TARGETED MAPPING APPROACHES TO IDENTIFY DNA MARKERS LINKED TO THE RFP1 RESTORER GENE FOR THE POLIMA CMS OF CANOLA (BRASSICA-NAPUS L.)

We have used two targeting approaches [pairs of nearly isogenic lines (NILs) and bulked segregant analysis] to identify DNA markers linked t o the Rfp1 restorer gene for the pol CMS of canola (Brassica napus L.) . We were able to target the Rfp1 locus as efficiently by comparing NI Ls as by bulked segregant analysis, and it was demonstrated in this in stance that double-screening strategies could significantly improve th e overall targeting efficiency. The chance occurrence of shared homozy gosity at specific unlinked chromosomal regions in the bulks was found to limit the efficiency of bulked segregant analysis, while the effic iency of NIL comparison was limited by residual DNA from the donor cul tivar at scattered sites throughout the genome of the NILs.