| Alfalfa is an excellent legume forage.It has the largest cultivated area and the widest distribution in the world with richness genetic resources.In order to understand the biological characteristics and breeding value of different alfalfa germplasm materials,this study identified and evaluated the phenotypic traits and drought resistance of alfalfa germplasms from different sources.The main conclusions are as follows:(1)The phenotypic traits of 190 germplasm resources were all significantly different,indicating that these 190 germplasm materials are rich in phenotypic genetic diversity.Among the 12 phenotypic traits,fresh and hay yield,number of branches and wintering rate were the main traits of phenotypic variation in alfalfa germplasm.190 alfalfa germplasms were divided into 5 categories by cluster analysis:The first category consists of 6 materials,such plants are small and weak,with slow growth,slightly lower yield but more branches;the second category consists of 3 materials,the overall growth of these plants is better,the growth is fast,and the root neck are well developed;the third category is the best type of growth,consists of 2 materials,such plants grow vigorously and fast,have a strong wintering rate;the fourth category includes 3 materials,which are generally wea,with long internodes,few branches,and poor growth;all the remaining materials are in the fifth category,such plants grow in general,the plants are delicate,and the wintering rate is low.(2)In the evaluation of drought resistance at the germination stage of alfalfa germplasm,the germination rate,germination index,shoot length and vigor index were closely related to the drought resistance.Comprehensive evaluation of drought resistance of 59 samples of alfalfa materials were made under comprehensive drought resistance evaluation value D,comprehensive drought resistance coefficient CDC and weighted drought resistance coefficient WDC.The materials with strong drought resistance were selected as materials 66,92,56,39,49 and 34;materials with extremely weak drought resistance were materials 184,82,137,102,67 and 134.(3)In the assessment of drought resistance of alfalfa germplasm at seedling stage,based on master analysis and correlation analysis,8 indicators including leaf area,leaf relative water content,plant height,stomatal conductance,intercellular CO2 concentration,Fv/Fm,Fv/Fo and chlorophyll content were considered as the main indicators for evaluation.A comprehensive evaluation was performed on the drought resistance at the seedling stage of 57 alfalfa materials,and 17 species of extremely drought-resistant germplasm materials were selected,including 67,93,46,33,123,43,72,130,80,134,39,57,82,77,112,45 and 49;5 species of extremely weak drought-resistant germplasm materials,including 34,119,92,154 and 44.(4)Comprehensive evaluation of the drought resistance at the germination and seedling stage,common screening for drought resistant materials 39,49. |
