|BHUSAL, SIDDHI - South Dakota State University|
|JIANG, GUO-LIANG - Virginia State University|
|CREGAN, PERRY - Retired ARS Employee|
|WRIGHT, DAVID - South Dakota State University|
|GONZALEZ=HERNANDEZ, JOSE - South Dakota State University|
Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/21/2017
Publication Date: 6/24/2017
Citation: Bhusal, S.J., Jiang, G., Song, Q., Cregan, P., Wright, D., Gonzalez=Hernandez, J.L. 2017. Genome-wide detection of genetic loci associated with soybean aphid resistance in soybean germplasm PI 603712. Euphytica. 213:144. https://doi.org/10.1007/s10681-017-1933-1.
Interpretive Summary: Soybean aphid insects were first reported in the United States in 2000, and they are now among the major pests of soybean in the northern United States and southeastern Canada. Soybean aphids suck plant sap, resulting in stunted plant growth and reduced seed yield, pod and seed set, and seed oil content. Soybean aphids also transmit various plant pathogenic viruses. There are few soybean genotypes of the early maturing varieties that possess aphid resistance. Our investigations discovered that PI 603712 was the earliest maturing soybean variety that exhibited resistance to heavy infestations of soybean aphids in South Dakota field trials. Thus, we characterized the resistance in PI 603712 and identified two regions of genes in the plant chromosomes that control the resistance. In addition, we identified markers for DNA in these regions that could be used by breeders for the selection of resistant lines in breeding programs. The accession PI603712 is a valuable source of natural genetic resistance needed to combat aphid infection in soybean, and these results will be used by soybean breeders at government agencies, universities and private companies to improve aphid resistance in soybeans.
Technical Abstract: Soybean aphid (Aphis glycines Matsumura) has become one of the major pests of soybean (Glycine max (L.) Merr.) in North America since 2000. At least four biotypes of soybean aphid have been confirmed in the United States. Genetic characterization of new sources of soybean aphid resistance will facilitate the expansion of the soybean gene pool for soybean aphid resistance and thus will help to develop soybean aphid resistant cultivars. To characterize the genetic basis of soybean aphid resistance in PI 603712, a newly identified resistant germplasm line, 142 F2 plants derived from the cross ‘Roberts’ x PI 603712 and their parents were evaluated for soybean aphid resistance in the greenhouse, and were genotyped with BARCSoySNP6K Illumina Infinium II BeadChip. A genome-wide molecular linkage map was constructed with 1495 polymorphic SNP markers. QTL analysis revealed that PI 603712 possessed two major loci associated with soybean aphid resistance, located on chromosome 7 and 16. The locus on chromosome 7 was dominantly expressed and positioned about one Mega-base-pair (Mb) distant from the previously identified resistance locus Rag1. The locus on chromosome 16 was positioned near the previously identified resistance locus Rag3, but expressed partial dominance differently from Rag3. Interestingly, two minor loci were also detected on chromosomes 13 and 17 but the alleles from PI 603712 decreased the resistance. Multiple interval mapping showed no significant QTL by QTL interaction. However, two-way ANOVA indicated that a significant interaction (p<0.05) existed between the locus associated with resistance on chromosome 7 and the locus associated with susceptibility on chromosome 13. In developing soybean aphid resistant cultivars through marker-assisted selection, an appropriate combination of resistance loci should be selected when PI 603712 is used as a donor parent of resistance.