Perennial Wheat?

October 20, 2007 in Uncategorized

Perennial wheat is being researched in several parts of the US. Although probably not something that would be used in Delaware anytime soon, I thought our Delaware farmers would be interested in the concept and current research.

Imagine planting a field of winter wheat that wouldn’t die, but would continue to grow and produce grain every year for five years in a row! No longer are you each year prepping fields and drilling on a Sunday afternoon because it’s the only dry stretch in October. You have more time for that weekend family picnic or football game. Instead of fighting ragweed and foxtail after summer harvest, you’re finding wheat re-growth as a valuable grazing crop. This is the vision for perennial wheat. Perennial wheat is a cross between annual wheat (Triticum aestivum) and intermediate wheatgrass (Thinopyrum intermedium).

The history of perennial wheat goes back to the mid-20th century when Soviet Union scientists flirted with the idea, but all seed from this program was lost. University of California at Davis scientists worked with perennial wheat in the 1970s, but abandoned the program when yields only reached 70 percent of annual wheat yields. Recently, scientists at Washington State University and The Land Institute in Kansas have revitalized perennial wheat breeding, and have made rapid progress.

The goal for perennial wheat is to produce substantial grain quantity and quality for multiple years, not by re-seeding but by re-growing. When planted in the fall, each plant produces grain the following summer, develops a large root system and produces new leaves in the fall after grain harvest. During the second year of growth, these same plants send up new flowering shoots and produce grain again. This cycle can continue for many years assuming the plants continue to re-grow each fall and survive each winter.

In Washington, current populations of perennial wheat produce first year grain yields that average 35 percent lower than annual wheat, but vary from 5 to 70 percent lower than annual wheat.

The potential is tremendous: perennial plants require less maintenance time and energy, as well as protecting the soil. Reduced input costs may make up for potential loss of yield and gross profit. Perennial plants mean fewer trips across the field for tillage and planting as well as lower seed costs. Continuous growth patterns provide year-long competition against weeds. Fall re-growth has the potential to add value as a grazing crop, if winter survival after grazing turns out to be feasible. The research is in an early stage, but we are excited about the long-term potential of offering a new crop type to farmers. Subsidies and payments for conservation practices may also add value to perennial wheat. It is produced with little to no tillage, which is the topic of several conservation programs. Perennial plants reduce erosion and sequester more carbon in the soil than annual cropping systems. Carbon sequestration may provide options for payments via developing carbon markets, designed to offset rising carbon dioxide levels in the atmosphere. In addition, carbon is the main component of soil organic matter, which enhances soil cation exchange capacity as well as nutrient and water retention. Perennial plants are excellent scavengers for nutrients, allowing relatively small amounts of nitrogen to escape the soil into the atmosphere or groundwater. Bottom-line, we know that there are many challenges to successful perennial wheat integration into cropping systems:

First, we know little about long-term survival and grain production. We’re currently investigating how long plants can produce grain, and how to maintain grain yields at high levels for multiple years. Perhaps a perennial legume intercrop such as alfalfa or white clover will help to maintain soil fertility over multiple years, which should translate into high grain yields.

Second, are weeds a problem in perennial wheat fields and how do we manage them?

Third, current populations exhibit a wide range of reproductive phenology, meaning they mature at different times. Selection is needed to narrow the range of maturation to ease the harvest process.

Fourth, perennial wheat does not thresh as easily as annual wheat, but we believe that selection over time can increase threshability.

Finally, how does the nutritional quality and usability compare to annual wheat? Can we substitute perennial wheat grain for annual wheat grain as bread flour?

Extracted and modified from “Perennial wheat: a new crop for Michigan?” by Brook Wilke and Sieg Snapp, Department of Crop and Soil Sciences & W.K. Kellogg Biological Station, Michigan State University