Petiole and leaf traits of poplar in relation to parentage and biomass yield

•We examined leaf and petiole traits of 12 different poplar genotypes.•The genotypes clustered according to their breeding programmes and parentage.•Difficult-to-measure petiole traits correlated well with leaf dry mass.•Correlative biomass models were developed based on petiole and leaf traits.•These simple models provide useful early selection criteria for poplar.

Poplars grown under a short-rotation coppice (SRC) regime for biomass production offer a promising alternative source of renewable energy to fossil fuels. We examined the potential of leaf and petiole traits of 12 different poplar genotypes as early selection criteria for breeding and selection programmes. Petiole traits included theoretical hydraulic conductivity of the petiole, petiole xylem area and the number of vessels in each petiole. The different genotypes clustered largely according to their breeding programmes and to their parentage. Leaf and petiole traits showed strong correlations, which enabled the prediction of difficult-to-measure petiole traits as xylem area, total vessel lumen area and number of vessels based on the more common and easily measurable leaf dry mass. We found significant correlations between above-ground woody biomass and nine leaf and petiole traits. We developed three predictive correlative models based on the easy-to-measure petiole and leaf traits (petiole cross-section area, petiole thickness and leaf dry mass). These simple models can be used as early selection criteria for biomass yield in poplar breeding programmes. The usefulness of the easy-to-measure petiole thickness for biomass prediction should be further tested on other poplar genotypes.