U.S. soybean yields have been rising about one-half bushel per acre or 1 percent per year as farmers have found new and improved ways to grow the “miracle” bean.

So when DuPont’s Pioneer Hi-Bred business announced that its new “Y” series of soybean varieties promise to provide at least 5 percent more bushels per acre than its nearest competitors, that caused some heads to turn.

Pioneer’s announcement of a “step-change” in its approach to soybean breeding — and similar promises of higher yield increases by other companies — couldn’t come at a better time for farmers.

“In the current situation of high commodity prices and low stocks, we have been saying that we have the science to help address this incredible demand for agricultural commodities,” says Paul Schickler, DuPont vice president and president and general manager of its Pioneer Hi-Bred business.

“I’m very excited to announce today that we will deliver a step-change improvement in soybean yields in unprecedented volumes for the 2009 growing season.”

Pioneer plans to offer enough soybean seed containing its new Accelerated Yield Technology to plant 9 million acres in 2009. AYT will be included in 32 new varieties ranging from Group 0 to Group 7 in maturity.

“With the Y Series yield advantage, this new line has the potential to add about 19 million bushels of soybeans into U.S. production,” said Schickler who spoke at a press conference with other Pioneer executives.

“One of the most important traits to a grower when selecting new products for their farm is yield, and higher yields have never been more important to the ag economy and to the world than they are today,” said Don Schafer, senior marketing manager for soybeans at Pioneer.

“The entire Y Series class has shown a 5 percent yield advantage over key competitors in more than 1,800 on-farm comparisons with some of them yielding as much as 10 percent better than these key competitors.”

If a farmer producing about 50 bushels of soybeans per acre increases his yield by 5 percent, that’s another 2.5 bushels per acre he has to market. At mid-July prices, that’s $37 per acre additional income a grower could receive by growing the new Y Series varieties. (The Y series will be identified by a Y in the variety number.)

Much of the yield boost from the Y series varieties is due to the Accelerated Yield Technology and marker-assisted gene selection Pioneer has been employing in its breeding program, said John Soper, senior research director for Pioneer.

“Pioneer has been a leader in the use of molecular technology since the mid-1990s,” he said. “Historically, we’ve developed molecular markers for traits such as resistance to soybean cyst nematode, phytophthora root rot and brown stem rot.

“But one of the new breakthroughs in recent years is developing molecular markers that actually track genes that can enhance yield performance per se. Unlike genes for pest resistance that are controlled by one or two genes, yield is controlled by many genes working in combination. So it’s difficult to do it by just looking at yield data and determining which gene is causing yield enhancement.”

Fortunately, researchers have seed from the ancestors of current soybean lines, and Pioneer has developed patented, proprietary technology that has helped its scientists identify those yield genes. (Pioneer soybean breeder Scott Sebastian developed the approach.)

Soybeans have about 30,000 genes, says Soper. “After we ran the analysis comparing the current elite varieties with their ancestors, we wound up with a little over 100 genes that we focused on as potential yield enhancers. Then we started testing those genes one by one to see if they had yield-enhancing properties.”

The result of this work, he says, is that Pioneer researchers are doubling the rate at which they are bringing yield gains to customers from the historical level of about 1 percent per year to 2 percent per year.

“The Y Series is just the beginning,” says Soper. “We have a goal at Pioneer of increasing soybean productivity by nearly 40 percent over the next 10 years — to meet the growing demand for soybeans used for food, for feed and for fuel.

“We have a number of transgenic and nontransgenic crop protection traits against areas of diseases and pests such as Asian soybean rust, soybean aphids and other insects that will be added to soybeans in the next three to five years. We’ll be coming to market with the Optimum GAT trait, which we will expect to also have a yield-enhancing effect. By 2015, we hope to have another transgenic yield enhancement trait which can raise the bar another 10 percent for yield.”