Effects of rogue thinning on genetic diversity by SSR in a Larix olgensis clone seed orchard

To find out the changes of genetic diversity in the Larix olgensis Henry elementary clone seed orchard after rogue thinning,the genetic diversity of 38 L.olgensis clones(260 individuals) in Qingshan orchard were studied by using 14 pairs SSR primers.According to the individuals’ ability of growth,bearing and their progeny,the simulation thinning activities with intensity from 10% to 60% were conducted,and the changes of genetic diversity parameters before and after thinning were analyzed by POPGENE3.2.The results show that the reduction level of genetic diversity was positive correlation with the thinning intensity,the thinning intensity less than 40% affected genetic diversity of clones slightly(reduction was less than 0.5%) and can maintain the orchard’s broad base of genetic.If the genetic diversity of one clone is preserved,at least 7~9 individuals need to be reserved,in accordance with the preservation rate of 60% after thinning,at the beginning of building a L.olgensis orchard,each L.olgensis clone needs to consist of more than 12~15 individuals.