8个苜蓿品种抗寒性的比较

Comparison of cold resistance of 8 alfalfa varieties

【目的】探究8个国产苜蓿品种的抗寒性判定方法,为科尔沁沙地筛选抗寒性强的苜蓿品种提供理论依据。【方法】以8个苜蓿品种(草原2号、草原3号、东苜1号、农菁1号、农菁8号、肇东、龙牧801、公农1号)的1龄期越冬器官为材料,对其分别进行-10,-15,-20,-25,-30和-35℃低温处理,4℃处理为对照,统计不同处理材料在盆栽试验中的存活率,测定其相对电导率、根颈活力,计算半致死温度(LT50),拟合Logistic回归方程,对8个品种抗寒性进行聚类分析。【结果】东苜1号和草原3号存活率表现较好,而草原2号和农菁8号存活率表现较差。8个苜蓿品种根颈相对电导率均随处理温度下降而上升,根颈活力均随处理温度下降而减弱;用电导率法协同Logistic回归方程所得LT50的8个苜蓿品种抗寒性强弱排序为:草原3号>东苜1号>农菁1号>公农1号>肇东>龙牧801>草原2号>农菁8号;根据根颈活力法协同Logistic回归方程所得LT50的8个苜蓿品种抗寒性排序为:东苜1号>草原3号>农菁1号>公农1号>龙牧801>肇东>农菁8号>草原2号;用单一电导率法或根颈活力法对8个苜蓿品种抗寒性的聚类分析结果不同,且以根颈活力法可信度较高,而综合2种方法的聚类分析更具代表性、准确性更高;8个苜蓿品种抗寒性可分为3类,其中东苜1号、草原3号和农菁1号为高抗寒品种,公农1号、肇东和龙牧801为一般抗寒品种,草原2号和农菁8号为低抗寒品种;8个苜蓿品种不同低温处理下的植株存活率与其抗寒性测定结果表现一致。【结论】利用电导率法或根颈活力法协同Logistic方程计算苜蓿LT50可行,LT50可作为评价苜蓿抗寒性的指标。

【Objective】This study tested the determination method for cold resistance of 8 domestic alfalfa varieties to provide theoretical basis for screening cold resistant alfalfa varieties in Horqin area.【Method】In this experiment,the annual overwintering organs of 8 alfalfa varieties(Caoyuan No.2,Caoyuan No.3,Dongmu No.1,Nongjing No.1,Nongjing No.8,Zhaodong,Longmu No.801,and Gongnong No.1)were treated at low temperatures of-10,-15,-20,-25,-30 and-35℃,respectively.The control was stored at 4℃.The survival rates in different treatments were measured in pot experiment,the relative conductivity and root neck vitality were measured,and the semi lethal temperature(LT50)was calculated.Logistic regression equation was also used for cluster analysis of LT50.Cluster analysis of cold resistance of 8 alfalfa varieties by fitting Logistic regression equation.【Result】The survival rates of Dongmu No.1 and Caoyuan No.3 were better,but the survival rates of Caoyuan No.2 and Nongjing No.8 were poor.The relative electrical conductivity of root neck of 8 alfalfa varieties increased with the decrease of temperature,while the vigor of root neck decreased.According to the Logistic regression equations obtained by conductance method,the LT50 of the 8 alfalfa varieties showed that the cold resistance was in the order of Caoyuan No.3>Dongmu No.1>Nongjing No.1>Gongnong No.1>Zhaodong>Longmu No.801>CaoyuanNo.2>Nongjing No.8.According to the Logistic regression equation,the LT50 obtained from root neck vigor method indicated that the cold resistance was in the order of Dongmu No.1>Caoyuan No.3>Nongjing No.1>Gongnong No.1>Longmu No.801>Zhaodong>Nongjing No.8>Caoyuan No.2.The root viability method was more reliable than conductivity method,and the integrated cluster method was more representative and accurate.The 8 alfalfa varieties were divided into 3 categories.Dongmu No.1,Caoyuano.3 and Nongjing No.1 were high cold resistant varieties,Gongnong No.1,Zhaodong and Longmu No.801 were general cold resistant varieties,while Caoyuan No.2 and Nongjing No.8 alfalfa were low cold resistant varieties.The survival rates of 8 alfalfa varieties under different low temperature treatments were consistent with cold resistance.【Conclusion】The combined method of conductance or root neck activity with Logistic equation was feasible to calculate LT50 of alfalfa and it could be used for evaluating cold resistance of alfalfa.