RAPD Markers Linked to Major Genes for Common Bacterial Blight and Purple Flower Color in a Tepary Bean Cross

Abstract

Common bacterial blight (CBB), incited by Xanthomonas campestris pv. phaseoli (Xcp), is an important disease of common bean (Phaseolus vulgaris L.). Tepary bean (P. acutifolius A. Gray) is of interest to bean breeders because of resistance to CBB. The objective was to identify RAPD markers linked to major dominant genes for CBB resistance and purple flower color using bulked segregant analysis in an F2 population from a tepary bean cross Nebr#19 [resistant (R) to CBB and white flower color] × Nebr#4B [susceptible (S) to CBB and purple flower color]. Ten RAPD primers (600 RAPD primers screened) showed polymorphisms between bulked DNA derived from R and S plants. All markers showed coupling linkage with CBB resistance. The RAPD marker of G-14 primer was 5.2 cM distant from the gene for resistance to Xcp strain LB-2. The RAPD marker of L-18 primer was 6.8 cM distant from the gene for resistance to Xcp strain SC-4A. The RAPD marker of G-14 primer was 26.2 cM distant from the gene for resistance to Xcp strain EK-11. Seven RAPD primers showed polymorphisms between bulked DNA derived from purple and white flower plants. All markers showed coupling linkage with the gene for purple flower color. The RAPD marker of Y-6 primer was 3.6 cM distant from the gene for purple flower color.