Genetics of Resistance to Ascochyta Blight in Four Chickpea Lines

Abstract

Inheritance of resistance to race 3 of Ascochyta blight (Ascochyta rabiei (Pass.) Lab.), an important disease in chickpea (Cicer arietinum L.), was studied in four resistant lines at ICARDA in Syria from 1983 to 1986. The parents, F1, and F2 populations were evaluated for Ascochyta blight resistance under artificial epiphytotic conditions in the greenhouse during the 1983 to 1984 season. The F3 progenies from selected F2 resistant plants for each of the four crosses involving resistant and susceptible lines were evaluated for segregation of blight resistance and susceptibility in. the greenhouse during the 1985 to 1986 season. Results suggested that a single dominant gene conditioned resistance to race 3 in the four parents, ILC 72, ILC 202, ILC 2956, and ILC 3279. Allelic tests indicated that the resistance gene present in these four resistant lines was the same. When these resistant parents were evaluated against six races of A. rabiei, each was resistant to races 1 and 3 and to at least two other races, but no two lines showed the same resistance pattern. Furthermore, the disease reaction of these resistant lines differed when tested in 13 countries. The variation in reaction of four resistant lines to six races and in different countries appears to be due to the presence of some other resistant genes in addition to a common gene.