Abstract: Aiming at the selection and breeding of cold tolerance of hybrid rice cultivars, we investigated the effects of chilling on five hybrid rice combinations. The results indicated that cold tolerance was different among these hybrid rice varieties. The order of cold tolerance (in decrease) expressed by the degrees of root electrical conductivity, transitional green of etiolated seedling and survival rate of seedling after chilling treatment was as follows: Japonica type Xiu-You 57, Indica type Qing-You-Zao, Shah-You 63, Shan-You 64 and Wei-You 64. The increase of relative electrical conductivity of root and relative decrease of chlorophyll content were in agreement with the survival rate of seedlings. Cold tolerance of hybrid progeny was similar to that of maternal lines but not similar to paternal lines. Cold telerance of maintainer lines was similar to that of the male sterile lines. The results of these experiments on the impact of selecting and breeding of cold tolerance in hybrid rice was discussed.

Key words: Chilling, Hybrid rice, Characteristic of cold tolerance: Seedling stage

摘要： 根据杂交水稻抗冷性选育种的需要，我们研究了低温对五个杂交水稻组合的影响。从低温对幼苗根系电解质泄漏，黄化幼苗转绿和幼苗存活率的影响来看：根系外渗液的相对电导率增加，叶绿素合成能力的降低与幼苗存活率具有一致性，其抗冷顺序为粳稻型的秀优57>籼稻型的青优早>汕优63、汕优64和威优64。杂交水稻Fl的抗冷性与母本近似．与父本关系不大。保持系的抗冷性相似于不育系。本文对该结果在杂交水稻抗冷性选育中的意义进行了讨论。

关键词: 低温, 杂交水稻, 抗冷特性