Zhang, T., Lamb, E. G., Soto-Cerda, B., Duguid, S., Cloutier, S., Rowland, G., Diederichsen, A. and Booker, H. M. 2014. Structural equation modeling of the Canadian flax (Linum usitatissimum L.) core collection for multiple phenotypic traits. Can. J. Plant Sci. 94: 1325-1332. Flax seed yield is a complex trait that results from the inter-relationship between many crop characteristics. Structural equation modeling (SEM) is a statistical method used to determine the relationship between measured variables such as crop characteristics. Crop phenology, canopy traits, yield, and its components were included in structural equation models to determine how these crop characteristics relate to seed yield in a phenotypically diverse collection of flax germplasm. Early season vigor (scored as greater plant stand) was positively associated with canopy light interception and higher seed yield. Plant height also had a significant positive effect on seed yield. Moreover, yield components such as 1000-seed weight, number of bolls per unit area, and boll weight were strongly and positively correlated with seed yield. Focusing on yield-related traits, canopy architecture and expansion, and seed weight may be advantageous over yield per se in breeding for yield improvement.