Phenotypic and Genotypic Characterization of New Kabuli-Type Chickpea Lines in Australia for Resistance to Ascochyta Blight

Abstract

Ascochyta blight (AB) is a major threat to Kabuli-type chickpea production worldwide. This study aimed to identify AB-resistant Kabuli-type chickpea lines through combined phenotypic and genotypic screening. Twenty-six Kabuli-type chickpea lines were phenotyped at the seedling stage using spray inoculation with conidial suspension. Genotyping employed marker-aided selection (MAS) with markers linked to quantitative trait loci (QTL) for AB resistance. The allele-specific marker, CaETR, closely linked to QTLAR1, and the sequence-tagged microsatellite (STMS) markers GAA47, TAA146, and TA194 linked to QTLAR1, QTLAR2, and QTLAR3 were used to assess their utility in distinguishing between resistant and susceptible chickpea lines. The study revealed that none of the lines tested were completely resistant (R) phenotypically. However, some lines, such as AVTCPK#6 and AVTCPK#14, were found to be moderately resistant (MR). Of the two MR lines identified phenotypically, only AVTCPK#6 was found to have bands linked to QTLs for adult plant resistance. The other MR line for AB showed the presence of bands in only one or two of the four markers used. These MR lines can be further utilized in chickpea breeding programs for the development of AB-resistant chickpea cultivars. It is recommended that these results be verified through repeat experiments, using more diverse isolates, and including additional chickpea lines as reference checks for resistance and susceptibility. The allele-specific marker, CaETR, closely linked to QTLAR1 and sequence-tagged microsatellite (STMS) markers GAA47, TAA146 and TA194 linked to QTLAR1, QTLAR2, and QTLAR3 were used to explore these markers’ utility in discriminating between resistant and susceptible chickpea lines. The study showed that phenotypically, none of the lines tested are completely resistant (R). However, some lines, namely AVTCPK#6 and AVTCPK#14, were found to be moderately resistant (MR). Of the two MR lines identified phenotypically, only AVTCPK#6 was identified to have bands linked to QTLs for adult plant resistance. The other MR line for AB showed the presence of bands in only one or two markers among the four markers used. These MR lines can be exploited further in chickpea breeding programs for the development of AB-resistant chickpea cultivars. It is recommended that these results are verified by repeat experiments, using more as well as diverse isolates alongside additional chickpea lines for resistant and susceptible reference checks.