As food for people or livestock, the more the protein, the better the soybean. By that standard, the University of Arkansas (UA) Division of Agriculture is making a better bean.

Soybean breeder Dr. Pengyin Chen (photo) in the UA Department of Crop, Soil, and Environmental Sciences has developed a high-yielding breeding line for likely release as a new public variety with protein levels that are well above average. His work is supported by the Arkansas Soybean Promotion Board.

Oil and protein are the two main commercial soybean components. Oil has the most value in the U.S. market. But the United Soybean Board says protein is increasingly important to American farmers because it is important in Asia, a major export market.

Soybean breeders keep score by the numbers posted in performance trials, such as those conducted by the U.S. Department of Agriculture. Like baseball box scores, the differences are small, but they mean a lot to those who understand the game.

One of Chen’s advanced breeding lines was a winner in the scores published this June from the 2004 Uniform Soybean Testing Program. His R98-1821 breeding line had the highest percent protein and the second highest yield in it’s category. The category is (maturity) Group 5 soybeans, which are widely planted in Arkansas and the South.

The breeding line had two-year-average scores of 42.4 percent protein, 18.7 percent oil and 53.4 bushels per acre across 25 test locations from South Carolina to Kansas and Florida to Texas. The oil and yield scores are in the range expected for high-yielding varieties, and the protein score is well above the norm of 40 percent.

The breeder is pleased with those results. “Yield and protein are not genetically compatible traits,” he said. “When you increase protein by even 1 percent, you usually will reduce yield.”

Yield is most important to most farmers, who are paid by the bushel and are not rewarded for high protein, although they might be in the future as the Asian export market grows.

A few farmers in Arkansas and other states grow soybeans under contract with companies that pay a premium for non-GMO, high-protein beans. But, for most, the incentive currently is just to help keep U.S. beans competitive in the export market.

Chen said he set his sights on developing a soybean with both high yield and high protein when he joined the UA faculty in 2001.
“I had a target of increasing protein by 2 or 3 percent, which I thought could be done without sacrificing yield,” Chen said. He identified varieties with diverse genetic pedigrees that all had high protein, and he crossbred them over several generations with high-yielding lines.

In addition to the R98-1821 line, another one with 45 percent protein but lower yield is being considered for release as a public germplasm line for use by other breeders and farmers. Yield potential of the 45 percent protein line is some 10 percent lower than standard varieties, but it is better than others in the same protein range, Chen said.

Farmers growing for the high-protein bean market would then have the choice of two lines well adapted to Arkansas conditions — one with high-yield potential and a 2 percent protein advantage and the other with lower yield but a 5 percent protein advantage.

The high-protein initiative is just one element of Chen’s breeding program. He also has had success in realizing the main objective of developing high-yielding conventional varieties for Arkansas conditions.

The Ozark variety released in 2003 is one of the most popular high-yielding, non-transgenic varieties now planted in Arkansas. A 2005 non-transgenic variety, UA4805, is similar to Ozark in yield, disease resistance and other traits, but it matures a week to 10 days earlier.

Another major goal that Chen is close to realizing is to provide transgenic varieties for Arkansas conditions that include Monsanto’s patented Roundup-Ready gene for herbicide resistance. Herbicide-resistant varieties account for about 95 percent of the current Arkansas soybean crop.