Selection Of Cross Combinations＆Clonal Test At Nursery Stage For Hybrid Liriodendron

Hybrid Liriodendron has significant heterosis, and it is an important afforestation speciesboth in mountain area and for landscaping. In this paper, to make cross combination selection, the5-6a offspring growth for each combination were analyzed based on three progeny test sites. Onthis basis, the genetic parameters of growth traits were estimated and preferable crosscombinations, along with superior individuals were selected. Finally, the clonal test at nurserystage was conducted for those clones originated from superior individuals. The main results areas follows:(1) Based on5-6a growth census data from three test sites, the annual increment of heightand DBH of hybrids Liriodendron are0.73-1.92m,1.03-2.85cm, with an average of1.35m,1.94cm respectively. The fastest growing cross combinations is M×S, with the largest annualincrement of height and DBH1.92m,2.85cm respectively (data from Jindezhen test site).(2) ANOVA results based on single site showed that there was a significant differenceamong cross combinationgs, indicating selection of superior combination would be profitable.ANOVA results based on multiple sites showed that the site×combination interaction effect wassignificant, and the site×combination interaction effect and the adaptability of5combinationswhich were apparent in3test sites were also estimated.(3) Considering family heritabilities were higher than individual heritabilities in earlygrowth traits of Liriodendron, the selection for hybrids Liriodendron should be focused on crosscombinations. According to the results of5-6a progeny test,23cross combination was selectedfor further test based on an inclusion criteria of μ+1δ, and the annual increment for DBH andheight of these selected combinations are16.3%,16.5%than that of group average.(4) Clonal test was conducted at nursery stage for276clones of hybrid Liriodendron. theresults of ANOVA showed that there was a significant difference existed among clones,indicating that clonal selection was possible. Finally,92clones were selected for next round testbased on an absolute standard on tree height, and taking account of the survival rate of each clonesimultaneously.