Genomic-Mediated Breeding Strategies for Global Warming in Chickpeas ( Cicer arietinum L.)

Although chickpea ( Cicer arietinum L.) has high yield potential, its seed yield is often low and unstable due to the impact of abiotic stresses, such as drought and heat. As a result of global warming, both drought and heat are estimated to be major yield constraints between one-quarter and one-third per annum. In the present review, genomic-mediated breeding strategies to increase resilience against global warming. Exacerbated drought and heat stresses have been examined to understand the latest advancement happening for better management of these challenges. Resistance mechanisms for drought and heat stresses consist of (i) escape via earliness, (ii) avoidance via morphological traits such as better root traits, compound leaves, or multipinnate leaves and double-/multiple-podded traits, and (iii) tolerance via molecular and physiological traits, such as special tissue and cellular abilities. Both stresses in chickpeas are quantitatively governed by minor genes and are profoundly influenced by edaphic and other environmental conditions. High-yield genotypes have traditionally been screened for resistance to drought and heat stresses in the target selection environment under stress conditions or in the simulacrum mediums under controlled conditions. There are many drought- and heat-tolerant genotypes among domestic and wild Cicer chickpeas, especially in accessions of C. reticulatum Ladiz., C. echinospermum P.H. Davis, and C. turcicum Toker, J. Berger, and Gokturk. The delineation of quantitative trait loci (QTLs) and genes allied to drought- and heat-related attributes have paved the way for designing stress-tolerant cultivars in chickpeas. Transgenic and “omics” technologies hold newer avenues for the basic understanding of background metabolic exchanges of QTLs/candidate genes for their further utilization. The overview of the effect of drought and heat stresses, its mechanisms/adaptive strategies, and markers linked to stress-related traits with their genetics and sources are pre-requisites for framing breeding programs of chickpeas with the intent of imparting drought tolerance. Ideotype chickpeas for resistance to drought and heat stresses were, therefore, developed directly using marker-aided selection over multiple locations. The current understanding of molecular breeding supported by functional genomics and omics technologies in developing drought- and heat-tolerant chickpea is discussed in this review.