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

Authors: CATES, SARAH - North Carolina State University; GORNY, ADRIENNE - North Carolina State University; Taliercio, Earl; GILLENWATER, JAY - North Carolina State University; LUX, LEANN - North Carolina State University

Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/8/2026
Publication Date: N/A
Citation: N/A

Interpretive Summary: Meloidogyne enterolobii (guava root-knot nematode) is an emerging pest in North Carolina threatening multiple crops with potential to spread to other regions of the U.S. Soybean is sensitive to guava root-knot nematode (GRKN) and known resistance to other root knot nematodes is ineffective against Meloidogyne enterolobii . GRKN resistant soybean is particularly important because it can be used in rotation with other crops to manage GRKN as well as being an important row crop in the U.S.. One hundred and ninety-one accessions of soybean (G. max), mostly derived from the USDA Glycine germplasm collection, were screened in the greenhouse for resistance to an NC isolate of Meloidogyne enterolobii . Three resistant lines were identified based on reduced galling, lower egg counts and reproduction factors below 1. These lines represent the first G. max lines shown to be resistant o Meloidogyne enterolobii to our knowledge. This availability of these lines will be useful to soybean breeders to introduce Meloidogyne enterolobii resistance soybean to U.S. farmers to preserve soybean yields threatened by this pest.

Technical Abstract: The production of soybean is a vital industry within North Carolina and the United States of America, accounting for millions of dollars in annual revenue, but it is currently under threat due to the presence of Meloidogyne enterolobii (guava root-knot nematode). Plant resistance is a crucial management technique for combating this nematode, but M. enterolobii is known to overcome resistant cultivars that have suppressed the infection of other root-knot nematodes such as M. incognita. Due to this, identifying novel resistance genes that work antagonistically to M. enterolobii is paramount. In this study, 198 lines of commercial soybean, Glycine max, were assessed for resistance to M. enterolobii through a greenhouse assay. The soybean lines were selected due to their commercial usage, maturity group, and geographical diversity. An initial screening took place where all lines were inoculated with M. enterolobii eggs from a North Carolina culture and assessed after 60 days for resistance using three metrics. The root galling severity was observed, the reproduction factor was calculated (final egg count/initial inoculation egg count, RF), and the eggs per gram of root was determined in order to quantify a specific line as resistant. Each of the 198 lines were tested twice within the initial screening and the top ten most resistant lines were tested in a confirmation screening in high replicate counts. The confirmation screening found three soybean lines to be resistant, PI 548555, PI 639740, PI 556852, with all three soybean lines resulting in resistance metrics under the 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.