ORIGINAL ABSTRACT

BACKGROUND: A major concern about growing transgenic glyphosate-tolerant (GT) soybean (Glycine max) is the potential for gene flow to the wild relative Glycine soja, through hybridization and introgression. This could create new and serious weed-control problems and pollute wild soybean germplasm resources. This risk deserves particular attention in northern China, which is the origin center for soybean, a key reservoir of wild genetic diversity, and a major region of soybean cultivation. Our previous research on F1-F3 hybrids of three wild soybeans (IMBT, JLBC-1, HJLHRB-1) from northern China and GT soybean showed hybrid fitness increasing over successive generations, with two distinct segregation patterns observed. RESULTS: Consistent with these two segregation patterns, two types of F4 hybrids were examined: trait-segregating hybrids (IMBT F4) and segregation-distorted hybrids (JLBC-1 F4, HJLHRB-1 F4). Both displayed increased relative composite fitness compared with their wild progenitors, driven by enhanced vegetative growth (vine growth habit, higher biomass) and reproductive capacity (seed number and weight). Specifically, trait-segregating IMBT F4 hybrids exhibited various traits among and within sister groups. Segregation-distorted JLBC-1 F4 and HJLHRB-1 F4 displayed uniform, weedy-like phenotypes. CONCLUSION: If initial hybridization occurs, GT transgenes could introgress into wild soybean populations to produce fitness-enhanced trait-segregating and segregation-distorted F4. Trait-segregating may have a major role in hybrids adapting to a wider range of ecological niches, whereas segregation distortion may promote establishment in wild soybean habitats. Thus, effective measures are needed to prevent gene flow from GT soybean released in regions sympatric with wild soybean. © 2026 Society of Chemical Industry.