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 genetics of resistance to blight have generated inconsistent reports due to year to year and between location variation in screening trial results. Most previous studies have relied on F2 or backcross populations for segregation analyses; however, inheritance patterns have been difficult to confirm because of the inability to repeat the evaluations in time and space. The objective of this study was to determine the inheritance of resistance to ascochyta blight in chickpea using recombinant inbred line (RIL) populations. The RILs were derived from two intraspecific crosses, PI 359075(1) × FLIP 84‐92C(2), ‘Blanco Lechoso’ × ‘Dwelley’, and one interspecific cross, FLIP 84‐92C(3) × C. reticulatum Lad. (PI 599072). The resistant parents, FLIP 84‐92C and Dwelley, had a common source of resistance derived from ILC‐72. Disease reactions of the parents and RILs were scored using a 1 to 9 scale and also by using the area under the disease progress curve (AUDPC). Segregation among RILs indicated that three recessive and complementary major genes with several modifiers conferred ascochyta blight resistance. Absence of one or two of the major genes confers susceptibility, whereas the presence of the modifiers determines the degree of resistance.