中文摘要：

对青山林场14年生落叶松杂种F2代2组子代测定林进行分析，探讨杂种落叶松F2代是否存在较大的分离，杂种后期生长优势能否保持。试材包括日本落叶松×兴安落叶松、日本落叶松×长白落叶松、兴安落叶松。日本落叶松。研究结果表明，杂种F2代的树高同F1代相比未存在较大分离，变异系数平均只增加了2．3％和5．8％，杂种优势稳定且具有较大生产潜力，营建杂种F1代种子园是我国高寒地区大量生产具有较高遗传增益杂种种子的途径之一。7个杂种F2代家系树高、胸径和材积家系内存在一定幅度的变异，变异系数随着树木年龄的增加而减小，14年、8年、7年和6年生树高的变异系数分别为17．6％、22．1％、23．9％和24．3％。15个杂种R代家系随着树木年龄的增长，增产幅度呈下降趋势，但仍具有较大的杂种优势。以小北湖种源作参照，14年生高生长比8年生下降了18．5％，相比于长白落叶松种子园则下降了10．3％，杂种优势下降了2．4％，但14年生杂种F2代生长优势仍然明显，树高、胸径和材积分别超过优良种源小北湖28．1％、43．8％和123．8％，超过长白落叶松种子园7．8％、15．7％和33．8％，杂种优势为7．1％、4．1％和12．1％。7个杂种F2代家系树高、胸径、材积遗传力较高，属于强度遗传，遗传增益都在10％以上，材积的遗传增益高达33％，所以杂种落叶松F2代仍可以利用。

英文摘要：

In this paper, two progeny trials of F2 hybrid larch（ Larix ） in 14 years old from Qingshan Forest Farm, including the materials of Larix kaempferi × L . gmelinii , L . kaempferi × L . olgensis and L . gmelinii × L . kaempferi , were studied in order to know their separation in F2 generation and growth heterosis in later stage. The result shows that there is no great separation in height growth of F2 generation compared with F1 generation, and the average of their variation coefficient only increases 2.3 % and 5.8 % . That means the hybrid larch is good in both of heterosis stability and growth potential. Therefore, establishing F1 hybrid seed orchards is a good way to produce hybrid seeds with higher genetic gain in cold area of China. Also, some differences in height, diameter and volume for each family exist among 7 F2 families, whose variation coefficient decreases along with the tree age, with 17.6%, 22.1%, 23.9% and 24.3% in 14, 8, 7 and 6 years old separately. This heterosis is also in existence among 15 hybrid families, although it is lower. The height growth of hybrid F2 in 14 years old is 18.5% lower compared with that in 8 years old, and 10.3% lower compared with materials from seed orchards of L. olgensis, whose heterosis decreases 2.4%. Taking Xiaobeihu provenance as control, the growth potential of hybrid F2 in 14 years old is obviously higher, whose gn）wth in height, diameter and volume exceeds Xiaobeihu provenance in 28.1% ,43.8% and 123.8%, and exceeds seed orchards of L. olgensis in 7.8%, 15.7% and 33.8%, whose heterosis is 7.1%, 4.1% and 12.1% respectively. Higher heritability can be seen among 7 hybrid families, who have gotten 10% genetic gains in height and diameter growth and 33% genetic gain in volume. For this reason, it is possible to use hybrid larch in second generation in forestry production.