Wheat: Balance Risk with Complementary Varieties

By Jane Fyksen Crops Editor
Thursday, September 4, 2008 7:42 AM CDT

Wheat growers can get consistent performance by planting multiple varieties that offset each other's strengths and weaknesses. Complementary varieties should be “basic to your crop planning,” says University of Nebraska Cropping System Specialist Robert Klein.

An example of “complementation” might be growing a high yielder with less winter hardiness and a variety that yields a bit less but has good winter hardiness,” he notes.

Because there is no single perfect wheat variety for all production systems or all years, using complementary varieties enable a producer to realize the greatest benefit from a specific variety's strengths and offset, to a high degree, its potential weaknesses. This compensation improves the opportunity for yield stability and profitability of your entire wheat production system. The number of complementary varieties depends entirely on specific production conditions and special needs (i.e. common diseases or insects encountered).

Farmers who don’t have enough acres to justify planting several varieties, may want to consider using a blend of three or four varieties, Klein suggests. Also, tenants whose landlords don't have enough acres to justify planting several varieties could reduce risks by planting a blend.

There are four steps to developing your wheat variety complementation strategy:

- Identify your workhorse varieties. These are varieties you now grow on a majority of your wheat acres because they have a reliable and proven record of performance over several years in your preferred production management system.

- Complement your production needs and limits. Select a variety or varieties that have characteristics needed for specific production practices (i.e. straw strength or height) and typical soil conditions. Choose varieties that offer the best level of protection from expected diseases and other yield-limiting factors common to your growing conditions or area.

- Complement with a range in maturity. One limiting factor to wheat can be a short grain fill period. Because you can never be sure about the weather during this critical time of year, select varieties that will mature earlier or later (or some of both) than your workhorse variety. A spread of maturities also allows you to stagger your harvest schedule and take maximum advantage of available equipment, plus it reduce losses to yield (from shattering) and end-use quality (from weathering).

- Complement with different genetic families. Varieties with closely related genetic backgrounds often can be susceptible to the same diseases and production stresses. “You can lower those risks by selecting varieties that share 50 percent or less common parentage with your workhorse variety and each other,” notes Klein, adding that varieties with similar backgrounds often can be susceptible to the same disease, insects and production risks.

Wisconsin saw a record number of winter wheat acres planted (350,000) in the 2008 growing season, up from the 290,000 planted the previous year. Good soil moisture conditions and favorable temperatures in September and October 2007 allowed for timely establishment. Although winterkill due to cold temperatures wasn’t prevalent, ice damage due to record snowfall did cause significant injury to some low-lying fields. Spring growing conditions were mostly favorable across the state; however, acres were lost due to extreme rainfall and subsequent flooding across much of the southern part of the state in early June. Cooler-than-normal temperatures in May, June and July delayed crop maturity, but they also extended the grain fill period for winter wheat.

Winter wheat yields were variable across the UW variety testing locations due to variable rainfall and disease pressure. Wheat yield at Lancaster (66 bushels per acre test average) was lower than expected due to significantly greater-than-normal rainfall and heavy disease pressure. Wheat yields at Janesville and Chilton averaged 78 and 89 bushels, respectfully. The Arlington site was abandoned due to ice sheeting that caused significant stand loss.

The combined 2007 and 2008 two-year mean yield performance in UW trials turned up these top varieties (with yields not statistically significant from the top-yielder): Pioneer 25R47, 89 bushels; Pioneer 25R51, 87 bushels; Jung 5988, 85 bushels; Growmark FS 637, 84 bushels; Kaltenberg KW 60, 84 bushels.

Growers can source complete UW variety test results for 2008 on line at http://soybean.uwex.edu/documents/A3868WinterWheat.pdf.

Tom Anderson, Shawano County UW-Extension ag agent, thinks wheat growers have “good prospects for profits in 2009.”

He shares a few planting pointers:

- Plant between Sept. 15 and Oct. 10. Wheat planted before that runs the risk of Barley Yellow Dwarf Virus, and later-planted wheat suffers yield loss due to lack of development and tiller formation.

- Wheat should be planted at 1 inch. “After planting, the soil should settle so that the wheat is about 3/4 inch, which is ideal,” says Anderson. Shallow wheat results in uneven germination and heaving. Too deep and there could be premature leaf opening that kills the plants.

- Nitrogen is commonly limiting, but N needs to be carefully managed, according to Anderson. A late fall or early spring application causes tillering and maximizes productivity, but too much N can lead to weak straw strength and lodging.

- Anderson says with strong wheat prices, producers should definitely think higher quality seed and not plant bin-run.

- As for seeding rate, growers should aim for 30 to 35 live plants per square foot in the fall. That requires a seeding rate of about 1.5 million seeds per acre. Because size of seed varies, that’s a range of 75 to 120 pounds of seed per acre. Check the seed tag and do the math.

- Get plans in place well ahead of time for combining. Leaving the crop stand in the field too long increases the risk of lodging. Make provisions for harvest and storage of the straw, which is a valuable part of the crop Good quality, clean straw will reward you with a premium price, says Anderson.

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