Nature of adult plant resistance in some Triticum timopheevi derivatives to pathotype 121R63-1 of leaf rust

Wheat rusts continue to pose a serious threat to wheat production by causing damage in different parts of the country. Amongst, leaf rust is wide spread. The life span of cultivars is generally short due to the evolution of new virulences of rusts. The screening of wheat x Triticum timopheevi derivatives and few other genetic stocks against leaf rust pathotype 77-5 (121R-63-1) revealed that Sel. T3171, Sel. T3114 and Sel. T3170 exhibited resistance in seedling and in adult stage, while Sel. T3168, Sel. 3073, WR544 and Kundan showed susceptibility in seedling stage but exhibited moderate to high degree of resistance at adult plant stage. The study of inheritance indicated that adult plant resistance (APR) in Sel. T3171, Sel. T3114, Sel. T3170, WR544 and Sel. T3168 is controlled by a single dominant gene, whereas Sel. T3073 carried a recessive gene for adult plant resistance. Further, test of allelism demonstrated that WR544 and Sel. T3168 possessed an APR gene different from that of Kundan ( Lr 34). Also, the resistance in Sel. T3073 is diverse than that of Lr 34 present in Kundan and Lr 13 carried by Thatcher. It is presumed that newly discovered resistance will be useful in wheat improvement.