Ready for genetically engineered alfalfa?

University of California Cooperative Extension farm advisors and researchers are growing genetically engineered alfalfa in small experimental plots to determine whether the technology will be beneficial to California farmers.

“We would like to be ready with research-based answers when this technology is introduced,” said Steve Orloff, UC Cooperative Extension farm advisor in Siskiyou County. “It's somewhat controversial, but providing unbiased research results will enable growers to make intelligent decisions about it for themselves.”

Although final results are not yet in, the UC scientists believe that the new varieties, which have been genetically engineered to be resistant to the herbicide glyphosate (Roundup), could be an important new tool for alfalfa growers. These crops are called Roundup Ready varieties.

“It looks like it might be a good fit for California,” said Fresno County UC Cooperative Extension weed science advisor Kurt Hembree. “But it won't be a silver bullet for all farmers. Roundup is weak on some important alfalfa weeds, like malva, nettle, hairy fleabane and filaree. Successful weed control with this technology will depend a great deal on the ability of the growers and pest control advisers to accurately identify their specific weed problems before treating.”

Alfalfa is grown on more acres in California than any other crop and is the third-most valuable crop in the United States. It was one of the earliest domesticated crops and makes a tremendous contribution to world food production. However, because it is a few steps removed from the dinner plate, the general public does not often recognize its importance. Dairy feed is the primary use of alfalfa. For this reason, UC alfalfa specialist Dan Putnam often refers to the crop as “ice cream in the making.”

Evaluation and analysis of new technologies are not new to UC Cooperative Extension researchers. UC agricultural scientists have been active in analyzing technologies ranging from hybrid corn in the 1950s to integrated pest management techniques in the 1970s and 1980s, to genetically engineered crops in the 1990s. Alfalfa is among the most recent crops to be altered with Roundup Ready technology, which has already been commercialized by Monsanto Corp. in corn, soybeans, cotton and several other crops. To date, 40 percent of the corn and over 80 percent of the soybeans grown in the United States are genetically engineered.


In anticipation of a possible 2005 commercial release of Roundup Ready alfalfa, UCCE farm advisors Orloff, Hembree, Mick Canevari and Ron Vargas, and UC Davis specialists Putnam and Tom Lanini are evaluating the usefulness and performance of Roundup Ready alfalfa in the Intermountain Region and throughout the Central Valley as part of a statewide effort to assess the benefits and risks of this new weed-control technology.

Utilizing Monsanto's Roundup Ready seeds, the advisors' and specialists' goal is to provide information for farmers about the crop's growth under different environmental conditions and to determine the overall efficacy of the system compared with conventional weed-control approaches.

UC's involvement in the alfalfa trials gives California farmers research information they know is not clouded by financial interest in the success or failure of the product.

“We rate the trials blind,” Orloff said. “We don't favor one approach over others. We're not pushing Roundup Ready crops at all. We are simply evaluating a new agricultural weed-control technology.”

Weed control is a major challenge for alfalfa growers. Alfalfa contaminated with too many weeds may be unpalatable to livestock and less nutritious. In California, lower-quality alfalfa hay is worth an average of about $44 per ton less than premium alfalfa hay, and a common cause of low-quality hay is contamination with weeds. With the Roundup Ready alfalfa plant, growers can broadcast spray Roundup or generic glyphosate over the crop after the alfalfa and weeds have emerged, eliminating nearly all weeds. Later weed control sprays may be unnecessary as the alfalfa grows vigorously and shades later-emerging weeds.

According to Putnam, the major advantages of Roundup Ready technology in alfalfa appear to be simplicity, flexibility and broad-spectrum control of weeds. There may be other advantages as well.

“Alfalfa growers are working closely with state agencies to prevent runoff of insecticides and herbicides into streams and rivers,” Canevari said. “This new technology may reduce the amount of pesticides that are needed to grow the crop, and thereby reduces the risk of pesticide runoff with some of our winter-applied herbicides.”

‘Weed shift’

However, concerns remain. Canevari has seen a “weed shift” in his experimental plots where Roundup Ready alfalfa has been grown for three years.

“When we started this study, there were four or five stinging nettle plants on this end of the field,” Canevari said, pointing to one of his plots at a farm west of Stockton. “Now you can see nettle all along the field. We're seeing more and more nettle each year.”

Mixing into the tank with Roundup another herbicide that kills nettle and other weeds not controlled by Roundup may be one way to manage a weed-shift problem.

Another worry is the development of herbicide-resistant weeds. Certain weeds, such as ryegrass, over the years have developed levels of resistance to glyphosate.

“At this point, we already have Roundup Ready corn and cotton. Alfalfa is being studied and I have a project with Roundup Ready wheat. If you were to rotate between these crops, I wouldn't recommend growing Roundup Ready crops successively,” Vargas said. “That's really setting yourself up for weed resistance.”

The economic feasibility of growing Roundup Ready alfalfa has not yet been studied because, to date, Monsanto has not announced the pricing formula for Roundup Ready alfalfa seed. Unlike most other Roundup Ready crops, alfalfa is perennial. An annual lease on the Roundup Ready trait or a price premium for the seed that takes into consideration multiple years of growth are being considered. The UC field trials should assist growers in making an economic evaluation of the technology, since comparative yields, application rates and weed-control efficacy are being studied.

UC researchers are also considering the potential market acceptance, since growers will want to know whether buyers will purchase Roundup Ready alfalfa hay. Putnam said he does not expect much resistance from the major market for alfalfa, the dairy industry, since it has already absorbed a number of similar technologies. Most cheese, he points out, is currently made from rennin from genetically engineered microorganisms. However, he said, there might be some consumer resistance to the Roundup Ready alfalfa crop in markets that import California hay, such as Japan.

Export resistance

“In my discussions with exporters, there will likely be initial resistance from the export market, since some Japanese consumers are reluctant to purchase genetically engineered foods. That will likely moderate over time and will be price dependent,” Putnam said. “Organic producers will reject the technology, as they do all herbicides. Some horse owners may also initially balk at the use of genetically engineered alfalfa, but they may also quickly realize the benefits, since a number of horses die each year from poisonous weeds that could be easily removed through this technology.”

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