日本落叶松木材性状与生长曲线参数的关系及其种源变异对降水的响应

Understanding the genetic variation in wood traits and their relationships to growth traits and environmental variables is essential for the genetic improvement of forest tree species.The aims of this study were to investigate the variation in wood traits and their relationships with growth curve parameters and to identify the main climatic factors affecting wood traits.Fifteen wood anatomical and wood chemical traits and annual growth traits were measured in 450 Larix kaempferi(Lamb.)Carr.(Japanese larch)individuals from six provenances.Linear mixed models and Pearson correlation analysis were used to estimate the genetic parameters of these traits as well as the correlations between wood traits and growth curve parameters of tree height and diameter at breast height.Linear regression analysis and the Mantel test were used to examine the relationships and the correlation strength between climatic variables and wood traits.Most wood anatomical traits varied significantly among different provenances,with heritabilities(ℎ𝑖2 = 0.07 to 0.65)generally higher than those of wood chemical and growth traits(ℎ𝑖2 = 0.01 to 0.17);the ℎ𝑖2 of earlywood anatomical traits(0.09 to 0.65)were higher than those of latewood anatomical traits(0.08 to 0.45).Among the traits with significant provenance variation,wood fiber length was positively correlated with the maximum growth value of tree height,and wood fiber width was positively correlated with the diameter at breast height.Precipitation variables were significantly correlated with most of the traits,including EWFW,LWFW,EWFL_W,LWP and BD(Figure 2a).Spatial variables showed significant correlations with EWFL,EWFL_W,and LWP.Temperature variables showed significant correlations with EWFL_W and LWP.Strong correlations and predictive trends were observed between earlywood fiber width and spring precipitation(R2 = 0.45 and 0.78),as well as latewood fiber width and summer and fall precipitation(R2 = 0.55 to 0.80).Wood anatomical traits of earlywood presented high heritability values with high selective accuracies.Significant genetic correlations were found between maximum value,growth rate of tree height and wood fiber length,and between maximum value of diameter at breast height and wood fiber width.Hence,earlywood fiber dimension is an important reference phenotype for breeding and recurrent selection of L.kaempferi.Fiber width and length-to-width ratio of earlywood fiber and wood basic density had strong predictive relationships with precipitation variables.In the process of long-term adaptation to different environments,the genetic composition and phenotype of the fiber width and length could be shaped by precipitation in different provenances.For the introduction of L.kaempferi with different breeding purposes,we provided a reference of precipitation range.These findings provide guidance and empirical support for L.kaempferi breeding programs in the context of current climate change.