Description
In the southeastern United States, perennial warm-season grasses constitute the backbone of many forage production systems, whether for grazing or harvested feed. North American native plants offer unique ecosystem benefits as well as high forage quality when managed properly. Popular native grasses used for grazing in the southeastern US include Andropogon (bluestems), Sorghastrum (indiangrass) and members of the genus Tripsacum including eastern gamagrass (T. dactyloides) in North and Central America; Guatemala grass (T. fasciculatum syn. T. andersonii) in Latin America and the West Indies; and wide-leaf gamagrass (T. latifolium) throughout Mesoamerica. Eastern gamagrass - a hearty, long-lived perennial warm-season bunchgrass - has seen wide popularity throughout the Midwest, Mid-Atlantic, and Deep South as a forage and is also popular for its contribution to environmental and ecosystem services. A major limitation to more widespread use of eastern gamagrass is high seed dormancy, which leads to increased seed cost. This research project used recurrent phenotypic selection breeding methods to increase germination percentage and velocity in eastern gamagrass seed without stratification. Commercial varieties ‘Pete’ and ‘Iuka’ were screened for germination without prior stratification beginning in 2012. Successive breeding nurseries were established annually beginning in 2013 and maintained throughout the duration of this study. Seed were harvested in 2016 to begin evaluation of effects of selection on daily germination percentage (DG%) and cumulative germination percentage (CG%). These trials were conducted alongside replicate experimental units that had been cold, moist stratified for six weeks as a positive control. Selection significantly increased DG% (P < 0.01) and CG% (P < 0.001) after only two cycles. Following a third cycle of selection, 2018 seedlot evaluation yielded cumulative germination percentage of 37.3% for the most advanced cycle (Cycle 3), as compared to 13.5%, 17.5%, and 16% for cycles 0-2, respectively. Recurrent phenotypic selection has proven useful in improving germination percentage in eastern gamagrass, potentially eliminating the need for cold, moist stratification prior to planting.
Included in
Agricultural Science Commons, Agronomy and Crop Sciences Commons, Plant Biology Commons, Plant Pathology Commons, Soil Science Commons, Weed Science Commons
Strategies for Seed Quality Improvement in Eastern Gamagrass, a Tripsacum Species
In the southeastern United States, perennial warm-season grasses constitute the backbone of many forage production systems, whether for grazing or harvested feed. North American native plants offer unique ecosystem benefits as well as high forage quality when managed properly. Popular native grasses used for grazing in the southeastern US include Andropogon (bluestems), Sorghastrum (indiangrass) and members of the genus Tripsacum including eastern gamagrass (T. dactyloides) in North and Central America; Guatemala grass (T. fasciculatum syn. T. andersonii) in Latin America and the West Indies; and wide-leaf gamagrass (T. latifolium) throughout Mesoamerica. Eastern gamagrass - a hearty, long-lived perennial warm-season bunchgrass - has seen wide popularity throughout the Midwest, Mid-Atlantic, and Deep South as a forage and is also popular for its contribution to environmental and ecosystem services. A major limitation to more widespread use of eastern gamagrass is high seed dormancy, which leads to increased seed cost. This research project used recurrent phenotypic selection breeding methods to increase germination percentage and velocity in eastern gamagrass seed without stratification. Commercial varieties ‘Pete’ and ‘Iuka’ were screened for germination without prior stratification beginning in 2012. Successive breeding nurseries were established annually beginning in 2013 and maintained throughout the duration of this study. Seed were harvested in 2016 to begin evaluation of effects of selection on daily germination percentage (DG%) and cumulative germination percentage (CG%). These trials were conducted alongside replicate experimental units that had been cold, moist stratified for six weeks as a positive control. Selection significantly increased DG% (P < 0.01) and CG% (P < 0.001) after only two cycles. Following a third cycle of selection, 2018 seedlot evaluation yielded cumulative germination percentage of 37.3% for the most advanced cycle (Cycle 3), as compared to 13.5%, 17.5%, and 16% for cycles 0-2, respectively. Recurrent phenotypic selection has proven useful in improving germination percentage in eastern gamagrass, potentially eliminating the need for cold, moist stratification prior to planting.
