Performance and genetic variation of big-leaf mahogany (Swietenia macrophylla King.) provenances in Mindanao, Philippines
2012
Ata, J.P.
This study was conducted to characterize and assess the performance and genetic variation of provenance-family trial of S. macrophylla established in 2007 in Ampayon, Butuan City using economically-important traits. The trial contained 73 seedlots of families with 6 duplicates and 1 bulked collection representing the provenances of the S. macrophylla found in the different regions in the Philippines. Average growth of the species at age four years ranged from 9.517 m height with 11.844 cm diameter at breast height. It also had a relatively good stem form and an average density of 0.433 g/cm. The analysis indicated significant provenances and families-within-provenance differences for diameter at breast height. Best performing families in the trial were also identified. Significant differences among provenances were found for diameter and height. Incidence of Hypsipyla was found to be significant for both provenances and families-within provenances. Estimates of individual tree heritability for diameter and stem straightness were moderate (0.296 and 0.235, respectively). Negative genetic correlations were found between density and the growth traits expect for diameter. Results from this study suggest potential tree improvement for the species through selection. Seed sources from the top performing families in this trial may be the best option as source of planting materials for future plantation programs in areas having conditions similar to the trial site.
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