Study on heterosis among subspecies or varieties in B. campestris L

摘要

35 hybrids were produced through crossing 5 sterile lines (subspecies or varieties in B. campestris L., such as Chinesecabbage, no-heading Chinese-cabbage, purple Tsai-tai and rapeseed in B. campestris L.) with 7 restoring lines using NCⅡ mating design. Their genetic effect of agronomic characters and yield characters as well as vegetative and yield heterosis of F1 were studied for the application value of the germplasm resource of B.campestris L in rapeseed breeding. The results indicated that ①yield per plant was controlled completely by dominant genes, and length of main inflorescence, except for additive genes, was mainly controlled by dominant genes too. ②plant height, No. of primary branches, siliques of primary branches, siliques of main inflorescence, seeds per silique and 1000-seed weight were controlled by additive and dominant genes together. ③No. of secondary branches, siliques of secondary branches, siliques per plant and density of silique were mainly controlled by additive genes. The mean heterosis of all vegetative characters were positive in F1 generation, that of petiole fresh weight was the highest (44%) and significant at 0.05 levels. Except No. of leafs, width of root-stem zone, Length of root and fresh weight of root system,other characters showed higher positive over-parent heterosis in F1 generation .The mean-heterosis of plant height, effective branch height, length of main inflorescence, seeds per silique, 1000-seed weight and yield per hectare were positive significant at 0.05 or 0.01 levels and the mean-heterosis and over parent heterosis of yield per hectare were positive significant at 0.05 or 0.01 levels in F1 generation, their value were 63% and 48%, respectively. All these showed yield heterosis of subspecies or varieties in B. campestris L. was better, so its utilization value is rather high in production.