More farmers 'stacking' genetically modified seeds

Data compiled by the U.S. Department of Agriculture (USDA) last month showed that more farmers are relying on "stacked" crops grown from seeds that have both herbicide-tolerant (Ht) and insect-resistant traits (Bt).

Ht-only crops were down 24 percent and Bt-only crops were down 27 percent while the use of stacked seeds to produce crops is up, with 77 percent of corn crops planted using this method this year, the USDA said.

Stacked crops have become increasingly popular in the past 20 years, especially with corn farmers who grow their crops for many different uses in the United States and abroad.

Ht seeds were developed to survive the use of certain herbicides that normally would kill the plant and the targeted weed. Bt seeds contain a gene from the soil bacterium Bacillus thuringiensis that produces a protein that is deadly to specific insects.

When stacked, the overall yield is generally higher than when only one of the types of seeds is used. 

The USDA, along with American farmers, hopes that the use of stacked crops will help in the production of more corn per harvest.