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United States Department of Agriculture

Agricultural Research Service

Research Project: Redesigning Forage Genetics, Management, and Harvesting for Efficiency, Profit, and Sustainability in Dairy and Bioenergy Production Systems
2013 Annual Report


1a.Objectives (from AD-416):
Objective 1: Develop appropriate defoliation (grazing and harvested) and nitrogen application management guidelines for temperate grass-legume pastures of the North Central and Northeastern USA to improve seasonal yield distribution, extend the grazing season, and improve the efficiency and utilization of energy inputs. Sub-objective 1A. Determine the influence of manure source and time of application on temperate grass productivity, seasonal yield distribution, nutritive value, and persistence, pasture composition, and soil chemical and physical properties. Sub-objective 1B. Determine the influence of nitrogen source, nitrogen application date and rate, and defoliation management on the productivity and persistence of red clover grown with orchardgrass.

Objective 2: Improve establishment, harvest management, and storage methods to reduce nitrogen inputs, increase the profitability of crop rotations, increase the recovery of dry matter and nonstructural carbohydrates, improve the energy density of baled hays, and mitigate the negative effects of rainfall on ensiling, storage, and feeding characteristics of rain-damaged silages. Sub-objective 2A. Identify optimal plant spacing to maximize yield of biomass alfalfa. Sub-objective 2B. Develop improved methods for interseeding alfalfa into maize to bring alfalfa into full production the following year. Sub-objective 2C. For large hay packages, quantify the effects of several baling factors on subsequent preservation performance of stored hay.

Objective 3: Improve pasture grass and legume production systems through increases in establishment capacity, persistence, productivity, resilience to climate extremes, and quality. Sub-objective 3A. Measure comparative effectiveness of mass selection, maternal half-sib selection, and marker-assisted paternal half-sib selection for persistence and biomass yield in diploid red clover. Sub-objective 3B. Determine optimal plant-selection age after establishment to simultaneously maximize genetic gain for persistence and biomass yield of red clover.

Objective 4: Improve profitability, conversion efficiency, and adaptability to climatic variation in forage and bioenergy crops. Sub-objective 4A. Quantify the effect of decreased lignin and decreased etherified ferulates on agricultural fitness of three temperate pasture species, including their tolerances to drought, heat, and grazing. Sub-objective 4B. Use a biomimetic model based on the artificial lignification of plant cell walls to identify new lignin bioengineering targets for improving the fermentability of forage and biomass crops. Sub-objective 4C. Create and evaluate a series of upland x lowland switchgrass hybrids of differing origins to determine if heterosis is related to geographic origin of either parent.


1b.Approach (from AD-416):
Objective 1. Solid and liquid manure applications will be evaluated in a series of grazing experiments designed to improve seasonal availability of nutrients and seasonal distribution of pasture productivity. Defoliation and manure application treatments will be applied to grass-clover mixtures to identify combinations that increase the competitiveness of red clover in mixed grazed swards.

Objective 2. High vs. low-density plant spacing will be evaluated to determine the effect on biomass yield for high-biomass alfalfa cultivars. Gibberellin-based growth regulator treatments will be evaluated for their effect on establishment and seeding-year biomass yield for alfalfa interseeded into maize. Propionic acid preservatives will be evaluated to determine their effect on reducing spontaneous heating and nutrient loss of large-rectangular bales of alfalfa hay.

Objective 3. The comparative effectiveness of mass selection, half-sib selection, and marker-assisted half-sib selection will be determined in an empirical study designed to improve persistence and forage yield of red clover. The optimal age for selection of red clover plants will be identified by evaluating empirical gains from selection for persistence and forage yield on selection nurseries of various ages and degrees of plant mortality.

Objective 4. The effect of lignin and etherified ferulates on persistence and forage yield will be evaluated in a series of field experiments designed to evaluate progeny with high or low levels of each cell-wall component in three grass species. The direct effects of monolignol substitutes on cell-wall fermentability and saccharification will be evaluated by using these novel compounds, compared to classical monolignols, as substrates for artificial lignification of maize primary cell walls. Heterosis between upland and lowland switchgrass ecotypes will be evaluated in a series of experiments to quantify hybrid vigor and to identify sources of variation that contribute to variation in hybrid vigor.


3.Progress Report:
Progress was made with the establishment of several new field experiments focused on genetic improvements of meadow fescue, orchardgrass, reed canarygrass, and smooth bromegrass, and with the establishment and evaluation of new red clover breeding nurseries. Cell walls artificially lignified with alternate monomers were evaluated for effects on ruminal fermentation. At two experimental sites, researchers examined plant spacing effects on biomass alfalfa yields and evaluated various rates and application times for spraying prohexadione-CA for enhancing the survival and subsequent yield of alfalfa interseeded into corn; one of these two sites had to be abandoned due to adverse weather: a drought in 2012 and excess precipitation in 2013.


