| Heterosis is a biological phenomenon that is ubiquitous in nature and has been widely used in agricultural production.Chinese cabbage is a kind of cruciferous vegetables with significant heterosis and self-crossing.Studying the heterosis phenomenon of Chinese cabbage can not only improve its yield,but also lay a foundation for improving its comprehensive traits,such as disease resistance and stress resistance.In this study,the genetic diversity of 96 Chinese cabbage inbred lines was analyzed based on Indel marker and genetic diversity analysis based on agronomic traits,combining the strength analysis,and the identification of the dominant characteristics of Chinese cabbage hybrids.The four dominant genes were combined in different dominances.Analysis of the expression level,the following conclusions were obtained:(1)Based on the genetic diversity analysis of Indel marker,the genetic distance between Chinese cabbage inbred lines was 0.3333~0.8333,and the average value was 0.5884.Based on the genetic distance of 0.52,96 Chinese cabbage inbred lines were divided into six categories.The first group contained 21 points,the second group contained 12 materials,and the third group contained 16 materials.The four groups contain 15 materials,the fifth group contains 14 materials,and the sixth group contains 18 materials.(2)Based on the analysis of genetic diversity of agronomic traits,the coefficient of variation of 16 agronomic traits between parents was found to be large.When the Euclidean distance was 5,78 Chinese cabbage inbred lines could be divided into 6 groups.The first category consists of 19 points,the second category contains 8 materials,the third category contains 24 materials,the fourth category contains 16 materials,the fifth category contains 3materials,and the sixth category contains 8 materials.(3)By analyzing and analyzing the dominance of Chinese cabbage hybrid combinations,it was found that the average of all the traits in the hybrid generation was higher than the average of the parent traits except for the length of the shortened stem and the height of the leaf.The heterosis analysis of 129 hybrid combinations found that in addition to the height of the leaf ball and the length of the shortened stem,the other traits were positively combined with more negative combinations than the negative one.(4)For the analysis of the combining ability of 14 parents,it was determined that the general combining ability of A75,A17-1,A218,A51-4,YOUSANand A222 was higher.The combined fitness effect values of the combination A54-1×C30 and A84-1-1-1×A230 parents are relatively small,but their special combining ability effect values are relatively large,while thecombined A51-4×A17-1 parents generally have relatively large combined force effect values.However,their special combining ability effects are small.(5)Based on the genetic distance of Indel marker,96 Chinese cabbage inbred lines were divided into six groups,among which the first large group and the fourth largest group hybridized with each other compared with other groups,and the genetic distance was based on agronomic traits.The 78 materials were divided into six groups,and the first large group and the third large group hybridized with each other to have an advantage over other groups.(6)Based on the analysis of three superior indicators of super-middle advantage,super-parent advantage and over-standard advantage,the combination was found:YOU SAN×A17-1,A66-2-1×A17-1,A51-4×C15-111-1,A222×C15-111-1,A209-1×A17-1 and A118×A75 have strong heterosis compared to other combinations.(7)By analyzing the expression levels of four dominant genes of Br DDM1,Br CCA1,Br TOC1 and Br LHY in different dominance combinations,the expression levels of Br DDM1 and Br LHY genes were positively correlated with dominance. |
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