Perennial Wheat Offers Environmental And Other Benefits

Annual wheat, which is traditionally grown in the Great Plains, is planted in the fall and dies after harvest in mid-summer. But Dr. Charlie Rush, Experiment Station plant pathologist, is testing some perennial lines of wheat bred in Washington state.

These perennial lines regrow after harvest and may survive for up to five years, Rush said. And eastern Washington is climatically similar to the Texas Panhandle, except it has harsher winters.

"This wheat, if it works here, will start growing back as soon it rains or is irrigated after harvest," he said. "Right now, we don't know if it will work in our area or not. But there definitely could be some applications for it if it does."

The perennial wheat could be used as a ground cover for highly erodible lands, wildlife habitat and an alternative crop for Conservation Reserve Program lands, Rush said. However, primarily he is interested in evaluating use of perennial wheats in dual purpose grain-grazing cropping systems that are prevalent in the southwestern Great Plains.

Over the years, different breeders have crossed bread wheat with wild wheat grass in order to acquire a variety of desirable traits, such as drought tolerance and resistance to diseases and insects, Rush said. In making these crosses, some of the resulting lines inherited the perennial trait.

Perennial wheat programs are already underway in Kansas and Washington. But it was work on disease resistance by Dr. Tim Murray, professor and chair of the plant pathology department, and Dr. Stephen Jones, wheat breeder, both at Washington State University, that first gained Rush's interest.

"For perennial wheats to have a place in our dual-purpose cropping systems, they must have good resistance to disease and insects," Rush said.

For this reason, his primary concern is determining how the 20 experimental lines will hold up against wheat streak mosaic and greenbugs, something both Jones and Murray also are researching.

In addition to screening for disease and insect resistance, Rush is also evaluating the perennial wheat lines for forage quality and yield, water use efficiency and drought tolerance.

"If they have drought tolerance and natural resistance to diseases and insects, it opens up real possibilities," he said. "Producers could save the cost of replanting at the very least. But it could also allow cattle to graze later in the spring and earlier in the fall, and still allow farmers to harvest for grain."

Also, Rush said, producers would be able to avoid the fallow period that sets fields up for erosion. If the perennial wheat is rained on or irrigated in July, it is possible that cattle might be able to start grazing as early as August.

"Since perennial wheats typically yield only 70 percent of the best bread wheat cultivars, I don't see this as competition for the grain crop, but primarily as another option on forage," he said.

Lower yields are the primary reason researchers have not been very interested in perennial wheats, Rush said. But with increasing energy costs and environmental concerns, perennial wheats are worth a new look, especially for the dual-purpose systems.

In September, Rush planted three replications of 20 lines of perennial wheat in September, plus seven non-perennial varieties already in commercial production in the High Plains for comparison. Additionally, he bordered the plots on one side with a variety highly susceptible to wheat streak mosaic virus and on the other side with a highly resistant variety.

"One of the things that could quickly kill this project is if all the perennials are highly susceptible to wheat streak mosaic," he said. "We don't want to have that bridge for the virus and mites to over-summer and threaten the fall wheat crop.

"However, we are confident that some of the lines will be disease-tolerant, because some of Dr. Murray's preliminary findings on resistance to wheat streak in Washington state," Rush said.

Additional testing for insect and disease resistance will be conducted in the greenhouse with the perennial lines being inoculated with wheat streak mosaic virus and tested for resistance to greenbug and possibly bird cherry oat aphids, which also vector barley yellow dwarf virus, he said.

All the insect screening will be conducted by Dr. Jerry Michels, Experiment Station entomologist at Bushland.

"Because this whole research is so brand new, we're limited in the number of treatments we can do until there's more of this perennial wheat seed available," Rush said.

Disease screening and forage quality sampling using remote imaging techniques to measure the biomass, instead of clipping it, has already started and "we're getting good data," Rush said.

In the first sampling, some of the perennial wheat lines yielded roughly the same amount of forage as the bread wheats and also exhibited good resistance to wheat streak, he said.

"I can hardly wait until our next field day to show our regional wheat producers these new wheat lines," Rush said.