Ascochyta blight resistance inheritance in three chickpea recombinant inbred line populations

Ascochyta blight (caused by Ascochyta rabiei [Pass] Labr.) is a devastating and widespread disease of chickpea (Cicer arietinum L.). Studies of the ge netics of resistance to blight have generated inconsistent reports due to y ear to year and between location variation in screening trial results. Most previous studies have relied on F-2 or backcross populations for segregati on analyses; however, inheritance patterns have been difficult to confirm b ecause of the inability to repeat the evaluations in time and space. The ob jective of this study was to determine the inheritance of resistance to asc ochyta blight in chickpea using recombinant inbred line (RIL) populations. The RILs were derived from two intraspecific crosses, PI 359075(1) x FLIP 8 4-92C(2), 'Blanco Lechoso' x 'Dwelley', and one interspecific cross, FLIP 8 4-92C(3) x C. reticulatum Lad. (PI 599072). The resistant parents, FLIP 84- 92C and Dwelley, had a common source of resistance derived from ILC-72. Dis ease reactions of the parents and RILs were scored using alto 9 scale and a lso by using the area under the disease progress curve (AUDPC). Segregation among RILs indicated that three recessive and complementary major genes wi th several modifiers conferred ascochyta blight resistance. Absence of one or two of the major genes confers susceptibility, whereas the presence of t he modifiers determines the degree of resistance.