Main traits observation of young growth family and superior family selection of Neolamarckia cadamba

Forty trees of Neolamarckia cadamba were chosen from Yunnan，Guangxi and Guangdong province in 2011，and then contrast test was performed through family afforestation in May 2014. The results from survey in Jan 2015 showed that there were extremely significant differences among families on the tree height（H），ground diameter（GD），individual tree volume（V），height under branch（BH），crown diameter（CD）， the ratio of crown diameter to ground diameter（RCDGD），and the ratio of height to height under branch（RHBH）. The family heritability of all traits were higher than 0.50，which indicated that an extensive selection potential existed among families. For the given traits，many of them had significant positive phenotypic and genetic correlations with each other，which were favorable for the comprehensive selection with multi-traits. On the base of traits -combining selection，a selection index equation was constructed. Under 10% selection pressure，four superior families were chosen. Compared with the trait mean of control（CK），the expected genetic gains on H，GD，V，BH，CD，RCDGD and RHBH of the four selected families were 17.34%，20.49%，46.20%，20.39%，13.47%，2.45% and -8.95%， respectively.