Genetic Variation and Selection for Wood properties in Pulpwood Hybrid poplar.

Key words: 
• hybrids /
• Populus /
• wood property /
• variaiton(genetics)

Abstract: The 12-year-old tree height (Ht),DBH(Dt) and volume(Vt) of 14 clones from Suihua poplar test plantation in Heilongjiang were examined.Diameter(Dr),specific gravity(Sg),fiber length(Lf),widness(Wf),ratio of Iength to widness(Lw),(double)wall thickness(Tf),lumen diameter (Df)and ratio of wall thickness to lumen diameter (Td) for each 2-year's growth ring of the cores which extracted from sampled trees at breast height from bark to pith were evaluated.Analysis of variance showed significant differences among clones for all traits.The best clone exceeds the worst one by 106%~20%.Reapitabilities calculated on plot mean basis(Rc) for Ht,Dt and Vt are 0.85,0.62 and 0.64 respectively,whereas reapitabilities on clone mean basis (Rc)for sg,Wf,Tr and Td are 0.91 or more,forDr,Df and Lw0.56 or more,for Lf 0.63.The high parameters indicate the strong inheritance of these traits.Dr,Lf and Lw were linearly regressed to age,Sg and Wf were curvely regressed to age.The gains from single trait selection based on 12-year-old's phenotypes were ranged from 25.2% for Vt to 3.4% for Lf.The gain from combined(Vt,sg,Lf,,Wf,and Tf)index selection was as high as 31.9% when the best 3 clones were selected. .............................................................................,fiberlength(LJ),widness(矶),ratio ofIengthtowidness(L。),(double)wallthiekness(T,),lumendiameter (Dz)andratioofwallthieknesstolumendiameter(Td)foreaehZ一year,s growthringoftheeoreswhiehextraetedfromsanlpledtreesatbreastheight frombarktopithwereevaluated.Analysisofvarianeeshowedsignifieant differeneesamongelonesforalltraits.Thebesteloneexceedstheworst oneby106%~20%.ReaPitabilitiesealeulatedonPlotmeanbasis(R`)forH,, D,andV,are0.55,0.62and0.64respeetively,whereasreapitabilitieson elonemeanbasis(R:)fors。,平,,TrandTdare0.91ormore,forDr,DI andL。0.56ormore,forL,0.63.Thehighparametersindieatethestrong inheritaneeofthesetraits.刀r,L,andL口werelinearlyregressedtoage,aS andw,wereeurvelyregressedtoage.Thegainsfromsingletraitseleetion absedon12一year一old,5phenotypeswererangedfrom25.2%forV,to3.4% forL,.Thegainfromeombined(F,,s。,石,,万,,石,andT,)indexseleetion wasashighas31.9%whenthebest3eloneswereseleeled.