Abstract: Through identification and index selection of salt tolerance of 59 alfalfa germplasm materials,this study selected basic materials for researches about salt tolerance breeding,salt tolerance mechanism,and salt tolerance gene cloning of alfalfa. The alfalfa germplasm materials from different sources were conducted with salt stress using a NaCl solution of 220 mmol·L^-1,and eight relevant indicators were determined in the germination period of alfalfa. Principal component analysis,stepwise regression analysis and cluster analysis were used to comprehensively evaluate their salt tolerance and screen salt tolerance indicators. The results showed that the difference between control and treatment group of each index reached a very significant level (P<0.01). Salt tolerance coefficients of root length,root bud ratio,germination index and vitality index are all distributed in the range of 0 to 0.4,and the distribution frequency is 100%,which are sensitive to salt stress. Vitality index,germination index and bud index have higher loads in principal component analysis. The germination ratio,bud index,germination index,vitality index,and germination energy are all related with D value and WSC value. The coefficient (R²) is greater than 0.99,according to the stepwise regression equation of D value,B value and WSC value. Numbers of the top 10 salt tolerance germplasms,based on comprehensive evaluation of B and WSC values,are 38,46,20,54,43,56,48,41,19,32. Numbers of the top 10 salt tolerance germplasms,based on D value,are 38,46,54,43,20,19,56,32,41,48. The cluster analysis divided 59 germplasm materials into 5 categories. According to the D value,material 38 has extremely strong salt tolerance,and materials 27,29 and 47 have very low salt tolerance. To sum up,the germination index and vitality index can be used as the evaluation indices of salt tolerance of alfalfa germplasm resources during the germination period. Germplasm materials with strong salt tolerance in the alfalfa germination period include ‘Ackershlre’,‘WL903’,‘WL404HQ’,‘East Germany’,‘Kanserin’;and germplasms with weak salt tolerance include ‘Aohan’,‘Golden Empress’ and ‘Challenger’.

Key words: Alfalfa, Germination stage, Salt tolerance

摘要： 通过对59份紫花苜蓿种质材料耐盐性鉴定和指标筛选，从而为紫花苜蓿耐盐育种、耐盐机制以及耐盐基因克隆等研究提供基础材料。本试验采用220 mmol·L^-1的NaCl溶液对不同来源的紫花苜蓿种质材料进行盐胁迫，测定紫花苜蓿萌发期8个相关指标，用主成分分析、逐步回归分析和聚类分析等方法对其耐盐性进行综合评价和耐盐指标筛选。结果表明：各指标对照组与处理组间的差异达到极显著水平（P<0.01）；根长、根芽比、发芽指数和活力指数的耐盐系数全部分布在0～0.4范围内且分布频率均为100%，对盐胁迫的敏感程度较高；活力指数、发芽指数和萌芽指数在主成分分析中具有较高载荷；发芽率、萌芽指数、发芽指数、活力指数、发芽势与耐盐性度量值（D值）和加权耐盐系数（Weight salt resistance coefficient，WSC）关联度均较大；根据D值、综合耐盐系数（B值）和WSC值得出的逐步回归方程决定系数R²均大于0.99；综合评价中依据B值、WSC值耐盐性程度排前10的种质编号为：38，46，20，54，43，56，48，41，19，32，依据D值耐盐性程度排前10的种质编号为：38，46，54，43，20，19，56，32，41，48。聚类分析将59份种质材料划分为5类，根据类群中D值大小可认为38号材料具有极强的耐盐能力，27，29，47号材料耐盐能力极弱。综上可知，发芽指数和活力指数可作为紫花苜蓿种质资源萌发期耐盐性评价指标；紫花苜蓿萌发期耐盐性强的种质材料有‘爱开夏’、‘WL903’、‘WL404HQ’、‘东德’、‘康赛’，盐性弱的种质材料有‘敖汉’、‘金皇后’、‘挑战者’。

关键词: 紫花苜蓿, 萌发期, 耐盐性