Table 1.

Summary of experimental procedures, insect pressure, and effects of transgenes on fecundity in cultivated rice and crop–weed hybrid progeny

		Experimental procedure	Insect pressure	Difference in no. of seeds per transgenic relative to nontransgenic plant under pure or mixed cultivation†
Year*	Plant type	Pot versus plot	No. of replicates	No. of plants sampled/replicate (mixed, pure cultivation)	Percentage of damage on non-genetically engineered plants	Bt pure	Bt mixed	Bt/CpTI pure	Bt/CpTI mixed	CpTI pure	CpTI mixed
2003	Crop	Pot	20	6, 6	4	15%	−10%	19%	−30%	−4%	−15%
2003	Crop	Pot	20	6, 6	30	36%	65%	61%	−9%	21%	4%
2004	Crop	Plot	5	30, 60	1	−15%	−52%	24%	−53%	26%	−28%
2004	Crop	Plot	5	30, 60	14	−4%	−2%	0%	3%	−6%	−3%
2006	Crop	Plot	3	42, 63	1	3%	−4%	5%	−42%	2%	−28%
2006	Crop	Plot	3	42, 63	23	19%	12%	45%	33%	41%	−8%
2008	Weedy F2 hybrid	Plot	8	18§, 36	8‡	–	–	−6%	11%‡	−2%	−2%§
2008	Weedy F2hybrid	Plot	8	18§, 36	28‡	–	–	25%	34%‡	6%	−4%§
2009	Weedy F3 hybrid	Plot	4	18, 36	8‡	–	–	−3%	−19%	−4%	13%
2009	Weedy F3hybrid	Plot	4	18, 36	22‡	–	–	47%	3%	9%	10%

^*Data from the present study were collected in 2008–2009, and data from experiments in 2003–2006 were from Chen et al. (2006) and Xia et al. (2010). Boldfaced values with gray shade indicate natural insect pressure, while unshaded values with normal face indicate low insect pressure.

^†Differences was estimated by the percent increase (fitness benefit)/decrease (fitness cost) in fecundity of transgenic rice or crop–weed progeny relative to nontransgenic controls; the values with underlines indicate significance at P < 0.05.

^‡Calculated based on the average of the nontransgenic control of cowpea trypsin inhibitor (CpTI) and Bt/CpTI.

^§In 2008, the mixed treatment involved crop plants as competitors. In all other years, the mixed treatment involved transgenic and nontransgenic plants competing against each other in the same plot or pot.