RR alfalfa expected in 2004-2005 Multiple location forage yield trials of Roundup Ready alfalfa varieties will begin late this year with commercial release of herbicide resistant alfalfas in 2004 or 2005, according to Mark McCaslin, president of Forage Genetics International.

McCaslin reported to the combined 29th national Alfalfa Symposium and 30th California Alfalfa symposium that the commercial release date will depend largely on the regulatory review process.

The Roundup Ready gene has been backcrossed into a wide variety of germplasm sources, he said. "RR alfalfa varieties will be available with excellent adaptation to most alfalfa production areas in the world," he said.

In greenhouse and field trials throughout the country, McCaslin said the first RR alfalfa varieties yielded equal to or better than commercial varieties of the same fall dormancy.

"RR alfalfa cultivars also will have the same multiple pest resistance and high forage quality that characterizes many of the newer commercial varieties," he added.

More than 90 percent of the plants in a RR variety will show tolerance to Roundup, which can be sprayed at any development without crop injury. This makes the technology ideal for both stand establishment and weed control in established alfalfa.

He said Roundup over the top of the plants "provided virtually perfect weed control, significantly better than other treatments."