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采用具有优良遗传特性的种籽,对于创建高产林分,是一个必不可少的条件。为此,就要建立母树林和种籽园,以做为固定性林木良种基地。鉴于母树林中植株间在单株产籽量上是互有差异的。因而,选择产籽量高的植株,能够提高母树林的生产能力。可是,由开始达到结果年令的,15～20年生的植株上得到的种籽,成本太高;而为了使林分在临近结果的几年中能郁闭成林,疏林进行得迟晚;另外,规定的管理措施,对于进入正常结果年令的林分,也可能只会引起减少结籽量的效果。在处于结果前的阶段,显示种籽高产的生殖形态特征,在植株上尚未出现,这时要选择高产植株就无法实现;然而,要求按选种理论创建固定性良种基地,却必须弄清楚这一事实。
The use of seeds with excellent genetic characteristics is an indispensable condition for creating high-yield stands. To this end, we must establish a mother tree and seed garden, as a fixed tree seed base. In view of the fact that there is a difference in seed yield per plant between the plants in the parent tree. Therefore, the choice of high-yielding seed plants, can increase the production capacity of the parent forest. However, the cost of planting seeds from 15 to 20 year-old plants that begin to reach the year of the result is too high. In order to keep the forest stand closed for several years in the immediate vicinity, In addition, the prescribed management measures may only have the effect of reducing the yield of seeds in the stands entering the normal year of results. At a pre-stage stage, reproductive morphological characteristics that show high seed yield have not yet appeared on the plant, and high-yielding plants can not be achieved at this point; however, the requirement to create a fixed seed base by selection theory must be clarified A fact.