Abstract: The effect of GA₃ on plant height in 47 lines with different semidwarf gene was presented. The plant height of the lines with sd-1 gene is sensitive to GA₃, but this responses is not significant in lines possessing semidwarf gene non-allelic to sd-1 gene in indica rice. It indicated this responses could be regard as a new simple approach to identify sd-1 gene in indica rice. In japonica rice, the lines possessing d-47,d-7,d-12,d-13,d-14,d-18^h,d-19 and d-30 genes are sensitive to GA₃ in plant height, and the lines with d-1,d-2,d-3,d-17 and sd-s(t)genes are not sensitive toGA₃. The effects of GA₃ on different components of the plant height are different among semidwarflines. The 3rd and 4th internodes from the top have most significant responses to GA₃ among the plantheight components.

Key words: Semidwarf rice, Gibberellic acid, Semidwarf gene, Plant height component

摘要： 就47个水稻矮秆品种对GA₃的反应进行了研究，结果表明，在籼稻中凡携带有sd-1基因位点的材料其株高对GA₃反应均较敏感，而株高对GA₃反应迟钝甚至无反应者均可推断其携带有与sd-1非等位的矮生基因，这将可作为鉴别sd-1基因位点的一种新的简捷方法；在粳稻中，具有d-47、d-7、d-12、d-13、d-14、d-18^h、d-19、d-30位点的矮秆材料其株高对GA₃反应敏感，而具有d-1、d-2、d-3、d-17和sd-s(t)等13个矮秆基因位点的材料其株高对GA₃反应不敏感：GA₃对各株高构成因素的影响随材料不同而异，但第III、IV节间对GA₃的反应最明显。

关键词: 水稻, 赤霉素, 矮生基因, 株高构成