水稻是雌雄同花,白花授粉作物。当前主要采用“三系法”配制杂交稻,利用其杂种优势,如生产上现已广泛使用的“汕优二号”等。培育三系杂交稻要经过长期复杂的育种程序,选育出“不育系”、“保持系”和“恢复系”,缺一不可。这在选择亲本,配制组合上受到一定限制。为摆脱这一束缚,近来育种工作者采用了化 Rice is monoecious, white pollination crops. At present, the hybrid rice is mainly formulated by the “three lines method”, and by utilizing its heterosis, such as “Shanyou No.2” that is now widely used in production. To cultivate three-line hybrid rice through long-term complex breeding program, breeding “sterile line”, “keep line” and “restore line” are indispensable. This is in the choice of parents, preparation of combinations subject to certain restrictions. To get out of this bond, breeders have recently adopted it