Theme 2-1: Forage Production and Utilization--Oral Sessions

Description

Eastern gamagrass is a perennial warm-season grass native to North America and endemic to the eastern United States. The species is highly valuable as both a forage and hay crop. In 2012, 171 wild-type eastern gamagrass accessions were collected from the southeast, mid-Atlantic and Atlantic coast regions. Each accession was relocated to Starkville, MS (33.423585, -88.792394) and established in a long-term nursery. Accessions were analyzed for ploidy level and during 2013-2014 were further evaluated for desirable forage characteristics including: cold tolerance, delayed maturity, rust resistance, and digestibility. Fourteen elite individuals were identified from the original collection and were propagated for further research. Elite genotypes were divided into individual proaxes and transplanted into a RCB design with three replications. Plots measured 3.04 m x 1.21 m with five replicate plants evenly spaced within the plot. Following a one-year establishment period, whole plots were harvested on a 28-day cycle from May to October. Plots were harvested to a 15 cm stubble height with a Wintersteiger Cibus S harvester. Following each harvest, nitrogen fertilizer was applied to all plots at 56 kg N ha-1 using urea ammonium sulfate (32-0-0-12S). Homogenized subsamples were taken to determine percent dry matter, neutral detergent fiber (NDF), acid detergent fiber (ADF), and in-vitro dry matter digestibility (IVDMD). The commercial cultivar ‘Highlander’, was included in the study as a check. Seasonal yields ranged from 1.19 - 2.73 Mg ha-1. Three accessions – originally collected in Alabama and North Carolina – produced significantly greater forage yield than the check (P > 0.0001). Digestibility of the commercial check as well as one accession – collected in Tennessee – were significantly greater than all other accessions (P > 0.0001).

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Identifying Forage Quality Eastern Gamagrass [Tripsacum dactyloides (L.) L.] Genotypes from a Wild Regional Collection

Eastern gamagrass is a perennial warm-season grass native to North America and endemic to the eastern United States. The species is highly valuable as both a forage and hay crop. In 2012, 171 wild-type eastern gamagrass accessions were collected from the southeast, mid-Atlantic and Atlantic coast regions. Each accession was relocated to Starkville, MS (33.423585, -88.792394) and established in a long-term nursery. Accessions were analyzed for ploidy level and during 2013-2014 were further evaluated for desirable forage characteristics including: cold tolerance, delayed maturity, rust resistance, and digestibility. Fourteen elite individuals were identified from the original collection and were propagated for further research. Elite genotypes were divided into individual proaxes and transplanted into a RCB design with three replications. Plots measured 3.04 m x 1.21 m with five replicate plants evenly spaced within the plot. Following a one-year establishment period, whole plots were harvested on a 28-day cycle from May to October. Plots were harvested to a 15 cm stubble height with a Wintersteiger Cibus S harvester. Following each harvest, nitrogen fertilizer was applied to all plots at 56 kg N ha-1 using urea ammonium sulfate (32-0-0-12S). Homogenized subsamples were taken to determine percent dry matter, neutral detergent fiber (NDF), acid detergent fiber (ADF), and in-vitro dry matter digestibility (IVDMD). The commercial cultivar ‘Highlander’, was included in the study as a check. Seasonal yields ranged from 1.19 - 2.73 Mg ha-1. Three accessions – originally collected in Alabama and North Carolina – produced significantly greater forage yield than the check (P > 0.0001). Digestibility of the commercial check as well as one accession – collected in Tennessee – were significantly greater than all other accessions (P > 0.0001).