Evaluations On Cold Resistance And Production Performance For Different Alfalfa Varieties

In order to evaluate accurately the cold resistance of alfalfa varieties, this paper, aiming at development situation of many alfalfa varieties of low yield and strong cold resistance in North China, using for reference the physiology and biochemistry indexes, such as ELR, Pro, POD, which had been adopted in the identify of germ plasm resource, carried out systematical research on the cold resistance and production performance of 12 alfalfa varieties from home and abroad, by means of field observation, physiological and biochemical experiment as well as trial analysis. Main results were as follows:1. The membrane injury percentage was significantly different among alfalfa varieties under cold stress (-25℃, 20min).The greater the injury percentage, the weaker the cold resistance. Experiment of 12 alfalfa varieties showed that the varieties with strong cold resistance included Gannong No.1, Gannong No.2 and Caoyuan No.2, the varieties with medium cold resistance included Rambler, Polato and the varieties with weak cold resistance included Beijixing, WL323 and LoBo.2. The Pro accumulation was significantly different among alfalfa varieties under cold stress, the cold resistance increased with the increasing Pro accumulation. Beijixing(58.75μ)had maximal Pro accumulation, indicating that its cold resistance was the strongest. Secondly, the varieties including Ailegao(50.00μg/g), WL323(47.50μg/g), LoBo(47.50μg/g)had medium Pro accumulation, suggesting a medium cold resistance. Gannong No.1(1.25μg/g), Defi(3.75μg/g)had minimal Pro accumulation, indicating the weakest cold resistance.3. The POD activity was significantly different among alfalfa varieties under cold stress. The POD activity of Caoyuan No.2 was obviously stronger than that of the others, indicating its cold resistance was the strongest; Rambler, Gannong No.1, Gannong No.2 had significantly different POD activity, showing their cold resistance were medium; the POD activity of LoBo was the weakest, suggesting the weakest cold resistance.4. Cluster analysis of 12 alfalfa varieties showed that the varieties with strong cold resistance were Caoyuan No.2, Gannong No.1. The varieties with medium cold resistance...