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A COMPARISON OF TWO METHODS OF ASSESSING GENETIC VARIABILITY IN VOLUME, WOOD DENSIY AND DRY MATTER OF Pinus tecunumanii (Schwd) Eguiluz and Perry

ABSTRACT

Eighty-four trees, of seven open-pollinated families from the Mountain Pine Ridge (MPR), Belize provenance of Pinus tecunumanii (Schwd) Eguiluz e Perry were assessed for volume growth, wood density and dry matter at 12 and 17 years of age at Planaltina, Federal District. Family differences for all traits were significantly different except for wood density at 17 years of age. Two methods were used for wood density evaluation at 12 years of age; one with the three better individuals within each parcel, and another one with all individuals in each parcel. Average individual wood density were 0.424 and 0.425 g/cm3, practically equal for the two samplings. There was a positive and significant wood density correlation between the two ages, with an increase of density of 0.031 g/cm3 from the age 12 to 17. Individual, family and within family heritability for wood density for the two kind of sampling (3 and 6 individuals), was of 0.43, 0.81, 0.33 and 0.47, 0.63, 0.37 respectively. Selections for wood density should be made preferably in ages when the competition between individuals still did not reach high levels. Sizable improvement both in volume and wood density can be made in the MPR, Belize population, in the Cerrado region. However, a larger genetic base is needed.

Key words:
Pinus tecunumanii; wood density; dry matter; heritability

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