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  • Author or Editor: Carl D. Clayberg x
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Abstract

A periclinal chimera was produced with an epidermis of Solatium pennellii Correll and a core of tomato (Lycopersicon esculentum Mill.). The tomato strain was susceptible, and S. pennellii highly resistant, to both greenhouse whitefly, Trialeurodes vaporariorum (Westwood), and potato aphid, Macrosiphum euphorbiae (Thomas). The chimera was highly resistant to whitefly and susceptible to potato aphid.

Open Access

Abstract

Among more than 1200 tomato lines of a world-wide collection, 4 of Lycopersicon esculentum Mill, were found to be resistant to ozone: PI 109835, PI 237136, PI 285663, and PI 303792. When these were tested against a sample of American cultivars, 2 additional resistant cultivars were found: ‘Heinz 1439’ and ‘New Yorker’.

Open Access

Abstract

Four cultivars of Phaseolus vulgaris L. were studied in a growth chamber experiment to determine the effect of high temperature stress on pollen viability and pollen tube growth in styles. Compared with an optimal growing temperature (25/20°C, day/night), stress temperatures (35/20°, day/night or 35° constant) reduced the percentage of viable pollen for all cultivars, but cultivar differences were apparent. Beans generally produced only small quantities of pollen under normal growing temperatures but much more under high temperatures, again with cultivar differences. Finally, stress temperatures did not reduce the ability of pollen tubes to grow to the base of the style. Our results suggest that injury to pollen at high temperatures up to 35° is not likely to hinder the ability of beans to set pods.

Open Access

Abstract

Two laboratory techniques for estimating genotypic differences in response to heat stress—the electrical conductivity and the 2,3,5-triphenyl tetrazolium chloride reduction tests—were compared in tests with 26 cultivars of beans (Phaseolus vulgaris L.) previously evaluated for heat tolerance. After heat acclimation of plants, leaf disks were subjected to heat stress over a range of temperatures. The temperature causing 50% injury above the control, considered as the killing temperature, was estimated by fitting the data to a sigmoidal model. Although cultivar killing temperatures were correlated between tests, only killing temperatures for the conductivity test were correlated with yield performance under stress in the field.

Open Access

Abstract

Cleome hasslerana Chod., a cross-pollinated species, has 5 corolla colors: violet, lilac, red, pink, and white. F1 and F2 progenies produced from crosses among the cultivars Helen Campbell Snow Crown, Cherry Queen, Pink Queen, and Violet Queen indicate that 3 loci with 2 alleles per locus control flower color. The allele W, for colored corolla, is dominant to w, for white corolla; R, for violet color, is dominant to r for red; and I, for dilute flower color, is dominant to i, determining intense flower color.

Open Access