Abstract: The regulation of GA₃ and PP333 applied at initial heading stage on rice grain filling characteristics was studied in some hybrid rice combinations and conventional rice varieties. The results indicated that the panicle apical dominance could be enhanced by application of GA₃ and inhibited by PP333. GA₃ treatment could increase 1000-grain weight with low seed-setting rate, eventually decrease the grain yield of hybrid rice. PP333 application at initial heading stage could increase grain yield both in hybrid rice and in conventional varieties. High concentration of GA₃(>30 mg/L) and PP333 (>50 mg/L) treatment could have negative effects on grain yield. The two-component plant growth substance, Lilibao (meaning every grain will be filled), were formulated.

Key words: rice, apical dominance, seed set, plant growth regulator

摘要： 以杂交水稻为主要参试材料，辅之以常规稻品种进行了外源植物生长物质调节水稻“粒间顶端优势”的试验。于水稻初穗期施用浓度为10 mg/L的GA₃可增强单穗粒间顶端优势，虽增加粒重，提高结实率，但效果不稳定，有些处理反有下降，且多数杂交水稻未获增产，仅提高常规晚粳稻产量。于水稻初穗期施用浓度为10 mg/L的PP333可抑制单穗粒间顶端优势，增加每穗实粒数，提高结实率和千粒重，增加杂交稻和常规稻产量。此外，高浓度GA₃或PP333（GA₃≥30 mg/L，PP333≥50 mg/L）均可能引起水稻减产。将GA₃和PP333适当复配后，研制成二元植物生长物质“粒粒饱”。

关键词: 水稻, 顶端优势, 结实, 植物生长调节剂