Genetic control of some physiological attributes in wheat under drought stress conditions

Abstract

Investigation of inheritance, mode of gene action and determination of effective breeding strategy for improvement of physiological and morph-physiological traits specifically in drought stress conditions is very important. Therefore, this study was conducted using two drought susceptible and tolerant wheat cultivars. Cultivars Sakha8 (tolerant) and Pishtaz (susceptible) as parents along with F1, F2, BC1 and BC 2 generations were sown in a randomized complete block design with three replications in drought stress conditions. Results of analysis of variance indicated significant difference between generations for all the traits. Degree of dominance revealed over-dominance for all the traits. Fitting simple additive-dominance model designated that the model accounted for genetic changes of harvest index and biological yield. Additive-dominance model was not able to account for changes of traits relative flag leaf water content and mean of grain filling rate. It was revealed that m-d-h-i-j model for relative flag leaf water content and m-d-h-i model for mean of grain filling rate are the best models. Estimation of heritability and mode of gene action indicated that selection for improvement of traits studied in stress condition and specifically in early generations have medium genetic gain. Therefore, it is concluded from the present study that can propose use of traits mean of grain filling rate and harvest index as indirect selection criteria for improvement plant grain yield in drought stress condition. © 2006 Asian Network for Scientific Information.