Identification of drought tolerance in chickpea (Cicer arietinum L.) landraces

Drought is a major limiting factor for agricultural production in most parts of the world and landraces are important genetic resources for crop improvement in dry areas. During the 2007-2008 cropping season, 23 chickpea (Cicer arietinum L.) genotypes consisting of 21 Kabuli chickpea landraces provided by the National Plant Gene Bank of Iran and two known commercial varieties (Hashem and Arman) were evaluated under varying drought stress environments imposed using a line-source sprinkler irrigation system. Most measured traits were significantly decreased by drought stress. The reductions in plant canopy width, seed weight per plant, biomass yield and plant weight were proportional to the severity of stress. For all stress treatments, significant variation was observed for seed yield and yield components, and harvest index. The coefficient of variation for these traits increased with the severity of drought stress. Harvest index, pod and seed number per plant, pod and seed weight per plant, total pod weight, plant weight, biomass and plant canopy width showed the highest positive and significant correlation with seed yield, especially under drought treatments; these traits should therefore be taken into account when selecting genotypes under drought conditions. Variation in drought tolerance and susceptibility indices suggested high genetic variation among the genotypes. Geometric mean productivity (GMP) and stress tolerance index (STI) in combination with stress susceptibility index (SSI) were the best indices for selecting drought tolerant genotypes. Accessions 216066, 216084, 215296 and 215664 were superior genotypes as compared to other accessions under drought conditions.