大白菜和黑芥种间杂种的获得及鉴定

Production and Identification of Interspecific Hybrids between Brassica campestris L.ssp.pekinensis and B.nigra

为丰富大白菜的抗病基因类型,特别是培育根肿病抗性种质,以品质优良的大白菜(Brassica campestrisL.pekinensis)自交系为母本,具有黑腐、根肿病抗性的野生黑芥(B.nigra)为父本,通过种间杂交,获得了13株杂种植株。利用形态学、细胞学和分子标记3种方法对杂种进行了鉴定,并分析了杂种的花粉活力及其育性。结果表明:杂种表型介于白菜和黑芥双亲之间,SRAP分子标记结果的聚类分析表明杂种在DNA水平上更趋向于白菜母本。F1雄蕊发育不好,花粉育性低,13株杂种中,仅获得杂种H4的回交后代。杂种H4的部分细胞染色体数目超过18条,约48%的细胞染色体数目为26条,超过了预期杂种染色体的数目。不育F1植株染色体数目等于和少于18条,结果提示杂种育性和细胞染色体数目有一定关系,染色体数目的增加提高了杂种的育性。

In order to enrich the germplasm resources of pekinensis and B. nigra were made and thirteen hybrids were B. campestris, crosses between Brassica. campestris L. produced. Three methods including morphology, cytology and SRAP （sequence-related amplified polymorphism） molecular makers were used to verify the hybrids. The pollen stain ability and fertility of the hybrid plants were also analysed. Morphologically the lybrids showed an intermediate phenotype while the dendrogram on SRAP data indicated that the hybrids were homophylic to the female parent. The pollen stainability of the hybrids was low, among which only one（H4） could produce seeds after backcrossed to the B campestris. Some of the cells in the hybrid H4 had 18 chromosomes while 48 percent of cells contained 26 chromosomes; The other twelve sterility hybrids had 18 or less than 18 chromosomes. Results indicated that the fertility of the hybrids was related to the chromosome number and the increased number of chromosomes could enhance fertility.