Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 5, 2003
Publication Date: January 4, 2005
Citation: Casler, M.D. 2005. Ecotypic variation among switchgrass population from the northern USA. Crop Science. 45:388-398. Interpretive Summary: Switchgrass (Panicum virgatum L.) is a widely adapted warm-season perennial that has considerable potential as a biofuel crop. Casler characterized phenotypic variation of 49 switchgrass populations from a wide geographic section of the USA. Little of the phenotypic variability among populations could be attributed to systematic climatic, edaphic, or geographic factors. There was a trend toward phenotypic differentiation between ecoregions and hardiness zones of the eastern USA, suggesting that these classifications can be useful in characterizing switchgrass germplasm. Most switchgrass populations can be utilized for conservation and restoration projects throughout a combined ecoregion and hardiness zone without undue concern over contaminating, diluting, or swamping the local switchgrass gene pool.
Technical Abstract: Alfalfa use by dairy cattle has decreased in recent years because of excessive non-protein nitrogen and low fiber digestibility. New uses of alfalfa to remove nitrates from contaminated soils and new processing of valued added alfalfa products increase the potential of alfalfa being included in crop rotations of cash crops. Value-added traits of alfalfa are needed to provide farmers new high value profitable products. Processing alfalfa to obtain value added products includes three different fractionation methods: 1) wet fractionation; separation into juice fraction and a fiber fraction, 2) dry fractionation; separation into leaves and stems, and 3) fractionation by passage of the whole herbage through the digestive systems of ruminant animals, leaving a high fiber residue. Phytase from transgenic alfalfa has been tested in poultry and swine rations. Chicks supplemented with Phytase from transgenic alfalfa juice or leaf meal had growth equal to chicks fed phosphorus supplemented rations and manure from these chicks supplemented with alfalfa Phytase contained less than half the phosphorus levels of manure from chicks fed inorganic phosphorus supplements. The economic value of Phytase alfalfa product could generate $750 to $1500/A income from alfalfa grown in the Midwest. Alfalfa hay can be fractionated to yield stems and leaf meal. Alfalfa leaf meal has been shown to be acceptable supplement to replace a portion of alfalfa hay and soybean meal in diets of lactating dairy cattle, replace protein supplement in beef cow diets, finishing steer diets and diets of growing turkeys. The fiber portion of alfalfa can produce lactic acid and ethanol. The fiber from alfalfa manure has yielded pressboard and water filters capable of removing heavy metals from contaminated water.