ARS | Publication request: Assessment of Genetic Diversity and Population Structure of Accessions in the US Sweet Sorthum Germplasm Collection

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 30, 2009
Publication Date: September 16, 2009
Repository URL: http://hdl.handle.net/10113/44037
Citation: Wang, M.L., Zhu, C., Barkley, N.L., Chen, Z., Erpelding, J.E., Murray, S., Tesso, T., Pederson, G.A., Yu, J. 2009. Assessment of Genetic Diversity and Population Structure of Accessions in the US Sweet Sorthum Germplasm Collection. Theoretical and Applied Genetics. Online DOI 10.1007/S00122-009-1155-6 120:13-23.

Interpretive Summary: Sweet sorghum has the potential to become a versatile feedstock for large-scale bioenergy production given its sugar from stem juice, cellulose/hemicellulose from stalks, and starch from grain. There are 2,180 sweet sorghum accessions in the US historic collection when the project started. For researchers to tap into its feedstock potential requires studying the 2,180 sweet sorghum accessions with varied origins. To assess genetic diversity of this collection for bioenergy breeding and population structure for association mapping, 96 accessions were randomly selected and genotyped with a set of 95 simple sequence repeat (SSR) markers. Subsequent genetic diversity and population structure analysis methods identified four subpopulations in this panel, which correlated well with the geographic locations where these accessions originated or were collected. Model comparisons for three quantitative traits revealed different levels of population structure effect on flowering time, plant height, and Brix. Our results suggested that for broadening the genetic diversity of the current sweet sorghum collection, accessions have to be acquired from different geographic locations and for developing new sweet sorghum cultivars or hybrids, diverged germplasm accessions curated from different geographical regions have to be considered and used in future breeding programs.

Technical Abstract: Sweet sorghum has the potential to become a versatile feedstock for large-scale bioenergy production given its sugar from stem juice, cellulose/hemicellulose from stalks, and starch from grain. However, for researchers to tap into its feedstock potential requires studying the 2,180 sweet sorghum accessions with varied origins in the US historic collection. To assess genetic diversity of this collection for bioenergy breeding and population structure for association mapping, we selected 96 accessions and genotyped them with 95 simple sequence repeat (SSR) markers. Subsequent genetic diversity and population structure analysis methods identified four subpopulations in this panel, which correlated well with the geographic locations where these accessions originated or were collected. Model comparisons for three quantitative traits revealed different levels of population structure effect on flowering time, plant height, and Brix. Our results suggest first that diverse germplasm accessions curated from different geographical regions should be considered for plant breeding programs to develop sweet sorghum cultivars or hybrids, and second that this sweet sorghum panel can be further explored for association mapping.