Submitted to: Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/20/2006
Publication Date: 9/23/2006
Citation: Chen, Y., Wang, D., Arelli, P.R., Ebrahimi, M., Nelson, R.L. 2006. Molecular Marker Diversity of SCN Resistant Sources in Soybean. Genome. 49:938-949 Interpretive Summary: In the United States soybean cyst nematode is a major pest on soybean crop. The annual crop losses are estimated to be over billion dollars. Nematodes are tiny round worms that suck nutrients from the soybean roots, decreasing its ability to produce beans. Planting resistant varieties in the grower’s fields will reduce yield losses. Resistant cultivars have derived their resistance from three sources; Peking, PI 88788 and Hartwig. Nematodes have adapted to these sources. New sources of resistance may provide durable resistance. More than one hundred sources of resistance have been identified but information on pedigrees is not available to determine their relationships. We have fingerprinted these soybean sources using DNA markers and identified unique types. These new sources may provide durable resistance and reduce yield losses. Soybean growers will have more profit.
Technical Abstract: Soybean cyst nematode (SCN) (Heterodera glycines Ichinohe) is one of the most destructive pests of soybean (Glycine max (L) Merr) in the United States. Over 100 SCN resistant accessions within the USDA Soybean Germplasm Collection have been identified, but little is known about the genetic diversity of this SCN resistant germplasm. The objective of this research was to evaluate the genetic variation and determine the genetic relationships among the SCN resistant accessions. One hundred and twenty-two genotypes were evaluated by 85 simple sequence repeat (SSR) markers from 20 linkage groups. Nonhierarchical (VARCLUS) and hierarchical (Ward’s) clustering were combined with multidimensional scaling (MDS) to determine relationships among tested lines. The 85 SSR markers produced 566 allelic fragments with a mean PIC value of 0.35. The 122 lines were grouped into seven clusters by two different clustering methods and the MDS results are consistently corresponded to the assigned clusters. Assigned clusters were dominated by genotypes that possess one or more unique SCN resistance genes and were associated with geographical origins. The results of analysis of molecular variance (AMOVA) showed that the variation differences among clusters and individual lines were significant, but the differences among individuals within cluster were not significant.