged, however, and multiple regression analyses indicated that seed Ca content was not significantly correlated with TVC (R2 = 0.014). In addition, no significant correlations were found between TVC and seed K contents or Ca to Mg ratios. On the other hand, a significant negative correlation occurred between seed Mg contents and degree of TVC (R2 = 0.298). This correlation, however, depended largely upon varietal differences in seed Mg content and may not represent a causal relationship with TVC. Varietal characteristics other than seed mineral content apparently account for differences in susceptibility to TVC.
Factors Influencing Premature Cyathia Abscission in Poinsettia ‘Annette Hegg Dark Red’
Authors: Miller Steven H. , Heins R. D.
Published: August 2022

Low irradiance levels, high temperatures, and water stress all promoted premature cyathia abscission in poinsettia ‘Annette Hegg Dark Red’ (Euphorbia pulcherrima Willd.). Abscission was greater in plants placed under 75% shade at 16°C night temperature (NT) than on plants placed under normal daylight (ND) at 16° or 21° NT. Water stress (0.6 MPa) promoted abscission on plants grown at an 18° NT and ND but did not promote abscission on plants grown at 16° NT and ND or on under 75% shade (13° to 21° NT). As plant density increased, transmission of photosynthetically active radiation (PAR) through the bracts to the leaf canopy decreased while cyathia abscission increased concomitantly. More than 90% of the PAR above the bracts was absorbed or reflected 5 cm below the bracts on 20 cm tall plants spaced at 65 or more plants m-2. Reducing natural irradiation 75% by shading leaves of poinsettia promoted cyathia abscission, whereas removing immature bracts decreased abscission. Leaf removal on plants with intact bracts promoted abscission to a degree that 100% of the cyathia abscised prior to anthesis, whereas bract removal on plants with intact leaves resulted in only 23% abscission of the cyathia 25 days after first anthesis. Measurements of nonsoluble carbohydrate showed a significant increase in leaf carbohydrate on plants with bracts removed while carbohydrate decreased in leaves of plants with bracts intact. Carbohydrate depletion appears to be the primary factor responsible for premature cyathia abscission in poinsettia.
Ethylene and Temperature Effects on Softening and White Core Inclusions of Kiwifruit Stored in Air or Controlled Atmospheres
Authors: Arpaia M. L. , Mitchell F. G. , Kader A. A. , Mayer G.
Published: August 2022

The effects of C2H4 concentration, duration and timing of exposure to C2H4, and temperature on storage performance of kiwifruit (Actinidia chinensis Planch. ‘Hayward’) kept in air or a controlled atmosphere (CA) of 2% O2 + 5% CO2 were investigated. The presence of 0.05, 0.1, 0.5, 1.0, or 5.0 μl·liter−1 C2H4 in CA accelerated softening and induced white core inclusions (WCI) which increased with storage time and C2H4 concentration. There was no difference between a 2-week or a 4-week exposure to 0.5 μl·liter−1 C2H4 at the beginning of CA storage in the extent of softening or WCI incidence and severity, but prolonged exposures accelerated deterioration. The softening rate of kiwifruit kept in air or CA increased with temperature. The incidence and severity of WCI were much greater in fruit kept in CA + 0.5 μl·liter−1 C2H4 at 0° or 2.5°C than in fruit stored at 5° or 10°.
Effect of Light Intensity and Carbohydrate Reserves on Flowering in Olive
Authors: Stutte G. W. , Martin G. C.
Published: August 2022

Experiments were designed to alter the carbohydrate status of olive (Olea europaea L.) leaves during the presumed flower induction period. Bearing and nonbearing ‘Oblonga’ olive trees were exposed to either 850 μmol s-1n-2 PAR for 14 hr daily in a 1000 ppm CO2-enriched atmosphere, 150 μmol s-1m-2 PAR for 14 hr daily in 340 ppm CO2, or maintained in a lathhouse at ambient winter conditions of about 350 μmol s-1m-2 PAR and daily temperature fluctuations from 5° to 20°C. The trees exposed to 850 μmol s-1m-2 had 3 to 5 times the starch concentrations of either the 150 μmol s-1m-2 PAR or lathhouse treatments. There were few and inconsistent differences in sucrose, fructose or mannitol concentrations between treatments. The high levels of starch in the 850 μmol s-1m-2 PAR treatment had no effect on the flowering pattern of bearing or nonbearing trees. Gross levels of carbohydrates do not appear to limit flower induction of olive.
Effect of a Hydrophilic Polymer Seed Coating on the Field Performance of Sweet Corn and Cowpea
Authors: Baxter Lawford , Waters Luther
Published: August 2022

