Genetic analysis and mapping of a thermosensitive genic male sterility gene, tms6(t), in rice (Oryza sativa L.).

Thermosensitive genic male-sterile (TGMS) rice is widely used in hybrid rice production. Because of its specific temperature requirement, it can be used only in a narrow rice-growing zone in Asia. A newly discovered TGMS line, G20S, has an opposite phenotype compared with normal TGMS lines. G20S is completely sterile when the temperature is lower than 29.5 degrees C. Thus, it can be widely used in a larger area. Genetic analysis indicated that the sterility of G20S was controlled by a single recessive gene that was named tms6(t). An F2 population from the cross between G20S and Jing226 was developed and used for molecular mapping of the tms6(t) gene. The simple sequence repeat technique, combined with bulked segregant analysis, was used to screen markers linked to the target gene, and linkage markers such as RM216, RM2504, RM3152, and RM4455 were identified. These markers are all located on chromosome 10; therefore, tms6(t) was subsequently mapped on chromosome 10. Co-segregation analysis using the F2 population showed that two of these markers, RM3152 and RM4455, were closely linked to tms6(t) at distances of 3.00 cM and 1.10 cM, respectively. Additionally, integration of the genetic and physical maps showed that there were 15 BAC/PAC clones overlapping between RM3152 and RM4455, and tms6(t) was mapped to an interval of 1455 kb.