IDENTIFICATION AND MAPPING OF RANDOM AMPLIFIED POLYMORPHIC DNA (RAPD)MARKERS LINKED TO RESISTANCE AGAINST BEET NECROTIC YELLOW VEIN VIRUS (BNYVV) IN BETA-ACCESSIONS

Molecular markers linked to resistance genes are useful to facilitate the introgression of one or more of these genes in breeding materials. Following the approach of bulked segregant analysis, RAPD markers lin ked to resistance genes against beet necrotic yellow vein virus were i dentified in the four Beta accessions Holly-1-4, R104, R128 and WB42. Two primers were found which generate RAPD markers tightly linked to r esistance in segregating families of Holly-1-4, R104 and R128, indicat ing that the resistance genes in these accessions might be situated at the same locus. Other, specific, primers were identified which genera te RAPD markers linked to resistance in each of these accessions. Shor t-range maps were established around the resistance locus in these acc essions. For WB42, RAPD markers were only identified at a relatively l arge distance from the resistance gene. Conversion of three RAPD prime rs of Holly-1-4, R104 and R128 into STS primers resulted in STS marker s which can be readily used for marker-assisted selection in breeding programmes.