Obtaination And Studies Of Allotriploid Hybrid And Its Derivatives In Chinese Cabbage And Cabbage

Microspores culture of the allotriploid hybrids between autotetraploid Chinese cabbage (AAAA, 2n=4x=40) and diploid Cabbage (CC, 2n=2x=18) was studied, and embryoid and plant regeneration were successfully produced, which will be used for constructing Chinese cabbage-cabbage addition lines, substitution lines and translocation lines. The morphology, cytology of microspore plant and backcross generation were studied. Moreover, allotriploid hybrids(2n=3x=28,ACC )were produced by crossing diploid Chinese cabbage (Brassica campestris L. ssp. pekinensis AA, 2n=2x=20) and autotetraploid cabbage (B. oleracea var capitata L. CCCC, 2n=4x=36) using ovary and ovule culture method, which will be used for constructing cabbage-Chinese cabbage addition lines, substitution lines and translocation lines. The morphology, cytology, and pollen characters of the allotriploid hybrids were studied, which provided theoretic basis for obtained alien addition lines, alien substitution lines and translocation lines. Results were as followed:1. It's feasible that microspores culture of the allotriploid hybrids(AAC) between autotetraploid Chinese cabbage and diploid Cabbage was studied for producing embryoid and plant regeneration. 53 microspore plants were successfully obtained. Every hybrid equally produced embryoid, but the induced frequency of microspore embryoid was low. The induced frequency of microspore embryoid of different hybrid combinations was different. Medium NLN supplemented with 13% sucrose was more adapt to microspores culture than medium NLN supplemented with 10% sucrose. The fitting low temperature treatment to buds was helpful for microspore culture. The effect was better if the while of low temperature treatment was 12h~24h, and the induced frequency of microspore embryoid was higher.2. The number of chromosome of 15 microspore plant was identified, the result showed that the number of chromosome of 60% microspore plant was 17-19. The percentage of plant (2n=18) was 46.7%. Otherwise, the number of chromosome of 40% microspore plant was more than 19. The characters of microspore plant from allotriploid hybrids separated badly. The plant vigor, plant height, leaf shape, leaf color, flower color, flower shape, flower size, florescence and fertility were different among lines. Moreover, the occurrence of diverse chromosome associations at diakinesis such as trivalent, bivalent and univalent suggested that the pollen-mother-cell's meiotic chromosome behavior of plant regeneration was complicated.3. The morphology of different backcross generation plant was different.4. Allotriploid hybrids(ACC) were produced by in vitro culture of embryo. The positiveand negative crossing test between diploid Chinese cabbage and autotetraploid cabbage was studied. The result showed that diploid Chinese cabbage as female parent could be successful. Otherwise, different parents could affect the result of ovary culture. Diploid Chinese cabbage 05-58, 05-116 was respectively selected as female parent, the result showed that ovary culture could get success when 05-58 was selected as female parent. The embryo of hybrid came to plant through callus.5. The pollen-mother-cell's meiotic chromosome behavior of the allotriploid hybrids between diploid Chinese cabbage (AA, 2n=2x=20) and autotetraploid cabbage (CCCC, 2n=4x=36) was complicated. The occurrence of diverse chromosome associations at diakinesis such as multivalent, bivalent and univalent. There were high frequently trivalent, which indicated that high homoligization between Chinese cabbage and cabbage was involved. Several dissociative chromosomes were observed at methaphaseI .There were distributions of 13-15, 12-16, 14-14. 11-17, 10-18. 13-2-13. 14-1-13 and so on at anaphase I . Otherwise, there was few chromosome bridge phenomena.6. Pollen regularity had remarkable positive correlation with pollen activity. The pollen activity, pollen regularity of allotriploid hybrids between diploid Chinese cabbage and autotetraploid cabbage was remarkably lower than diploid Chinese cabbage's and autotetraploid cabbage's. The number of pollen was remarkably lower than autotetraploid cabbage's.