A Comparison of Characteristic of Cold Tolerance from Different Seedlings of F_1 Hybrid Rice Cultivars and Their Parents (Three Lines)

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.