Start Date: Mar 01, 2008
End Date: Feb 28, 2013
Alfalfa is the backbone of sustainable practices for producing crops and animals while protecting water and soil resources. However, use of alfalfa is not always maximized due to several limitations, and new germplasm and management systems are needed for biofuel production. The objectives of this project are to: (1) develop germplasm and determine genetic and biological processes that regulate forage use for bioenergy and livestock production, and (2) develop and evaluate crop management strategies to increase use of perennial forages for livestock and bioenergy, and to protect the environment. Alfalfa germplasm with greater stem in vitro neutral detergent fiber digestibility (IVNDFD) will be developed through selection and breeding utilizing near-infrared reflectance spectroscopy. Populations will be assessed for changes in cell wall chemistry and biofuel conversion under conventional and biomass management systems. Breeding strategies will be evaluated to increase yield potential. Yield will be evaluated in replicated field trials in multiple locations. Populations with highest yield will be evaluated for total forage yield under conventional and biomass management systems. Management methods for reducing diseases that impact yield and persistence will be assessed. The effect of glyphosate on foliar diseases (rust, powdery mildew, anthracnose, spring black stem) will be evaluated in Roundup Ready alfalfa. Alfalfa cultivars will be screened for resistance to brown root rot and the role of crop debris in pathogen survival and increase will be measured. The potential for green manures and traffic tolerance to reduce crown rot will be evaluated. Genes for disease resistance, cell wall biosynthesis, and nutrient uptake will be isolated to provide new knowledge on the genetic underpinnings of these traits and markers for plant improvement. Transcript profiling will be done to identify candidate genes involved in these traits. The function of specific genes will be investigated through detailed transcript expression studies, investigating promoter activity, biochemical assays, over-expression, and gene knock down. Alfalfa germplasm with greater capacity to remove soil nitrate will be developed by recurrent selection using bromide as a nitrate analog. Populations will be evaluated in multiple field locations for bromide and nitrate uptake. Removal of nitrogen from soil by alfalfa will be tested at the field scale in replicated plots in multiple locations. Forage samples will be analyzed for dry matter and N yield; topsoil will be measured for total N and C. Removal of nitrate from irrigation water via phytofiltration will be tested on a field scale. Replicated plots will be irrigated at normal, high, and intermediate rates and the total nitrate leached determined. Biocurtain strips along tile drainage sites will be managed using conventional and biomass systems along side a corn-soybean rotation. Inorganic N will be measured throughout the growing season in tile drainage water. Fulfilling the objectives will help meet the emerging needs of the nation in livestock and bioenergy production and environmental protection.