不同疏枝方式对降低华北落叶松种子园.doc

疏枝对华北落叶松种子园结实的影响 Effect of branch-thinning on seed quality and production from a seed orchard for Larix principis-rupprechtii (Mulanweichang National Forestry Administration of Hebei Weichang County, 068450 摘要：该试验对华北落叶松种子园在进入结实盛期后，采取不同的疏枝方式，对降低大小年现象及种子品质做了初步的测定试验，其结果表明，通过人工疏枝措施，可降低明显的大小年现象，提升种子品质。在同一个无性系中选择出不同的5个单株，分别对5个单株采取不同的疏枝措施，强度由小到大，分别去掉母树主枝的1/4、1/3、1/2、2/3和对照，随着疏枝强度的加大，翌年和后年（小年）的结实量呈正相关，种子品质也相应提高。 关键词：华北落叶松 疏枝 种子园 结实 Abstract: In the present study, an initial-step trial was conducted to test the potential possibility for decreasing the risk of declined seed production driven by alternatively annual cycles controlling production through branch-thinning (BT) at gradient intensities in a seed orchard of Larix principis-rupprechtii (Huabei Larch). Also, quantified were seed quality and production. Briefly, BT can obviously weaken the impact on declined seed production driven by alternatively annual cycles, hence improved seed quality. Specifically, five units of transplanted Huabei larch trees from one clonal group were chosen and marked to receive BT treatment. Four BT treatments of “1/4”, “1/3”, “1/2”, and “2/3” were employed at gradient intensities in which one quarter, one third, one half, and two thirds of the main branches were thinned by cutting, respectively, with one untreated control. As a result, both seed production and seed quality were enhanced with the intensity of BT treatment on units marked using a label from control to the “2/3” treatment in the second and the third years post treating, although the third year had been predicted to be a low-production-season. Key words: Larix principis-rupprechtii, branch thinning, seed orchards, seed production, seed quality 华北落叶松因具有抗寒、抗旱、速生、优质、耐腐朽等优点，使其成为华北地区的主要造林树种之一。但是，由于其生物特性所致，结实大小年现象十分明显，每隔3-5年才产生一个结实大年，制约了良种的生产与利用。近些年，木兰林管局龙头山种苗场一直致力于此项工作，为了探讨降低大小年现象的有效途径，本文比较了不同疏枝处理强度对华北落叶松翌年和后年（小年）的结实量和种子品质的影响。通过疏枝的方式影响种子结实，在园艺果树领域应用比较广泛，但在华北落叶松种子园建设中试验得很少，国内外也缺少对此的深入研究，本文对创新华北落叶松种子园促进结实方式提高种子品质将发挥一定的积极作用。 1、试验区域自然