Studies On Cross Breeding Of Brassica Oleracea L. Var. Acephala D.C.f. Tricolor Hort. And Inheritance Of Ornamental Characters In Brassica

To emphasize introduction and neglect breeding is a common phenomena that exists in flower breeding field in our country. The efforts to select good materials from the introduced species or cultivars and breed new cultivars by use of them are rarely done. So it does in Brassica oleracea L. var. acephala D.C. f. tricolor Hort., and its seeds must rely on the import. In this study, the self-incompatibility lines and self-bred lines of Brassica oleracea var. acephala have been selected by continuous selfing of introduced materials; the male sterile lines have also been produced by transferring the male sterile gene into elite selfing lines, which lay a foundation of F₁ seed production of Brassica oleracea var. acephala. Moreover, the heredity characteristic of leaf color of leaf mustard was investigated, and radiation mutation method was applied to B. napus to produce some ornamental lines with dwarf plant size. The results were as follows:About 40 self-incompatibility lines have been obtained from introduced Brassica oleracea var. acephala materials by 3-4 successive generation of self-pollination in bud stage and selection. The most ornamental characters were close to homozygous to some degree, which laid a foundation for F₁ production of Brassica oleracea var. acephala.The self-fertility rate of the flowers treated by 3%-6% salt solutions was equal to, even better than, that of the flowers with bud pollination, which suggested that spraying salt solution during blooming period can replace bud pollination for propagation of the self-incompatibility lines.The embryogenesis rate of microspore is improved significantly by supplying 16% of sucrose in the induction and differentiation media, and low concentration of colchicine in the induction medium did not affect embryogenesis. Now 404 pollen embryos have been obtained from 6 of 20 genotypes tested.The sterile gene of ogura CMS in Brassica oleracea was transferred into some selfing lines of Brassica oleracea var. acephala cv Osaka and cv Nagoya.Leaf color of leaf mustard (B. juncea) was controlled by a pair of dominant gene, and red leaf is dominant to green leaf.The "dwarf 8500" line was selected from M₄ population of ⁶⁰Co-radiated fourth filial generation (F4) of interspecific hybrid of Brassica oleracea×B. chinensis, which had many advantages such as early flowering (on the first ten days of Feb), long blooming period (45-50 days), dwarf plant size (40-50cm), more branch number (3-4) and flower number, bright flower color (bright yellow), so it can be used as ornamental flower ofearly Spring.