Adaptability and genetic diversity of 25 alfalfas in the middle and lower reaches of Huaihe River

The related yield and quality traits of 25 alfalfa breeds were determined in the middle and lower reaches of Huaihe River over a period of 2 years. Their genotypes were identified using 66 SSR markers evenly distributed on 8 chromosomes. The results showed that the yield-related traits (fresh weight, plant height, and node number of the main stem) of alfalfa were significantly affected by year, batch times, and variety. The yield in the second year was 2.24-fold of the first year. The crude protein content, acid detergent fiber, neutral detergent fiber, and relative feeding value were also significantly affected by year, batch times, and variety. The ether extract content was affected by variety and stubble, but not by year. The yield and quality of the first and second batch were the highest and best, respectively. The results of cluster analysis showed that the 25 alfalfa varieties were divided into 3 subgroups by phenotypic clustering. Medicago falcata belonged to one subgroup, 5 relatively high-yield varieties were clustered into another, and the third group comprised the remaining varieties. Genotype clustering divided the varieties into 2 subgroups, with 7 semi-fall dormancy varieties in one, and the remainder in the other. Parental selection for alfalfa should be based on the phenotypic traits of high yield and quality and wide genetic differences in breeding, in order to breed more productive varieties.