Breeding Of Autotetraploid Non-Heading Chinese Cabbage Material With High Quality And The Characters Study

Induced diploid non-heading Chinese cabbage(Brassica campestris ssp. chinensis,2n=2x=20) by treating the growing point of seedlings with different solution of colchicine. The result had shown that tetraploid induction rate increased with increasing concentrations of colchicine, treatment with0.2%colchicine for6times made the best for getting autotetraploid plants, the probability was7.02%. Through the observation and comparison, autotetraploid had a significant difference in stoma, floral organ and silique compared with diploid. Stomatal length and width increased by64.91%and54.17%, the pollen grains length and width increased39.29%and32.18%, the difference was extremely significant, confirming the reliability of non-heading Chinese cabbage morphology preliminary identification. The successful induction of autotetraploid non-heading Chinese cabbage had an important practical significance for vegetables polyploidization breeding.From the successful homologous tetraploid breeding of high quality, dwarfish, tight white handle autotetraploid non-heading Chinese cabbage. The results show that, the breeding of tetraploid than diploids obtained quality has significantly improved; Soluble sugar and protein, Vc content significantly increased10%-40%;14.42%reduction in plant height, leaf width increased by27.38%,14.96%of the petiole shorter, plant expansion degrees decreased6.70%X8.55%, compact plant type with bright green leaves. After two generations of breeding, the tetraploid pure degree reaches100%and the uniformity reaches95%, the yield of plot increased by18.10%than the diploid, while it has good application prospects.The experiment has improved paraffin sections fabrication method in the application of leafy vegetables with high water content. The improved method simplifies the manufacturing process, optimize the production method, greatly save time. The production cycle of traditional methods is generally two weeks, while the improved method just consume one week, especially, the embedding stage just cosume12hours, to avoid the non-interrupt operation of the process lead to be forced to stay up all night. Using the improved method to observe the cross-section of blade and the longitudinal section of root tip in diploid and tetraploid non-heading Chinese cabbage discovered that vascular bundle and parenchyma in petiole of tetraploid are more development than diploid, the cells of palisade tissue and spongy tissue in leaves are quantities and to be tight arrangement, root tip tissue. The root tip meristem cells are larger, but fewer in number.Polyploid widely have a problem of low fertility. The materials were diploid non-heading Chinese cabbage and its artificial tetraploid, compared their in vitro pollen viability during flowering, observed their in situ pollen germination and tube growth. The results indicated that, both diploid and tetraploid in vitro pollens had a high viability in the initial time, both are more than70%. With the extension of time in vitro, pollen viability were gradually reduced, especially the tetraploid, and it lost the most viability after10hours. Pollen germination on the stigma was no significant difference, but the pollen tube growth of the diploid was significantly faster than the tetraploid. Generally tetraploid tube growth is later more than24hours than the diploid, speculated pollen tube growth hindered and low frequency of fertilizaed ovules result in the low seed setting rate of the tetraploid.