Genetic variation in wood shrinkage, and its correlations with tree growth and wood density of Calycophyllum spruceanum at an early age in the Peruvian Amazon
Calycophyllum spruceanum (Benth.) Hook. f. ex Shum. is an important timber tree species in the Peruvian Amazon Basin. Farmers and industry use wood from young trees of this species, so tree breeders should investigate genetic variation in juvenile wood properties to verify whether they can be improved. A previous study using the same provenance/progeny test showed that there was significant genetic variation in tree growth and wood density, that heritability was higher for density than for growth, and that density and growth were positively correlated at 39 months. This paper presents results for wood shrinkage at 39 months and their correlations with tree growth and wood density. Data were collected on thinned trees. Shrinkage values were relatively low when considering wood density of this species. There was significant genetic variation in wood shrinkage due to families within provenances and, in some cases, due to provenances. Heritability estimates were moderately high for linear and volumetric shrinkage (0.37-0.50) and lower for the tangential/radial shrinkage ratio (0.21-0.29) across zones. The genetic correlations that were considered significant ranged from 0.30 to 0.80. In general, genetic correlations suggest that selection of faster-growing trees with higher wood density would result in wood with greater shrinkage and a larger tangential/radial shrinkage ratio.