依据生长和材性指标的滇楸优良无性系选择OA

To explore the variation characteristics and genetic regularity of growth and wood property traits among 22 Catalpa fargesii f.duclouxii clones,screen high-quality clones,and provide basic materials for the popularization of improved C.fargesii f.duclouxii varieties,a study was conducted.Twenty-two 14-year-old clones preliminarily selected in early-stage research were used as test materials.Twelve traits were measured,including growth traits(tree height,diameter at breast height,crown width)and wood property traits(moisture content,ethanol-benzene extractive content,lignin content,α-cellulose content,holocellulose content,air-dried density,absolute dry density).Additionally,stem volume and hemicel-lulose content were calculated.Genetic parameter estimation,analysis of variance(ANOVA),correlation analysis,and principal component analysis(PCA)were adopted to conduct comparative analysis,comprehensive evaluation,and selec-tion of the 12 traits across the clones.The results showed that except for air-dried density,oven-dried density,and diame-ter at breast height,extremely significant differences were detected in the other traits among the 22 clones.The coefficient of variation(CV)of all traits ranged from 3.35%to 40.32%.Among these traits,stem volume exhibited the highest CV,while holocellulose content had the lowest.The repeatability of the 22 clones varied from 0.126 to 0.999.Specifically,the repeatability of chemical composition traits was as high as above 0.950,and that of tree height and crown width exceeded 0.720.Weak correlations were observed between growth traits and wood property traits.Within growth traits(tree height,diameter at breast height,stem volume,crown width),all pairwise traits showed extremely significant positive correlations except for the non-significant correlation between tree height and crown width,with the strongest correlation found between diameter at breast height and stem volume.Among wood property traits,extremely significant positive correlations were identified between density-related traits and among some chemical composition traits.Principal component analysis indica-ted that the first four principal components accounted for 79.000%of the total variance,retaining most information of the 12 traits.Using the contribution rate of each principal component as the weight coefficient,clones were ranked by their comprehensive scores(F values).With a 20%selection rate,5 elite clones were screened out,namely DQ010-8,DQ020-3,DQ049-1,DQ134-1,and DQ148-1.The average values of tree height,diameter at breast height,stem volume,and crown width of the selected elite clones were 12.97 m,20.86 cm,7.79 m3,and 5.50 m,with corresponding genetic gains of 78.84%,54.61%,82.68%,and 79.80%,respectively.The average values of ethanol-benzene extractive content,lig-nin content,holocellulose content,hemicellulose content,air-dried density,and oven-dried density were 9.02%,31.80%,63.89%,19.33%,0.49 g·cm-3,and 0.44 g·cm-3,with genetic gains of 0.62%,1.80%,0.23%,1.42%,0.26%,and 0.48%,respectively.