Location: Corn, Soybean and Wheat Quality ResearchTitle: Genetic mapping of soybean aphid biotype 3 and 4 resistance in PI 606390A
Submitted to: Molecular Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/25/2019
Publication Date: 3/16/2019
Citation: La Mantia, J.M., Mian, R.M., Redinbaugh, M.G. 2019. Genetic mapping of soybean aphid biotype 3 and 4 resistance in PI 606390A. Molecular Breeding. 39:53. https://doi.org/10.1007/s11032-019-0956-9.
Interpretive Summary: Soybeans are one of the two most important field crops cultivated in the U.S., with about 90 million acres planted in 2017. The soybean aphid was first found in the U.S. in 2000 and has become one of the most economically important pests threatening soybean production in the Midwestern states. Severe infestations of aphids in soybean fields can result in leaf curling, wilting, and premature leaf drop. Yield losses in soybean attributed to the aphid were reported to be greater than 50% in Minnesota and significant losses of seed oil content have also been observed. Soybean PI 606390A was previously identified as having resistance to three biological variants of soybean aphids. In the present study, we observed that PI 606390A has resistance to a fourth biological variant of soybean aphid. We then identified a region on chromosome 18 of the soybean genome that is linked to resistance to two of the soybean aphid variants, where aphid resistance had not previously been identified. Thus we discovered a new broad aphid resistance locus. Genetic markers associated with resistance can be used to breed durable aphid resistance into high yielding soybean cultivars. PI 606390A can be used to further study soybean - aphid interactions. The release of aphid resistant soybean cultivars will reduce the cost to farmers to control aphid infestations while protecting yield and reduce the environmental impact of broad insecticide applications.
Technical Abstract: The soybean aphid (Aphis glycines Matsumura) is a major pest of soybean [Glycine max (L.) Merr.] in many soybean growing countries of the world, mainly in Asia and North America. While numerous aphid resistance loci have been mapped, new and virulent aphid biotypes continue to be identified. PI 606390A confers resistance to all four characterized soybean aphid biotypes. The objectives of this study were to identify single nucleotide polymorphism (SNP) markers closely linked to the loci conferring resistance to soybean aphid biotypes 3 and 4. One hundred and eight F6:7 families from a cross between the susceptible experimental line HR09-018 and the resistant PI 606390A plus the two parental lines were screened with aphid biotypes 3 and 4 using greenhouse choice tests. Broad-sense heritability estimates ranged from 0.69 – 0.91. Correlation between biotype 3 and biotype 4 resistance was also moderate (45 – 55%). A total of 1847 SNP markers were mapped to 22 linkage groups, and loci for resistance to both aphid biotypes mapped to a 14 cM region on chromosome 18 using composite interval mapping. The locus explained between 26 and 40% of the phenotypic variation suggesting the presence of a major locus and additional unidentified minor quantitative trait loci (QTL). A new symbol qRag-G is proposed to designate this new locus that will be useful for development of durable aphid resistant soybean cultivars.