Search Results
Abstract
Young onion plants were grown in glass tubes under short daylength non-inductive for bulbing. Ethrel was added to the growth medium and caused swelling of leaf-bases, bulb initiation and a pronounced increase in the bulbing index. Swelling of leaf-bases was also observed in Ethrel treated plants of leek. In a replicated field experiment seedlings of 5 cultivars were sprayed once or several times with Ethrel at rates of 500, 1,000, 5,000 and 10,000 ppm. Except for one very early cultivar, which showed bulbing due to natural daylength, the treatments resulted in early bulb initiation and in a greatly increased rate of bulbing. Rates of 5,000 and 10,000 ppm Ethrel were more effective than lower concentrations but they also caused retarded leaf growth and a decrease in the final size of bulbs. The possible role of ethylene in bulbing of onion is discussed.
Abstract
Effects of growth regulators on parthenocarpic fruit development in muskmelon (Cucumis melo L.) were tested under field conditions. Parachlorophenoxyacetic acid (4-CPA) β-naphtoxyacetic acid (β-NOA), gibberellin (GA4+7), and 2-chloro-9-hydroxyfluorene-9-carboxylic acid (chlorflurenol) caused parthenocarpy, when applied directly to flowers at anthesis. Seed coat developed in all parthenocarpic fruits. A positive correlation (r = 0.80) was found between number of seeds, seed coats, and fruit weight. Fruit set was induced under field conditions without bees, by a single spray of 4-CPA or β-NOA or chlorflurenol applied to the entire plant.
Abstract
The interaction of the gibberellins GA3 and GA4+7 with SADH on growth and sex expression was tested on andromonoecious muskmelon (Cucumis melo L. cv. Ananas PMR). SADH effectively reduced internode length and increased female tendency of plants. GA4+7 had an opposite effect on both growth and sex expression. GA3 was much less effective in both respects. The growth regulators were mutually antagonistic when plants were treated with both GA and SADH. The endogenous level of gibberellin decreased in SADH-treated plants 2 and 7 days after treatment. Gibberellin content reached the level of untreated plants 2 weeks after treatment, some time before the growth retarding effect of SADH treatment disappeared. These results indicate that the effect of its effect on the endogenous levels of gibberellin.
Abstract
Mother bulbs of onion (Allium cepa cv. Grano) were treated with gibberellic acid (GA3) at 0, 50, 150 and 450 ppm upon emergence of first flower stems. A single application at 50 ppm shortened by one-half the time required for emergence of 80% of floral stems and increased the uniformity in height of the flower stalks. GA3-treated plants produced larger and more productive umbels, resulting in an increase in seed yield by about 30%. There was no difference in seed viability between treatments.
Abstract
(2chloroethyl)phosphonic acid (ethephon) induced bulbing of short-day, intermediate and long-day onion cultivars under noninductive short-day conditions. Seedlings with roots and sheaths constantly immersed in ethephon solution as low as 1.5 ppm initiated bulbing after 7 days. Application of ethephon as leaf spray, as soil drench, or by injection into the root growing zone, caused bulbing at minimum concentrations of 1200, 480 and 600 ppm, respectively. The number of leaves per plant was reduced in all treatments that caused bulbing, but the reduction was not significant in the soil drench 480 ppm treatment. Injection of ethephon solutions of 37.5 or 75 ppm to the root growing zone appeared to promote leaf emergence and did not initiate bulbing.
Abstract
Foliar sprays of (2-chloroethyl)phosphonic acid (ethephon) retarded the height of onion (Allium cepa L.) and when applied to nonbolting plants partially prevented seedstalk emergence and reduced seed yield of early developing inflorescences. Two field applications of 480 ppm ethephon, starting when 75% of the plants had visible seedstalks, reduced seedstalk height. This treatment had no adverse effect on seed yield or germination and may have promise as a means of preventing lodging of seedstalks and of increasing the efficiency of mechanical seed harvest.
Abstract
The abstract for the paper, “Effect of the Fruit-ripening Mutant Genes rin and nor on the Flavor of Tomato Fruit” by E. Kopeliovitch, Y. Mizrahi, H. D. Rabinowitch, and N. Kedar [J. Amer. Soc. Hort. Sci. 107(3):361–364. 1982.], contains several errors. The correct version of the abstract is as follows: Organoleptic tests of the nonripening tomato mutants rin and nor and their F1 hybrids with the normal-fruit-bearing cultivar ‘Rutgers’ indicated that fruits of the rin heterozygous plants (rin/+) were slightly inferior and that those of heterozygote nor (nor/+) were distinctly inferior in flavor to fruits of the normal genotype (+/+), all sampled 3–5 days after ethylene and CO2 evolution rates attained maximum levels. The flavor of fruits of the double heterozygotes rin/+, nor/+ was poorer than either of the 2 single-gene heterozygotes, while fruits of both homozygous plants, nor/nor and rin/rin, were unpalatable. Analyses of pH, titratable acidity, total soluble solids, and reducing sugars did not indicate that any of these parameters are responsible for the inferior flavor of the genotypes containing the nonripening genes. Comparisons of reciprocal crosses provided no evidence of cytoplasmic inheritance of fruit flavor.
Abstract
Organoleptic tests of the non-ripening tomato mutants rin and nor and their F1 hybrids with the normal-fruit-bearing cultivar ‘Rutgers’ indicated that fruits of the rin heterozygous plants (rin/+) were slightly inferior and that those of inferior in flavor to fruits of the normal genotype (+/+), all sampled 3–5 days after ethylene and CO2 evolution rates attained maximum levels. The flavor of fruits of the double heterozygote nor heterozygotes (nor/+) were distinctly rin/+, nor/+ was poorer than either of the 2 single-gene heterozygotes, while fruits of both homozygous plants, nor/nor and rin/rin, were unpalatable. Analyses of pH, titratable acidity, total soluble solids, and reducing sugars did not indicate that any of these parameters is responsible for the inferior flavor of the genotypes containing the non-ripening genes. Comparisons of reciprocal crosses provided no evidence of cytoplasmic inheritance of fruit flavor.
Abstract
The effect of growth regulators indoleacetic acid (IAA), parachlorophenoxy-acetic acid (4-CPA), β-napthoxyacetic acid (β-NOA), gibberellin (GA3 and GA4+7) and benzyladenine (BA) applied directly to flowers at anthesis, caused parthenocarpy in cucumbers (Cucumis sativus L.), while (2 chloroethyl)phosphonic acid (ethephon) and abscisic acid (ABA) were ineffective. Only synthetic auxins and BA effectively induced parthenocarpy in treated whole plants. 4-CPA was the most effective treatment for induction of parthenocarpic fruits, as determined by number and shape. Application of GA to the entire plant caused increase in vegetative growth, but fruit development was inhibited even under conditions of natural pollination.
A half diallel including 11 parents was conducted under high temp. conditions in Florida and low temp. conditions in Israel. Blossom scar (BS) size was measured relative to the fruit size for 20 mature fruits per plot. Griffing's analysis showed that both GCA and SCA effects were highly significant at both locations (p< 0.0001). Analysis according to Hayman indicated no epistatic effects. In both environments, additive and dominant gene action was significant (p < 0.0005), although the additive gene effects were most important. Averaged over all loci, the incomplete dominance was in the direction of small BS. Narrow sense heritability estimates were 0.62 and 0.57 for Florida and Israel, respectively. Combined analysis showed that the genetic system was unstable over the 2 environments, as both additive and dominant gene effects interacted significantly with environment (p < 0.0001). The implication for breeding programs is that hybrid performance should be tested at several locations to insure stability of small BS.