Study On Multiple Selection And Genetic Improvement Of Chinese Fir Clones For Growth And Wood Property

In this paper, 12 years old Chinese Fir clones were studied on the genetic variation of growth properties, basic density and tracheid morphological characteristics. The main results were as follows.(1)The distinctive differences in tree height, diameter at breast height, tree volume and wood basic density were found among most Chinese Fir clones. The clonal repeatabilities of the main growth properties and basic density were highly under genetic control. In the last annual ring, the variations of tracheid length, tracheid width, ratio of length to width, double cell wall thickness, cavity-diameter, ratio of cell wall to cavity and microfibril angle were obviously different among clones, while the variations of cavity - circularity and cavity - rectangle were not. The differences of cavity - perimeter andcavity - area were significant only among some clones. (2) From the pitch outwards, the basic density firstly decreased and then increased with the annual ring. The tracheid length, tracheid width, ratio of length to width,double cell wall thickness, cavity-diameter, cavity - perimeter, cavity - area and cavity - circularity increased with the annual ring, contrarily, cavity - rectangle and microfibril angle decreased. The radial variation of ratio of cell wall to cavity was very complex. Liner regression equations could be ideally established between annual ring and average value of all the properties except basic density and ratio of cell wall to cavity. (3)Wood basic density had a significant, negative genetic correlation with tree volume and tracheid length, and had no significant correlation with tree height, diameter at breast height, ratio of length to width and ratio of cell wall to cavity. Significant, negative genetic correlations were also found between the main growth properties and tracheid length, ratio of cell wall to cavity. There was a weak negative genetic correlation between the main growth properties and ratio of length to width. (4) 6 superior clones were selected by the means of simple index selection. They provided not only superior clones for plantation, but also scientific basis for clone breeding.