
Doubling
Wildrye's Chromosomes Brightens Pasture Grass' FutureBy Don Comis December 23, 2002It's amazing what 14 more
chromosomes can do for Russian wildrye, a pasture grass introduced to the U.S.
Northern Plains area from Siberia in 1927. John Berdahl, a plant geneticist with the Agricultural Research Service, has created
Russian wildrye plants that are called tetraploids because they have double the
usual 14 chromosomes. The extra chromosomes result in a plant that produces
larger seeds and much more robust seedlings, solving the biggest barrier to
wider use of the grass. Russian wildrye helps keep cattle well fed by providing forage with higher
digestibility and protein, especially in late summer and fall when other
grasses, such as crested wheatgrass, tend to become less nutritious. But
farmers and ranchers still often choose those other grasses because they're
easier to grow. Berdahl, plant physiologist Al Frank and colleagues at the
ARS Northern Great Plains Research
Laboratory in Mandan, N.D., hope to change that by using tetraploids to
breed new Russian wildrye varieties. They expect to one day see them planted
extensively on marginal land in the Northern Plains and Intermountain Region.
Berdahl and colleagues created the new plants without any gene transfer or
sophisticated biotechnology. Instead, they induced chromosome doubling by
pressurizing flower-bearing stalks in canisters filled with nitrous oxide gas.
Nitrous oxide is commonly known as "laughing gas." The nitrous oxide
technique enables production of numerous tetraploid seeds and development of
genetically diverse populations from which to select superior plants. It will take about five years to release the first tetraploid Russian
wildrye variety to seed growers. Then it will take a few more years for seed
growers to produce enough pedigreed seed for sale to farmers, bringing the new
variety to market around 2010. ARS is the U.S. Department of
Agriculture's chief scientific research agency. Story contacts Mandan, North Dakota Natural Resource Management Research Albert B Frank John D Berdahl U.S. Department of Agriculture |