Abstract:

A provenance test forest of Pinus massoniana was established in 1984, and the major growth parameters were respectively measured at 5, 10, 15, 20 and 25 years to detect the genetic variation in major growth traits among provenances and to evaluate the selection effect at different test age. Genetic variation in DBH, plant height, and volume index among provenances was detected, and the result demonstrated that the degree of variation was increased with the testing age. The variation coefficient at 25-years was 94.85%, 47.66% and 355.68% for DBH, plant height and volume, respectively. These results provided insights into the strategy of the provenance selection of P. massoniana . Although the trait value and the rank based on major traits were correlated significantly between different selection ages, the selection at too early age might lead to false-selection or miss-selection for some potentially superior provenances. Based on this result, to obtain the correct selection rate of 90%, the appropriate selection age for P. massoniana provenance test should be in 10-15 years, and the selection intensity should be >20% gain for volume index, or 30%-40% of provenances being selected.

Key words: Pinus massoniana, provenance test, early selection, selection effect