Reaction of Dry Bean Genotypes to Natural Infection of Foliar Diseases in the Dominican Republic

Abstract

Seventeen dry bean genotypes were tested in 18 field trials on small farms and experiment stations in the Dominican Republic in the 1981-1982 growing season, and 20 bean genotypes were tested in 10 trials in the 1982-1983 growing season to measure the reaction of promising dry bean genotypes and standard cultivars from the Dominican Republic to natural infection of foliar diseases, and to determine the frequency and intensity of foliar diseases when dry beans are generally grown in the Dominican Republic. Bacterial blight [Xanthomonas campestris pr. phaseoli (Smith) Dye] was the most serious disease during the September plantings. Rust [Uromyces phaseoli (Reben) Wint.] was the most prevalent disease when beans were planted in January, which is a drier month. There was little difference among the dry bean genotypes in reaction to bacterial blight. All of the genotypes developed at least a moderate level of infection of bacterial blight following the September plantings. However, several genotypes expressed high levels of resistance to rust. Among the standard red mottled cultivars, Pompadour developed the lowest level of rust infection. Angular leaf spot (lsariopsis griseola Sacc.) and chaetoseptoria leaf spot (Chaetoseptoria wellmanii Stevenson) also were observed in several experiments. One genotype, 5B-42-2-1, expressed a low level of infection to angular leaf spot having an average score of 1.5, whereas all genotypes were found to be susceptible to chaetoseptoria leaf spot.