Investigation of changes in stomatal conductivity, canopy temperature and relative leaf water content of pinto bean genotypes

About 60 percent of the lands under bean cultivation in the world are in areas face with water shortage during the growth season. In order to investigate the influence of deficit irrigation (supply of 100, 80 and 60 percent of crop water requirement) on pinto bean genotypes(Sadri, C.O.S.16, KS21193 (Koosha193), Taylor Line and KS21486) the present experiment was conducted as split plots based on randomized complete block design at the research farm of Faculty of Agriculture of Shahrekord University during 2013-14. Results showed that reducing the amount of water used decreased succulence index and the amount of leaf water content of under investigated genotypes. In addition, canopy temperature increased due to reduction inthe amount of water irrigation. Stomatal conductance of both sides of all genotypes decreased due to reduction of the amount of using water.The highest grain yield in supply conditions of 100 and 80 percent of plant water requirement conditions, was obtained from C.O.S.16 (594.6 and 289.2 gram per meter square, respectively). In the supply conditions of 60 percent of water requirement conditions, KS21486 genotype allocated the highest grain yield (109.5 gram per meter square). There was a significant and inverse relationship between canopy temperature and grain yield in all the measured stages both before and after irrigation. Also, a positive and significant correlation between stomatal conductance bottom of leaves in all stages of measurement before irrigation with grain yield was observed. It seems that stomatal conductance indices, canopy temperature and stomatal index are good indicators for determination the effect drought tension in pinto bean and through the mentioned traits, identification of drought tolerant and sensitive genotypes would be easy.