Evaluation of Glycine max genotypes (maturity groups IV and V) for resistance to Meloidogyne enterolobii via phenotypic and GWAS assays

The production of soybean is a vital industry within North Carolina (NC) and the United States, accounting for millions of dollars in annual revenue, yet is currently under threat due to the presence of Meloidogyne enterolobii. Plant resistance is a crucial management technique for this nematode, but M. enterolobii is known to overcome resistant cultivars that have suppressed infection by other root-knot nematodes such as M. incognita. Therefore, identifying novel resistance genes that work antagonistically to M. enterolobii is paramount. In this study, 198 lines of Glycine max were assessed for resistance to M. enterolobii through a greenhouse assay. During initial screening, soybean lines were inoculated with a NC isolate of M. enterolobii and assessed after 60 days for resistance using three metrics, including root galling severity, reproduction factor, and eggs per gram of root. The ten most resistant soybean lines were then tested in a confirmation screening. Three soybean lines: PI 548555, PI 639740, and PI 556852, were confirmed to be resistant with all three lines resulting in resistance metrics under the defined resistance threshold. The use of these lines could provide much needed support to soybean growers in NC and allow for novel resistance loci or genes to be bred into existing cultivars. A Genome-wide association study analysis was performed using publicly available marker data for resistance traits, but no significant associations were detected in the current analysis.