Four levels (1.1, 2.3, 4.6, and 9.1 g/kg seed) of the hydrophilic polymer Waterlock B100 were used as seed coatings to enhance stand establishment and plant growth of sweet corn (Zea mays) and cowpea (Vigna Unguiculata) during the spring and summer of 1983 on 2 soil types in Minnesota. The level with the best overall response in 1983 was used in 1984 to observe the response of 4 sweet corn hybrids. The 2.3 and 4.6 g treatment were most beneficial in enhancing stand establishment in sweet corn. At all levels, however, Waterlock B100 had a deleterious effect on cowpea germination and seedling development. One sweet corn hybrid showed a significant positive response to the coating during 1984. This reponse was attributed to a uniform pericarp which allowed an even seed coating.
Harvest Maturity and Acceptability of Flora-Dade Tomatoes
Authors: Kavanagh E. E. , McGlasson W. B. , McBride R. L.
Published: August 2022

Composition and sensory acceptability of fresh market tomatoes (Lycopersicon esculentum Mill ‘Flora-Dade’) were investigated to determine the influence of harvest maturity on quality after fruit had ripened to a tableripe stage. Tomatoes were harvested from commercial plots at ‘immature green’, ‘mature green’, ‘breaker’, ‘light pink’, and ‘light red’. The differentiation between tomatoes harvested ‘mature green’ and ‘immature green’ was aided by application of 40 μl/liter of ethylene in a ripening room at 20°C. Tomatoes harvested at ‘breaker’ were more acceptable when ripe than all other maturities at harvest. Tomatoes harvested at ‘immature green’, ‘mature green’, ‘light pink’, and ‘light red’ were of similar sensory acceptability. The tomatoes harvested at ‘light pink’ and ‘light red’ when ripe were similar or lower in total soluble solids and generally lower in locular content compared to other harvest maturities. There was a high correlation between sensory scores for color and measured external and internal color.
Prediction of Bulk Density of Pine Bark and/or Sand Potting Media from Laboratory Analyses of Individual Components
Authors: Pokorny F. A. , Gibson P. G. , Dunavent M. G.
Published: August 2022

An equation for predicting bulk density (BD) of pine bark and sand potting media was devised using BD data from laboratory analysis of individual components. BD values calculated from the predictive equation and actual values obtained from potting medium samples were compared. Actual and predicted BD increased linearly with each incremental increase in percentage sand in the medium. Actual and predicted BD values were not significantly different. The devised equation is applicable to media other than bark and sand.
Morphological Differences in Neoregelia Trichomes and Uptake of Foliar-applied Copper
Authors: Fisher B. D. , Emino E. R. , Gogue G. J.
Published: August 2022

Four bromeliad species in the genus Neoregelia were studied by scanning electron microscopy (SEM) for morphological characteristics and density of trichomes that may influence absorptive capacities. Neoregelia trichomes were classically peltate, generally elliptic, exhibiting a web-like cap characteristic of the Bromelioideae. Minor variations were evident between species in morphology, density, and distribution. Copper from copper sulfate applied to leaf surfaces was absorbed and translocated as determined by atomic absorption spectrometry, but uptake was not related to trichome density as determined by SEM nondispersice technique.
Relationship between Rhizome Temperatures and Shoot Temperatures for Floral Initiation and Cut Flower Production of Alstroemeria ‘Regina’
Authors: Healy W. E. , Wilkins H. F.
Published: August 2022

When Alstroemeria ‘Regina’ shoots were grown in a continuous 13°C air temperature, and the underground structures (rhizomes and roots) were placed in a 5°, 10°, 15°, 20°, or 25° water bath, plants produced 22%, 33%, 13%, 14%, or 5% generative shoots, respectively (Expt. 1). When the underground structures were grown at 13°, there were no differences in percentages of generative shoots, regardless if shoots were in a 13° or 21° air temperature, and regardless if shoots were under short or long photoperiods. When soil temperature was 21° and air temperature was 13°, 12% generative shoots were produced only with a night interruption photoperiod (Expt. 2). Data from these 2 experiments led us to conclude that floral induction was controlled primarily by temperatures to which the underground structures were subjected, regardless of the air temperature or photoperiod. Storage root and rhizome dry weights were promoted by 13° air, 13° soil temperatures and night interruptions with incandescent light. Treatments which had a high percentage of generative shoots also had high root and rhizome dry weights.
An Evaluation of Germination Media for Turfgrass Salinity Studies
Authors: Dudeck A.E. , Peacock C.H. , Sheehan T.J.
Published: August 2022

