论文部分内容阅读
选择杂种一代生长健壮而速迅的苗木,淘汰生长慢而瘦小的,从而将这些健壮的幼苗再加以培育与繁殖形成品种,这是树木选种工作的过程。经验证明:生长良好的植株,在今后仍会保持其特点。为了培育优良的新杨树品种,因而,在杂种第一年生长结束时,根据高生长加以分级。因为在一级情况下,高生长与径生长成正比,生长高的,径也粗。现将苗木高生长与径生长的比较列表如右:
Select a generation of hybrid robust and rapid growth of seedlings, out of slow growth and thin, so these robust seedlings and then to nurture and breed to form varieties, which is the process of tree selection. Experience has shown that plants that grow well will retain their character in the future. To breed good new poplar varieties, therefore, the grading is based on high growth at the end of the first year of hybrid growth. Because in the first case, high growth and diameter growth is proportional to the growth of high diameter coarse. Now seedling height growth and diameter growth of the list as follows: