GENETIC-VARIABILITY OF COLLETOTRICHUM-LINDEMUTHIANUM IN WILD POPULATIONS OF COMMON BEAN

The genetic structure of wild populations of Colletotrichum lindemuthi anum was evaluated for virulence and molecular markers. Forty-five iso lates were collected from five wild common bean populations located in their South-Andean centre of origin. The five pathogen populations we re monomorphic in their ITS regions, but 45 polymorphic markers were i dentified using RAPDs. Polymorphism for virulence was also observed; 1 5 pathotypes were characterized on an international set of 12 differen tials. A molecular variance analysis (AMOVA) showed that a very large part of the total genetic variation was within populations. Statistica l analysis showed that there was a weak though significant differentia tion among the five populations for the RAPD and virulence markers. A positive and significant correlation was found between geographic dist ance and the distances from RAPD and virulence data, suggesting migrat ion between adjacent populations along the Argentinian transect. Our r esults suggest that the Andean wild isolates of C. lindemuthianum do n ot reflect all the putative diversity found in the isolates from culti vated common bean.