Genetic diversity among Ethiopian sweet sorghum [Sorghum bicolor (L.) Moench] accessions using simple sequence repeat markers

Abstract

Sweet sorghum (Sorghum bicolor (L.) Moench) is the only grain and stalk crop that can be used for multipurpose. Despite its global significance and potential, it faced genetic erosion. These are due to low productivity and lower farmers' preferences, which is not considered one of the most important cereal crops in Ethiopia. To utilize and popularize these crops, understanding the genetic diversity and population structure is a pre-request. Therefore, this study was aimed to assess the genetic diversity and population structure of selected 82 Ethiopian sweet sorghum accessions using 10 simple sequence repeat (SSR) markers that represent seven geographic regions of Ethiopia. The study revealed a total of 116 alleles with a mean of 11.6 alleles per locus. All used microsatellite loci were highly polymorphic with polymorphic information content (PIC) ranging from 0.75 to 0.90 with an average of 0.82. They showed high gene diversity ranging from 0.59 to 0.81 with an overall mean of 0.70. There was a moderate genetic differentiation (FST = 0.21) showing the presence of high gene flow (Nm = 5.033) where 91 % of the total variation was accounted for within populations genetic variability. The clustering, principal coordinate analysis (PCoA) and population structure did not cluster the studied populations into a separate group according to their geographical origin. In conclusion, the highest intra-population diversity was observed among populations of North Wollo (He = 0.81) and South Wollo (He = 0.79), and hence these areas can be considered as hot spots for the identification of novel traits. Therefore, the present study has generated baseline information for breeders to improve Ethiopian sweet sorghum through breeding, management, and conservation of the available genetic resources.