Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/12/2014
Publication Date: 4/5/2014
Publication URL: http://handle.nal.usda.gov/10113/58951
Citation: Kim, K., Chirumamilla, A., Hill, C.B., Hartman, G.L., Diers, B.W. 2014. Identification and molecular mapping of two soybean aphid resistance genes in soybean PI 587732. Theoretical and Applied Genetics. 127:1251-1259. Interpretive Summary: Host plant resistance is often the most important component of an integrated pest management system for insect control. Accessions from the USDA Soybean Germplasm Collection have been screened to identify sources of both antibiosis and antixenosis type of host plant resistance to the soybean aphid. Several soybean aphid resistance genes have been identified and genetically mapped onto soybean chromosomes. The objectives of this study were to determine the inheritance of soybean aphid resistance in PI 587732 and to map this resistance. For this study, populations derived from crossing PI 587732 to two susceptible soybean genotypes were challenged with three soybean aphid biotypes and evaluated with genetic markers. Resistance to the soybean aphid Biotype 1 was controlled by a gene on chromosome 7, while resistance to Biotype 2 was controlled by a gene on chromosome 13. The two soybean aphid resistance loci and genetic marker information from this study will be useful in increasing diversity of soybean aphid resistance sources and marker-assisted selection for soybean breeding programs. This information will be useful for scientists in commercial companies interested in improving resistance in soybean to the soybean aphid.
Technical Abstract: Soybean [Glycine max (L.) Merr.] continues to be plagued by the soybean aphid (Aphis glycines Matsumura: SA) in North America. New soybean resistance sources are needed to combat the four identified SA biotypes. The objectives of this study were to determine the inheritance of SA resistance in PI 587732 and to map resistance gene(s). For this study, 323 F2 and 214 F3 plants developed from crossing PI 587732 to two susceptible genotypes were challenged with three SA biotypes and evaluated with genetic markers. Choice tests showed that resistance to SA Biotype 1 in the first F2 population was controlled by a gene in the Rag1 region on chromosome 7, while resistance to SA Biotype 2 in the second population was controlled by a gene in the Rag2 region on chromosome 13. When 134 F3 plants segregating in both the Rag1 and Rag2 regions were tested with a 1:1 mixture of SA Biotype 1 and 2, the Rag2 region and an interaction between the Rag1 and Rag2 regions were significantly associated with the resistance. Based on the results of the non-choice tests, the resistance gene in the Rag1 region in PI 587732 may be a different allele or gene from Rag1 from Dowling because the PI 587732 gene showed antibiosis type resistance to SA Biotype 2 while Rag1 from Dowling did not. The two SA resistance loci and genetic marker information from this study will be useful in increasing diversity of SA resistance sources and marker-assisted selection for soybean breeding programs.