Phenotypic Traits of Switchgrass Cultivars Associated with Increases in Biomass Yield.

Switchgrass is highly productive native grass that has been selected as a model dedicated energy crop. In order to efficiently make gains in biomass yield it is beneficial to understand the yield components of biomass increases, which to date have had inconclusive results. To survey which improvements have been made thus far in available commercial varieties a randomized block design with 9 diverse varieties of switchgrass was planted and sward plots were measured for 18 response variables. MANOVA, univariate ANOVA, and principal component analysis were used to discover significant differences between varieties. Principal components were used to reduce data complexity and the PC’s were found to accurately and collectively assess switchgrass phenotypes. Analysis of PC scores shows that there has been recent divergence of yield for bred and natural populations. Contrasts for bred and natural varieties resolve for which variables they have been improved. Future efforts at yield improvement will be enhanced by use of principal components as a metric for assessing overall phenotype.