Genetic analysis of grain yield and physiological traits of hybrid maize cv. SC704 under full and water deficit irrigation conditions

Seven generations of B73, MO17, F1, F2, F3, BC1 and BC2 were evaluated in this study for grain yield and several physiological traits. Field evaluation was conducted in a randomized complete block design with twenty replications under water deficit condition in agricultural research station at the University of Tabriz (Iran) in 2017. Statistical analyses were indicated that significant difference among seven generations for all studied traits and the presence of genetic diversity between selected parents under experimental conditions. According to percent reduction in grain yield and carotenoids (33.79% and 10.99% reduction, respectively), MO17 was ranked as resistant in comparison with B73 (56.06% and 26.03% reduction, respectively) under severe stress condition. However, for chlorophyll index the reduction was less in B73 than in MO17. The results of multivariate analyses were also indicated the reduction in grain yield by water deficit stress due to the decrease in the carotenoids and chlorophyll index. Simultaneously, the selection considering these traits can be used in breeding programs for improving grain yield and water deficit stress resistance. Generation mean analysis and genetic variances indicated that non-additive gene effects and dominance variance had an important role in the inheritance of grain yield, total chlorophyll, carotenoids and chlorophyll index under all three water regimes, whilst chlorophyll a and b mostly governed by additive variance suggested the selection of the early generation could be helpful for improvement of these traits. In conclusion, it is essential for exploiting non-additive gene action by producing hybrid varieties in maize.