|SMART, ALEXANDER - South Dakota State University|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/18/2012
Publication Date: 1/9/2013
Citation: Casler, M.D., Smart, A. 2013. Plant mortality and natural selection may increase biomass yield in switchgrass swards. Crop Science. 53(2):500-506.
Interpretive Summary: Switchgrass is an important candidate for bioenergy feedstock production, prompting significant efforts to increase the number of breeding programs and the output of those programs. The purpose of this experiment was to determine the potential value of natural selection in switchgrass as a tool for improving breeding efficiency. The procedure involved digging up surviving plants from 5-year-old plots of several switchgrass varieties and then comparing the progeny of these plants to the original varieties. Biomass yield increased by an average of 7% in naturally selected progeny, compared to the parents. The best population was 44% higher in biomass yield than the parent. Natural selection of surviving plants appears to have value for switchgrass breeders with a goal of improving efficiency of their breeding program.
Technical Abstract: Switchgrass (Panicum virgatum L.) is an important candidate for bioenergy feedstock production, prompting significant efforts to increase the number of breeding programs and the output of those programs. The objective of this experiment was to determine the potential utility of natural selection for survivorship in switchgrass swards as a tool for improving efficiency of progeny-test-based recurrent selection programs in switchgrass. Surviving plants were selected from 5-year-old plots of six cultivars grown at five locations. Progeny of each population were grown in a four-location field experiment in Illinois and Wisconsin in direct comparison to their parent populations. On average, natural selection for survivorship increased biomass yield by 6.7%. The northernmost (i.e. coldest) selection location had the greatest response among the five locations (13.2%), while the most genetically diverse cultivar had the greatest response among the cultivars (23.5%). Results were highly variable among cultivars and selection locations, but there were no significant negative responses, suggesting that the genetic correlation between survivorship and biomass yield in switchgrass ranges from zero to some intermediate positive value. Selection for survivorship within switchgrass sward plots has the potential to improve efficiency of family-based selection methods designed to improve biomass yield potential.