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Potential for perennial wheat
There is nothing unique about plant scientists trying to develop commercially viable perennial wheat. Russian researchers were actively involved in the effort from the turn of the nineteenth century through the 1950s. And wheat breeders from the University of California at Davis engaged in similar activities until they abandoned their quest for a consistently high-performing perennial wheat in 1965.
“The reason perennial wheat went away in California in the 1960s was because of yields,” says Steve Jones, a Washington State University (WSU) wheat breeder. “The thinking at the time was unless perennial wheat lines could yield as well as annual wheat, they were nonstarters.”
Times have changed. Now, WSU plant breeders view perennial wheat as practical. Higher production costs include rising fuel and fertilizer prices. This is coupled with an emerging global consensus of developing sustainable cropping systems to turn the world's most commonly grown small grain annual into a perennial.
Jones notes that there are real changes in how some in the agricultural community view wheat production.
“These growers are still interested in yield but not yield at any price,” he says. They are also trying to find ways to stabilize and reduce input costs while attaining a higher sustainability level.
This new ethos is particularly relevant to eastern Washington's grain-growing communities. While their farms are some of the world's most productive, the light soils are highly susceptible to erosion. When fields are left fallow, they are vulnerable to wind erosion throughout the year. Much wheat production occurs on 5° to 30° slopes prone to severe runoff on exposed ground between November and May. Soil losses of over 200 tons per acre per year are not uncommon on steeper, conventionally tilled production sites.
Jones and others in the Northwest believe that perennial wheat could play a major role in reducing soil disturbance by eliminating the need to till and plant every year.
Producer Pushes Perennial Wheat
A 27-year supporter of perennial wheat development in the Northwest is Jim Moore, a Kolutus, Washington, wheat producer. “I've taken my share of teasing over this,” he says. “But I just keep pushing.”
In the early 1980s, Moore was told by a previous generation of wheat breeders at WSU that perennial wheat was impractical. They cited the breeding program conducted by University of California at Davis.
Moore resumed his quest after being elected Washington State Wheat Commissioner in 1991. “The district I represented is extremely dry and prone to wind erosion,” Moore says. “I figured if we could find perennial wheat, we could keep the soil from blowing and get something off it.”
Meanwhile, Moore found a new wave of wheat breeders at WSU far more receptive to his vision for perennial wheat.
In 1997, with the support of the Washington State Wheat Commission, Jones and Tim Murray, a WSU plant pathologist, began collecting germplasm for WSU's new perennial wheat-breeding program.
Years Of Work Lost
With over 100 years of perennial wheat breeding already completed, WSU researchers assumed they would be able to carry on where the others had left off by obtaining the relevant plant material.
“The breaks in the breeding chain were most discouraging,” says Jones. “All of the Russian material was either unattainable or gone. There were a few populations left from California, but most of it was thrown out.”
Instead, the WSU team had to rely heavily on germplasm from new lines created by crossing local native wheat grasses with existing annuals.
Kevin Murphy, a WSU plant breeder, sees progress being made in developing lines better suited to the Pacific Northwest.
“In 2005, we did an advanced yield trial with our best 30 perennial lines,” he says. “On average, the perennial wheat yielded about 60% of the annual wheat, depending on location.”
In the same trials, perennial wheat regrowth ran 20% to 70%. The lowest regrowth occurred in the most arid dryland wheat-production regions in the state.
Murphy points out that a major goal of the WSU program has been to identify the specific gene responsible for regrowth – the most important trait in perennial wheat development. Once determined, corresponding markers could verify the existence of that trait in a plant from a single tissue sample.
In 2004, the chromosome that contains that genetic material was identified. “The next step is to identify the gene,” says Murphy. “When that happens, we should be able to reduce the time it takes to identify a trait in a plant from two years to a couple of months.”
Local Challenges, Global Effort
Many traits – such as yield, insect resistance, and frost hardiness – are desirable in both annual and perennial wheat. Still, perennial wheat comes with its own set of challenges. For example, Murray has focused on developing resistance to wheat streak mosaic virus.
“Annual wheats in the Northwest escape serious infection. But with perennial wheat, we have this plant persisting from season to season,” Murray says. “This gives the virus an opportunity to establish itself the first year and then have a serious impact on the plant when the regrowth occurs the following season.”
Since every region has its own unique growing conditions and locally developed wheat lines, Murray says it's important that the sharing of plant material occurs. This helps maintain a broad and diverse gene pool. WSU has shared germplasm for perennial wheat with plant breeders in Australia, China, Canada, and Wales, and it works collaboratively with programs in Kansas, Texas, and Oklahoma.
“There is certainly a growing interest worldwide in perennial wheat development,” he says. “That should benefit all programs.”