QTL analysis of rice low temperature germinability

A double haploid population, derived from anther culture of F1 hybrid between a typicalindica and ajaponica (ZYQ8/JX17), has been used to investigate the low temperature germinability (LTG) at 15°C. The low temperature germinability of two parents was significantly different. In 6–11 d, the germination percentage of ZYQ8 was higher than that of JX17. In 12–16 d, the germination percentage of JX17 was higher than that of ZYQ8. The quantitative trait loci (QTLs) of every day for low temperature germinability have been mapped based on a molecular linkage map constructed from this population. In 8–11 d, qLTG-9 was identified in C397B-RZ617B on chromosome 9, the additive effect was positive, showing that the allele from JX17 could increase low temperature germinability. In 12–16 d, qLTG-4 was mapped between RG908 and CT563 on chromosome 4, the additive effect was negative, showing that the allele from ZYQ8 could increase low temperature germinability. These two QTLs were detected at different stages, showing the complexity of the mechanism of low temperature germinability.