4.Accomplishments
1. Rapid DNA-based paternity testing assay for alfalfa will speed rate of alfalfa improvement. Alfalfa is one of the most widely grown crops in the United States. In alfalfa variety development programs, the pollen donors of plants being evaluated are most often unknown. This lack of paternal identity leads to slower improvement in alfalfa variety development. ARS researchers in Madison, Wisconsin conducted research in collaboration with an alfalfa breeding company to develop a low-cost rapid DNA-based paternity testing laboratory assay for alfalfa, including necessary computational software. This new technology has the potential to double the rate of alfalfa variety improvement over existing breeding methods.

2. Forage growers gain assurance that propionic-acid-based preservatives work with large rectangular bales. Past studies have shown clear benefits (reduced heating, better preservation of nutrients) from applying propionic-acid-based preservatives to alfalfa hay made in 100-pound small-rectangular bales, but their effectiveness within large-round bales has been disappointing. ARS researchers in Marshfield, Wisconsin, in partnership with collaborators, wanted to determine how propionic-acid-based preservatives performed on large-rectangular bales because these bales are formed with a different packing mechanism (plunger) than round bales. The research showed that acid preservative limited spontaneous heating in these hays, and results were impressive, regardless of initial bale moisture. Modest benefits also were observed for post-storage nutritive value of hays, as well as apparent digestibilities of dry matter and organic matter in growing lambs. These results suggest that spontaneous heating can be limited, and nutrients can be preserved, by using these preservatives within large-rectangular bale packages.


Review Publications
Dien, B.S., Casler, M.D., Hector, R.E., Iten, L.B., Nichols, N.N., Mertens, J.A., Cotta, M.A. 2012. Biochemical processing of reed canarygrass into fuel ethanol. International Journal of Low-Carbon Technologies. 7:338-347.

Coblentz, W.K., Coffey, K.P., Young, A.N., Bertram, M.G. 2013. Storage characteristics, nutritive value, energy content, and in-vivo digestibility of moist large-rectangular bales of alfalfa-orchardgrass hay treated with a propionic-acid-based preservative. Journal of Dairy Science. 96:2521-2535.

Parrish, D. J., Casler, M. D., Monti, A. 2012. The evolution of switchgrass as an energy crop. In: Monti, A., editor. Switchgrass. London, UK: Springer. pp. 1-28.

Riday, H., Johnson, D.W., Heyduk, K., Raasch, J.A., Darling, M.M., Sandman, J.E. 2013. Paternity testing in an autotetraploid alfalfa breeding polycross. Euphytica. Euphytica 194:335-349.

Brink, G.E., Jackson, R.D., Alber, N.B. 2013. Residual sward height effects on growth and nutritive value of grazed temperate perennial grasses. Crop Science. DOI: 10.2135/cropsci2013.01.0068.

Casler, M.D., Smart, A. 2013. Plant mortality and natural selection may increase biomass yield in switchgrass swards. Crop Science. 53(2):500-506.

Vogel, K.P., Mitchell, R., Sarath, G., Jung, H.G., Dien, B.S., Casler, M.D. 2013. Switchgrass biomass composition altered by six generations of divergent breeding for digestibility. Crop Science. 53:853-862. DOI 10.2135/cropsci2012.09.0542

Lu, F., Lipka, A.E., Glaubitz, J.C., Elshire, R., Cherney, J.H., Casler, M.D., Buckler IV, E.S., Costich, D. 2013. Switchgrass genomic diversity, ploidy and evolution: novel insights from a network-based SNP discovery protocol. PLoS Genetics. 9(1):e1003215. DOI:10.1371/journal.pgen.1003215.

Watrud, L., Reichman, J., Bollman, M., Smith, B., Lee, E., Jastrow, J., Casler, M.D., Collins, H.P., Fransen, S., Mitchell, R., Owens, V.N., Bean, B., Rooney, W.L., Tyler, D.D., King, G.A. 2012. Chemistry and microbial functional diversity differences in biofuel crop and grassland soils in multiple geographies. BioEnergy Research. 6(2):601-619.

Casler, M.D. 2012. Switchgrass breeding, genetics, and genomics. In: Monti, A., editor. Switchgrass. London, UK: Springer. p. 29-54.

Last Modified: 7/31/2014
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