Identificação de fontes de resistência e avaliação de métodos de inoculação de Curtobacterium flaccumfaciens pv. flaccumfaciens em feijão-de-vagem

Abstract

The bacterial wilt of bean was first reported in Brazil in 1995, in São Paulo state and since then, this bacteria has also been identified in other states in Brazil. The disease is caused by Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff) and has become a serious problem in bean crop. The aims of this study were to evaluate the resistance of snap bean genotypes considering bacterial wilt and also to define the most accurate method to distinguish resistant and susceptible genotypes to Cff. Two experiments were carried out, one of them from December 2005 to February 2006, in a randomized block design, six replications and 39 treatments. The second experiment was carried out from May to July, 2006, in a randomized block design, with five replications, in a factorial arrangement (three inoculation methods x 11 genotypes), in order to compare three inoculation methods for Cff. The genotypes used in this test were the most resistant and susceptible according to the first experiment. The rates of evaluation were used to determine the area under disease progress curve (AUDPC). The genotypes Novirex, IAC Carioca Tybatã and Amarelo Baixo were considered resistant. The toothpick inoculation method allowed an efficient discrimination among resistant and susceptible genotypes and it was also faster and easier to perform than the other methods.