象水稻这样的一朵花结一粒种子的“单颖果作物”,是不是制种困难,不适于生产应用?这曾是一个长期有争议而没有得到解决的问题。日本等国研究水稻杂种优势利用比我国早,但至今未用于生产,其原因除不育性不够稳定,优势不够明显外,还和繁殖制种技术没有很 Is not it difficult to plant seeds and not suitable for production and application? This is a long-debated and unresolved issue. Japan and other countries to study the utilization of rice heterosis earlier than our country, but has not been used for production, the reason is not stable enough sterility, the advantage is not obvious enough, but also breeding and seed production technology is not very