Contrasting Early Vigor and Water-Use Strategies Regulate Biomass Partitioning and Yield Stability under Water Stress in Chickpea (Cicer arietinum L.)

Abstract

Drought stress is a major constraint to chickpea productivity in semi-arid regions, particularly when it occurs during the reproductive phase. While early vigor is often considered advantageous for rapid canopy establishment and resource capture, it may also lead to excessive water use before flowering, thereby compromising yield under terminal drought conditions. The present study investigated the relationship of early and late vigor developments and water-use strategies on biomass accumulation, yield components, and seed yield under well-watered (WW) and water stress (WS) conditions. Two chickpea genotypes were evaluated: ICC 283, a late vigor genotype with conservative water-use behavior, and ICC 8261 an early vigor genotype characterized by rapid early growth and higher transpiration rates. The experiment was conducted using a randomized block design with three replications under lysimeter system. Significant genotypic differences were observed across traits and environments. The early vigor genotype exhibited substantially higher shoot biomass under both WW and WS conditions; however, this increased vegetative growth did not translate into proportional increases in reproductive output. In contrast, ICC 283 maintained relatively stable seed yield across environments, indicating superior assimilate partitioning and drought adaptation. Under WS conditions, both genotypes produced comparable seed yield, but the early vigor genotype showed greater variability between environments. Under WW conditions, ICC 283 outperformed the early vigor genotype in terms of seed yield despite lower biomass accumulation. The results highlight a critical trade-off between early vigor and yield stability under water-limited conditions. The findings suggest that conservative water-use strategies and efficient biomass partitioning are more important determinants of yield under drought than early vigor alone. These insights have important implications for chickpea breeding programs targeting drought-prone environments.