Sociedade Brasileira de Melhoramento de Plantas Crop Breeding and Applied Biotechnology

Abstract

ABSTRACT Genetic resistance in common bean (Phaseolus vulgaris L.) is the most effective control of anthracnose caused by Colletotrichum lindemuthianum (Sacc. et Magnus) Lams.-Scrib. In a previous report, two genetic symbols, Q and B, were assigned to describe the gene(s) controlling the resistance of the cultivar AB 136 to races 31 and 69 of the pathogen, respectively. In the present study, progeny tests with two identical sets of F 2:3 population were used to obtain the first experimental evidence whether one single gene controls the resistance to both races 31 and 69. The absence of recombinations between the putative genes (Q and B) allowed the conclusion that a single dominant gene controls the resistance of the cultivar AB 136 to both races 31 and 69. The symbol Co-6 was assigned to the gene. In addition, linkage analysis with RAPD marker indicated that Co-6 also controls the resistance of AB 136 to other races of the pathogen, or that different genes are present in the same linkage block