Reduced or Low Lignin Alfalfa: Advantages for Hay and Grazing

Lignin is an essential structural component of all land plants. It fills spaces in the cell wall between cellulose, hemicellulose, and pectin. Lignin provides the strength to plants from giant Sequoia trees to alfalfa growing in hay fields. A good analogy is that lignin is like the steel reinforcing rods in concrete. Life on earth would not be possible without lignin to allow plants to grow upright. The limitation for livestock is that lignin is indigestible. Forage breeders have long realized that the quickest way to improve forage quality would be to reduce lignin concentration, but if lignin is reduced too much then the stand will lodge. When the brown-midrib (BMR) trait was discovered it provided the first practical way to breed reduced lignin forages. Varieties of corn, sorghum, and sorghum-sudangrass with the BMR trait showed reduced lignin and improved digestibility. Although the first BMR varieties had improved digestibility, but they were also more prone to lodging. Further developments have resulted in BMR corn and sorghum that provide high yield, improved digestibility and no greater lodging potential than traditional varieties. In recent years, forage breeders have also developed reduced lignin alfalfa varieties. These varieties have often been called low-lignin alfalfa, but in the term “Reduced Lignin” is preferred because it is essential that enough lignin remains in the alfalfa stems to prevent lodging.