In about two years, livestock producers who want to replace toxic-endophyte-infected tall fescue with non-toxic varieties will have more options to choose from, says University of Arkansas agronomist Chuck West.
West and retired Arkansas animal scientist Edgar Piper discovered four non-toxic, or novel, endophyte strains and plan to license them to seed companies for incorporation into commercial tall fescue varieties. Field tests have shown that varieties infected with any of the recently patented strains is as persistent during summer droughts as Kentucky 31, and in cattle performance trials with three of them, infected fescue didn't cause toxicosis symptoms, West reports.
Varieties with the endophytes should compare favorably with current MaxQ novel-endophyte varieties, he adds.
“We expect them to be at least as good, but they really haven't been compared extensively side by side,” points out West. West found the new strains in plants growing in the Mediterranean region.
“I wanted to find endophytes that were native in fescues that were adapted to long, hot, dry summers,” he explains.
Over a 12-year period, seeds from hundreds of plants from that region were tested by West and Piper with early help from University of Missouri agronomists Dave Sleper and Craig Roberts. The seeds were planted in a greenhouse, and those that contained endophytes were tested for ergot alkaloids, especially ergovaline, the main cause of fescue toxicosis.
“We screened a lot of plants, and almost all of them produced ergovaline, but just a very few did not,” West reports.
Those plants were grown out and tested again to make sure harmful alkaloids weren't present in any plant parts. Further screening ensured the presence of two types of loline alkaloids that deter aphids.
“We wanted to increase the chances that the ones we selected would maintain insect resistance.”
Several seed companies have expressed interest in commercial licensing rights to the endophytes. West says seed of one or more new novel-endophyte varieties could be available in small quantities by 2010, and widely available by 2011.