Submitted to: American Journal of Plant Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/25/2012
Publication Date: 12/1/2012
Citation: Burow, G.B., Franks, C., Burke, J.J., Xin, Z. 2012. Genetic diversity in a collection of Chinese sorghum landraces assessed by microsattelites. American Journal of Plant Sciences. 3:1722-1729. Interpretive Summary: Genetic diversity is one of the important cornerstones of crop improvement. Diversity or variation provides the raw materials from which desirable or favorable alleles for improved agronomic traits of interest can be selected from. Subsequently, breeding for improved varieties are facilitated through the incorporation of new alleles into well adapted or elite lines. Genetic variation was evaluated in a group of land races or traditional lines of sorghum germplasm collected from colder regions of China which are of interest because they were targeted to serve as germplasm sources of early season cold tolerance. Using molecular marker tools specifically microsattelites, an extensive genetic variation was found between entries in the collection of sorghum landraces from China. Groupings of entries into clusters were also calculated and will be useful in selecting parental lines that in better genetic gain for important agronomic traits.
Technical Abstract: Genetic diversity was characterized in a collection of 171 sorghum landraces originally gathered from the colder region (primarily the northwestern provinces) of China. Genetic diversity was analyzed using 41 microsattelite or simple sequence repeat (SSR) markers distributed throughout the 10 chromosomes of sorghum. Majority (40 out of 41 or 98%) of the SSR markers utilized for genotyping were polymorphic and highly informative based on their polymorphism information content value (65% of markers showed PIC value >0.50). An estimation of genetic similarity coepreficients (GSC) resulted in values ranging from 0.13 to 0.92, and subsequent cluster analysis revealed extensive genetic variability in this collection of sorghum landraces. Eight clusters of accessions were identified at a cut off at 0.35 GSC and these groupings were supported by the analysis of subpopulations using Structure. The clusters were weakly stratified by province from which the accessions were collected. This study provides evidence that Chinese landraces of sorghum contains a wealth of genetic diversity and results from cluster analysis are expected to aid in identification of diverse accessions that can serve as parental lines which could result in better genetic gain for important agronomic traits.