Development of STS marker KC1 for brown planthopper resistance gene Bph18(t) and marker assisted selection efficiency.

To facilitate application of the elite brown planthopper(BPH) resistance gene Bph18(t) to rice breeding program by molecular assisted selection(MAS), a STS marker, KC1, for Bph18(t) gene was developed. To test the MAS efficiency of KC1 for Bph18(t), the F_2 plants derived from the cross between Yangdao 6(i.e.9311)[without Bph18(t), susceptible to BPH] and C4064 [harboring Bph18(t)] were subjected to both bioassay of BPH resistance in the field and molecular identification with the STS marker KC1 in the laboratory. Among the F_2 plants, 292 plants were resistant to BPH while the other 84 plants were susceptible, indicating a single gene [Bph18(t)] controlling the BPH resistance in the F_2 population. The results of molecular identification showed that the MAS efficiency of KC1 for Bph18(t) was 82.6%, indicating that the STS marker KC1 could be useful to trail Bph18(t) gene in rice breeding program.