Genetically-controlled leaf traits in two chemotypes of Salix sachalinensis Fr. Schm (Salicaceae)

Salix sachalinensis has two chemotypes: one biosynthesises ampelopsin as a major component of low molecular weight phenolics in their leaves (A-type), and the other biosynthesises β-d-glucopyranose-1-trans-p-coumarate (PG1) and β-d-glucopyranose-1-trans-cinnamate (PG2) in addition to ampelopsin (AP-type). We investigated phenotypic and genetic variations and clonal repeatabilities of the pubescence density, leaf mass per area (LMA), and concentrations of total phenolics, condensed tannin, ampelopsin, PG1 and PG2. Leaves of wild A-type trees contained significantly higher concentrations of total phenolics and ampelopsin, and lower concentration of condensed tannin than those of wild AP-type trees. In the greenhouse experiment that compared leaf traits between cloned trees obtained from wild chemotypes, there were significant between-type variations in the leaf phenolic concentrations, pubescence density, and LMA. Since chemotypes of cloned trees in the greenhouse were the same as those of wild parent trees, chemotype can be considered as a genetically controlled property. There were also significant within-chemotype variations in the pubescence density, LMA, total phenolics, ampelopsin, PG1, and PG2 concentrations, but not in concentration of condensed tannin for either chemotypes. Genetic variation of leaf traits except for LMA in AP-type was significant. PG1 and PG2 exhibited the highest clonal repeatabilities (0.73 and 0.78, respectively). Thus, the ability to produce and the amount of production of PG1 and PG2 are genetically controlled.