XVI International Botanical Congess

Introgression from crops to wild relatives may make genetically engineered (GE) crops risky since fitness related transgenes could move into invasive weeds. We compared seed production among three generations of GE hybrids of Cucurbita pepo to test if backcross progeny were superior to F1 hybrids. We pollinated wild plants with F1 pollen (from hybrids between wild plants and GE virus-resistant cultivars) to obtain a BC1 generation, and pollinated other wild plants with BC1 pollen to obtain a BC2 generation. We tested all four types near their native habitat. There were no significant differences in seed set among wild, BC1, and BC2 plants, but these types had significantly higher seed set than F1 plants. This suggests that after the F1 generation, movement of crop genes into wild genotypes is not impeded by linkage with deleterious crop-specific traits.