| Alfalfa is a good forage grass planted widely around the world which belongs to dicotyledonous bean alfalfa and it has a very strong adaptability. Due to the saline-alkali soil is increasing year by year in our country, it has a positive effect in practice to screene out some strong salt-tolerant of alfalfa mutants. The research combined the mutation breeding technology with tissue culture technology,explores the condition of screening the alfalfa salt-tolerant, and obtains 21 the salt-tolerance of alfalfa mutants. Then determines the condition of transplanting the tube seedlings preliminarily, and finally analysis of 21 salt-tolerant mutantst using ISSR-PCR Markers.The main research results as follows:1.Callus of Alfalfa no vaccine can be survived on 2-100 Gy radiation dose by 60Co-γ irradiation.According the increase rate and the relative increase rate of the callus tissse is induced by different60Co-γ radiation doses in 28 days, the optimal radiation dose is 40 Gy on alfalfa callus. We stutied the mortality rate of the callus tissue on high salt concentration and the results showed when the Na Cl is 10g/L, l0 Gy, 20 Gy, 40 Gy, 60 Gy radiation doses mortality rate of the callus tissue were 20.00%, 25.00%,19.00%, 25.00% respectively; when the Na Cl is 15 g/L, l0 Gy, 20 Gy, 40 Gy, 60 Gy radiation doses mortality rate of the callus tissue were 45.70%, 44.70%, 52.60% and 53.60% respectively; when the Na Cl was 20 g/L, it was deadly for callus tissue, none survival. The callus tissue was cultured with different Na Cl concentrations, and it was founded that the callus tissue survavil rate was differeng as radiated different dose.2.When transplant the alfalfa tube seedlings, roots of tube seedlings are very important. The study showed the effect of test tube seedlings roots on two different kinds of plant hormone: NAA and IBA and two different concentration respectively.When NAA is 0.2 mg/L, rooting rate of the tube seedlings are the highest. In addition, stutied the effect of different seedling method smelting on tube seedlings survival rate and the influence of different substrates on tube seedlings survival rate. The research results show that when without smelting plants, the tube seedlings survival rate are highest. When all the substrate is vermiculite, tube seedlings have the highest survival rate.When the salt concentration was 0, the comparison had the highest plantlet rate; When salt concentration was 3 g/L and 5g/L, callus had the highest plantlet rate under 2Gy irradiation dose; When salt concentration was 7 g/L, callus had the highest plantlet rate under 20 Gy irradiation dose; When salt concentration was 10g/L or 15g/L,callus had the highest plantlet rate under 40 Gy irradiation dose.3.Through analysis of 21 salt-tolerant alfalfa mutants and its control using ISSR molecular markers,result showed 39 ISSR primers can produce 262 bands, including polymorphism bands for 185, the ratio of polymorphic bands was 70.61%. The UPGMA dendrogram based on ISSR markers indicated, the genetic similarity coefficient ranged from 0.637-0.996. As the genetic similarity coefficient 0.79 was threshold, test materials can be divided into 4 clusters, the first includ C11, C13, C15 and they were grown under 40 Gy radiation levels; C9 was the second cluster and C16 was the third cluster; The fourth cluster consist the rest of 15 mutants and the control. |
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