A technique using salinized agar as a germination medium in sealed, plastic petri dishes is described. Agar concentrations of 0.5%, 1%, 2%, and 3% solidified with up to 35,000 mg·liter−1 of total salts derived from a formula for full-strength seawater. Water loss from petri dishes sealed with a plastic film after 28 days averaged 1.7% and was negligible. Saline-agar media held more moisture initially and lost less water than standard, double germination blotters after 7 days. Germination of perennial ryegrass (Lolium perenne L. ‘Derby’) on unsalinized agar was not different from germination on unsalinized blotters. Total germination of ‘Derby’ perennial ryegrass averaged 94% and was unaffected by salt concentrations up to 5000 mg·liter−1 but germination rate (days to 50% germination) was progressively delayed from 3.98 ± 0.09 days for the controls having no salinity to 5.15 ± 0.33 days at 5000 mg∙liter−1 of salinity.
Influence of Raised Beds and Plant Spacing on Growth and Yield of Strawberry
Authors: Goulart Barbara L. , Funt Richard C.
Published: August 2022

Strawberry, Fragaria × ananassa Duchesne ‘Redchief’, plants were grown in single plant-width rows on raised and flat beds at spacings of 13 cm, 50 cm, and 50 cm with runners set at 13 cm. Raised beds had more negative soil water potentials and more variable soil temperatures than flat beds. Plants on raised beds had deeper root distribution, poor runner-plant establishment, higher photosynthetically active radiation (PAR) penetration at one half canopy height in May, and earlier yield than those on flat beds. On raised beds, earliness of yield was enhanced by close spacing, and plants at the 13-cm spacing had more crowns per unit area than wide spacings. Total yield per unit area was not influenced by any treatment.
Influence of pH and Medium Composition on Rooting of Hardy Deciduous Azalea Microcutting
Authors: Economou Athanasios S. , Read Paul E.
Published: August 2022

Sphagnum peat (peat) media (adjusted to pH 4.0, 4.6, 5.5, 6.6, and 7.4 with ground dolomitic limestone) and unadulterated peat (pH 3.6) were tested for their effectiveness on rooting of hardy deciduous azalea (Rhododendron sp.) microcuttings in high-humidity chambers. Rooting of more than 90% occurred in media with pH 4.0, 4.6, and 5.5; however, a) shoot height and quality rating and b) root length and quality rating were superior at pH 4.0. Clonal differences in rooting percentages were found for 3 clones of azalea microcuttings rooted in 5 soilless mixtures. A mixture including equal parts (v/v) of peat and either sphagnum, vermiculite, or perlite, or a combination of 2 peat : 1 vermiculite : 1 perlite (by volume) increased rooting percentages over peat alone for all 3 azalea clones examined.
Carrot Response to Sludge Application and Bed Type
Authors: Harrison Helen C.
Published: August 2022

A 2-year carrot (Daucus carota L.) nutrition experiment involving 3 sludge treatments, 3 bed types, and 3 advanced hybrid carrot selections was conducted on a silt loam in Arlington, Wis., to determine the influence of these variables on growth and elemental concentration levels in edible, mature carrot roots. Sludge treatments included a 90 MT/ha/year application of municipal or industrial sludge plus a control with no sludge application. When significant differences occurred, highest yields and elemental concentration levels in edible roots occurred with hybrids grown in municipal sludge-amended soils. Root Cd levels in 1982 were the only exception, being greatest in plants grown on industrial sludge-amended soils. Lowest yields and highest heavy metal concentrations in the edible root were found in carrots grown on overcover beds (15-cm raised bed of unamended topsoil over prepared level or flat bed) as compared to those grown on 15-cm raised beds or level beds. Hybrid carrot selection (B6373 × B6345) × B6274 (B) accumulated less heavy metals in its edible root tissue than did B4367 × B6274 (A) or (B34602 × B3316) × F524 (C).