In view of the high χ2 values, the hypothesis of independent linkage (9:3:3:1) could be discarded, indicating that the RAPD markers were linked to the resistance locus (Table II). The estimates of the genetic distance between the RAPD locus CSOPA1800C and the resistance locus varied between 2.3 cM for the CB cross and 5.6 cM for the UB cross. The estimated genetic distances between RAPD locus CSOPA21,250C and the resistance locus varied between 3.4 cM for the PB cross and 4.7 cM for the CB cross. CSOUB11,100C was 6.7 cM from the resistance locus.