Study On Mutation Of White Clover By Using Seed And Embryoid

White clover is an excellent leguminous forage with high adaptability, which can be used as forage for livestock, as well as lawn grass for environment greening. A preference for mild and humid climate and fertile soil conditions makes White Clover can not adapt to a high temperature and drought environment, even death in the less rainfall region, and the disease occurred seriously, thus limiting the use and promotion of white clover. Many researchers work with mutation breeding techniques to improve the drought resistance of the forage. Somatic embryoid way produces stable genetic variation in organisms, and there were few Mosaic, so it plays the irreplaceable role in the breeding of superior strains of biological system.To solve the problems above, bud drought evaluation by testing seed germination rate, germination potential, chlorophyll, osmotic potential, effects of auxin and cytokinin in somatic embryogenesis, and impact of 60 co-γ irradiation on the rate of embryonic callus differentiation were researched, to provide the basis for clover drought resistance and disease resistant breeding of new varieties. The main results were as follows:1.Six different varieties of White Clover has been Irradiate by 60Co-y,then simulating drought water stress with PEG-4000 solution,theirGP,GV,GI,VI,radicle length, chlorophyll content, leaf water potential and root water potential were measured during their seed germination period; the above indicators of Huia variety of PEG stress, have been taken a comprehensive evaluation which used the standard deviation coefficient allocation weighted method; the measurement indicators of the 6 white clover varieties are identified screening,by using principal component analysis, based on the best PEG concentration which have been filtered out; then the drought resistance of each varieties have been evaluated by a comprehensive analysis, which based on the screened indicators and the best PEG stress concentration. Experimental results show that PEG120g/L is the best drought stress concentration of white clover mutagenesis seed germination; Principal component analysis shows that the cumulative Proportion of GP,GV,GI,VI of White clover are between 91.13% and 98.35%, so that these four indicators can be used as a major drought resistance assessment indicators; During the germination period, drought resistance of white clover mutagenesis seed is been evaluated by a comprehensive analysis using the standard deviation coefficient allocation weighted method, The results show that The best irradiation dose of six varieties was difference.2. The cotyledon and hypocotyl of white clover were used as the explants and the effects of different levels of the factors on white clover callus induction and subculture were studied with orthogonal design. The results showed that the optimum medium for cotyledon and hypocotyl of Huia varieties seeds was modified SH+2,4-D2mg/L+6-BA0.2 mg/L+KT0.2 mg/L; cotyledon of Rivendel varieties seeds was modified SH+2,4-D2mg/L+6-BA0.35mg/L+KT0.5mg/L,hypocotyl was modified SH+2,4-D2mg/L+6-BA 0.2mg/L+KT0.35mg/L;cotyledon of Prop varieties seeds was modified SH+2,4-D2mg/L+6-BA0.5mg/L+ KT0.5mg/L, hypocotyl was modified SH+2,4-D5mg/L+6-BA0.35mg/L+KT0.5mg/L; cotyledon of Cauca sian varieties seeds was modified SH+2,4-D2mg/L+6-BA0.5mg/L+KT0.5mg/L, hypocotyl was modified SH+2,4-D2mg/L+6-BA0.35mg/L+KT0.5mg/L; cotyledon of Haifa varieties seeds was modified SH+2,4-D2mg/L+6-BA0.2mg/L+KT0.35mg/L, hypocotyl was modified SH+2,4-D5mg/L+6-BA0.5mg/L +KT0.5mg/L; cotyledon of Cllilka nova varieties seeds was modified SH+2,4-D2mg/L+6-BA0.5mg/L +KT0.2mg/L, hypocotyl was modified SH+2,4-D5mg/L+6-BA0.35mg/L+KT0.5mg/L.3.Calli of three white clover varieties at different growth stages (50d and 70d) have been taken mutagenesis processing in different 60Co-y irradiation dose and statistical differentiation rate of mutagenesis. This experiment investigates the mutagenic effects of radiation Trifolium repens Embryonic Callus, which will provide evidence for white clover breeding. Experimental results show that, with increasing radiation dose, the differentiation rate variation of the different varieties in the same growth period is inconsistent, as well as the callus differentiation rate of same species at different growth stages mutagenesis. Linear linear regression analysis shows that the 70d callus mutagenic has a better effect, semi-lethal doses of all varieties have been obtained, and Rivendel is 23.18Gy、Haifa is 19.59Gy、Prop is 18.64Gy.4. By taking 60Co-γ radiation dose mutagenic treatment with white clover embryogenic callus (70d), the results show that,1221 calli of Rivendel varieties are irradiated, of which 144 are differentiation, the differentiation rate of 20,30Gy irradiation treatment were 51.61% and 55.33%, respectivly.826 calli of Haifa varieties are irradiated, of which 157 are differentiation, the differentiation rate of 15,20Gy irradiation treatment were 27.43% and 49.73%, respectivly.1470 calli of Prop varieties are irradiated, of which 227 are differentiation, the differentiation rate of 15,20Gy irradiation treatment were 58.4% and 24.7% respectively. Two variations plants have been got preliminarily, which has large and thick leaves, and thicken stems.