Study On Induction Of Radiated Mutants And Establishment Of A High Efficient Regeneration System In Alfalfa

After sterilizing, seeds of Medicago sativa L.cv. Xinjiang Daye , Medicago varia.cv. Xinmu No.1 and Xinjiang Medicago Falcata. L. were planted on MS medium without hormone. Hypocotyl segments of 2~3mm in length were cultured on 7 kinds of MS medium to induce calli. The calli were subcultured on MS medium supplementing 0~20mg/L GSH and 0~6mg/L ABA. Based of the establishment of a high efficient regeneration system in alfalfa, the paper went on researching the mutants of three kinds alfalfa calli by 60Co-γradiated seed. Results were as follow: (1) Establishment of a high efficient regeneration system in alfalfa: ①Induction culture, MS+2,4-D2mg/L+NAA2mg/L+KT1mg/L (under dark condition); ②Division culture, MS+2,4-D 2mg/L+NAA2mg/L+KT1mg/L+GSH15mg/L+ABA3mg/L(under light condition)for Medicago sativa L.cv. Xinjiang Daye and Medicago varia.cv. Xinmu No.1, MS+2,4-D2mg/L+NAA2mg/L+KT1mg/L+GSH 15mg/L+ABA6mg/L(under light condition)for Xinjiang Medicago Falcata. L.; ③Differentiation culture, MS medium without hormone and adding 0.8% agar and 3% sugar(under light condition);④Rooting culture,1/2MS medium with 0.6% agar and 2% sugar(under light condition). (2) During enrichment and differentiation culture, lighting culture is better than dark, and lighting culture condition can shorten the period of shoot regeneration. (3) The experiment got 17 genotypes with high regeneration capability (6 genotypes come from Medicago sativa L.cv. Xinjiang Daye, 5 genotypes come from Medicago varia.cv. Xinmu No.1, 6 genotypes come from Xinjiang Medicago Falcata. L). The tube seedlings were successfully transferred to soil and grew well. (4) Under tissue culture condition, the half lethal radiation dosage in Medicago sativa L.cv. Xinjiang Daye is 200KR and lethal dosage is 500KR; the half lethal radiation dosage in Medicago varia.cv. Xinmu No.1 is 150KR and lethal dosage is 500KR; the half lethal radiation dosage in Xinjiang Medicago Falcata. L is 150KR and lethal dosage is 350KR. (5) Through comparing, the radiation sensitivity is followed as: Xinjiang Medicago Falcata. L > Medicago varia.cv. Xinmu No.1 > Medicago sativa L.cv. Xinjiang Daye. (6) Planting in the field, the half lethal radiation dosage in Medicago sativa L.cv. Xinjiang Daye is 100KR and lethal dosage is 350KR; the half lethal radiation dosage in Medicago varia.cv. Xinmu No.1 and Xinjiang Medicago Falcata. L is 50~100KR and lethal dosage is 350KR.