Abstract:

Thirteen inbred lines were used in incomplete diallel crosses (7×6) to analyze genetic effect of main nutrient quality characters in normal maize. The results indicated that main nutrient quality characters were controlled by embryo, endosperm, cytoplasmic and maternal genetic effects, which did not have much more difference among each other. The embryo genetic effects were represented as embryo additive effects of protein, starch and oil content. Endosperm effects of these main nutrient quality traits were all represented as endosperm dominance effects, and maternal additive effects was more important than maternal dominance effects. Predicted genetic effects showed that inbred lines 9636, 99s2041-1-1-1 and 478 were better than other parents, their genetic effects could play the role on the improvement of main nutrient quality characters in normal maize. Correlation analysis showed that there were different degree of genetic correlations between different nutrient quality characters; these quality characters could be improved by indirect selection and utilization of heterosis. The method applied in this study revealed much more genetic information than traditional NCⅡ analytic method. The results revealed by traditional NCⅡ analytic method could cooperate with Zhu’s method to instruct our breeding practice exactly. Because by the Zhu’s method, the total genetic effects is divided into some small parts, and which are difficult to use in practice. But it could help us to realize these complex characters such as nutrient characters more deeply than ever. The traditional NCⅡ analyze method could be easy operated in breeding practice. In this study, the experiment data were analyzed by using traditional NCⅡ analytic method. The results indicated that these four main nutrient quality characters all were controlled by female parent’s genetic effects, which were significantly different. These genetic effects, such as embryo, endosperm and maternal genetic effects have very complex relationships between each other. These three genetic effects all were controlled more or less by female parent and couldn’t be distinguish clearly. In fact, there were 2/3 endosperms as same as female parent in genetic components. And characters of kernel were controlled mostly by female parent in whole growing stage. So that, these female parent genetic variance of four main nutrient quality characters all were significantly different, because these genetic variance included some other genetic components. For oil content, the genetic variance of female parent and male parent were significantly different at 0.01 and 0.05 probability levels respectively. These correspond with high oil content maize breeding and utilization in practice, for example, the selection and synthesis of high oil content maize population and the xenia effect on normal maize of high oil content. In this study, P₁, P₂, F₁ and F₂ generation were need to predicate every genetic variance, covariance, effect and so on for four main nutrient quality characters. This method could be improved by increasing other generations, such as backcross generations, and by strictly experimental control and so on.

Key words: Normal maize, Nutrient quality character, Genetic effect, Near-infrared spectroscopy (NIRS), Genetic variance and covariance