Study On Inductive Effects Of Medicago Ruthenica(L.)Sojak.cv.’zhilixing’ By Colchicine Induction

Medicago ruthenica(L.) Sojak.cv.’Zhilixing’ is a perennial diploid plant of Medicago Linn., the grass is cold, drought, salinity resistance, barren, stems erect, blossom, and the forage quality is good, with high nutritional value, but the grass yield and seed yield were lower than alfalfa, while the giant polyploid plants can improve the shortcomings, so it can be obtained by colchicine inducing polyploid plants, which lay the foundation for breeding new cultivars with high yield and good quality of Medicago ruthenica.In this study, the seed and seedling of Medicago ruthenica(L.) Sojak.cv.’Zhilixing’are used as experiment materials. Polyploid induction experiment is carried out with the seed soaking and droping method in different concentration of colchicine, dimethyl sulfoxide(DMSO) and different treatment time. Through the appraisal of Mutagenic material’s morphology, cytology, the mutagenicity of photosynthetic physiology index and identification of ISSR molecular linkage map, the polyploid plants are selected. The main results are as follows:1. Different induced methods lead to different induced function. Dripping seedling’s survival rate is higher than seed soaking’s, but mutation rate is lower than seed soaking’s; germinating seed plant’s survival rate and mutation rate are higher than the germination of seed; considering the seedling survival rate and mutation rate, the optimum conditions of dripping method was:treat with0.1%colchicine and1.0%DMSO for24h; the optimal conditions of seed soaking treatment was:treat the germinating seeds with0.1%colchicine by adding1%DMSO for5h.2. Through the stomata parameters picked out148variants, and selected34plant with the stem diameter, spacing becomes smaller, leaf became thick dark, leafy, leaf curling, leaf margin serrate or incised deepen strains, including12plants selected by dripping method, the variation rate was19.67%,using seed soaking method obtain22plants, the mutation rate was25.29%. Further identification showed that50%variants’ relative chlorophyll content was significantly higher than that of control,15.4%variants’ photosynthesis were significantly better than control plants. By chromosome identification from random variants, the results showed that8-5,②-3,③-13for double tetraploid plants.3. The34variants were detected by ISSR, the percentage of polymorphic loci of the variants obtained by dripping method and soaking method were92.06%and94.83% respectivel y.By cluster analysis of UPGMA,the mutant was divided into different categories,according to the characteristics of all kinds of plants,with number of chromosome,screened9chromosome doubling plants named the②-3、⑧-17、⑦-13、⑤-2、⑦-6、⑦-18、⑦-31、8-5、1-6、then the⑤-2、⑦-13and⑦-31were selected as high yield polyploid plants according to the hay weight.