GENETIC VARIATION IN EARLY GROWTH, STEM STRAIGHTNESS AND SURVIVAL IN ACACIA CRASSICARPA, A. MANGIUM AND EUCALYPTUS UROPHYLLA IN BUKIDNON PROVINCE, PHILIPPINES

Abstract

Results are reported from three provenance-family trials, one of Acacia crassicarpa, one of A. mangium and one of Eucalyptus urophylla, established in Bukidnon province on the southern Philippine island of Mindanao. All trials contained seedlots representing the species natural geographic wide ranges
and the A. mangium trial also included some seed orchard seedlots. Average growth at approximately age three years ranged from 9.3 m height with diameter at breast height (dbh) of 8.0 cm for E. urophylla up to 10.9 m height and 12.2 cm dbh for A. mangium. Eucalyptus urophylla showed good average stem straightness whilst both A. mangium and A. crassicarpa had relatively poor stem straightness. In A. crassicarpa there were significant differences between both provenances and families-within-provenances for dbh and survival. In A. mangium, there were significant differences between regions, provenances-within-region and families-within-provenance for dbh, and between regions and families-within-provenance for stem straightness. The only significant differences for survival in A. mangium were those between provenancewithin-region. Significant differences were found between provenances of E. urophylla for dbh, straightness and survival. However, these were much smaller than the differences between families-within-provenances for these traits. Estimates of individual tree heritabilities for growth traits and stem straightness were low to very low (0.07 to 0.15) for the three species, with the exception of straightness in A. crassicarpa which was moderate (0.25).