华北落叶松无性系结实能力变异与无性系再选择

为解决华北落叶松种子园种子数量少，空粒比例大，生产成本高，繁殖效率低的实际问题，对种子园无性系结实量的变异及选择利用问题进行了研究。结果表明：种子园无性系间结实量差异显著，无性系内分株间结实量差异不显著，遗传因素对结实量的影响远大于种子园内小环境的影响。与树高、胸径、材积、木材密度等性状相比，结实量受遗传因素控制程度高，无性系间变异幅度大，选择利用潜力也大。无性系结实量与年份间交互作用显著，无性系间结实周期不一致，正确评价结实量需进行年份间重复观测。结实量与子代生长不相关，种子园无性系再选择的正确途径是“结实能力一子代生长”联合选择。按27％的入选率进行种子园无性系再选择，可使单株种子产量提高1．5倍以上，并能显著提高种子品质和降低生产成本。

Genetic Variation in Seed Production and Re-selection of Clones in Seed Orchard of Larix principis-rupprechtii Mayr

Low seed production, high empty seed ratio, high production cost and low reproduction efficiency are major problems in seed orchard of Larix principis-rupprechtii Mayr. Clonal variation and selection of seed production trait in seed orchard of Larix principis-rupprechtii Mayr.were studied.There were significant differences in seed production among clones. However, no differences were found within clone.Moreover,the effect of genetic control was stronger than the effect of environmental factors.Clonal variation was significantly higher in seed production than other Clonal characteristic, e.g., height, diameter, volume, density and etc. therefore, there is a selection potential of seed production trait because of high genetic control. There was a significant interaction between seed production and year. There was also an inconsistence in seed-bearing interval.Therefore, accurate estimate of seed production needs repeat observations by years.There is no relationship between seed production and progeny performance.Therefore, proper selection of superior clones should combine seed production and progeny performance. If the re-selection of clones in seed orchard of Larix principis-rupprechtii Mayr.is by ratio of 27%, seed production of individual tree could be increased more than 1.5 times. Furthermore, the quality of seeds would be significantly increased and the production cost could be significantly lowered.