Hydraulic traits predict stem growth across Hevea brasiliensis clones in a Malaysian climatically marginal area

Competition for land resources is forcing rubber (Hevea brasiliensis Müll. Arg.) production into more agroclimatically vulnerable zones, which are likely to be affected by drought. It therefore of interest determine whether there particularly drought resistant genotypes. Established plant drought-resistance indicators include xylem resistance embolism under water stress (P50, potential at 50% conductivity lost), and hydraulic safety margins (HSM50), defined as the difference between P50 minimum leaf (Pmin) driest conditions in year. We report here on measurements in-situ growth performance nine mature clones an agro-climatically marginal site North-Western Malaysia their hydraulic, stem traits investigate inter-clonal variation rate. find that varies substantially across clones, −3.05 −1.37 MPa, while HSM50 varied within range −0.11 MPa 1.37 MPa. Similar what has been reported species, we a growth-hydraulic trade-off with faster rates associated lower less negative P50, one exception. Based hierarchic linear regression almost all best models traits, besides morphological indicating important predict accurately. Furthermore, genotypes high rate low margin (HSM50) were wood density, higher sapwood area larger area. Overall thus suited plantation areas, they tend productive.