| Researches on sweet sorghum genetic diversity are the basis of their genetic improvement, and are also of the great significance for the preservation, utilization and enhancement of sweet sorghum germplasms. But limited information on these germplasms has affected their effective use in sweet sorghum breeding and germplasm enhancement.In this paper, a total of 206 germplasms were used to assess their genetic diversity and relationship, of which 104 were from United States, 5 from Australia, 4 from Japan; 93 are domestic: 55 from Chinese Academy of Agricultural Sciences, 10 from Hebei, 6 from Liaoning, 5 from Xinjiang, 4 from Shanxi, 4 from Chinese Academy of Sciences, 3 from Anhui, 3 from Jilin, each 1 from Hubei, Heilongjiang and Yunnan. The assessment have done for genetic diversity and relationship based on information in agronomic traits and SSR markers in 206 accessions, the preliminary results were obtained as follows:Large variations were found among different accessions in the average, maximum, standard deviation, variability, the coefficient of variation and diversity for all traits studied. Diversity indexes of all traits were very high, with an average 1.9371, lowest for the juice extraction 1.5954, and highest for plant height, 2.1006. The correlation analysis showed that there was significantly positive correlation between period of duration and plant height, days from emergence to flag leaf, stem diameter and fresh stem weight per plant; extremely siginificant positive correlation were found between stem juice extraction and its brix and between stem brix and fresh stem weight per plant. The principal component analysis showed that the first principal component was known as the "biological yield" factor, the second principal component was called "brix" factor, the third principal component was called "single panicle factor." The cluster analysis was made using UPGMA clustering method. All 206 accessions were divided into 6 groups as per the genetic similarity coefficient of 0.20.220 allele variations were detected in the 206 sweet sorghum accessions using 24 pairs of SSR primers, 2-19 alleles for each primer, with an average 8.19. Primer site polymorphism information content index (PIC) ranged from 0.50 to 0.87, with an average of 0.76, the largest PIC 0.87 for primer xtxp65 site, the minimum PIC 0.50 for primer xtxp136 site. The largest Shannon index, 2.3534 were found in primer Xtxp297, the minimum 0.6924 in Xtxp136, with an average Shannon index 1.7413. The genetic similarity coefficients (GS) between 206 sweet sorghum varieties were calculated using 220 alleles, ranging 0.32-0.96, with an average 0.69. Cluster analysis was done for 206 accessions using the genetic similarity matrix by way of UPGMA. They were divided into two groups A, B. Group A was further divided into 15 subgroups I-XV.62 sweet sorghum accessions were selected for further analysis as per their comprehensive agronomic traits, particularly in stem brix, stem juice extraction, fresh stem weight per plant. Similarity coefficients were calculated and cluster analysis was done for 62 accessions. 28 accessions were recommended for breeding use according to their comprehensive performance, genetic diversity and relationships. The results also showed that genetic variations revealed by SSR markers and agronomic traits was not so consistent, combination of the two ways will be more reasonable to inspect sweet sorghum germpalsm relationship and genetic variations.
|
PDF Full Text Request