Abstract: According to the analysis about resistance to agression, competitive effect and synergistic effect of hybrid rice Youza 1 and its female parent Lemont, Youza 1 showed strong competitive ability over Lemont, resulted severe inhibition of tillering, panicle development of Lemont plants. It was demonstrated that there were no significant differences of grain yields when the range of the hybrid seed purities were from 70% to over 90% because of the compensation function by super competitive capacity of Youza 1.

Key words: competitive ability, hybrid rice, seed purity

摘要： 对化杀杂种稻优杂1号(Lemont/七桂早)的竞争力进行了分析。根据考种结果，杂种纯度在70%～90%以上的范围内，产量不会有明显的差异。根据侵略力、抵抗力、竞争效果、协同效果的概念及分析方法对优杂1号的竞争力进行评价的结果表明杂，种稻Le/Qi对其母本Lemont有明显强大的竞争优势。建议化杀杂种稻优杂1号这一类的杂种，其种子进行商品性生产时，其种子纯度的标准可定为70%。

关键词: 杂种稻, 竞争力, 种子纯度