Assessment of genetic diversity of sweet sorghum collection using phenotypic variation and ssr markers

In this study, 32 germplasm resources of sweet sorghum were identified to evaluate the phenotypic and genetic diversity. The results showed that the diversity index (H') of agronomic traits was within the range of 1.716 - 2.062, with a specially richer diversity of spike types. 899 polymorphic bands were amplified by 43 pairs of SSR primers, and the polymorphism information content (PIC) varied from 0.06 to 0.49, with the genetic diversity index (Nei) ranged from 0 to 0.646. Three principal components were extracted from nine agronomic traits, and the "grain yield" factors of the first principal component were negatively correlated with the "biological yield" factors of the second. 32 germplasm resources were divided into 4 groups, and group IV exhibited the wide distribution of spike types, high grain yields and brix rate. These indicated that the genetic diversity of the germplasm population was low although observing the variable phenotypes among different varieties, possibly due to the significant inbreeding within the population. The variety No.20, No.21 and No.31 exhibited a good improvement potential for breeding practice of sweet sorghum. (author)