Genetic interaction and inheritance of biochemical traits can predict tolerance of hybrid maize cv. SC704 to drought

To study gene action and inheritance of some biochemical traits generation mean and generation variance analyses of basic seven generations B73 (as maternal line), MO17 (as paternal line), F 1 , F 2 , F 3, BC 1 , and BC 2 were conducted at the University of Tabriz agricultural research station (NW-Iran) in 2017. The generations were sown in PVC pipes using a RCBD with 20 replications under three water regimes (100% FC, 55% and 75% available water depletion). The results revealed that based on percent increase of polyphenol oxidase, soluble sugars and proline, SC704 and MO17 were ranked as resistant (enhancement 41.39%, 58.39% and 55.47% in SC704 and 34.25%, 53.75% and 64.51% in MO17, respectively) under severe stress condition. Pearson’s correlation and principal component analysis indicated polyphenol oxidase activity most correlated with proline and soluble sugars and suggest that the important role of these traits in antioxidative defense mechanisms. The findings of the generation mean analysis implied the existence of digenic interactions. The prevalence of dominance variance and low narrow-sense heritability (0.07–0.47) for catalase, peroxidases, and polyphenol oxidase activities under severe stress condition suggest the utilization of a hybrid breeding program such as heterosis and selection in the later generation to facilitate breeding for improvement of these traits. In contrast, additive genetic variance and high narrow-sense heritability (0.53–0.71) for protein content, proline concentration and soluble sugars under severe stress condition revealed that the selection in the parents’ inbred lines or early segregating generations could be useful to improve the aforementioned traits in the maize.