落叶松是日本北部主要造林树种之一,在战后国土绿化中起到了很大的作用。但是,这些落叶松人工林的间伐材在较小龄级收获时,木材一经干燥便产生木纹扭曲,材面开裂,从而严重降低了落叶松木材的利用价值。据三上等人(1975和1980年)的试验证明,木材扭曲度与纤维倾斜度为紧密相关(r=0.75)。于是,人们提出了纤维倾斜度小的系统育种。对于这种育种的可能性,三上等人(1975年)从遗传角度探讨了如何进行扭曲度小的个体选择。其结果如图所示, Larch is one of the major afforestation species in northern Japan and played a significant role in post-war landscaping. However, when thinning woods of these larch plantations were harvested at a younger age, wood was distorted and its surface cracked as soon as it was dried, severely reducing the value of larch wood. Trials (1975 and 1980) have shown that wood twist is closely related to fiber inclination (r = 0.75). As a result, systematic breeding of small fiber inclination has been proposed. For this possibility of breeding, Third Gentlemen (1975) examined, genetically, how to make distorted individual choices. The result is shown in the figure,