Evaluation of dry beans for resistance to ashy stem blight

Abstract

Experiments were conducted to determine the effectiveness of two inoculation methods in the field evaluation of beans for resistance to ashy stem blight. Seed inoculation resulted in lower germination and greater infection by Macrophomina phaseolina than that in nontreated plots. Stem inoculation did not significantly differ from the control in percentage disease. Least significant differences among genotypes were smaller toward the end of the growing season. Therefore, bean genotypes should be evaluated for ashy stem blight infection near senescence. Spearman rank correlations between percentage germination and percentage infection near senescence were significant in 2 years. Seed inoculation combined with germination tests may be useful in the preliminary screening of bean genotypes for resistance to ashy stem blight.