Genetic Variation, Gene Control Pattern And Environment Effect Of Growth And Wood Property In Pinus Massoniana

Masson pine (P. massoniana) with better quality of fast growth, wide distribution and strong resistance, is a native tree species in China and has been one of main conifers for afforestation in Southern China and used widely in papermaking, building and rosin. In this thesis, growth and wood quality of masson pine was studied to reveal genetic variation in different variation level, mode of genetic control and response to initial density and phosphorus for growth, stem-form qualities and wood basic density used provenance trail, clonal breeding population, full-sib progeny test of in a testcross mating design, initial stand density by provenance interaction trail and phosphorus by provenance interaction trail, individually. the aim was providing important theories for genetic improvement of growth and wood quality. The results show as follow:(1) There existed significant differences between twenty-four-year-old provenances for growth rate and wood quality. A classical clinal variation pattern responding to the latitude of seed source was found for DBH, height, individual volume and stem straightness, and water and heat resources of seed sources were the main climatic factors which led to the variation pattern. The productivity of southern provenances was higher than that of northern provenances. Strong negative correlation existed between wood basic density and annual mean temperature, temperature in January, frostless season and accumulated temperature over 10℃of the seed source. Genetic correlation suggested that stem straightness could be concurrently improved with the selection of fast-growing provenances, whereas the wood basic density was decreased. The range of Masson Pine in China can be divided into Southern, Middle and Northern provenance zone by cluster analysis. Nineteen and six superior provenances were selected for pulpwood and building timber respectively, most of which were from Southern provenance zone and some from Middle provenance zone.(2) There existed significant differences between provenances for ring width and wood density of every segment except the ring width of 1～5 rings. The variation of wood density was relatively stable with cambial age compared to ring width among provenance and the variation of ring width was easy to be influenced by environment. Pattern for the radial variation of ring width was similar for provenances in difference zones, which increased and then decreased from pith to bark and reached maximum in 6～10 rings. Pattern for the radial variation of wood density was s- type increasing from the pith outward then following by a leveling off period toward the bark. Five superior provenances including of Hengxian GX, Gongcheng GX, Xincheng GX and Ruyuan GD, were selected for pulpwood according to wood density uniformity. The early-late correlation showed, slower growth provenance could be eliminated in 7-year-old, then growth and wood basic density could be combined selection for wood density in 12-year-old.(3) Significant differences existed among seed sources and clones within seed source, and the variation among twenty-three-year-old seed source were 1.87-2.38 time higher than that among clones within seed source. Variance component of seed source for wood density were larger compared growth. Ring width of all seed source was decreasing from the pith to bark excepting Anhui seed source of which was unimodal. Except for Sichuan and Guangdong seed source, pattern for the radial variation of wood density was increasing from the pith outward then following by a leveling off period toward the barks. Early-late correlation showed that radial growth and wood density could be selected in five-year old except the selection for wood density of Jiangxi, Guangdong and Sichuan seed sources was later than radial growth. The 180 clones could be divided into three categories and four subclasses by cluster analysis.(4) Effect was significant differences of general combining ability (GCA) and special combining ability (SCA) for tested trait using the 14-year-old full-sib progeny test. Full-sib family heritability of tested traits under strong genetic control, ranged from 0.746 to 0.908. Additive effects played a more major role than dominance effects for DBH, volume, stem straightness, wood basic density and dry matter accumulation. Height appeared to be almost equally subject to both dominance and additive effects, while stem straightness was controlled completely by additive effect. GCA of parents and SCA varied with either trait or cross combination. Seven cross combinations were selected and could obtain genetic gain of 20.25%～60.13%. (5) Effect of initial stand density was significant on different provenances of 12-year old and traits. DBH and height under branch were most sensitive to initial stand density, effect of initial stand density on height was next and has little effect to stem straightness and wood basic density. DBH of these provenances was sensitive including Cenxi Guangxi, Xinyi Guangdong, Chongyi Jiangxi and Wuping Fujian and grew best under the initial stand density of 2.5 m×2.0 m. Height under living branch of all provenances was significant between different initial stand density and increasing initial stand density resulted in an increase in height under living branch. There also exists significant difference between provenances for height under the initial stand density of 1.5 m×2.0 m and 2.5 m×2.0 m. The study also found provenance by initial stand density interaction on growth, stem-form quality and wood basic density was little and initial stand density did not effect their relative growth performance. Based on comprehensive consideration of growth and wood quality, optimal initial stand density was configured for all provenances according different cultivation objectives.(6) Effect of phosphorus was significant on different provenances12-year old and traits. Wuping FJ was excellent provenance with tolerance of low phosphorus. Gaozhou GD was sensitive to phosphorus and the effect of phosphorus was long duration. Relative to growth, the influence on stem straightness and wood basic density was slight. Wuping FJ was more superior to the other provenances when phosphorus was lack. Provenances from Guangdong, Guangxi and Chongyi JX showed fertilizer efficiency after phosphorus was supplied, in which Cenxi GX and Gaozhou GD even exceed Wuping FJ. The difference of wood basic density and stem straightness was slight between provenances under three phosphorus level. Individual heterogeneity of wood basic density between or within provenances was decreased by phosphorous supply. The experiment also showed that provenance by phosphorus interaction was significant for height and wood basic density,and phosphorous should be supplied according to the effect of provenance to phosphorous.