Analyses On Heterosis And Combining Ability Of The Traits Related To Plant Types In Brassica Napus L.

For now, the yield traits and quality traits Brassica Napus L had been improved for a long time and made great achievements. There little researches on plant type traits were reported. Up to now, the precise definition of Ideal plant type of rape had not found. Only there are little researches on the plant height, branching habit, leaf traits of rape. And those researches paid more attention to the traits related to yield. Along with the development of production technology, practical production needs the rape variety which has greater diversity of plant type and the actual production condition of supporting. As the basis of cultivated and breeding, it is necessary to study on the traits related to plant types. In this paper, two varieties of the compact conformation type (CCT) and the loose conformation type (LCT) as crossing parents were made. The average performance of Fi was invested. The maternal effect and heterosis are observed along with a preliminary analysis.The combining, heterosis, corresponding of those characters were analyzed in the next step. These studies are helpful on parent and powerful combination choosing.and provide the theory reference and practice basisThe main search results were showed as follow:1. Analysis of reciprocal crossing showed that the maternal effect of main plant type traits were not significant.2The analysis results of variance for the traits related to plant types showed that all the plant type traits of parents were highly significant, except the blade length, straight blade length, beak length, rhizomes, stem, pod beak length. All the plant type traits of cross combination were highly significant.3. The heterosis analysis results indicated that there was significant heterrosis in plant type traits of Brassica Napus L.28cross combinations showed mid-parent heterosis, but overparent heterosis diversity. Angle between stem and leaf, plant height, primary branch position, end branch position, Angle between stem and primary branch, primary branch number showed that negative advantage. The others characters were positive advantage.4. The analysis results of variance for combining ability showed that the general combining ability (GCA) and specific combining ability (SCA) of traits were significant. Estimate value of combining ability showed that the values of GCA for the different characters of one parent were diverse. And the values of GCA for one character of different parents were diverse. GCA of width of leaf, plant height, the first branch height, end branch height, angle between stem and primary branch, length of main raceme of MC0614were lower. GCA of primary branch number of N103-2was higher. GCA of width of leaf, plant height, the first branch height and end branch height of MC0411were higher. GCA of angle between stem and leaf of ZS-6was least. GCA of width of pod and length of main raceme of1718-1were higher. GCA of angle between stem and leaf, angle between stem and primary branch of102-34were higher. SCA of all cross combinations were different and the SCA of different characters of one combination were diverse. SCA of width of leaf, angle between stem and leaf, plant height, the first branch height, end branch height, angle between stem and primary branch were highest in these combinations (ZS-6×102-34, ZS-6×102-34, N103-2102-34, N103-2×102-34, MC0614×N103-2,N102-5x MARWES). SCA of length of primary branch, primary branch number, length of main raceme, length of pod, pod beak length, width of pod, length of carpopodium were highest in these combinations(MC0614x1718-1,1718-1×102-34, MC0614x MC0411, MC0614x MARWES, N103-2xN102-5, N102-5×MARWES). The GCA was directly related to the performance of parent. The SCA have some connections with GCA, but GCA is not the same as SCA.5. Variance of specific combining ability of parental characters showed that the variance of angle between stem and primary branch, length of main raceme in MC0614were the lowest. Variance of special combining ability of primary branch number of MC0411and ZS-6were least. Variance of specific combining ability of pod length of1718-1was least, but the Variance of specific combining ability of primary branch number was highest. Variance of special combining ability of the most traits of parent102-34was higher.6. Estimated proportions of variance components of combining ability and heritability showed that variance components of GCA of width of leaf, angle between stem and leaf, angle between stem and primary branch, length of primary branch, length of main raceme, carpopodium length were great than variance components of SCA. Variance components of SCA of plant height, primary branch position, end branch position, primary branch number, beak length, width of pod,were great than variance components of GCA. The heritability of between stem and primary branch and carpopodium length were83.28%,74.61%.7. Analysis result of correlation among characters showed that the leaf traits did not have a correlation with the angle between stem and primary branch The leaf length and blade broad had a positive correlation with straight blade length. The leaf length and blade broad, straight blade length had a significant correlation with rhizomes, stem diameter. Angle between stem and leaf had a negative correlation with primary branch position, end branch position. The plant height had higher correlation with most of the traits related to plant types. Correlation coefficient between rhizomes and stem diameter was0.8155. The pods of main raceme had higher correlation with plant he ight, primary branch position, end branch position, etc. But the pods of main raceme had a negative correlation with primary branch length, beak length.8. Correlation coefficients among combining ability and performance of traits and heterosis indicated bat GCA and combining ability sum were highly correlated with performance of traits, and SCA was highly correlated with heterosis. There were little relation between GCA and SCA.