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Abstract
Ohio is a major horticultural state with well-educated growers willing to adopt new technologies. Because of geographic location, climate, soils, and population density, Ohio has wide diversity of horticultural industries. It ranks first in the U.S. in greenhouse vegetable production, third in floral crop production, second in the production of processing tomatoes, third in the production of cucumbers for pickles, eighth in apple production, third in nursery crop production, and fifth in food processing. Ohio ranks sixth in population in the U.S. with 57% of the total U.S. expenditures for food made within a 600-mile radius of Columbus. Because of Ohio’s high population density, many of the horticultural industries have capitalized upon their nearness to market. The development of garden centers, as well as retail fruit and vegetable markets with a recreational atmosphere, have become commonplace.
Abstract
Inheritance of the ability of tomato (Lycopersicon esculentum Mill.) to sprout at 10°C was evaluated in a diallel study involving 7 inbred parents. For each parental and F1 progeny family, sprouting indices were used to estimate genetic and environmental components of variation. Significant additive gene effects with partial dominance for inability to sprout at low temperature were found. Epistatic gene effects were not important, but a significant maternal effect was found. The estimate of narrow sense heritability was 69% and that for broad sense heritability was 85%.
Take-all patch, caused by Gaeumannomyces graminis (Sacc.) Arx. & D. Olivier var. avenae (E.M. Turner) Dennis (Gga), is a disease of creeping bentgrass (Agrostis stolonifera Huds.), which most often is associated with golf courses. Synthesis of ligneous and phenolic compounds by plants requires adequate Mn+2 and Cu+2 nutrition and may be a factor in disease resistance. An experiment was conducted on a creeping bentgrass fairway naturally infested with Gga to determine if foliar applications of Mn+2 (1.02 and 2.04 kg·ha–1 per application) and Cu+2 (0.68 kg·ha–1 per application) would reduce take-all severity. Prior to initiating treatments, soil pH was 6.4 and Mehlich-3 extractable Mn+2 and Cu+2 were 5 mg·kg–1 and 1.7 mg·kg–1, respectively. Manganese and copper sulfate treatments were initiated in July 1995 and foliarly applied every 4 weeks through 1997 with the exception of December, January, and February. Disease incidence was decreased from 20% on untreated turf to 5% with the high rate of MnSO4. For both years, turf treated with the high rate of Mn+2 had less disease than turf receiving the low rate of Mn+2. The application of CuSO4, however, did not influence disease development.
Abstract
The inheritance of peroxyacetyl nitrate (PAN) resistance in Petunia hybrida Vilm. was studied using the inbred parents of ‘White Cascade’, a susceptible F1 hybrid, and ‘Coral Magic’, a resistant hybrid. In each of 6 experiments, 4-week-old plants of the parents, their reciprocal F1 hybrids, the F2 generation, and reciprocal backcross generations were simultaneously tested for PAN resistance. Plants were exposed to 742 μg/m3 (0.15 ppm) PAN for 1.5 hours in a controlled environment chamber. The percent area of bifacial necrosis was determined for each leaf on a plant and an average was calculated to yield an injury rating. Significant genetic variation was detected in each experiment, but the best fitting genetic model varied among experiments, indicating large genotype by environment interaction. In the experiment with the most severe PAN injury, genes for susceptibility exhibited almost complete dominance to those for resistance and epistatic effects were not significant. In other experiments with lower levels of PAN injury, resistance was partially dominant to susceptibility and one or more epistatic parameters were significant.
Abstract
‘Hull Thornless’ (Rubus sp., is a vigorous and productive thornless blackberry cultivar with firm, sweet, fruit. It is named for the late John W. (Jack) Hull, formerly of the University of Maryland, the University of Arkansas, and the U.S. Department of Agriculture, who spent most of his life breeding blackberries and raspberries. ‘Hull Thornless’ is the fifth in a series of tetraploid, genetically thornless blackberry hybrids developed by the USDA and cooperating agencies (4). It is adapted principally to USDA Plant Hardiness Zones 6-8.