Foliar Sensitivity of Soybeans from Early Maturity Groups to Ozone and Inheritance of Injury Response. J. P. Damicone, Department of Plant Pathology, University of Massachusetts, Amherst 01003. W. J. Manning, S. J. Herbert, and W. A. Feder. Department of Plant Pathology, and Department of Plant and Soil Sciences, University of Massachusetts, Amherst 01003, and Suburban Experiment Station, University of Massachusetts, Waltham 02154. Plant Dis. 71:332-336. Accepted for publication 10 November 1986. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-0332.

Soybean genotypes of maturity groups 00, 0, and I were evaluated in 1982 and 1983 for foliar sensitivity to ambient ozone (O₃). PI 153.283 and PI 153.284 were sensitive to O₃, showing 25–50% foliar stippling and premature defoliation. Nineteen of the 35 genotypes evaluated for 2 yr were tolerant to O₃, showing little or no visible injury. PI 189.907 and PI 153.317 showed no visible injury in the field both years despite frequent O₃ episodes in 1983. Crosses were made between two O₃-tolerant (PI 189.907 and PI 153.317) and one O₃-sensitive (PI 153.283) genotype. Parental, F₁, F₂, and backcross populations were exposed to 0.30 ppm O₃ for 4 hr in a greenhouse fumigation chamber. Injury response distributions were not significantly different within O₃-tolerant parents, reciprocal F₁ populations, and F₂ populations. F₁ plants were intermediate in injury response compared with the parents. Injury response distribution in the F₂ was nonnormal and exhibited three peaks. Foliar sensitivity to O₃ appears to be qualitatively inherited in these genotypes, and a possible genetic model is discussed.