Assessing phenotypic diversity in silflower (Silphium integrifolium Michx.) to identify traits of interest for domestication selection

Silflower (Silphium integrifolium Michx.) has been identified as a candidate for domestication as a perennial oilseed crop. In order to successfully domesticate silflower it will be necessary to identify traits that should be targeted for selection. We have conducted the first multilocation trial of replicated silflower genotypes at six sites across four states. By observing architectural, phenological, and yield traits in a diversity panel of silflower breeding material, we were able to estimate the heritability of these traits, as well as patterns of correlation across years and environments. We found that this population expressed heritable variation for many, but not all, traits of interest, and that targeted introgression of diversity may be beneficial for some traits. In addition, we used regression analysis to identify several traits, particularly height, number of stalks per plant, and stalk diameter as important contributors to determining levels of yield and levels of lodging. These results will help to guide future silflower domestication efforts and have already shaped the direction of our breeding program.