evaluation of morphological characteristics of root chickpea(cicer arietinum l.) in response to drought stress

in dry region, root systems play a major roll in controlling plant growth and yield due to their importance in absorbtion of water and nutrients. in order to evaluate the morphological characteristics of root chickpea and obtaining proper morphological makers for screening drought resistant genotypes, four experiments were conducted in different phenological stages of growth including, seedling, flowering, podding and seed filling stages. ten conventional iranian genotypes of chickpea with different geographical regions were selected from mashhad chickpea collection. except in seedling stage, genotypes were grown in drought stress (25% field capacity) and control (field capacity) conditions. experiments were arranged in a factorial based on randomized complete block design with three replications. in seedling stage, significant differences were found among genotypes for root traits. the value of ra, rv, rdw and trl was highest in mcc358 genotype, however r/s ratio was highest in mcc30 genotype. despite that drought and genotype intraction had not significant effects on tap root length in flowering and podding stages but in seed filling stage, drought stress decreased tap root length significantly compared to control. r/s ratio increased up to flowering stage in response to drought stress. this result was related to decrease in shoot growth compared to the root. we didn’t find uniform changes for root traits at different growth stages among the genotypes for introducing high performance genotypes throughout the growing season. so, in order to screen, selection must be done at the phenology of growth, which is most effective. key word: chickpea, drought stress, root, root/shoot ratio