| Yellow rapeseed (Brassica napus L.) possesses many better characters. For example: thinner seedcoat, without pigment; lower cellulose and polyphenol; higher protein and oil etc. But it seed color is unstable. In the quality breeding of yellow-seeded rape (Brassica napus L.), selfing line breeding from field culture will cost ten years, yet pure line by haploid breeding will save time and shorten the proceeding of growing. First, some factors in anther culture of yellow-seed rape (Brassica napus L.) was studied in this research. It was shown that callus induction rate was influence by flower bud size, medium and sucrose concentration in the medium, Flower buds 2mm-3mm in length were most desirable, and B5 supplemented with 6%-lO% sucrose appeared to be the optimum medium. Best results in callus differentiation was obtained in B5 medium enriched with 6-BA 4.OmgIL and NAA O.2mgIL. Second, haploid plant regeneration of microspore culture from yellow-seeded rape (Brassica napus L.) was studied. The condition of improving embryo production was obtained in F1 of hybrid combination which were prehandled in 30Cfor 2-3 days on NLN medium with 13%-16% sucrose. The addition of 6.OmgIL AgNO3 and 2.Omg/L 6-BA to MS medium was found to be the best for the bud differentiation. And the shoots?rapid propagation needed MS medium with 1.Omgl 6-BA and 0.lmg/L NAA. Finally, haploid plants were examined by cytological, morphological and embryological methods, and dissecting microscope after they were cultivated in the field. In the course of haploids growing, they were diploidized by 0.1% colchicine. Physiological and biochemical characters of dihaploids were measured. The data indicated that some dihaploids showed a higher genetic stability than parents and yellow rapeseeds were gained, so it suggested that haploid regeneration system provided by this experiment is suitable for yellow-seeded pure line breeding from the F1 of yellow-seeded lines crossed with black-seeded lines (Brassica napus L.). |
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