Submitted to: Plant Varieties and Seeds
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 12, 1999
Publication Date: N/A
Interpretive Summary: The development of a new soybean variety is an expensive process that requires time and extensive laboratory, greenhouse and field testing. Because of this large cost, public institutions and private industry seek protection of their investment through the Plant Variety Protection (PVP) Office of the USDA Agricultural Marketing Service. In order to obtain a PVP certificate, the developer of a new variety must demonstrate that it is different from all previously developed varieties. Until now, the PVP Office generally has relied on standard pigmentation, morphological, and disease resistance traits to distinguish varieties. With ever increasing numbers of new varieties, the standard traits are no longer adequate to distinguish new varieties. In this report a system of soybean variety identification is defined using Simple Sequence Repeat (SSR) DNA markers which are similar to those used in human identification. From an initial group of 48 SSR loci, a subset of 13 was identified that gave unique DNA fingerprints to each of 66 elite N. American soybean cultivars. This system can be used by developers of new soybean cultivars to protect their cultivars and also will be useful to soybean geneticists for pedigree analysis, population genetics studies, and other basic genetic analyses.
Soybean [Glycine max (L.) Merr.] cultivars are identified for purposes of Plant Variety Protection (PVP) by standard pigmentation and morphological traits. However, many commercial soybeans arise from a limited number of elite lines and are often indistinguishable based on these traits. A system based on DNA markers would provide unique DNA profiles or fingerprints of cultivars. Simple Sequence Repeat (SSR) allele size profiling is used in human forensics to provide unique DNA fingerprints of an individual. It was the purpose of the work presented here to select and evaluate a small set of SSR markers with maximum repeatability that would provide a high level of discriminatory power to distinguish soybean genotypes. A total of 48 fluorescently labeled SSR primer sets were used to amplify genomic DNA of the 35 ancestors of N. American soybeans as well as a diverse group of 66 elite N. American soybean cultivars. The informativeness of the 48 loci was evaluated via cluster analysis. The analysis resulted in the identification of a subset of 13 loci, from 12 different linkage groups, that produced unique SSR allele size profiles for each of the 66 elite N. American soybean cultivars. This set of 13 loci is proposed as the standard set for use in DNA profiling of soybean cultivars for purposes of obtaining protection under the PVP Act.