NATIONL CENTER OF PLANT GENE RESEARCH(WUHAN)
A genetic analysis of low-temperature-sensitive sterility in indica-japonica rice hybrids
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A genetic analysis of low-temperature-sensitive sterility in indica-japonica rice hybrids Li, H. B., Q. Zhang, A. M. Liu, J. S. Zou and Z. M. Chen. 1996. Plant Breeding 115:305-309. ABSTRACT Low-temperature sensitive sterility has become one of the major obstacles in indica-japonica hybrid rice breeding. The objectives of this paper were to evaluate the extent of the fertility reduction and to determine the genetic basis of low-temperature sensitive sterility. Seventeen varieties were crossed in various ways to produce 21 F1s including 16 indica-japonica hybrids. Fertility of the F1s and their parents was examined under both high and low temperature conditions. Considerable reduction in spikelet fertility was observed under low temperature conditions in the majority of the indica-japonica hybrids having at least one wide compatibility parent. However, the extent of fertility reduction varied greatly depending on the parental genotypes. Data from five pairs of reciprocal crosses indicated that the cytoplasm had no effect on the fertility reduction. The more or less bimodal distribution of the fertility segregation of two F2 and one BC1F1 populations under low temperature conditions suggested that the low-temperature sensitive sterility was controlled by one or a few genes. It was also shown that the low-temperature sensitivity is not related to wide compatibility. We conclude that it is possible to develop indica-japonica hybrids with wide compatibility and also insensitivity to the low temperature conditions. Key words Oryza sativa, hybrid rice breeding, wide compatibility, inheritance