Genetic variations of growth traits in a 21-year-old stand progeny of Shanxi natural Pinus tabuliformis forests.

Shanxi Province is both the central distribution area of Pinus tabuliformis and the major seed sources for surrounding provinces. In this paper, genetic variations of growth traits in 21-year-old progeny tests of 23 natural stands mainly from Shanxi provenance of P. tabuliformis were investigated. The results showed that variations in growth traits among progeny tests of 23 natural stands were highly significant. Natural distribution of P. tabuliformis in Shanxi Province exhibited a feature of geographic regionalization and mountainous regionalization. Similar performance in growth traits of stand progenies within the same mountain region, but highly different among mountain regions were observed. In order of descending of progeny growth of 23 stands in different geographic regions, it went as middle region, south region and north region. While in different mountain regions, it went as Guandi Mountain region, Taiyue Mountain region, Zhongtiao Mountain region, Lliang Mountain region, Taihang Mountain region and Guancen Mountain region, which were different from the stand growth determination in situ. Growth of progenies in 6 selected elite stands was much higher than stand progeny in testing region. Conserving elite natural stands, developing seed stands for improvement would be facilitated for afforestation of P. tabuliformis in testing regions.