Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/29/2004
Publication Date: 5/14/2004
Citation: Cho, S., Chen, W., Muehlbauer, F.J. 2004. Pathotype-specific genetic factors in chickpea (Cicer arietinum l.) for quantitative resistance to ascochyta blight. Journal of Theoretical and Applied Genetics. 109(4):733-739. Interpretive Summary: Ascochyta blight is the most serious disease of the leaves, stems and seeds of chickpea (garbanzos) throughout the U.S. and also worldwide. In the research report we describe the identification of a major genetic region in chickpea that is responsible for resistance to an important strain of the disease causing pathogen. By locating this important part of the genetic makeup within the germplasm of chickpea, we can now use that information to develop varieties that will have improved resistance to this important disease. This development provides information on the nature of disease resistance in the chickpea crop and provides insights into further research on the nature of disease resistance in chickpea and other crop plants.
Technical Abstract: Ascochyta blight in chickpea (Cicer arietinum L.) is a devastating fungal disease caused by the necrotrophic pathogen, Ascochyta rabiei (Pass.) Lab. The objectives of our study were to elucidate the genetic mechanism of pathotype-dependent blight resistance in chickpea and to identify genomic regions associated with blight resistance on an intraspecific genetic linkage maps. F7-derived recombinant inbred lines (RILs) from the intraspecific cross of PI 359075 (blight susceptible) x FLIP84-92C(2) (blight resistant) were inoculated with pathotypes I and II of A. rabiei. The pattern of blight resistance varied among the RILs depending on the pathotype of A. rabiei. Using the same RIL population, an intraspecific genetic linkage map comprising 53 Sequence-Tagged Microsatellite Site (STMS) markers was constructed to identify genomic associations with blight resistance. A major QTL for resistance to pathotype II of A. rabiei and two QTLs for resistance to pathotype I were identified on LG4A and LG2+6, respectively. Qualitative genetic effect of major blight resistance gene contributing to quantitative blight resistance was detected and additive interaction among blight resistance genes appeared to determine genetic resistance of chickpea to A. rabiei. Further genomic study is required to identify qualitative blight resistance genes and their interaction for pathotype-dependent blight resistance in chickpea.