To the editor:

Your editorial 'Drugs in crops—the unpalatable truth' (Nat. Biotechnol. 22, 133, 2004) was timely and important, but ends with the terrible proposal “Let's grow pharma plants, but let those plants be Arabidopsis, or flax, or duckweed.” The tiny mustard plant, Arabidopsis, might work in very small farms and duckweed may not be all wet, but flax is an abominable suggestion.

Flax is grown extensively in Canada and the United States for fiber (linen), oil (linseed) and animal feed. The crop is both inbreeding and insect pollinated1 meaning that the transgenes from pharma crops could easily pollinate the common weedy relatives of flax along with the very common feral weeds of the crop plant2. One transgenic herbicide-resistant form of flax has been approved for commercial production2. Flax is therefore not a good candidate for pharma crops because it is known to be insect pollinated, allowing the pharma transgenes to spread to commercial crops used in human foods, such as salad dressing and in animal feed cake along with industrial oil and fiber.