Reação de genótipos de feijão-fava a Sclerotium rolfsii

Abstract

The collar rot caused by Sclerotium rolfsii is an important disease in faba bean (Phaseolus lunatus) at the Northeastern Brazil. The objective of this work was to evaluate the reaction of faba bean genotypes to S. rolfsii in order to select materials with potential use in the collar rot management. In the first step, 50 faba bean genotypes were evaluated in relation to an isolate of S. rolfsii. Ten-day old plants were inoculated by the collar injury method and deposition of sclerotia of the pathogen. Disease incidence was assessed 10 days after inoculation. Most genotypes (60%) behaved as highly susceptible to the pathogen, while 36% were classified as susceptible. Only two genotypes (F-2 and F-25) behaved as highly resistant, representing 4% of the total. The stability of resistance of these two genotypes was evaluated against 11 isolates of S. rolfsii, both of them showing satisfactory level of resistance, constituting promising sources of resistance to collar rot.