Mapping and breeding application of the brown planthopper (Nilaparvata lugens)-resistance genes derived from a durable resistant PTB33 rice variety (Oryza sativa)

The brown planthopper (BPH) is a substantial threat to rice production in Asian countries. The variety PTB33 exhibits a high and durable resistance to BPH. Here, three resistance genes from chromosomes 3, 4 and 6 were detected, with LOD scores of 6.2, 5.0 and 4.3, respectively. The gene from chromosome 4 flanked by markers RM5757 and RM6997 was allelic to Bph6. They shared an 89% amino acid similarity. Another gene detected on chromosome 6 was linked with RM598 and was the reported gene Bph3. The gene from chromosome 3, harbouring markers RM5626 and RM6283, was a novel resistance gene. Moreover, by crossing different rice lines with PTB33, 27 backcrossing lines were developed that contained a genetic background of restorers, maintainers, sterile lines and cultivated varieties. These lines displayed resistance to BPH and had a survival rate >50%. Among these, seven lines were highly resistant to BPH and showed agronomic merit traits. Thus, the detected genes and developed BPH resistant lines can significantly contribute to breeding programmes for BPH resistance.