“Soybean King” Kip Cullers surpassed the 100-bu./acre soybean yield mark with record harvests in 2007 (154 bu.) and 2006 (139 bu.). But when will soybean growers see varieties consistently break the 100-bu./acre barrier?

Probably not anytime soon, says Brian Diers, University of Illinois soybean breeder. Between 1973 and 2007, the average yield gain has been just .448 bu./acre/yr. The current national average is about 41 bu./acre. You do the math. But that's not to say there isn't room to increase the size of these yield gains. With molecular-assisted selection, breeders are making strides.

Monsanto, for example, is taking a three-pronged approach to increasing yields: a combination of conventional breeding and marker-assisted selection, agronomic systems that focus more on crop inputs (such as fungicides and insecticides) and management to boost yields, and biotechnology, says Roy Fuchs, global oilseed technology lead, Monsanto. Taking this approach, the company is committed to doubling soybean yields by 2030, he says.

Monsanto has used marker-assisted breeding and biotechnology to develop the Roundup Ready 2 Yield platform and will launch several late Group I to late Group III Roundup Ready 2 Yield varieties for 2009 planting. The company has field tested the new technology, and over the last four years, the new varieties have produced on average 7 to 11% higher yields than those with the original Roundup Ready trait.

Fuchs points out that the last soybean product developed via biotechnology was introduced in 1996. The Roundup Ready 2 Yield platform will be the foundation from which Monsanto launches biotech products (such as dicamba-tolerant soybeans) in the future.

Tech combo

Pioneer Hi-Bred also has launched a new generation of soybeans, including 32 new varieties introduced in 2008. The Y series represents the largest volume of commercial products launched in the company's history.

Pioneer says that field testing of these new soybeans has indicated a 5% yield improvement over competitive varieties, with some yielding 6 to 10% better. John Soper, soybean research director, says that Pioneer developed the soybeans using its Accelerated Yield Technology (AYT), which uses a combination of gene mapping, field and molecular breeding technologies, doubled haploids and precision phenotyping.

Before using AYT, Pioneer breeders were seeing a 1% yield gain per year. Soper expects that, using the new technology, the breeders will be able to obtain yield gains of 2% per year. Soper says that yield enhancements will be seen across all maturity groups.

Although it is unlikely for soybeans to consistently break 100 bu. across all maturities, growers could see 100-bu./acre yields more often in elite lines in certain Group II and Group III maturities under favorable environmental conditions, says Steve Knodle, NK soybean brand manager and AgriEdge manager. “Soybeans are where corn was over a decade ago regarding new levels of yield potential,” he says.

Allen LeRoy, soybean breeding and genetics project leader, Purdue University, agrees that yield gains will most likely be seen in maturity Groups II, III and IV because they are the maturities that are grown in regions of the country with the greatest amount of good soils.

No silver bullet

Over the next several years, growers could see yields increase by as much as 10 bu./acre due to improved breeding, but also due to new herbicide yield-enhancing trait technology that will allow growers to manage glyphosate weed resistance, Knodle says.

Marker-assisted selection will help increase yields, as will the new Roundup Ready 2 Yield technology and improved disease resistance genes that do not adversely impact yield, LeRoy says.

Diers cautions that, although improved genetics will help growers obtain higher yields, there is no silver bullet. To obtain high yields, growers also must have optimal weather conditions, good soils and good crop management. Growers need to match the best variety for their fields (taking into account insect and disease pressures, for example) and make sure fertility is right.

Pioneer's Soper observes that higher farm gate prices for soybeans have boosted the use of fungicides, which could continue to have positive impacts. Fungicide use could help result in 2 to 3% increases in yield, he says.

Jim Specht, professor of soybean genetics and physiology, University of Nebraska, says that one of the best things a grower can do is to plant soybeans early enough in the season to help the plants realize their full yield potential. Potential yield can drop every single day that planting is delayed.

Consistent 100-bu./acre yields will be a long time coming, Specht says, adding that Nebraska growers currently produce just 55 bu./acre under irrigation. Some growers produce 80 to 90 bu./acre with some degree of consistency, but that's with irrigation and good river-bottom soil, Specht says.

Global demand for soybean oil and protein will continue to expand. This, coupled with a finite amount of arable land, will keep soybean breeders and growers striving to increase per-acre efficiency. Although 100 bushels of soybeans per acre may not become the national average in our lifetimes, the industry is making significant gains. Some growers may even come close to giving Soybean King Kip Cullers some stiff competition.