36 / SEEDWORLD.COM OCTOBER 2017 whether to use if for grain or forage alone. This is where the cattle industry and wheat breeding intersect,” Carver says. “The characteristics cattlemen want in their wheat are different from what grain-only producers want. They are both looking at yield, but yield means something very different to each of them.” The cattle producer measures yield by the amount of early- season biomass production and regeneration of biomass during the grazing period, Carver explains. The grain farmer looks at grain production with little concern for vegetative biomass production. In some scenarios, the grain producer could actually consider heavy biomass production a detriment. The cattle producer wants a plant that can be grazed as late as possible with minimal or no loss in grain yield relative to a grain-only system. In this case, grazing recovery is the driving factor for a variety best fit for forage-plus-grain production. The grain producer wants a plant with stiff straw that will stand erect and not lodge or go down until harvest. The ideal plant will have the characteristics desired on both sides with no yield drag when harvested for grain. Revamped Breeding Strategy “When I took leadership of the OSU wheat improvement pro- gram in 1998, I realized we could not — with any kind of regu- larity — develop an ideal variety for dual-purpose use without selecting for characteristics unique to a dual-purpose system. There is not that much genetic variation in wheat,” Carver says. “So we had to jump in and breed for it. It is difficult to breed a variety strictly for grain production and then hope it will fit a dual-purpose system. “We changed our whole strategy. We went from breeding varieties strictly for grain production to now breeding varieties for dual-purpose adaptation. I don’t know of another program that will actually breed — not simply test — the variety for dual-purpose use. The GrazenGrain lines is a moniker we use to designate those varieties that were developed under, and best fit, actual grazing conditions. It is a more cumbersome system and more expensive because we have to bring in the cattle. We may simulate grazing stress by using a lawn mower, but it is not the same. I have to rely on cattle at key points in the breeding process, especially during the early generations of line develop- ment when gene segregation occurs. “It is amazing to see what happens to your germplasm during consecutive years of grazing. The appearance of segregating F2 through F5 populations will change in response to a grazing system. The plants may become more prostrate, and crown tissue is more robust and better capable to regenerate vegeta- tion. It matures a little bit later as it becomes more adapted to a grazing system.” The response to selection is not the result of epigenetics or genetic changes; it is expression of the natural variation in the original F2 population. Through the years, Carver and his team have released a number of varieties. In 2004, OSU released Endurance, the first GrazenGrain variety. Duster, another GrazenGrain variety, was released in 2006 and has become a leading variety with mini- mum grazing penalty. Grain yields after grazing can be reduced up to 30 percent. Carver aims for 10 percent or less when it comes to yield reduction. SW ORGANIC WHEAT: AN UNEXPECTED APPLICATION In developing a dual-purpose wheat for farmers and ranchers in southern Plains states, Oklahoma State University’s Brett Carver says they also ended up with a product suitable for organic production. “Organic wheat seed is a small, niche market,” Carver says. “But for no more expense to redesign our breeding process, we have developed a seed product in some cases ideally suited to organic cropping systems.” Carver explains the GrazenGrain varieties were bred for early season planting, which allows for early canopy closure. However, this same trait helps organic producers control early-season weeds. Additionally, he says increased insect and disease resistance requires less chemical pesticide control, and increased nitrogen use efficiency results in less need for fertilization. Brett Carver is the Regents Professor, Wheat Genetics Chair in Agriculture, Wheat Breeding and Genetics at Oklahoma State University in Stillwater. WHERE ON THE WEB At the National Association of Plant Breeders annual conference, Seed World Publisher Shawn Brook had a chance to visit with OSU’s Brett Carver. Listen to the Giant Views interview at seedworld.com/brett-carver-osu-exploring-genomics-undoing- miscommunication-wheat-germplasm-availability/.