Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/8/2013
Publication Date: 5/21/2013
Publication URL: http://handle.nal.usda.gov/10113/57475
Citation: Bales-Arcelo, C., Zhang, A., Liu, M., Mensah, C., Gu, C., Song, Q., Hyten, D., Cregan, P.B., Wang, D. 2013. Mapping soybean aphid resistance genes in PI 567598B. Theoretical and Applied Genetics. 126:2081-2091. Interpretive Summary: The soybean aphid is a relatively new pest on soybean in North America and is now considered to be an economically important pest in U.S. soybean production. Plant Introduction PI 567598B, an unimproved soybean from the USDA Soybean Germplasm Collection, was found to be a source of resistance to the soybean aphid and resistance was previously determined to be controlled by two genes. The purpose of the research that was conducted was to determine the chromosome positions of the two resistance genes and to find genetic markers near the genes that could be used as surrogates to identify breeding lines that carried the two resistance genes without the need to undertake the complex and time consuming process of inoculating plants with aphids to determine if they carried the resistance genes. Breeding lines derived from crosses of aphid resistant with aphid susceptible soybeans were analyzed in both the field and the greenhouse and were inoculated with aphids to assess the resistance of each line. DNA marker analysis was done on the same lines in order to identify DNA markers that were associated with aphid resistance. The analysis of aphid resistance and the DNA marker data for each line resulted in the identification of two positions on soybean chromosomes 7 and 16 where the genes for aphid resistance were located. The DNA markers that were identified can be used by soybean breeders to identify breeding lines that carry resistance to soybean aphid without the need to inoculate each breeding line with the soybean aphid.
Technical Abstract: The soybean aphid (Aphis glycines Matsumura) has been a major pest of soybean [Glycine max (L.) Merr.] in North America since it was first discovered in 2000. Plant introduction PI 567598B possesses strong antibiosis resistance to soybean aphids. Our previous study revealed that the aphid resistance in PI 567598B was controlled by two recessive genes. The objective of this study was to locate these two genes on the soybean genetic linkage map using molecular markers. A mapping population of 282 F4:5 lines derived from PI 567598B was evaluated for aphid resistance in a field trial in 2009 and in a greenhouse trial in 2010. Two quantitative trait loci (QTLs) were found using the composite and multiple interval mapping methods. These two QTLs were mapped on chromosomes 7 (linkage group M) and 16 (linkage group J). PI 567598B derived parent (E06902) conferred resistance at both loci. In the 2010 greenhouse trial, each of the two QTLs explained over 30% of the phenotypic variation. Significant epistatic interaction was also found between these two QTLs. However, in the 2009 field trial, only the QTL on chromosome 16 was found and explained 56.1% of the phenotypic variation. These two QTLs and their interaction were validated with a population consisting of 94 F2:5 lines in the 2008 and 2009 greenhouse trials, where these two loci together explained about 50% and 80.4% of the total phenotypic variation, respectively. Our study shows that the soybean aphid isolate used in the 2009 field trial defeated the QTL found on chromosome 7. However, the QTL on chromosome 16 still conferred aphid resistance. The markers linked to the aphid-resistant QTLs in PI 567598B can be used in marker assisted breeding for aphid resistance when using PI 567598B or its derived lines as the aphid resistance source.