February 14, 2006

Various factors affect choices of wheat varieties

by K.C. Jaehnig

CARBONDALE, Ill. -- Noting that Kentucky farmers have nearly doubled their wheat yields with intensive management techniques, researchers at Southern Illinois University Carbondale began looking four years ago at whether the same strategies would work here.

The answer is, "Yes." Also, "No." And, "It depends."

"After four years of research, we have found that you can achieve those higher yields, but it seems to be more variable and less predictable than I had hoped," said SIUC agronomist Bryan G. Young.

"In some years, we did achieve a 90- to 100-bushel-per-acre yield with intensive management, but there were so many variables involved, it made achieving that goal a little complex. It's how you implement those practices that's important — and what your limiting conditions are within each year."

Intensive management involves scouting the fields for problems both winter and spring, spraying to control weeds, insects and disease, and applying multiple splits of fertilizer. For this study, Young set up small research plots both in Carbondale and in Belleville, where SIUC maintains a crops research station. In the first two years, he compared the effects of low, medium and high levels of management on three wheat varieties. In the second two years, he looked at five wheat varieties and tried to pinpoint which management strategies produced the greatest benefits.

It turns out that the most important thing farmers can do is to pick the right variety right from the get-go. And no, Young can't tell you exactly which one to choose.

"Our trial included only five varieties in 2004-05 — that's hardly inclusive," he said.

"Growers have limitless choices. And the varieties we tested in 2002 might not even be available now because improvements in agronomic traits keep occurring."

What Young can do is tell you what to look for when making your varietal choices. He also recommends getting the yield information on which you base those choices from unbiased sources.

"The University of Illinois conducts wheat variety trials throughout the state every year just like they do with corn and soybeans — they're just less publicized," Young said.

"Here at SIUC, we have also conducted variety trials, and some local extension agents conduct them, too. Look for those research sites that are closest to your own farming operation."

Yields should be consistent. Try to look at how the variety did at several sites over time to make sure the results weren't just a fluke.

While yield matters, farmers should also look at disease resistance; for some diseases, that's the best form of management. Look at test weight — the milling companies do, and test weight varies by variety. Consider the maturity date; if you plan to double-crop your wheat with soybeans, you want a variety that matures early.

Farmers also may want to consider varieties in which seeds come treated with insecticide.

"The idea is to reduce insect populations early, and it eliminates the need for fall spraying," Young said.

"It wasn't available when we set up our trials, so I don't have a good sense of what it will do in the spring, and I'm not sure how the cost compares with foliar insecticides."

Insecticides matter because after variety selection, insect control — particularly when it comes to aphids — is the second most important factor in boosting wheat yields.

Aphids plagued all of Young's research plots.

"In most cases, we found such significant populations that it justified fall spraying," he said.

Young recommends scouting fields for aphids weekly.

"Don't go out just once a month — aphid populations can explode quickly," he noted. He also suggested keeping track of what growers are doing on neighboring farms.

"If they're seeing aphids, you should look a little more often to be sure your populations are below threshold," he said.

Farmers interested in details on the SIUC wheat trials may find them on Young's Web site at www.siu-weeds.com/research. Click the annual reports for the years 2002 through 2005 and choose wheat from the contents menu.

"Everything is there in terms of what yielded what, though we don't yet have it sorted out (with a separate heading for intensive wheat management)," he said.

Young also is putting together a fact sheet that will be available in time to help with fall crop selections. For more information, call him at 618/453-7679 or e-mail him at bgyoung@siu.edu.

Leading in research, scholarly and creative activities is among the goals of Southern at 150: Building Excellence Through Commitment, the blueprint the University is following as it approaches its 150th anniversary in 2019.