Genetic Variations in Growth Traits of Juvenile Stage Hybrid Larch in Southern Xiaoxing'an Mountains and Selection of Superior Families

Genetic variations,variance analysis,and correlation analysis were carried out on the growth traits(including tree height,diameter at breast height) of larch hybrids in an experimental forest in southern Xiaoxing`an Mountain,China.The results showed wide ranges of tree height variation were observed among 7-,5-and 3-year-old larch hybrid families with variation coefficients of 20.90%,26.40% and 26.96%,respectively.With the increase of tree age,the overall variations of height and DBH gradually decreased.Very significant and positive correlations were found among the tree height and DBH with different ages,and between the tree height and width.The Pearson correlation coefficients of height between 3-year-old and 5-,7-year-old trees were 0.713 and 0.578,respectively.The larch hybrid families haa a stable performance in the juvenile stage.A preliminary selection could be carried out among the trees with 7 years old.L.gmelinii × L.kaempferi and L.kaempferi × L.gmelinii had the outstanding performance.Their tree height(and DBH) were 10.0%(22.9%) and 5.2%(18.1%) respectively higher than Wuyiling(Larix gmelinii) provenance.Five larch hybrid families were selected as the superior ones.The heritability of height and DBH were 0.652 and 0.606.The genetic gains of them were 7.83% and 12.53%.The average height and DBH of 5 superior families were 9.97% and 26.20% higher than those of Wuyiling provenance.