A genetic map of common bean to localize specific resistance genes against anthracnose.

A bean genetic map was developed to locate resistance genes against anthracnose and genes involved in plant defense mechanisms. One hundred and fifty-seven markers (51 restriction fragment length polymorphism, 100 random amplified polymorphic DNA, 2 sequence characterized amplified regions, and 4 morphological markers) were used to construct a genetic map covering 567.5 cM of the bean genome. Morphological markers consisted in two resistance genes towards anthracnose (Are and RVI), a dominant gene for nuclear male sterility (Ms8) and a pod-shape character (SGou). This map was established by using a backcross population (BC1) of 128 individuals, derived from a cross between two European bean genotypes: Ms8EO2 and Corel. Nine percent of the markers showed segregation distortions and mapped to three regions. Clusters of 2-10 markers were observed in every linkage group. The possible origin of these clusters is discussed. Nineteen markers shared with a previously published bean linkage map allowed us to establish a preliminary correspondence between the two maps. Finally, seven genes involved in plant defense mechanisms were located on this map.