关键词: 紫花苜蓿, 种子萌发, 盐胁迫, 隶属函数法, 聚类分析

Abstract: To screen alfalfa （Medicago sativa L.） germplasm suitable for cultivation on saline soils， this study evaluated the salt tolerance of 59 alfalfa germplasm accessions during the germination stage. Six parameters—germination potential （GP）， germination rate （GR）， germination index （GI）， vigor index （VI）， root length （RL）， and shoot length （SL） were measured. A comprehensive evaluation was conducted using coefficient of variation analysis， correlation analysis， principal component analysis （PCA）， subordinate function analysis （SFA）， and cluster analysis. The results revealed significant variation in salt tolerance during germination among the 59 alfalfa accessions. Based on PCA and correlation analysis， four key indicators were selected for salt tolerance evaluation： relative germination potential （RGP）， relative germination rate （RGR）， relative germination index （RGI）， and relative shoot length （RSL）. Cluster analysis based on D-values derived from SFA classified the 59 germplasms into five salt tolerance categories： highly salt-tolerant （1 accession）， moderately salt-tolerant （22 accessions）， low salt-tolerant （11 accessions）， salt-sensitive （11 accessions）， and highly salt-sensitive （14 accessions）. Seven accessions exhibiting strong salt tolerance were identified： ‘Juneng 6’‘Ningmu No.1’‘Salt treasure’‘Shockwave’‘Aohan’‘Hunter River’ and ‘Challenger’. These findings provided a theoretical basis for alfalfa salt tolerance breeding.

Key words: Alfalfa, Seed germination, Salt stress, Affiliation function method, Cluster analysis