Abstract: By using the parents,Kunmingxiaobaigu,a landrace variety with cold-tolerance from Yunnan,China,and Towada,a cold-sensitive variety bred in Japan,as well as their F₈ and F₉(RIL) progenies as tested materials,cold tolerance of rice at the booting stage in 2002 and 2003 under four different altitudes(environments),and the correlationship between spikelet fertility and specific spikelet fertility(spikelet fertility of nine spikelets from the 3rd to the 5th spikelets of three primary branches at the top of each panicle) of single plant were analyzed.Variance,correlation and stepwise regression analysis revealed that there was significant correlationship between spikelet fertility and specific spikelet fertility with the range from 0.7364 to 0.9011.However,under the cold stress conditions,the correlation coefficients were higher than those without cold stress.Panicle exsertion was correlated to both spikelet fertility and specific spikelet fertility.It was suggested that specific spikelet fertility could replace spikelet fertility as an indicator and panicle exsertion be used as an assistant indicator for cold tolerance identification at the booting stage.

Key words: rice(Oryza sativa), spikelet fertility, cold tolerance, indicator of identification

摘要： 以十和田与昆明小白谷的重组自交系（RIL）F8和F9群体为研究材料，在4种海拔条件下连续两年进行孕穗期耐冷性鉴定，采用方差分析、相关分析和多元逐步回归分析等方法对单株结实率与单株特定位颖花结实率间的相关性进行了研究。结果表明，单株结实率与特定位颖花结实率呈极显著相关（r=0.9011~ 0.7364），在低温冷害条件下，单株结实率与特定位颖花结实率间的相关系数高于无冷害条件；单株结实率和特定位颖花结实率与穗抽出度均呈极显著正相关。遗传分析表明，特定位颖花结实率可以替代单株结实率作为孕穗开花期耐冷性鉴定指标，而穗抽出度可作为孕穗开花期耐冷性鉴定的一个辅助指标。

关键词: 水稻, 单株结实率, 耐冷性, 鉴定指标