Characterization of genetic resistance in Andean common bean cultivar Amendoim Cavalo to Colletotrichum lindemuthianum

Abstract

The Anthracnose, caused by Colletotrichum lindemuthianum (Sacc. and Magnus) Briosi and Cavara, is one of the most importante fungal disease of common bean. Several strategies have been used for its control, such as the use of pathogen-free seeds, chemical control and crop rotation. However, the most efficient method to control this disease is the use of resistant cultivars. Previous studies conducted by the Laboratory of Common Bean Breeding and Molecular Biology of the Nucleus of Research Applied to Agriculture (Laboratório de Melhoramento de Feijão Comum e de Biologia Molecular do Núcleo de Pesquisa Aplicada à Agricultura-NUPAGRI) revealed that the Andean cultivar Amendoim Cavalo is resistant to races 2, 7, 9, 19, 23, 39, 55, 65, 73, 89, 1545, 2047 and 3481 of C. lindemuthianum. The objective of this work was to characterize the genetic resistance to anthracnose in Amendoim Cavalo using inheritance and allelism tests. The results of inheritance tests in F2 generation of Amendoim Cavalo × PI 207262 cross, inoculated with 2047 race, fitted in a ratio of 3R:1S, proving the action of a single dominant gene in Amendoim Cavalo cultivar. Allelism tests demonstrated that the dominant gene present in Amendoim Cavalo is independent from the genes previously characterized. The authors propose the Co-AC symbol to designate the new resistant gene to C. lindemuthianum. The results show high contribution to breeding programs, once Amendoim Cavalo cultivar can be considered an important Andean source of resistance to C. lindemuthianum.