Study On Isolated Microspore Culture And Plantlet Formation In Heading Chinese Cabbage

In order to improve the isolated microspore culture system in heading Chinese cabbage and creat new germplasm resource, and expand of this technology in breeding practice of heading Chinese cabbage. Isolated microspore culture was carried out with 15 F1 hybrids and inbred lines of heading Chinese cabbage (Brassica campestris ssp. Pekinensis (Lour) Olsson). Major factors influenced embryogenesis and microspore plant generating rate in heading Chinese cabbage during microspore culture were investigated. Explore the methods of ploidy identification for microspores-derived plants. The principal results are as follows:1. The production of microspore-derived embryos from bud in full flowering stage is higher than the bud in semiblooming stage and in end flowering stage; The appropriate length of'Xiuyue'bud was 2.5～2.99mm; The heat shock at 33℃for 24 hour could promote Chinese cabbage embryo emergence.2. NLN liquid medium added 0.2 mg/L 6-BA can only promote the production of embryo in embryo-prone materials.3. Genetic type is the key factors affecting the embryoid production of Chinese cabbage. There was significant difference in embryoid induction, among different genetic types. 12 varieties of 15 genetic types used in this experment got embryoid. The highest embryo yield was 65.4 per bud.4. Transferring mature embryos to the regeneration medium in good time and the embryo development degree was closely related to the rate of plantlet regeneration rate. The best time of embryo stay on liquid medium was 21 days, the rate of plantlet regeneration up to 75%. With long or short of 21 days, it had a certain impact on plantlet regeneration; Mature cotyledonary and Germinated embryos had the strongest capacity of regeneration, the rate of plantlet regeneration up to 100% and 56% respectively, Torpedo embryo had lower rate of plantlet regeneration, only 6.7%, Globular and abnormal embryo can not plantlet differentiation.5. Regeneration medium added with different hormones had a certain impact on microspore embryo differentiation. Embryoid had the fastest differentiation on the medium added 0.2 mg·L-1 6-BA and 0.02 mg·L-1 NAA, and the rate of differentiation up to 75%; The 1?2 MS medium added 0.1 mg·L-1 NAA was most suitable for rooting of microspore plantlets in heading Chinese cabbage.6. The rusults of ploidy indentifications have over 60% consistency among field morphology, chromosome numbers and self-fruitfulness indentification, but they were significant difference with character of stoma.