Graphical Analysis for Grain Yield Related Traits in Maize (Zea mays L.) using Diallel Crosses under Normal and Water Stress Conditions

This study was carried out in order to investigate the genetic structure of the F1 hybrids along with their parents (6 inbred lines) evaluated in field under normal and water stress regimes to determine the nature and magnitude of genetic variances and heritability estimates at dezful research station in safi abad, from 2012, using RCBD with three replications. Results analysis of variance showed that Variation among genotypes were highly significant for all the traits studied under both regimes. Therefore, variations were partitioned into additive and non additive components according to Hayman and Hayman & Jinks methods. It was observed that a and b components which are due to additive and dominant gene effects respectively, were significant for all studied characteristics under both conditions. Considering the average degree of dominance, as well as Vr/Wr graphs revealed that the yield potential traits like plant height, grain number in row in ear, grain row number in ear, and grain yield per plant were controlled by over dominance type of gene action, while traits like ASI, and 100-kernel weight were under the control of partial dominance with additive type of gene action under both conditions. Overdominance for most of the parameters reveals that selection in later generations may be more effective and the selection in early generations will be more effective for the trait which is additively controlled.