Heterosis study on 4x Mt CMS and its maintainer line of non-heading chinese cabbage

Six crossing combinations were obtained by using 4x MtCMS line and 6 inbred lines of non-heading Chinese cabbage. Agronomic traits and heterosis of the F1 hybrids were studied. The result indicated that the main agronomic traits had a significant heterosis in the hybrid of non-heading Chinese cabbage. Yield per plant of 6 F1 hybrids had a certain degree of positive mid-parents and over-standard heterosis. Two of the hybrids,namely 4x Mt CMS?07P-10 and 4x Mt CMS?07P-8,were the largest. The mid-parents,over-parents and over-standard heterosis showed 18.90%,15.27% and 12.61%,respectively,in yield per plant. The 6 F1 hybrids were taller,the plant diameter larger,leaves thicker,leaf area larger and yield of plot greater than their parents,and these differences were significant. Quality was improved over their parents,and the mid-parents heterosis was positive but in minute amounts. The heterosis of the over-parents and over-standard were not significant.