Genetic variation of growth and form in Schima superba provenances with selection for wood processing materials

Key words: 
• forest tree breeding /
• Schima superba /
• provenance /
• growth /
• form traits /
• geographic genetic variation /
• selection index /
• wooden processed materials

Abstract: To aid in wood processing with superior Schima superba stock，provenance differences，geographic variation patterns，and genetic correlation of growth and form traits in provenance trails of five-year-old trees located at Jian’ou，Fujian Province and Chun’an，Zhejiang Province were determined using the variance，simple correlation and genetic correlation analysis. A random block design with five replications was applied in the trials，and the traits survey was conducted in December of 2007. Provenance broad-sense heritability and selection index were estimated with the quantitative genetics methods. Results showed signi-ficant differences between provenances for height（P＜0.05），DBH（P＜0.05），stem straightness（P＜0.05），total number of primary branches（P＜0.01） and length（P＜0.05），and diameter of primary branches（P＜0.05）. These traits were under moderate or even strong provenance genetic control with a provenance broad-sense heritability that varied from 0.34 to 0.61. No significant differences for stem bifurcation or maximum branch angle were found. The correlation analysis at Jian’ou （the central distribution area） showed a classic latitudinal clinal variation pattern with main growth and form traits negatively（r = － 0.313 to － 0.534） and significantly （P＜0.05） related to seed source latitudes. At the more northern Chun’an the total number of primary branches was negatively （r = － 0.380） and significantly （P＜0.05） related to seed source latitude. A significant （P＜0.05），positive（r = 0.320 to 1.164） relationship was found for the main growth and form traits in both locations，whereas stem straightness was not correlated to primary branch length. Based on the two selection indexes of：1） equal and 2） growth-emphasized economic weighting，10 superior provenances were selected with most superior provenances for Jian’ou in southern areas and for Chun’an in central areas. ［Ch，6 tab. 16 ref.］