DETECTION OF POLYMORPHISM IN PUCCINIA-HORDEI USING RFLP AND RAPD MARKERS, DIFFERENTIAL CULTIVARS, AND ANALYSIS OF THE INTERGENIC SPACER REGION OF RDNA

A world-wide range of isolates of Puccinia hordei and P. striiformis f . sp. hordei and UK isolates of P. striiformis f. sp. tritici and P. r econdita were characterized using DNA restriction length polymorphisms fragment (RFLPs), random amplified polymorphic DNAs (RAPDs), ribosoma l DNA (rDNA) intergenic sequence (IGS) or virulence on differential cu ltivars. The different species were readily distinguished by both RFLP s and RAPDs. Within a species, variability was detected using differen tial cultivars, RAPDs, and RFLPs with probes from the rDNA region, ind icating their potential for population analysis. However, RFLPs within a species were not detected using a wide range of random (anonymous) probes from a P. hordei genomic library. Previous assumptions about th e general uniformity of rust genotypes were reassessed from these data .