The Research Of Heterotic Group And Heterosis Model Of The Maize

Maize is the earliest and most productive crop to utilize heterosis, and also the earliest crop to divide heterotic groups and heterotic pattern. To improve the efficiency of maize breeding, selecting elite inbred lines with high combining ability, good agronomic traits, strong resistance and high yield to make excellent hybrids is an effective way.In this study, we built three heterotic patterns by crossing three heterosis groups Reid, Non-Reid and DOM. Pattern 1, on the basis of DOM×Non-Reid and Reid group as testers to build groups with diallel crosses; Pattern 2, on the basis of Reid×Non-Reid and DOM group as testers to build groups with diallel crosses; Pattern 3, on the basis of Reid×DOM and Non-Reid group as testers to build groups with diallel crosses. We analyzed the heterosis and combining ability of the three heterotic patterns and got a heterotic pattern with simple, practical and adapted to the region we researched. Test results are as follows:1. In the test of three heterotic patterns, the yield per plant with obvious strong heterosis. Pattern 1, the value of total average advantage value of yield per plant was 144.36%. The trend of 30 combinations was positive and 7 of them were strong heterosis with 20% over the value of total average advantage. Pattern 2, the value of total average advantage value of yield per plant was 142.35%. 5 combinations were strong heterosis among the 30 positive combinations. Pattern 3, the value of total average advantage value of yield per plant was 130.29%. 4 combinations were strong heterosis among the 30 positive combinations. Pattern 1 obtains the most combinations with strong heterosis among the three patterns. We concluded the best heterotic patterns in the region was on the basis of DOM×Non-Reid and Reid group as testers.2. The GCA(general combining ability, GCA) analysis of 15 inbred lines breeding from three heterotic patterns showed that both yield traits and ear traits of J1240 and J1511 with high GCA in Pattern 1. In Pattern 2, the GCA of yield traits and ear traits in J1545 was high. In Pattern 3, the GCA of yield traits was high and the GCA effective value of ear was positive in J1736.3. The SCA(special combining ability, SCA) analysis of 90 combinations from three heterotic patterns showed that the SCA effective value of yield per plan was positive in 20 combinations in Pattern 1. In Pattern 2, the SCA effective value of yield per plan was positive in 17 combinations. In Pattern 3, the SCA effective value of yield per plan was positive in 18 combinations. We concluded that it was easy to breed excellent hybrids with high yield potential in Pattern 1.4. Genetic parameter analysis of yield and its components showed that GCA variance(Vg) and specific combining ability variance(Vs) were significantly in three heterotic patterns. GCA variance is greater than the SCA variance and hereditary is in additive effect, which indicating that parents play a greater role in hybrid offsprings.The generalized heritability(hB2)and narrow heritability(hN2) of four traits in descending was rows per ear, kernels per row, yield per plant and kernel weight in Pattern 1.The four traits in Pattern 2 and Pattern3 were similar to Pattern 1, and hB2 and hN2 of the rows per ear were still the highest among the four traits. The rows per ear with high hB2 and hN2 indicated that the additive effect of the traits was greater than non-additive effect, and the variation was mainly caused by hereditary not environment. So we can select them in the low generations.5. Path analysis of 90 combinations from three heterotic patterns showed that fringe weight and seed yield rate directly and greatly effect on the yield, while plant height, kernels per row and ear diameter were negative to the yield. Therefore, coordinate fringe weight, kernel rate, plant height, kernels per row and ear diameter in the process of breeding, can we cultivate the excellent varieties with high-quality, high yield and highly resistant.Combine the results of heterosis and combining ability analysis from three heterotic patterns, we concluded the best heterotic patterns in the region was on the basis of DOM×Non-Reid and Reid group as testers.