Abstract: The difference of lodging resistance for nine japonica rice varieties from northern China with different panicle types was studied. The results showed that lodged culms frequently bend at the second or third internodes, 20 to 40 cm above the ground. The lodging index was significantly and positively correlated with the length of basal internodes and the culm length. Significantly positive correlations were also found between the fresh weight of culm from different internodes to the top, long or short external diameters, area of cross section and breaking resistance, bending moment. The panicle length significantly affected the bending moment of various internodes. Significantly positive correlations were also noted between the fresh weight of panicle, and breaking resistance, bending moment. The neckpanicle angle had no significant effect on the lodging index. For a certain variety, curved panicle doesn′t mean poor lodging resistance. Lodging resistance of varieties varied with the region and variety, therefore, the index should not be evaluated only based on panicle type. In general, rice varieties with erect and semierect panicle from northern China had smaller lodging index and stronger lodging resistance than those with curved panicle. The reasons were as follows: firstly, the varieties with erect and semierect panicle were dwarf with short basal internodes, which increased their lodging resistance; secondly, for the varieties with erect panicle, lodging resistance of basal culm was strong; finally, with short and light panicles, the varieties with erect and semierect panicles had slight bending degree of panicle neck, which reduced the force to stalk. In addition, the relationship between ecological environment, characteristics of varieties, panicle type and lodging resistance were also discussed.

Key words: rice, panicle type, bending moment, lodging index, lodging resistance

摘要： 选用北方稻区9个不同穗型粳稻品种为材料，初步探讨了不同穗型粳稻品种间抗倒伏性的差异。倒伏多发生在距地面20~40 cm的第2、3节间。基部节间长与倒伏指数呈显著正相关；秆长与倒伏指数呈显著正相关；节至顶鲜质量、长短外径、截面面积与抗折力和弯曲力矩均呈显著或极显著正相关；穗长显著影响各节间的弯曲力矩；穗鲜质量与各节间抗折力、弯曲力矩呈显著正相关；穗颈角对各节间倒伏指数影响不显著。就单个品种而言，弯曲穗型内也存在抗倒性强的品种，不能单纯以穗型来评价品种抗倒性，应综合考虑品种的地域性及品种自身的特性。但从总体水平分析，北方稻区直立、半直立穗型粳稻品种比弯曲穗型品种倒伏指数小，抗倒性好。主要原因在于：直立、半直立穗型品种株高偏矮，基部节间短，更有利于抗倒；直立穗型品种基部茎秆抗倒性状表现良好；直立、半直立穗型品种穗短、轻且穗颈弯曲度小，对茎秆作用力小。此外，还讨论了生态条件、品种特性、穗型与抗倒伏性的相互关系。

关键词: 水稻, 穗型, 弯曲力矩, 倒伏指数, 抗倒伏性