Reação de genótipos de feijão e agressividade de isolados do agente causal do mofo-branco

Abstract

White mold is a common bean disease caused by fungus Sclerotinia sclerotiorum, homothallic pathogen, that present high variability even in clonal populations. Use of resistant cultivars would be the most effective strategy to disease control, however, complete resistance is nonexistent. Artificial inoculation in greenhouse and in field should be part of evaluation methodology of common bean resistance to this pathogen. Aims of this study were to determine common bean cultivars reaction and S. sclerotiorum isolates aggressiveness in field and in greenhouse; and also know aggressiveness of monoascosporics strains derived from a S. sclerotiorum isolate. Reaction of 14 common bean cultivars to four S. sclerotiorum isolates was evaluated in two experiments, one in field and the other in greenhouse. Furthermore, aggressiveness of 11 monoascosporics strains from an isolate was evaluated to three common bean lines, Cornell 605 and Talismã are moderately resistant and, Corujinha, susceptible. Among evaluated common bean cultivars were not identified cultivars with high resistance level to white mold. Variation found in the cultivars reaction to the severity of white mold, in the evaluation in field and in greenhouse, was mainly due to difference in S. sclerotiorum isolates aggressiveness. The monoascosporics strains showed variability in aggressiveness.