Over the last 20 years, alfalfa breeders have made impressive improvements in disease resistance, winterhardiness and other important traits. But yield potential has stayed about the same.
That's about to change.
Dairyland Seeds, West Bend, WI, has developed a technology for hybridizing alfalfa. Branded msSunstra, it shows promise of delivering varieties that produce significantly higher forage yields.
University and on-farm tests of HybriForce-400, the first hybrid variety, show 8-15% yield improvements over current top varieties. And company officials say future generations of hybrids should perform even better.
But yield isn't the only advantage. Hybrid plants are stronger and stands probably will last longer, says Paul Sun, Dairyland's vice president of research.
“The plants can take more management abuse and provide farmers greater cutting flexibility with less risk of stand loss when harvesting high-quality forage,” says Sun.
Limited quantities of HybriForce-400 seed will be sold this year, and greater amounts will be available in 2002. By then, other hybrids likely will be available from other seed companies under licensing agreements with Dairyland.
No licensing agreements have been announced, but negotiations are progressing, says Tom Strachota, Dairyland's CEO.
“There is definitely interest among the elite alfalfa companies,” says Strachota.
The company may also license the hybridization technology so other companies can develop their own hybrids. All of Dairyland's future variety releases will be hybrids. And Strachota predicts that open-pollinated alfalfa varieties will someday be extinct.
Hybrids perform better than open-pollinated crops because of hybrid vigor. That's achieved in the first generation of offspring resulting from the crossing of two genetic lines.
Hybridizing alfalfa was difficult — in part because pollination is tough to control. Alfalfa flowers contain both male and female parts in close proximity and therefore can't be detasselled. Seed is produced via random pollination by bees. Random pollination results in inbreeding, which slows genetic gains.
Dairyland's just-announced hybridization technology was developed by Sun, who spent 24 years developing separate male and female plants so pollen flow could be controlled. Maintainer lines that produce only female offspring are another key component of the technology.
Sun and Strachota equate the expected yield gains from hybrid alfalfa with those that have been achieved with hybrid corn. Before corn hybrids were introduced in 1930, yields were stagnant. Similarly, there have been only slight incremental yield gains in alfalfa in the last 20 years, says Sun.
Corn hybridization bumped up yields an average of 1 bu/acre until 1960, when single-cross hybrids became available. Since then, corn yields have increased an average of 1.8 bu/year.
“We believe alfalfa yields are going to follow hybrid corn trend lines,” Strachota points out. “With msSunstra, we see the yield curve going up significantly.”
The lack of alfalfa yield gains in recent years was verified in a 1998 University of Wisconsin study. Researchers reviewed yield-trial data from several Midwestern and Northeastern states, in each case comparing the yield of the top variety with that of Vernal.
“Basically, we've seen very little increase in yield during that history of variety trial results,” explains Dan Undersander, extension forage agronomist at the university.
Undersander points out that increasing yields is much more difficult in perennial crops like alfalfa than in annuals. And breeders have emphasized traits like disease resistance and winterhardiness instead of yield.
“We've made a lot of progress with alfalfa varieties,” he says. “But we need to recognize that we really haven't done much for yield in a long time.”
He's optimistic that hybridization will change that.
“We've tested some of those materials, and they look pretty good,” he says.
Alfalfa Hybrid ‘Is Amazing,’ Says Dairyman
“This is the biggest thing to come along with alfalfa that I've ever seen,” says Roger Elliott.
Elliott, an Evansville, MN, dairy farmer, planted a two-acre strip of HybriForce-400 last spring, when it still was an experimental hybrid. He sandwiched it between strips of two highly rated conventional varieties planted on the same day.
The hybrid outyielded one conventional variety by 15%; the other by 8%.
“But that's a small part of it,” says Elliott.
“The first thing you notice is that the regrowth is amazing,” he says. “Within a couple of weeks after you cut it, it's 4-6" taller than other varieties cut at the same time.
“My theory is, the sooner it starts regrowing, the sooner photosynthesis will start, and the root reserves won't be drained nearly as much. It should help us get a longer stand life.”
The hybrid's stands are more consistent, too, he says. Current alfalfas have about a 20-day range of maturities. When they're cut, some plants are taller than others, some are at bud stage and some are in the vegetative stage.
“A hybrid, with its close maturity, should be a more consistent feed,” says Elliott. “And that should translate into higher milk production.”
The weather had turned dry by the time Elliott cut the hybrid last year. He got about 3,000 lbs an acre of dry matter from two cuttings.
“I believe the field is setting itself up to really produce this year,” he says.
He adds: “This is a major breakthrough. What's so exciting to me is, this isn't the end of the process, it's just the beginning.”