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- Author or Editor: L. L. Dean x
- Journal of the American Society for Horticultural Science x
Abstract
Evaluations of cooked fresh beans showed that the persistent-green color (PC) cv., Custer, was darker, greener, and less yellow than the normal-green cv., Canyon. Persistent-green color lines Xlda 71-2081 and Xlda 267-4 were intermediate between the 2. Chlorophyll concentrations were higher in all PC lines than in the normal-green cultivar but the ratio of chlorophyll a/b was lower. Chlorophyll content was significantly correlated with Gardner color values and with visual color scores. No color values correlated with pheophytin or carotene content.
Xlda 71-2081 had the highest work-to-shear values, % seed, % fiber, and highest panel scores for fibrousness. Whether the higher values were attributable to genetic controls or to a difference in maturity was not determined in this study. Little sloughing was observed. All cultivars had a slightly to moderately full, natural flavor. The PC beans were equal or superior to the normal-green cultivar in all measured quality characteristics with ‘Custer’ showing the most promise.
Abstract
Chlorophyll concns decreased rapidly as pods matured from the 1-day-old fruit stage. Total chlorophyll a + b per pod was influenced by pod length as well as pigment concn. Apparent chlorophyll synthesis occurred in field-grown green snap bean fruits up to 11-mm diam pods (sieve size 5 or 6), but a net decrease occurred with further maturation. Dry-mature persistent-green pods contained 300 ppm chlorophyll on a dry matter basis, whereas normal-green pods had none. Lack of consistent agreement between visual and chemical methods to rank cultivars for pod color suggested differences in chlorophyll distribution in external versus internal tissue.
Abstract
‘Jubilee’ sweet corn (Zea mays L.) was grown under conventional and strip tillage in 1982 and under conventional tillage, strip tillage, and no-till culture in 1983. Stand establishment was decreased by strip tillage in 1982, but was lower only in the no-till treatment in 1983. Midseason plant height in strip tillage was slightly less than in conventional tillage both years, whereas the no-till plants were much shorter than in other treatments the second year. Yields of husked ears from strip tillage were 7% and 16% lower than from conventional tillage in 1982 and 1983, respectively. In 1983, yield from the no-till treatment was 31% lower than from conventional tillage. The percentage of kernel moisture always was higher from plants in strip tillage and no-till, indicating these treatments had ears that were more immature at time of harvest than in conventional tillage. Average daily soil temperatures at the 5 cm depth for the first 30 days after planting in 1983 were highest for conventional tillage, followed by strip tillage and no-till.
Abstract
The environment created by ventilating a greenhouse with mine-air was suitable for the production of high quality spray chrysanthemums (Chrysanthemum morifolium Ramat.) and snapdragons (Antirrhinum majus L.) from mid-February through November without any additional energy requirement. The environment created in the greenhouse from December to February was extremely humid and favored botrytis development and physiological problems which reduced crop quality.
The effect of ethylene on tuber sprout growth and quality in potato (Solanum tuberosum L. `Russet Burbank') was tested in laboratory and commercial studies for 6 and 3 years, respectively, in comparison with untreated (laboratory study) and CIPC-treated tubers (laboratory and commercial studies). In both studies, ethylene was applied continuously at 166 μmol·m-3 for at least 25 weeks, beginning in early December (laboratory study) or early December to early January (commercial study). In the laboratory study, ethylene delayed the appearance of sprouts for 5 to 15 weeks, compared with untreated tubers. In the ethylene-treated tubers in both studies, sprouts appeared on many eyes but most of them remained very small (<5 mm long). Longer sprouts (>5 mm) appeared after 15 weeks but did not exceed 12 and 59 mm in the laboratory and commercial studies, respectively. Sprouts on ethylene-treated tubers were more easily detached up to 6 weeks after ethylene treatment ended, compared with untreated tubers. In both studies, ethylene treatment was not associated with decay, disorder or internal sprouting problems. In both studies, the Agtron fry color [or U.S. Dept. of Agriculture (USDA) color grade] of ethylene-treated tubers was darker than CIPC-treated tubers at almost all sampling times. Continuous exposure to ethylene was an effective sprout control agent but it produced a darker fry color, compared with CIPC-treated potatoes.
Gibberellins (GAs) are phytohormones that regulate plant height and flowering time in plants. Plants with reduced GA or disrupted in GA signaling exhibit a dwarf phenotype. DELLA proteins are transcriptional repressors that attenuate GA-mediated promotion of plant growth. Alleles in which the eponymous DELLA motif in these proteins is disrupted result in constitutive repression of GA signaling and a dominantly inherited dwarf phenotype. We found that the dwarf Helianthus annuus (sunflower) cultivar Sunspot is hyposensitive to GA3 as compared with the tall cultivar Mammoth Grey. Sequencing of the HaDella1 gene indicates that ‘Sunspot’ has a single nucleotide polymorphism resulting in a missense mutation in the DELLA motif as compared with ‘Mammoth Grey’ and the reference sequence. Helianthus annuus has five genes encoding DELLA proteins, including HaDella1. We propose that the DELLA motif alteration in the HaDella1 gene results in a dominant mutation in ‘Sunspot’ and is the cause of its dwarf phenotype.