Alfalfa breeders are using biotechnology along with traditional plant breeding methods to develop new and improved varieties, said Joe Bouton, director of the Forage Improvement Division of the Samuel Roberts Noble Foundation, Ardmore, OK. He spoke at the National Alfalfa Symposium last month.
Two such results: low-lignin alfalfas with high fiber digestibility that increase milk or beef production while reducing manure production, and tannin-containing alfalfas that reduce bypass protein problems and cause less bloating in animals.
Low-lignin alfalfa has been estimated to produce a 10% increase in fiber digestibility that could increase milk or beef production by $350 million/year and decrease manure production by 2.8 million tons/year in the USA, according to U.S. Dairy Forage Research Center (USDFRC) studies. New varieties containing this trait may be commercially available to seed producers as early as 2012.
Tannin alfalfa could reduce protein feed supplementation by 60% and nitrogen loses by 25%, bring up to a 12% increase in net return for dairies, and increase alfalfa silage value by $23/ton, according to a USDFRC dairy model. Tannins bind with plant proteins to slow the rate of protein degradation in the rumen, decreasing protein loss (called bypass protein). Tannin-containing alfalfa would also be non-bloating, potentially saving, worldwide, up to $200 million in bloat-related losses, Bouton said. It’s still in early stages of development.
Genomics and transgenics “are very efficient tools for making the process a lot more streamlined,” Bouton said. Genomics makes use of gene mapping, which helps identify where certain genes can be found. In tall fescue varieties, for example, gene mapping was used to detect digestibility genes that should help breeders select new varieties with higher digestibility.
Transgenics, or genetic engineering, can manipulate or move genes, he said. Although Roundup Ready was the first alfalfa trait developed this way, low-lignin alfalfa was also genetically engineered. Lignin-producing genes were “knocked out” of alfalfa to reduce the amount of lignin in the plant. To express tannins condensed in alfalfa, transgenes would also be used, Bouton added.
Drought-tolerant or “water-use efficient” varieties could be developed using transgenics or genomics – or a combination of the two. Genes could be identified or incorporated into alfalfa to keep it from using less water during growth.
Researchers are also using biotechnology to identify traits that would delay flowering. Slowing flowering would increase yield while keeping hay at a certain quality.
Gene modifications can also produce large-stem, low-input alfalfa for the biofuels market, Bouton said. “We’re looking for a lot of crops to fill the president’s and the Department of Energy’s vision of harvesting enough biomass to produce enough ethanol or biodiesel to replace 25-30% of current petroleum use.”
Alfalfa, he said, could be one of those crops.
