Meta analysis data and fitness-related trait values

Crop-wild gene flow may alter the fitness performance of the recipient i.e. crop-wild hybrids, then potentially impact wild populations, especially for the gene flow carrying selective advantage crop alleles. Given the continuous crop-wild gene flow since crop domestication and the occasionally stressful environments, the extant wild populations of most crops are still "wild". This paradox hints some mechanisms may mitigate the effects of crop-wild gene flow but never been examined.
We used wild rice (O. rufipogon) and transgenic (Bt/CpTI) rice as a crop-wild gene flow model and established cultivated, wild and hybrid rice populations (O. rufipogon × O. sativa) under four levels of insect (Chilo suppressalis) pressure. Then, we measured the fitness performance of the plants.
The fitness performance of all plants varied with the insect pressure level; wild plants displayed over- or equal-compensatory responses to insect damage, whereas hybrids exhibited under-compensatory responses, showing wild plants have higher insect-tolerance. The high tolerance results in better performance of wild rice under stressful conditions, while transgenes expressed a beneficial effect on plant performance only under certain levels of insect pressure. Hybrid advantage is remarkable. Transgenes and hybrid advantage may increase hybrid fitness, but such effect is reduced by tolerance under stressful environments.
Synthesis. These results suggest that high tolerance to environmental stress is a mechanism mitigating the impacts of crop gene flow on wild plants by weakening hybrid fitness performance.