Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2000
Publication Date: N/A
Interpretive Summary: Ascochyta blight is a devastating and widespread foliar disease of chickpea and is most important in the U.S. The disease can cause up to 100 percent yield loss and greatly reduced crop quality. The disease spreads by airbornes spores and also by infected seeds. Consequently, breeding efforts have focused on development of resistant germplasm for use by producers. In nthis research we developed and used a gene mapping population to determine that at least three genes that act additively confer resistance. Some modifiers of the resistance reaction were present. The information forms the basis of our mapping efforts for locating the ascochyta blight resistance genes in the chickpea genome and for identifying selectable molecular markers that can be used by breeders to transfer the resistance to enhanced germplasm.
Technical Abstract: Ascochyta blight (caused by Ascochyta rabiei [Pass] Labr.) is a devastating and widespread disease of chickpea (Cicer arietinum L.). Studies on the genetics of resistance to blight have generated inconsistent reports because of variation in screening trials from year to year and between locations. Most previous studies have relied on F2 or backcross populations and genetic interpretations have been difficult because of the inability to repeat the evaluations in time and space. To overcome this problem we established recombinant inbred line (RIL) populations from three crosses and evaluated the lines in 1997 and 1998 in the ascochyta blight nursery at Pullman, WA. The RILs were derived from two intraspecific crosses, PI 359075(1) x FLIP 84-92C(2), Blanco Lechoso' x Dwelley', and one interspecific cross, FLIP 84-92C(3) x C. reticulatum Lad. (PI 489777). Disease reactions of the parents and RILs were scored using a 1-9 scale and dalso by using the area under the disease progress curve (AUDPC). Segregation of RILs indicated that ascochyta blight resistance was conferred by three recessive complementary major genes with some modifiers. Absence of one or two of the major genes confers susceptibility while presence of the modifiers determines the degree of resistance.