The use of physiological, biochemical and morpho-anatomical traits in tree breeding for improved water-use efficiency of Quercus robur L.

Abstract

A im of study : In the present paper the nature and level of co-dependence between leaf functional traits and intrinsic water-use efficiency ( WUE i ) were studied in one-year-old Quercus robur L. seedlings, grown in a common garden experiment under moderate drought conditions. The study was established to identify those traits that might potentially be utilized to improve leaf-level WUE i , and therefore be used in breeding programmes to enhance drought adaptation of Q. robur . A rea of study : The study was carried out at the common garden site within the UNESCO Biosphere Reserve Mura-Drava-Danube. M aterial and methods : The study involved one-year-old seedlings of eight half-sib lines of Q. robur . \xa0Eighteen leaf parameters were analyzed; i.e. physiological, biochemical, morphological and anatomical. The data were processed using multivariate statistical methods: a) principal component analysis, b) stepwise regression analysis, and c) path coefficient analysis. M ain results : The results showed that leaf stomata traits, particularly stomatal density (SD), and leaf dry mass per unit leaf area (LMA) were the most important traits, closely associated with WUE i . Stomatal density achieved the highest score on PC1 (0.825), in which WUE i had the highest loading (0.920), as well. SD was also included first in stepwise regression model. R esearch highlights : These results demonstrate that under moderate water stress WUE i in Q. robur half-sib lines were mainly the result of the plants’ structural acclimation to surrounding environmental conditions. Keywords: Quercus robur L.; half-sib line; intrinsic water-use efficiency; leaf functional traits.