Scientific Paper

Genetic Parameters and Provenance Productivity of Pinus oocarpa and Pinus patula ssp. tecunumanii

Published in: South African Forestry Journal
Volume 173, issue 1, 1995 , pages: 1–7
DOI: 10.1080/00382167.1995.9629683
Author(s): B.I. NyokaForest Research Centre,, R.D. Barnes,


Results are presented of a provenance-progeny test of six populations of Pinus oocarpa Schiede and two of P. patula Schiede & Deppe in Schlecht. & Cham. ssp. tecunumanii (Equiluz & Perry) Styles; each population was represented by 8 or 16 families. Significant differences between provenances and between families within provenances were detected for height, diameter at breast height and stem straightness at two, five and eight years. Family heritability estimates were consistently highest for the Siquatepeque provenance of P. oocarpa with estimates of 0,73 for diameter and 0,86 for stem straightness at five years. For other provenances, however, estimates ranged down to 0,00 and 0,05 for diameter and height at eight years in Angeles (P. oocarpa) and San Rafael (P. patula ssp. tecunumanii) provenances respectively. Single tree heritabilities were also high for all traits in Siquatepeque provenance, ranging from 0,22 for eight-year diameter to 0,51 for five-year height. Standard errors were generally small except for a few cases where they exceeded the estimate itself. Genetic correlations between height and diameter in and between years were mostly large and positive for the P. oocarpa provenances but stem breakage in P. patula ssp. tecunumanii provenances after five years resulted in low correlations of five-year height with height and diameter at eight. Correlations between growth traits and stem straightness varied greatly in sign and magnitude with provenance but overall indications were that these were not unfavourable. The most productive provenances were Yucul and San Rafael (both P. patula ssp. tecunumanii); Dipilto and Mal Paso were the most productive P. oocarpa provenances.

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