Location: Dairy Forage ResearchTitle: Application of the Smith-Hazel selection index for improving biomass yield and quality of switchgrass
|JAHUFER, MZZ - Agresearch|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/2/2015
Publication Date: 4/27/2015
Publication URL: http://handle.nal.usda.gov/10113/62439
Citation: Jahufer, M., Casler, M.D. 2015. Application of the Smith-Hazel selection index for improving biomass yield and quality of switchgrass. Crop Science. 55(3):1212-1222.
Interpretive Summary: Switchgrass is undergoing development as a cellulosic biomass feedstock. While biomass yield is the principal target trait in breeding programs, biomass quality has a strong influence on conversion efficiency. This research created sophisticated selection indices combining biomass yield and biomass quality traits to assist plant breeders in simultaneously improving both yield and quality of biomass to improve economic sustainability of switchgrass biomass production. A combination of selection for high yield, high ethanol yield, and low lignin resulted in the most efficient selection index for economic improvement for a fermentation platform. Conversely, selection for high yield and high lignin concentration resulted in the most efficient selection index for a combustion platform. These results will be extremely valuable in guiding switchgrass breeders to develop more efficient selection protocols for improving economic sustainability of biomass production.
Technical Abstract: Apart from the importance of switchgrass (Panicum virgatum L.) as forage for livestock, it is useful as a high-value cellulosic biofuel feedstock. Breeding for a biofuel crop is complicated by the existence of multiple platforms for conversion of biomass to energy. Our main objective was to investigate the relative merits of single-trait selection, correlated response to selection and Smith-Hazel index based selection, for the following traits: biomass dry matter yield (YLD), ethanol (ETOH), Klason lignin (KL) and high heating value (HHV). The genetic analysis was based on a two-year data set generated from evaluation of 144 half-sib families in sward-plot trials at Arlington and Marshfield, Wisconsin. There was significant (P<0.05) additive genetic variation among the families for all traits, and for family × site interaction for the traits HHV and YLD. The estimates of narrow sense heritability on a half-sib family mean basis, ranged from 0.37 for YLD to 0.51 for KL. Genetic correlation of YLD with ETOH, HHV and KL were 0.38, 0.27 and 0.01, respectively. The index constructed to increase YLD and ETOH and reduce KL, was most successful for a fermentation platform. This index enabled identification of families for enhancing ethanol production that would have been missed if selection was based solely on YLD. The index weighted to increase YLD and KL best suited a combustion platform. Both of these two indices had superior economic impacts to any other selection index evaluated.