But seed orchards are difficult to control,because tree pollen spreads so far that alien,non-elite trees almost inevitably muddy the gene pool.

 
  • 但是有种子的果树很难控制,因为花粉传播的太远了,一些其它种类的树木就会不可避免地弄乱此基因库。
今日热词
目录 附录 查词历史