Abstract: Three combinations (Milyang 23/Tong 88-7, Milyang 23/TR22183, Milyang 23/Gaochan 102) between indica and japonica rice cultivars were used to analyze responses of some agronomic traits to cold selection at seedling stage. Cold water responses of selected individuals or lines for higher seedling cold tolerance to some agronomic traits were compared with those of unselected individuals or selected lines for lower seedling cold tolerance in F₂ and F₃ generations. There was no significant difference in culm length, panicle length and panicles per plant between the selected and unselected F₂ individuals by leaf discoloration at seedling stage through cold treatment, but spikelet fertility under cold water irrigation in the selected population by seedling cold tolerance was significantly higher than that in the unselected. The selection by cold tolerance at seedling stage in F 3 lines generally led to increase both cold tolerance for leaf discoloration at tillering stage and seed setting rate under cold water irrigation. Grain yield of F₃ lines selected for high seedling cold tolerance was much higher than that of lines selected for low seedling cold tolerance under cold water irrigation.

Key words: rice, seedling stage, cold tolerance, seed setting rate, agronomic character

摘要： 利用籼粳稻杂交后代（密阳23/通88-7、密阳23/TR22183、密阳23/高产102）探讨了水稻幼苗期耐冷性选择对主要农艺性状的影响。从籼粳稻杂交后代F2和F3中选择的耐冷个体群或系统群与随机个体群或敏冷系统群间进行主要农艺性状的比较结果表明，在F2和F3水稻幼苗期耐冷性选择对秆长、穗长和穗数并不产生显著的影响，但选择获得的幼苗期耐冷性强的F2个体群的孕穗期耐冷性(结实率)、F3系统群的分蘖期耐冷性(赤枯度)和孕穗期耐冷性(结实率)均显著强于随机个体群和敏冷系统群；在冷水处理下F3幼苗期耐冷性强的耐冷系统群的产量显著高于敏冷系统群。提出在水稻幼苗期以叶赤枯度来选择幼苗期耐冷性强的个体是获得高产耐冷后代材料的有效途径。

关键词: 水稻, 幼苗期, 耐冷性, 结实率, 农艺性状