Genotype × Environment Interactions and Identification of Stable Sources of Resistance to Ascochyta Blight in Chickpea

Abstract

Ascochyta blight (AB) caused by Ascochyta rabei (Pass.) Labr. is a significant constraint that adversely affects the productivity and quality of chickpea (Cicer arietinum L.). Over the past two decades, numerous resistant genes/QTLs have been identified for this pathogen. To establish a comprehensive collection of chickpea genotypes with resistance to AB, the Global Ascochyta Blight Resistant Set Collection (GABRSC) was initiated through GRDC funding. The GABRSC comprises 200 Desi and Kabuli-released resistant varieties breeding lines, and landraces. Field Phenotyping of GABRSC was conducted in 2022 and 2023 cropping seasons at six AB hot spot sites in India (Punjab), Turkey, Tunisia, Lebanon, Morocco, and Ethiopia. The experimental design was Alpha Lattice with two replications. The primary objective of this study was to identify sources of resistance that exhibit stability across multiple environments that favor AB epidemics. Genotypes were rated using a 1–9 scale where 1= highly resistant and 9= highly susceptible. REML analysis revealed highly significant effects of environments, genotype, and genotype × environment interaction. Genotype and genotype × environment (GGE) biplot analyses of multi-environmental results showed four genotypes (S0110227, S160454, S0110088, and S0110028) consistently exhibited resistance (<3) across all the environments. The four genotypes were derived from the ICARDA breeding program, which involved the pyramiding of various resistant genotypes through crosses and demonstrated higher levels of resistance across diverse locations. The resistant genotypes identified in this study hold significant potential for integration into breeding programs as stable sources of resistance, facilitating the development of agronomically desirable Ascochyta blight-resistant varieties. These findings contribute to the advancement of sustainable and resilient chickpea cultivation, ultimately leading to increased chickpea yields.