GENETIC CHARACTERIZATION OF NOVEL LR GENE STACK IN SPRING WHEAT VARIETY CHAKWAL86 AND ITS EFFECTIVENESS AGAINST LEAF RUST IN RAIN FED AREAS OF PAKISTAN

Abstract

Disease resistance remains a prime focus in crop improvement. Based on the field observations and marker assisted screening, we report the gene stack Lr10, Lr17a and Lr27+31 as a resistant combination for spring wheat cultivated in rain fed areas. To demonstrate this, a rain fed leaf rust resistant variety ‘Chakwal86’, has been genetically characterized following its cross with a susceptible variety ‘Inqilab91’. The parents, NILs and F2 population studied in the greenhouse through inoculation and in the field under natural conditions revealed a 3:1 resistance to susceptible ratio, while the F2:3 populations revealed a 1:2:1 ratio suggesting the dominant mode of resistance. The PCR-based markers developed to characterize individuals by selecting SSR based markers specific to Lr10; Lr17a and Lr27, revealed all three genes stacked in Chakwal86, while Lr10 and Lr27+31 in Inqilab91. The individual lines carrying gene combinations as found in Chakwal86 remained resistant in the field while all those not carrying Lr17a in the stack were susceptible. Hence the gene stack Lr10, Lr17a and Lr27+31 has been found an effective resistant combination for spring wheat in rain fed areas.