MOLECULAR GENETIC VARIATION FOR STRIPE RUST RESISTANCE IN SPRING WHEAT

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is a major biotic constraint to global wheat production. Stripe rust can be effectively controlled by developing resistant wheat varieties. This, however, requires identification of resistant sources to be used as parents in breeding programs. Molecular markers provide a quick way of detecting rust resistance genes in adapted wheat material. The present study was conducted to investigate genetic variation for markers linked with stripe rust resistance genes in 67 Pakistani adapted spring wheat varieties using 12 pairs of microsatellite and sequence tagged site markers. Seventy nine percent wheat varieties showed marker allele of Xgwm11 associated with stripe rust resistance gene Yr26, whereas 75% varieties had the Yr26 linked allele of sequence tagged site (STS) marker CYS5. Stripe rust resistance gene Yr5 was found in 45%, whereas Yr9 and Yr10 were present in 28% varieties tested based on the previously reported linked markers. Stripe rust resistance gene Yr17 was found in 10%, whereas Yr18 in 15% of varieties only. Three markers Xwe173, Xbarc181 and Xgwm140 did not produce the expected amplicons associated with the stripe rust resistance genes. Cluster analysis revealed considerable genetic variation for marker alleles linked with stripe rust resistance genes. Results of this study may be useful for wheat breeders in pyramiding stripe rust resistance genes in future wheat varieties of Pakistan through Marker Assisted Selection.