Genetic variation in the decay resistance of Scots pine wood against brownrot fungus

The role of genotype in the durability of Scots pine (Pinus sylvestris L.) wood against decay by brown rot fungus (Coniophora puteana (Schum. ex Fr.) Karst. (strain Bam EBW 15)) was studied in a laboratory test. The wood mate rial was obtained from 32-year-old half-sib progenies of Scots pine. The in crement core samples of sapwood and juvenile heartwood were decayed using a modification of the standardized EN 113 method. The mean densities of the sapwood and heartwood samples were 391 and 337 mg.cm(3), respectively, and the mean mass losses were 114 and 80 mg.cm(3), respectively. The additive g enetic components were small compared with the total phenotypic variance, w hich resulted in small narrow-sense heritabilities in mass loss. The most m arked feature was the wide phenotypic variation in mass loss observed in he artwood (range 199 mg.cm(3)) compared with sapwood (range 72 mg.cm(3)) samp les. Low heritability, together with the relatively high coefficient of add itive genetic variation (CVA) in heartwood mass loss, suggests that advance s in breeding can only be made through intensive testing in the environment s which the studied experiment represents.