UPDATE 1-Biotech corn, soy does little to boost yield-study

(Adds quotes from industry in paragraphs 6-8)

WASHINGTON, April 14 (Reuters) - Despite industry claims of higher yields from biotech corn and soybeans, much of the increase can be tied to other improvements in agriculture, according to a study released on Tuesday.

The Union of Concerned Scientists said its review found genetically engineered herbicide-tolerant soybeans and corn did not increase yields compared with conventional methods. Still, farmers embraced the technology partly because of lower energy costs and convenience associated with applying pesticides.

It also found another variety, BT corn, contributed to about 3.3 percent of the estimated 28 percent increase in corn yields since it was made available commercially in 1996. BT crops are resistant to certain insects.

“Genetic engineering, while it’s been good for some individual farmers, and great for the companies, really has not been very productive in terms of improving yields,” said Doug Gurian-Sherman of UCS who authored the report.

Instead, the study found much of the jump in yields can be attributed to successes in traditional breeding -- mixing genes to enhance one or a few genetic traits -- or conventional agriculture improvements such as more crop rotations and more efficient irrigation and fertilizer use.

The Biotechnology Industry Organization, which represents major firms involved in producing genetically engineered crops, noted that overall corn yields have increased 36 percent and soybeans 12 percent since the biotech crops were introduced.

“It’s absurd to deny biotechnology’s contribution, among other factors, to increased crop production,” said Sharon Bomer Lauritsen, an executive vice president at BIO.

“When farmer surveys have been conducted on yield benefits from biotech crops, the results have been overwhelmingly positive, with farmers finding their crop yields have increased,” she said.

The focus on improving food yields has grown amid higher food prices, growing populations and an increase in the number of people worldwide that are going hungry. An estimated 963 million people worldwide were undernourished last year, up from 923 million in 2007.

Biotech crops, primarily corn, soybeans, cotton and canola, have genes that have been manipulated to express specific traits, most commonly a resistance to herbicide, which helps farmers. Biotech developers such as Monsanto Co MON.N patent the crop technology and tightly control use of the seed.

Genetically modified crops were adopted quickly after introduction in the 1990s. Eighty percent of corn and 92 percent of soybeans grown in the United States in 2008 came from biotech crops, said the Agriculture Department.

The UCS report said as genetic engineers work to identify new genes “it would not be unexpected that some of them may eventually be successful in increasing yields.”

It warned, however, that as the manipulation of genes becomes more complex it will increase the need for stronger oversight to detect and prevent harmful side effects that may occur. These concerns may reduce the commercial acceptance of the crops.

The study also encouraged greater exploration of other methods, such as organic farming and improved traditional breeding, instead of placing too much dependence on biotech crops, especially in poor countries.

The UCS review was heavily dependent on nearly two-dozen studies conducted by university scientists and later published in peer-reviewed journals. (Reporting by Christopher Doering; Editing by Marguerita Choy)