Principal component analysis to evaluate the relative performance of nine year old hybrid poplar clones

Previous studies have identified particular hybrid poplar parentage lines associated with a certain level of growth or disease resistance. This study used principal component analysis (PCA) to evaluate the relative performance of 54 hybrid poplar clones based on nine year old measures of growth and canker disease. Growth was characterized by percentage survival and total basal area per clone, while disease was characterized by the number of cankers per living tree and canker appearance. The first principal component which accounted for 85% of the variation in the data set was used to rank the clones. In general, clones which exhibited high growth and low disease measures were ranked at the top of the list. One exception, clone GA88 (ranked near the top), was uncankered and despite having low survival, produced a relatively high basal area. PCA provided an ordering of clones based upon growth and disease which can be used to select clones for larger scale testing. Future applications of multivariate techniques can incorporate additional variables considered important for biomass, wood pulp, or veneer production.