FarmSelect Weblog

I found this reference while doing an unrelated search of ARS research papers. It seems that inserting a bt gene construct into corn doesn't leave us with a substantially equivalent plant after all.

Klaas

Technical Abstract: Information on the nutrient requirements and growth habits of newer transgenic corn hybrids is needed. To evaluate hybrid responses to fertilizer placement, a pot experiment was conducted in a controlled-climate chamber. Fertilizer was added to Clarion silt loam (fine-loamy, mixed, mesic Typic Haplaquolls) at two rates comparable to those used in a previous field trial (22-30-19 or 67-30-19 kg nitrogen-phosphorus-potassium ha-1, respectively). Three kg of soil (dry-weight basis) were placed in 3.8-L plastic pots, vertically divided into five parts with plastic screens. Fertilized soil was placed in a 0.20 fractional volume. Seedlings of two isolines (non-transgenic hybrids Pioneer 36R10 and 33P66 and transgenic hybrids Pioneer 36R11YG and 33P67YG) were planted two per pot and grown 13d. At harvest, roots growing in fertilized soil and a comparable unfertilized 0.20 fraction were removed separately. Preliminary results suggest that the non-transgenic corn hybrids were better able to take advantage of the available nutrients in the Clarion soil than were the transgenic hybrids. Dry matter accumulation was greater for both non-transgenic hybrids, regardless of fertilizer rate or placement. Based on measurements of root length in fertilized and unfertilized soil, the non-transgenic hybrids also were better able to respond to fertilizer placement. It is difficult to draw conclusions because information on plant uptake of nutrients is not yet available.

The ARS research page