Genetical Analysis of Ascochyta Blight Resistance in Chickpea

Ascochyta blight, caused by Ascochyta rabiei (Pass.) Lab. is a devastating disease of chickpea (Cicer arietinum L.) worldwide. Available genetic variation for Ascochyta blight resistance in genus Cicer has prompted interest in the development and use of resistant cultivars that can be sown in autumn and, to increase seed yield in chickpea. Understanding the mode of inheritance of resistance to Ascochyta blight in chickpea would assist breeding efforts. The objective of this study were determining number of genes confer Ascochyta blight resistance and leaf size as well as action of them. Thus F1, F2 F3 progenies derived from a cross between Iranian local variety Bivanij (susceptible local variety) and ICC12004 along with their parents were sown in a RCB design at the International Center for Agricultural Research at Dry Area (ICARDA) under artificial infection conditions. Results showed that in F2 and F2 generations the ratio of susceptibility did not differ significantly from those of 9:7 and 5:3 theoretical ratios. There was a negative correlation between leaf size and blight score, which means that large leaf genotypes could be more susceptible to Ascochyta blight. Generation mean analysis for resistance to Ascochyta blight in this study revealed that additive effect has main role in Ascochyta blight resistant, however the leaf size besides of additive effect showed dominance effect as well. For theses traits we detected dominant x dominant interaction (l) in the opposite sign which reveals the evidence of a duplicate epistasis. These findings showed that the genotype of resistant parent could be as R1R1R2R2. According to these findings and available knowledge, it would be suggested an appropriate breeding program for gene pyramiding to produce multiple resistant genotypes in chickpea.