Assessment of Iranian chickpea (Cicer arietinum L.) germplasms for drought tolerance

Iran is one the most important centers of diversity for chickpea in south western Asia. Landraces are well adapted to local environmental conditions, and have evolved a range of morphological, phenological and physiological mechanisms to efficiently utilize the available water in a dry environment. In order to study some of these mechanisms, 150 genotypes of chickpea (Kabuli type) were evaluated using Augmented Designs for Preliminary Yield Trials under stress (Rainfed) and nonstress (Irrigated) conditions in Research Field of Mashhad College of Agriculture, Ferdowsi University of Mashhad, during 2005-2006 growing season. Then, based on the obtained results, four candidate genotypes for drought tolerance and two susceptible ones were evaluated in a pot experiment at open door situation in stressed (25% Field Capacity) and non-stressed (Field Capacity) conditions based on a factorial trial in Randomized Complete Block Design. There were positive and highly significant correlations between quantitative drought resistance indices such as MP, GMP, STI and HM with yield in stress and nonstress conditions. Also, there were positive and high significant correlations for SSI and DRI with yield in nonstress and stress conditions, respectively. Based on drought resistance indices and DRI, MCC544, MCC696 and MCC693 genotypes were superior to others, so they can be viewed as promising genotypes for drought resistance. These results were approved using three dimensional scatter graph and multivariate biplot graph. In stress condition, there were negative and high significant correlations between yield and days to flowering. Drought stress decreased leaf area per plant in all genotypes, significantly. In stressed and non-stressed conditions, leaf area in susceptible genotypes was more than that in tolerant genotypes, thus drought tolerance may be attributed to less transpiration and water loss because of smaller leaf size and reduced leaf area expansion in tolerant genotypes when drought stress develops.