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Improved Selection with Newly Identified RAPD Markers Linked to Resistance Gene to Four Pathotypes of Colletotrichum lindemuthianum in Common Bean

Núcleo de Biotecnologia Aplicada à Agropecuária (BIOAGRO), Universidade Federal de Viçosa (UFV), 36571-000 Viçosa, MG, Brasil; fourth author: EPAMIG, Viçosa, MG, Brasil; fifth author: Departamento de Biologia Geral, UFV, Viçosa, MG, Brasil; sixth author: Departamento de Bioquímica e Biologia Molecular, UFV, Viçosa, MG, Brasil

Three F₂ populations derived from crosses between the resistant cultivar AB 136 and the susceptible cultivar Michelite (MiA), and one F₂ population derived from a cross between AB 136 and Mexico 222 (MeA), were used to identify markers linked to anthracnose resistance genes present in cultivar AB 136. Primer OPZ04 produced a DNA band (OPZ04₅₆₀) linked in coupling phase to the resistance gene for pathotype 89 (8.5 ± 0.025 cM) in one population derived from the cross MiA. In the same population, primer OPZ09 produced one band (OPZ09₉₅₀) linked in repulsion phase (20.4 ± 0.014 cM) to the same resistance gene. The simultaneous use of markers in coupling and in repulsion phases allowed the identification of the three genotypic classes. In the other two populations from cross MiA, OPZ04₅₆₀ was linked in coupling phase to resistance genes for pathotypes 73 (2.9 ± 0.012 cM) and 81 (2.8 ± 0.017 cM). In population MeA, OPZ04₅₆₀ was linked in coupling phase (7.5 ± 0.033 cM) to resistance to pathotype 64. These data suggest that a single gene or complex locus of linked resistance genes present in cultivar AB 136 confers resistance to all four pathotypes of C. lindemuthianum.

Additional keywords: MAS, Phaseolus vulgaris.