Edible Cotton

If it weren't poisonous, cotton would make a terrific food. Its seeds are rich in high-quality protein, and the plant is hardy. Nearly 80 countries produce 44 million metric tons a year. That's enough to feed 500 million people--if only it weren't for gossypol, a toxic chemical.

Now, after trying to develop gossypol-free cotton for several years, Keerti Rathore, a biologist at Texas A&M University, has finally managed to produce a strain that he says could meet the World Health Organization's standards for food. "We have brought down the level of gossypol in the seed."

The trick was to silence the gene that's responsible for producing gossypol in the seeds of the plant, but to allow the gene to produce the substance in the flowers and leaves. Scientists will have to study the new seeds extensively, so the plant won't be ready to be used as food for at least a decade. And remember: don't make a salad from the leaves.