Patent ID: 7994389

Claim:
A method for identifying the presence or absence of a gene coding for resistance to Aphis glycines in soybean germplasm comprising: analyzing said germplasm by marker-assisted selection (MAS) to: detect a resistance to Aphis glycines (RAG) locus that maps to soybean linkage group M of said soybean germplasm, wherein said RAG locus is flanked on opposite sides by SSR markers Satt435 and Satt463, which show allelic polymorphism between Aphis glycines -resistant and Aphis glycines -susceptible soybean genotypes and are linked to the RAG locus, and wherein the RAG locus comprises allelic DNA sequences that control resistance to Aphis glycines ; and determine the presence or absence of an allelic form of DNA linked to the gene coding for resistance to Aphis glycines in said germplasm; wherein the presence or absence of said allelic form of DNA linked to said gene is determined by comparing a first PCR-amplified polymorphic marker fragment of said soybean germplasm to a second PCR-amplified polymorphic marker fragment of soybean germplasm from a plant having Aphis glycines resistance conferred by said Rap1 gene, wherein said second fragment is made using the same marker used to make said first fragment, and wherein said second fragment has a size substantially the same as that of a PCR-amplified polymorphic marker fragment of germplasm of Aphis glycines -resistant soybean varieties Dowling and Jackson made using the same marker used to make said first and second fragments; and determining that said gene coding for RAG resistance is present in said soybean germplasm when said first fragment is substantially the same size as said second fragment, and determining that said gene is not present in said germplasm when said first fragment is not substantially the same size as said second fragment.