Shoot traits and their relevance in terminal drought tolerance of chickpea ( Cicer arietinum L.)

Abstract

Chickpea is the second most important legume crop largely grown under semi-arid tropics where terminal drought is one of the major constraints for its productivity. A trait-based selection had been considered more beneficial in drought tolerance breeding to overcome the environmental influence on drought yields. Large number of traits had been suggested in literature, with less indication on their importance and priority, for use in such breeding programs resulting in poor utilization of critical traits in drought tolerance breeding. To identify the most critical traits that contribute to grain yield under drought, 12 chickpea genotypes, with well-defined drought response, were field evaluated by sampling at regular intervals during the cropping period. Large range of variation was observed for shoot biomass productivity, specific leaf area (SLA) and leaf area index (LAI) at different days after sowings (DAS), canopy temperature depression (CTD) at mid-reproductive stages, growth duration and both morphological and analytical yield components. Grain yield under drought was closely associated with the rate of partitioning (p), crop growth rate (C), CTD, phenology, LAI at mid-pod fill stage, pod number m−2 at maturity, shoot biomass at reproductive growth stages and SLA at physiological maturity. The shoot trait(s) were prioritized based on their significance and contribution to drought tolerance. The trait(s) that conferred tolerance varied across genotypes. The order of traits/plant functions identified as important and critical for the drought tolerance were p, C, CTD, growth duration and other related traits. Relatively less important traits were LAI, SLA at the mid reproductive stage and pod number per unit area at maturity. The traits Dr, seeds pod−1 and 100-seed weight were found to be least important. Breeding for the best combination of p and C with the right phenology was proposed to be the best selection strategy to enhance terminal drought tolerance in chickpea.

Impact of High Temperature and Drought Stresses on Chickpea Production

“…Drought tolerance breeding research work on chickpea has been conducted for over two decades. Previous research has documented drought responses to different traits such as early maturity (drought escape), root traits (drought avoidance), carbon isotope discrimination, rate of partitioning, shoot biomass and grain yield [13][14][15][16][17]. The physiological and biochemical changes under drought are well documented in earlier reports and summarised in Table 1.…”

Developing Climate-Resilient Chickpea Involving Physiological and Molecular Approaches With a Focus on Temperature and Drought Stresses

“…Considerable progress has been made in elucidating the role of various root traits for drought stress tolerance in chickpea (Kashiwagi et al, 2006a;Kashiwagi et al, 2015). How root biomass, root length, and other rootrelated parameters, such as root length density (RLD), total root dry weight (RDW), and deep root dry weight (deep RDW), contribute to drought stress tolerance has been investigated in chickpea (Krishnamurthy et al, 2003;Kashiwagi et al, 2005;Gaur et al, 2008;Kashiwagi et al, 2008;Kashiwagi et al, 2015;Purushothaman et al, 2016;Chen et al, 2017). A significant amount of genetic variability for RLD in the mini-core collection and wild species of chickpea has been reported (Kashiwagi et al, 2005).…”

“…In the context, the major physiological traits involved in drought stress adaptation are categorized into "constitutive traits" and "acquired tolerance traits" (Sreeman et al, 2018). The notable "constitutive traits" involved in drought stress adaptation in chickpea include phenology (Kumar and Abbo, 2001), stomatal conductance (Liu et al, 2003), specific leaf area (Purushothaman et al, 2016), leaf area index (Purushothaman et al, 2016), chlorophyll content (Mafakheri et al, 2010), WUE (Kashiwagi et al, 2006b), and root traits (Krishnamurthy et al, 2003;Gaur et al, 2008;Kashiwagi et al, 2006a;Kashiwagi et al, 2015;Zaman-Allah et al, 2011b;Purushothaman et al, 2015). Likewise, canopy temperature depression (CTD) (Zaman-Allah et al, 2011a;Purushothaman et al, 2016), proline accumulation (Macar and Ekmekci, 2009;Mafakheri et al, 2010), regulation of ABA (Pang et al, 2017), and production of various antioxidant scavenging enzymes (Macar and Ekmekci, 2009) are the major "acquired tolerance" traits involved in drought stress tolerance in chickpea.…”

“…Insight into the genetic inheritance of stomatal conductivity and selection for lower stomatal conductance with higher leaf transpiration efficiency under drought could be promising for the development of drought tolerant chickpea genotypes. Likewise, correlations between crop growth rate and transpiration and transpiration efficiency are receiving attention in the development of droughttolerant chickpea (Purushothaman et al, 2016).…”

“…Across the globe, drought stress reduces chickpea yield by about 45-50% (Ahmad et al, 2005;Thudi et al, 2014). Numerous studies have been conducted on the drought effects on different chickpea traits, including early maturity, root traits, carbon isotope discrimination, shoot biomass (Kashiwagi et al, 2005;Krishnamurthy et al, 2010;Upadhyaya et al, 2012;Krishnamurthy et al, 2013b;Purushothaman et al, 2016), and morphological (Sabaghpour et al, 2006), physiological (Turner et al, 2007;Rahbarian et al, 2011), biochemical (Gunes et al, 2006;Mafakheri et al, 2010) and molecular traits (Mantri et al, 2007;Thudi et al, 2014;Garg et al, 2016). There have been various attempts to explain the advancements in "omics" technology for drought challenges.…”