Construction Of Genetic Linkage Map Of Non-Heading Chinese Cabbage And Identification Of Plant Type Phenotypic Traits

Non-heading Chinese cabbage(Brassica campestris ssp.chinensis Makino),as a kind of green vegetables with abundant resources in the south of China,supplies the nutrients that people need in people’s daily life.Many phenotypic traits that affect the yield and commerciality of non-heading Chinese cabbage are mostly quantitative traits,which were easily disturbed by the environment.The study of genetic mechanisms was also a difficult problem.The genetic linkage map of the non-heading Chinese cabbage and the analysis of QTLs will be benefit to genome research and breeding.In our study,the molecular genetic map was created through the RILs population,and several phenotypic traits were analyzed for genetic analysis and QTL mapping.The follows are the results of this study:1.The variability analysis,correlation analysis and principal component analysis were carried out on the RILs population constructed by ’Maertou’ and ’Suzhouqing’.The consequences indicated the eight phenotypic traits were typical quantitative traits and the variation coefficient were between 20.60%and 41.10%.It was found that the plant height was highly correlated with other traits in our correlation analysis.The coefficient r is 0.868 between the plant diameter length and width.The correlation between plant diameter width,number of leaves and petiole width was not significant,and the number of tillers had no significant correlation with petiole width and leaf width.The principal component analysis showed that the first principal component is influential in plant diameter length,plant diameter width,number of leaves and number of tillers,while the influence of the second principal components is petiole width and leaf width,the genetic variation of the group can be used as a material for further analysis.2.The RILs population was constructed from the non-heading Chinese cabbage’Maertou’ and ’Suzhouqing’.The molecular genetic map was obtained by SSR markers.We used QTL IciMapping V4.1 software to make the linkage map.The map had 65 SSR markers and 10 linkage groups and the number of chromosomes is the same as the number of linkage groups.There were 16 distorted markers among them,occupied about 24.62%.The groups’ length had 971.05 cM while the average distance was 14.94 cM,the length of these groups were between 24 cM and 172.5 cM,and each linkage group contained the number of markers between 3 and 10.We can use the map to do QTL analysis.3.Seven phenotypic traits of non-heading Chinese cabbage were used to analyze QTLs by the genetic linkage map of RILs population from non-heading Chinese cabbage’Maertou’ and ’Suzhouqing’.Two QTLs were detected on two linkage groups,involvng 1 for petiole width and 1 for number of tillers.These explained 10.31%and 3.57%of the phenotypes we surveyed respectively.These QTLs provide a theoretical basis for the molecular marker-assisted breeding of phenotypic traits of non-heading Chinese cabbage.