earticle

영어

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.
For QTL analysis fifty-eight SSR markers and one morphological marker (flower color) were
mapped on F2 individuals and F2:3 families derived from the cross ICC 12004 (resistant) ×
Bivanij (susceptible local variety) at the International Center for Agricultural Research at
Dry Area (ICARDA). The linkage map comprised eight linkage groups, excluding flower
color which didn't assign to any linkage group. Area under disease progress curve (AUDPC)
was used to evaluate the F2 population and F3 families. Using composite interval mapping,
three genomic regions were detected, which were in association with reaction to ascochyta
blight. These QTLs on LG3, LG4 and LG6 accounted for 46.5% of the total estimated
phenotypic variation for reaction to ascochyta blight. Fine mapping of the QTLs identified in
this study would lead to the identification of markers that could be used for marker-assisted
selection of chickpea genotypes with resistance to Ascochyta blight. These findings are
particular pertinent considering that we used Ascochyta rabiei pathotype III and ICC 12004
(resistant to pathotype III) for the first time.