Abstract: Salt stress limits the normal growth and development of plants， and has a particularly serious impact on seed germination. To evaluate the differences in salt tolerance of 61 alfalfa （Medicago sativa L.） cultivars， petri dish germination method was carried out to determine the effects of 150 mmol·L^-1 NaCl on seed germination and seedling growth indicators. Salt tolerance coefficient， principal component analysis， membership function analysis， comprehensive evaluation of salt tolerance D value， and systematic clustering analysis were used to comprehensively evaluate the salt tolerance of tested cultivars during seed germination. The results indicated that salt stress led to a decreasing trend in seed germination and seedling growth indicators of various alfalfa cultivars. Based on the D value of comprehensive evaluation of salt tolerance， a systematic clustering analysis was conducted to classify the salt tolerance of 61 tested cultivars into six levels， namely， super strong， medium strong， low strong， low weak， medium weak， and super weak. The super strong salt tolerance cultivars were ‘Zhongmu No.3’ ‘WL440HQ’ and ‘WL712’， and the super weak ones were ‘Three level’ ‘2065MF’ and ‘Zhonglan No.2’. This study would provide theoretical guidance for the screening， cultivation， and utilization of alfalfa germplasms with strong salt tolerance， as well as excellent parental materials for the mining and functional study of salt tolerant genes， genetic improvement， and new cultivar cultivation.

Key words: Alfalfa, Seed germination, Salt tolerance, Comprehensive evaluation, Cluster analysis

摘要： 盐胁迫限制了植物的正常生长发育，对种子萌发造成的影响尤为严重。为评价不同品种紫花苜蓿（Medicago sativa L.）耐盐性差异，本研究采用培养皿发芽法测定了150 mmol·L^-1 NaCl胁迫对61个品种种子萌发和幼苗生长指标的影响，运用耐盐系数、主成分分析、隶属函数分析、耐盐性综合评价D值和系统聚类分析对供试种子萌发期耐盐性进行综合评价。结果表明：盐胁迫导致各品种种子萌发和幼苗生长指标均呈下降趋势。根据耐盐性综合评价D值进行系统聚类分析，将61个品种种子萌发期耐盐性分为6个等级，即超强、中强、低强、低弱、中弱和超弱，并筛选出超强耐盐性品种为‘中苜3号’‘WL440HQ’和‘WL712’，而超弱耐盐性品种为‘三级’‘2065MF’和‘中兰2号’。本研究将为紫花苜蓿强耐盐性种质筛选与栽培利用提供理论指导，也为其耐盐候选基因挖掘与功能研究、耐盐性遗传改良及新品种培育提供优异亲本材料。

关键词: 紫花苜蓿, 种子萌发, 耐盐性, 综合评价, 聚类分析