论文部分内容阅读
一、选优的标准选择优树培育林木良种的方法,是一种单株选育法,它和农作物的单株或单穗选育法道理是一样的。优树叫法不一,国内有称优良单株、优良母树、正号树或加号树的。在国际上,通常称为正号树或加号树。优树用“+”号作标记,劣等树用“-”号作标记。不属于加号和减号的树木,统称为“中等树”。目前,用材树种优树的标准,国内尚没有统一的指标,有待今后研究制定。初步认为杨树选优应依下列标准:
First, the selection of the best choice of superior tree seedling cultivation methods, is a single plant breeding method, it and crop monoculture or single spike breeding method is the same. Youyoucao different, the country has called the excellent single plant, good parent tree, plus sign tree or tree. Internationally, it is often called a positive tree or a plus tree. The superior tree is marked with “+” sign and the inferior tree is marked with “-” sign. Trees that do not belong to plus and minus signs are collectively referred to as “medium trees.” At present, the standard of Timber Tree Species is not yet a unified index in China, and it needs to be studied and formulated in the future. Preliminary view that selection of poplar should be based on the following criteria: