Farmers in Washington, Oregon and Idaho grow a lot of alfalfa hay for dairies and for export. Alfalfa is an important part of Washington state’s $539 million hay industry, grown on more than 400,000 acres throughout the state — most extensively in the irrigated Columbia River Basin.
Some is exported around the world, mainly to China, Japan, Saudi Arabia and the United Arab Emirates.
Steve Norberg, regional forage specialist and irrigated cropping systems specialist at Washington State University, is leading a two-year, $250,000 effort to discover genetic areas — called molecular markers — that will enable plant breeders to create better alfalfa varieties. This study is funded by USDA’s National Institute of Food and Agriculture Alfalfa and Forage Research Program.
“Quality is crucial, especially when hay prices are low. Top-quality dairy hay is always worth more,” said Norberg. “We’re looking for genes that can be bred into traditional alfalfa varieties, making them more digestible, with less fiber. Dairy cows must eat a lot to produce milk, and less fiber means more nutrition and less waste.”
The idea is to provide breeders with another tool to breed for higher-quality alfalfa. They recruited several specialists, including a geneticist, USDA Agricultural Research Service scientist Long-Xi Yu.
“We’ll be using his expertise to evaluate DNA and look for genetic markers of all the varieties we test,” Norberg said.
The researchers are pulling 150 different varieties from the USDA-ARS National Plant Germplasm System Temperate-adapted Forage Legume Genetic Resources Program at Pullman, Wash.
“These are from all around the world. We’re also looking at another 50 commercial varieties from 4 commercial seed companies that are cooperating with us, one of which is an organic alfalfa seed supplier,” Norberg said. The conventional seed suppliers are three of the four largest alfalfa breeders in the U.S.
“We’ve selected varieties from around the world that have fall dormancy,” he said.
In the Pacific Northwest climate, alfalfa must go dormant for winter. Within the dormant varieties the researchers are looking for those that produce the highest quality.
They will plant those 200 varieties next spring at three locations — Prosser, Wash.; Union, Ore.; and Twin Falls, Idaho, which have different climates and elevations.
Participants in the project are WSU faculty members Don Llewellyn, a regional livestock specialist, and state forage specialist Steven Fransen; University of Idaho forage specialist Glenn Shewmaker; Oregon State University forage specialist Guojie Wang; and University of Wisconsin rumen nutritionist David Combs.
Next summer, the team will sample the plants and look for genetic markers that denote lower fiber and better digestibility.
“We will harvest all varieties at mid-bud stage and take samples. We will check yield, moisture content, et cetera, and run the samples through a testing technique developed in Wisconsin by David Combs,” Norberg said. The acronym for this test is TTNDFD, for total track neutral detergent fiber digestibility.
Samples will be evaluated based on fiber quality — how much fiber in the alfalfa, how much of the fiber is digestible, and the rate the fiber is digested.
“When we plant the varieties next spring for this trial we’ll include some check varieties (some with high fiber and some with low fiber) for comparison. Our goal is to figure out, in DNA for each variety, what genetic markers are associated with fiber quality, which varieties have higher quality and how they yield in forage trials,” he said.
“We’ll share that information with commercial breeders so they can select for those traits,” Norberg said.
He hopes their discoveries will speed up improvement in alfalfa seed programs worldwide and result in new varieties.
“Alfalfa exports are increasing. Many growers in Washington want the ability to export their first cutting. Those who raise alfalfa hay for dairies would like accessibility to both markets,” he said. “We’re trying to help make sure new varieties will be even better.”
For the two-year study, the main concentration is on the first cutting — for dairy quality and export — since that is the most likely cutting to go to both markets.
“It is expensive to do tests and we have enough funding to do first cutting for two years. We’ll publish the yields of all these varieties and look at how they differ in yield and quality in the three locations we’re planting,” said Norberg.