Abstract: To select alfalfa germplasm with favorable photosynthetic efficiency and drought resistance,in the greenhouse,the test was conducted to analyze drought resistance of genetic variations in 109 alfalfa (from 28 countries) at seedling stage. A number of traits,including plant height (PH),aboveground biomass (AB),relative water content (RWC),relative chlorophyll content (SPAD) and chlorophyll fluorescence parameters (phi2,NPQt,RFd,qL and Fv/Fm) were measured in the normal supply (WT) and drought stress (DT) with 109 alfalfa germplasm accessions. Germplasm with good drought resistance was identified by variance analysis,correlation analysis,and principal component analysis,clustering analysis and weighted membership function analysis. The results showed that differences appeared in 9 indices to varying degrees,the largest coefficient of variation was AB,with DT and WT groups reaching 0.61 and 0.59,respectively. Except for qL,RWC,the others were significantly correlated with the comprehensive evaluation method with D value,chlorophyll fluorescence parameters could be used as indices for screening favorable photosynthetic capacity of alfalfa under drought stress. These methods identified a group of 14 alfalfa accessions which were characterized by a favorable photosynthetic capacity (CF048333,ZW1231,CF031987,ZW0810,ZW1005,CF049861,CF031979,CF034260,ZW0730,CF031946,ZW0793,CF049906,CF031986,CF031988). Meanwhile,most of the materials were collected from drought-prone environment countries,such as Kazakhstan,Kyrgyzstan,Morocco,Azerbaijan,North America,Yemen. Therefore,the results of this study provide the basic materials for alfalfa breeding.

Key words: Alfalfa, Chlorophyll fluorescence parameters, Seedling stage, Drought resistance

摘要： 为筛选出干旱胁迫下抗旱高光效的紫花苜蓿（Medicago sativa L.）种质，本试验采用室内苗期抗旱评价方法，对109份（28个国家）紫花苜蓿种质在正常浇水（Water Treatment，WT）和干旱胁迫（Drought Treatment，DT）处理下的株高（Plant Height，PH）、地上生物量（Aboveground Biomass，AB）、叶片相对含水量（Relative Water Content，RWC）、相对叶绿素含量（Relative chlorophyll content，SPAD）以及叶绿素荧光参数（phi2，NPQt，RFd，qL，Fv/Fm）等9个指标进行测定，并利用方差分析、相关性分析、主成分分析、综合加权隶属函数法与聚类分析等方法进行综合评价。结果表明：通过对9个指标进行统计分析，在干旱胁迫下，各指标呈现不同程度变化，变异系数最大的为AB，DT组为0.61，WT组为0.59。相关性分析显示，除qL和RWC之外，其余指标均与综合度量D值显著相关，表明叶绿素荧光参数可作为干旱胁迫下筛选高光效紫花苜蓿的指标。通过聚类分析和综合加权隶属函数分析，筛选出抗旱高光效种质14份（CF048333，ZW1231，CF031987，ZW0810，ZW1005，CF049861，CF031979，CF034260，ZW0730，CF031946，ZW0793，CF049906，CF031986，CF031988），这些种质大部分来自干旱半干旱地区，如哈萨克斯坦、吉尔吉斯斯坦，摩洛哥、阿塞拜疆、北美、也门等。综上可得，本研究筛选出的抗旱种质可作为紫花苜蓿抗旱高光效育种的基础材料。

关键词: 紫花苜蓿, 叶绿素荧光参数, 苗期, 抗旱性