本试验采用双列式杂交方法,观察了以IR₂₆、IR₃₆等为代表的抗性品种的杂交优势。结果表明:杂交组合F₁代在分蘖末期抗性无优势,穗期抗性优势明显;F₂代两期鉴定正负向均有优势;F₁和F₂代均表现出正负向完全显性,部份显性,少数组合无显性。其中大都属于部份显性。优势指数分析也证明,对抗性亲本,优势指数d ≥ 1;对感病亲本,优势指数d<1。抗感品种杂交,其子代的抗性一般界于双亲值之间。这种优势可依亲本的抗性进行预测。

The heterosis of rice resistant varieties to bacterial blight have been observed by means of double cross method. The results indicated that the resistance at the end of tillering period of F1 showed no heterosis. The heterosis was significant at heading period, For F2,the heterosis had both positive and negative types, For the combination of Fl and F² complete dominance or partial dominance was observed. Most of them were clearly, some of them were the later. According to index of heterosis, the heterosis of resistance of crosses was also predicted. It was d ≥ 1 for resistant parents, but d<1 for susceptible parents. This heterosis could be predicted by the resistance of their parents.