Investigating the resistance of common bean germplasm to Colletotrichum lindemuthianum and its implications for breeding

Abstract

Common bean breeding obtained cultivars with high yield and resistance to diseases. We evaluated anthracnose resistance of genotypes from breeding programs where selection was made mainly to increase grain yield. A germplasm collection of 845 lines were assessed with four of the most frequent Colletotrichum lindemuthianum races found in Brazil (65, 73, 81 and 89). In addition to high reaction variability, we identified 633 lines resistant to at least one race. Most resistant lines have a Carioca grain type. The virulence indexes ranged from 51.7% to 63.2% (races 81 and 73) and resistance indexes ranged from 0% (susceptible) to 100% (resistant). This study presents complete characterization about resistance to anthracnose of a wide collection, provides information about cultivars that can be directly introduced in current breeding programs and shows that breeding focused on increasing grain yield has also been successful in selecting resistant genotypes to anthracnose disease.

Keywords: Colletotrichum lindemuthianum; genetic resistance; Phaseolus vulgaris; resistance sources