Study On Chromosome Doubling Technique Of M.Sativa Subsp.Caerulea(Less.Ex Ledeb.)Schmalh Cv.Jindera

Using the Jindera alfalfa as the experimental material, the tablet tested materials were identified at first, then use the improvement of L. D. Cua method to treat the top of alfalfa branches, doubling the chromosome of the growing point, using the colchicine solution to handle the alfalfa seed and alfalfa meristem, doubling the chromosome of them, in order to explore the optimum concentration of colchicine solution induced alfalfa tetraploid and the treatment days, forthermore, the above three methods compared to select a relative effective and ideal chromosome doubling method, laying a certain foundation for breeding of the polyploid.The results as following:Using the tissue in vitro chromosome doubling technology to inducte the callus of diploid alfalfa, the results show that the induction rate, the differentiation rate and the survival rate of regenerated plants were significantly low compared with the control, and with the concentration of the colchicine hormone, the treatment days extending, the toxic effects of colchicine are increasing. The morphological characteristics of the regeneration of plants show that0.07mg/ml colchicine,3days later, the regeneration plants identified as variants, and their root tip chromosome are mixed ploidy.Using the dipping seed to induce polyploidy, the results show that some seed after germinating, the external morphology changed obviously. The color of seedling cotyledon after treatment is dark green and leaf hypertrophy, hypocotyl thicker, the leaf appearance later, seedling growth is slower, because the concentration and treating time are different, the time of variation appearance and variability of germinated seeds did not have significant differences. Due to the seeds which after treatment, the germination rate, growth rate and induction rate, show that the0.2%of colchicine concentration and48h of processing time is the considerable treatment, the tetraploid induction rate is22.22%.Using the improved L.D.Cua method, the results of condition treat the branches of the top growing point show that the treatment which is0.05%colchicine solution concentration and treating time is24h has the highest survival rate, reaching88.89%. Due to the limited sample, this trial still cannot determine the best effect is at0.05%of colchicine concentration,24h of treatment time. But the results also proved that the greater the concentration of colchicine, the longer of treating time on the plant, the bigger toxic effects. The colchicine within a short period of time can ensure that the plant will not be affected by extensively, but it can cause chromosomal aberrations of alfalfa. The three induced polyploidy methods, although they have disadvantage, and shortcomings, the polyploid induction rate is not satisfied, which hindered the process. of alfalfa polyploid breeding. In the future polyploid breeding research, using the improved methods may get a better result of polyploid induction.