Study on Variations of Growth Traits of Pinus sylvestris Clones in Maowusu Sandland of Yulin Municipality

The height,DBH,crown size growth of the Pinus sylvestris var.monglica clones were investigated and analyzed in order to understand the growth variation among the clones.The variance analysis on growth traits of the clones showed that there were significant differences among clones and insignificant differences within the clones.The variation among the average value for the studied growth traits within clones was much smaller than that of among the clones,which demonstrated that the growth traits were mainly controlled by genetic factors.The repeatability values of the average height,DBH and crown diameter were 0.399-0.497,0.132-0.201 and 0.179-0.182 respectively,indicating that the height index had the greatest repeatability.The multi-comparison of height values showed that the clones No.7.No.9,No.1,No.2 and No.10 were superior,the average height of these clones exceeded the mean value of all the studied clones by 14.41% in the first and third district.The clones No.34,No.7,No.26,No.49 and No.51 were even better,the average height value of these clones exceeded the average value of the clones in the fifth and the sixth district by 28.65%.