Inheritance of resistance to fusarium wilt in common bean

Abstract

Fusarium oxysporum f. sp. phaseoli (Fop) is a soil pathogen that causes wilt in common bean (Phaseolus vulgaris L.) and is one of the most important diseases of this crop. The use of resistant cultivars is the most effective method of controlling losses from this pathogen, and studying the inheritance of Fop resistance could provide useful insights for developing cultivars with resistance. Thus, the aim of this study was to determine the inheritance of resistance to fusarium wilt in common bean. The parents, F1 and F2 plants from seven crosses between resistant and susceptible parents of a partial diallel scheme 3 × 5 were inoculated with the isolate FOP UFV 01. During each generation, the plants were individually evaluated to determine disease severity. Among the eight parents, five were resistant, and three were susceptible to fusarium wilt. Only two phenotypic classes were observed in the parents (resistant and susceptible). Based on the performance of the F1 generation, all the individuals were resistant, indicating that resistance is dominant over susceptibility. Different results were obtained for the segregation of plants from the F2 generation based on the methods applied to determine the inheritance of resistance. However, the maximum likelihood estimator method, which was the most suitable methodology, showed that Fop resistance in common bean is a dominant trait governed by few major genes plus polygenes. These findings can support breeding programs in obtaining Fop-resistant cultivars.