Registration of Two Soybean Germplasm Lines Containing Leaf-Chewing Insect Resistance QTLs from PI 229358 and PI 227687 Introgressed into ‘Benning’

Two soybean [Glycine max (L.) Merr.] germplasm lines, Benning-ME (Reg. No. GP-405, PI 679958) and Benning-MGHE (Reg. No. GP-406, PI 679959), were developed by the University of Georgia Agricultural Experiment Stations. Control of insect pests is crucial in soybean production; host-plant resistance reduces the need for insecticide applications, thus diminishing production costs and pesticide concerns. In soybean, resistance to a broad range of leaf-chewing insects is found in the Japanese accessions PI 229358 and PI 227687. In PI 229358, resistance is conferred by quantitative trait loci (QTLs) M, H, and G. In PI 227687, resistance is conferred by QTL-E. To enhance soybean resistance to leaf-chewing insects, QTLs of PI 229358 and PI 227687 were pyramided in Benning-ME and Benning-MGHE, which are near-isogenic lines of 'Benning' obtained through marker-assisted backcrossing. Under field conditions, Benning-ME and Benning-MGHE sustain 67 and 57% less defoliation than Benning, respectively. To determine the QTL introgressions in each line, high-density single-nucleotide polymorphism (SNP) genotypes were obtained using the SoySNP50K iSelect BeadChip (Illumina). To facilitate selection of lines carrying a specific QTL pyramid, Kompetitive Allele Specific Polymerase Chain Reaction markers were developed for high-throughput genotyping. These lines are valuable genetic resources for breeding of host-plant resistance to insects in soybean. The combination of QTL-M and QTL-E provides agriculturally relevant levels of resistance, and with only two loci, the use of this pyramid is feasible in a breeding program.