Ascochyta blight, caused by the fungus Ascochyta rabiei Pass. Lab. is a detrimental disease to chickpeas (Cicer arietinum L.) causing yield losses of up to 100% under conducive environments. With the emergence of more aggressive fungal populations and varying climatic conditions, there is a need for stronger and more durable resistance to ascochyta blight in chickpeas. Wild chickpea accessions harbor an abundance of genetic diversity, including resistance to ascochyta blight. Previous research has shown strong resistance to ascochyta blight in Cicer judaicum. However, fertile progeny from a cross between C. judaicum and C. arietinum has not been able to obtain. Cicer pinnatifidum has successfully been crossed with cultivated species and is currently being used as a bridge species. This study aimed to determine if novel QTLs for resistance to ascochyta blight are present in the interspecific population consisting of 196 F6 lines derived from a cross between C. pinnatifidum x C. judaicum. The population was screened for its reaction to ascochyta blight under field and greenhouse conditions in 2021-2023. The results demonstrated that there is moderate to high resistance present in the population. Progeny exhibiting high resistance similar to the parental line was identified. Genotypic analysis was done using genotyping-by-sequencing approach. After filtering for missing data and minor allele frequency of 20%, 7,240 SNP markers were used for QTL analysis. In total 1,640 SNPs aligned to C. arietinum’s chromosomes, and 86 SNPs were significantly associated with ascochyta blight resistance. Physical mapping revealed that these QTLs were clustered on chromosomes 1, 3, 6, and 7 with the highest R2 value accounting for 7.38% of variation for resistance on chromosome 6. Several of previously identified QTLs for resistance to ascochyta blight overlapped with those identified in this study. Of the 86 markers, 69 are potentially unique to this population. The resistance present in this population has the potential to enhance the resistance to ascochyta blight in the cultivated chickpeas.

Extension Messages

• Ascochyta blight is a major disease threatening the sustainability of chickpea production in western Canada.
• Higher resistance to ascochyta blight derived from the wild species was identified and is used as a means of diversifying resistance sources to the disease in new cultivars.
• The project developed tools in the form of DNA markers that allow rapid incorporation of the resistance into new breeding lines and cultivars that will enhance the competitiveness, profitability and sustainability of the pulse industry in Canada.