Developing resistance to Fusarium wilt in chickpea: From identifying meta-QTLs to molecular breeding

Fusarium wilt (FW) significantly affects the growth and development of chickpea (Cicer arietinum L.), leading to substantial economic losses. FW resistance is a quantitative trait that is controlled by multiple genomic regions. In this study, a meta-analysis was conducted on 32 quantitative trait loci (QTLs) associated with FW resistance, leading to the identification of seven meta-QTL (MQTL) regions distributed across CaLG2, CaLG4, CaLG5, and CaLG6 of the chickpea linkage groups. The integrated analysis revealed several candidate genes potentially important for FW resistance, including genes associated with sensing (e.g., LRR-RLK), signaling (e.g., mitogen-activated protein kinase [MAPK1]), and transcription regulation (e.g., NAC, WRKY, and bZIP). Subsequently, a marker-assisted backcrossing (MABC) trial was executed leveraging the MQTL outcomes to introgress FW resistance from an FW-resistant chickpea cultivar (Ana) into a superior high-yielding Kabuli cultivar (Hashem). The breeding process was extended over 5 years (2018-2023) and resulted in the development of BC₃F₂ genotypes. Consequently, 12 genotypes carrying homozygous resistance alleles were chosen, with three genotypes showing genetic backgrounds matching 90%-96% of the recurrent parent. The findings of this study have significant implications for upcoming programs, encompassing fine-mapping, marker-assisted breeding, and genetic engineering, consequently contributing to the effective control of FW and the improved production of chickpea.