利用1984年营造的马尾松全分布区种源试验林在5,10,15,20和25年生时测定材料,分析种源主要生长性状在不同测定年龄的遗传变异和早期优良种源选择效果。结果表明: 胸径、树高和材积等马尾松主要经济性状在种源间存在差异,这种差异有随试验林年龄增长而不断加大的趋势,25年生时各性状最大种源比最小种源分别大94.85%,47.66%和355.68%。虽然材积等主要生长性状在不同年龄间生长与秩次相关均极显著,但由于不同种源的早晚生长习性不尽相同,过早开展种源选择可能会误选或漏选部分优良种源,如把正确入选率控制在90%以上,则马尾松种源试验优良种源早期选择的合理年龄应在10~15年生,其相应的选择强度为材积遗传增益>20%或种源入选率在30%~40%。
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.