Studies On The High Rate Of Cotyledon Embryoid Induction And Plantset Formation In Brassica Microspore Culture Techniques

Microspore culture has been applied to the process of breeding research with its uniqueadvantages of reduceing the breeding generation and high cultural efficency. Athough it hasbeen successful on microspores culture of cabbage, there were lower rate of Cotyledonembryoid induction, and lower seedling rate.23superior cabbage varieties have been used astest materials for microspore culture. Study on the effects of different genotypes, plant age,adding colchicine and TDZ in culture medium on Cotyledon embryoids induction；and theeffects of different genotypes,different type of embryoids,different size of shoots,uniconazole on embryoids seedling induction. The main results are as follows:1. Genotype plays a major role in the microspore culture. Embryoids have beeninduced in13materials of all the15materials. The highest induction rate was14.0embryos/bud, and the lowest was0.2embryos/bud. The range of plant Cotyledon embryos was0.03to2.92embryos/bud.2. The embryoids induction in half of cabbage adult flower buds is higher than that ofcabbage adult. That half-adult plant is more suitable than the adult for microspore culture.donor plants in cabbage.3. Adding0.02mg/L of TDZ can significantly improve embryo rate and cotyledontype embryos rate in cabbage microspore culture. The rate of the embryoids and cotyledonembryoids ratio was increased12.7embryos/bud and18.8embryos/bud in Q10-4, and13.6embryos/bud and18.6embryos/bud in Q10-5.4. Adding30mg/L colchicine can significantly improve cotyledon type embryo rate anddouble haploid rate in cabbage microspore in the heat shock culture, The rate of theembryoids and cotyledon embryoids ratio was increased3.3embryos/bud,and the doublehaploid rate was85.9%.5. Cotyledon embryoids were easily form to single plants, and torpedo embryoids andball-type embryoids were easily form to multiple shoots in all different genotypes. The rate ofsingle plants and multiple shoots were different in different genotypes.6.The size of adventitious shoots was larger than2cm, the growth rate showed fast toslow after transferred to rooting medium, and the roots were fine and longer, The size ofadventitious shoots shorter than2cm, the growth rate showed slow to fast after transferred to rooting medium, and the roots were healthy and strong.7.Add0.5mg/L uniconazole MS+0.3mg/LNAA regenerated plantlets rooting mediumup to95.6%survival rate of regenerated shoots thick stems and roots.