Data from: Transgenes for insect resistance reduce herbivory and enhance fecundity in advanced generations of crop-weed hybrids of rice

Gene flow from transgenic crops allows novel traits to spread to sexually
compatible weeds. Traits such as resistance to insects may enhance the
fitness of weeds, but few studies have tested for these effects under
natural field conditions. We created F2 and F3 crop-weed hybrid lineages
of genetically engineered rice (Oryza sativa) using lines with two
transgene constructs, cowpea trypsin inhibitor (CpTI) and a Bt transgene
linked to CpTI (Bt/CpTI). Experiments conducted in Fuzhou, China,
demonstrated that CpTI alone did not significantly affect fecundity,
although it reduced herbivory. In contrast, under certain conditions
Bt/CpTI conferred up to 79% less insect damage and 47% greater fecundity
relative to non-transgenic controls, and a 44% increase in fecundity
relative to the weedy parent. A small fitness cost was detected in F3
progeny with Bt/CpTI when grown under low insect pressure and direct
competition with transgene-negative controls. We conclude that Bt/CpTI
transgenes may introgress into co-occurring weedy rice populations and
contribute to greater seed production when target insects are abundant.
However, the net fitness benefits that are associated with Bt/CpTI could
be ephemeral if insect pressure is lacking, for example, due to widespread
planting of Bt cultivars that suppress target insect populations.