Genetic Variation Of Wood Properties In Half Sib Families Of Pinus Massoniana

Pinus massoniana is an important timber forest species in China.By studying the genetic variation of wood properties of Pinus massoniana half-sib families,the selection of excellent families and plantation cultivation with the goal of improving wood quality can be carried out more pertinently.At the same time,the use of acupuncture instrument for indirect determination of wood basic density can effectively improve the research efficiency and reduce the experimental cost.In this paper,27-year-old Pinus massoniana half-sib families and their parental clones selected from three excellent provenances of Gupeng,Tongmian and Rongxian were used as materials.The growth traits and wood properties of half-sib families were analyzed and determined,and the excellent offspring families were evaluated.The effect of resin tapping treatment on wood basic density was analyzed and the correlation between wood resistance value and wood basic density was analyzed.The wood properties of parental clones were measured and the genetic variation between progeny and parents was studied.The main research results are as follows:（1）The tree height,DBH,volume and wood basic density of Pinus massoniana half-sib families were significantly different among families The heritabilities were0.358,0.273,0.310 and 0.350,respectively.Their heritability belongs to medium heritability.Several traits have rich genetic variation among families.The wood properties tended to be stable with the increase of age,and the older the tree age,the better the wood quality.There was no significant difference in the basic density of wood at the family level after 20 years.Among the 93 half-sib families,132 and 179 families had growth advantages while ensuring that the wood quality did not decrease.（2）The early wood tracheid length varied from 3340.3 to 4125.9μm at the family level.The length of late wood tracheid ranged from 3515.2 to 4801.6μm.The length of early wood tracheid was positively correlated with the length of late wood tracheid and the width of early wood tracheid,and positively correlated with the wall thickness of early wood tracheid and the wall thickness of late wood tracheid.It can be used as the main selection index in wood tracheid morphology in family selection.In addition,early wood fiber length was significantly positively correlated with tree age and late wood rate,and significantly negatively correlated with wood density.（3）The repeatability and heritability of provenance to clones and half-sib families were0.907 and 0.682,respectively.The wood basic density was controlled by provenance,but the effect on half-sib families was lower than that of parents.In terms of wood properties,Gupeng>Rongxian>Tongmian.The difference of half-sib families between different provenances was smaller than that of clones.Among the 93 families,28 half-sib families and their parents were higher than the average wood basic density at the population level.（4）Affected by the accumulation of pine resin,the basic density of wood treated with resin tapping was higher than that without resin tapping,and the influence gradually increased from pith to cutting surface.In the 11～15 years,the influence began to appear.There was a significant difference in wood density between resin-picking treatment and non-resin-picking treatment.The cutting surface was the most affected,and the density of the treated wood was 1.46 times that of the untreated wood.（5）The phenotypic correlation coefficient between wood basic density（W_d）and original amplitude（A_o）was 0.708.The regression equation(2₍（9）=0.33632+0.00635×was established to estimate the wood basic density.The estimated heritability of original amplitude was 0.462,which was higher than that of wood basic density.It has high reliability and application value in the direction of genetic improvement.