| Alfalfa,as a good quality forage,contributes an important position and role on the adjustment of agricultural industry structure,ecological construction and development of animal husbandry.In order to enlarge the germplasm resources of alfalfa in China,understand the genetic diversity and evolution relationship of alfalfa in the world,the performance characteristics of seeds and genetic diversity of DNA from 264 alfalfa variety resources of all over the world were analyzed,and screened the forage production and quality from 3 local cultivars.The results were as follows:1 Investigation of apparent characteristics of seeds and clustering analysis of germplasm resourcesAnalysis of variance to 264 alfalfa variety resources showed the significant differences between different alfalfa varieties on thousand grain weight,area,perimeter,the ration of length to width,length,width,diameter and roundness.1000-grain weight was significantly and positively correlated with area,perimeter,length,width and diameter;area was significantly and positively correlated with perimeter,length,width and diameter;Length was significantly and positively correlated with Width and Diameter;Width was significantly and positively correlated with Diameter.The results of principle component analysis(PCA)showed that first principal components should be preferentially considered,as well of the medium size for second principal components by using high-yielding seeds as breeding objective.Thus,all the apparent traits of alfalfa seeds can be used for cluster analysis.Clustering analysis of seed apparent characteristics showed that 264 alfalfa variety resources were grouped into seven categories as to the 5.728 of Euclidean distance:the first group contains 3 variety resources;the second,fourth and fifth group contain 2 variety resources;the third group contain 5 variety resources;the sixth group contain 10 variety resources,and the remains belong to the seventh group,with less than 5.728 Euclidean distance,especially the shortest 0.15 Euclidean distance for No.59 and 255 germplasm materials.2 Analysis of genetic diversityThe genomic DNA of alfalfa was detected by agarose gel electrophoresis.The results showed that the extracted DNA is perfect with high purity,which could be further used for the SSR-PCR amplification reaction.The 350 pairs of SSR primers were selected in 6 alfalfa germplasm materials from different sources,and 84 pairs with clear PCR band,good stabilization and polymorphism,was selected to analyze the genetic diversity of 264 alfalfa variety resources.The 84 SSR primer pairs yielded 637 alleles,with an average of 7.58 alleles per locus.The average polymorphic rate was 98.480%within 264 variety resources.The SSR clustering results of 264 alfalfa variety resources showed that 264 alfalfa variety resources could be clustered into 7 groups in the 0.515 of genetic similarity coefficient of DICE:the second,third and sixth group just contains 1 germplasm material;the first,fourth and fifth group contain 2 variety resources,the remains were clustered into the seventh groups.In the 264 variety resources,The variety No.202 and 203 showed the highest similarity coefficient of 0.92.However,there was partial uniformity among 264 alfalfa variety resources whereas some difference,when comparing the clustering analysis between seed apparent characteristics and SSR molecular marker.3 Comparison of forage production and quality between 3 local cultivarsOn the basis of previous experiment,the production and quality of three major alfalfa cultivars in contiguous base of Purple Pasture Co.,Ltd.in Anhui were analyzed.The results showed that the alfalfa is yearly mowed up to 5 times in the local region,and the yield of alfalfa between diverse mowing was significantly different.In 2015,the total yield of Weston was the highest with the lowest WL903,while the total yield of Weston was the lowest with the highest WL903 in 2016,and there was no significant difference of total yield with two year accumulation between three varieties.In addition,the quality between three alfalfa varieties is no significant difference,the yield of unit area was significantly and positively correlated with forage-use value,and the crude protein was negatively correlated with ADF(acidity detergent fiber)and NDF(neutral detergent fiber).In conclusion,Weston,WL525 and WL903 contribute well growth,relatively weak pests and diseases,the corresponding yield and quality according to the acceptance standard of high yield and quality alfalfa cultivation in the Ministry of Agriculture of China,and are up to one grade above in the requirement of forage grass quality,so suitable to extensively plant in Anhui. |
