**2.3. Genetic basis of resistance to root rot pathogens in selected common bean cultivars**

We selected two common bean genotypes based on their contrasting reaction to FSP under both controlled and field conditions: BAT 477 (resistant) and Pinto UI-114 (susceptible). Crosses between the two parents were carried out under greenhouse conditions at Chapingo, México during 2002. F1 to F<sup>8</sup> seeds were obtained in successive sowings in different locations of México. Reactions to a highly virulent isolate of FSP were measured in F9:10 recombinant inbred lines [3]. A genetic linkage map was built with genotypic data obtained with 30 + 3/+3 AFLP. QTLs associated with resistance to FSP were identified using R software ver. 2.10.1 [14, 15].
