Fine mapping of brown planthopper (Nilaparvata lugens Stal) resistance gene Bph28(t) in rice (Oryza sativa L.)

The brown planthopper (BPH; Nilaparv- ata lugens Stal) is one of the most destructive insect pests of rice (Oryza sativa L.) throughout the Asian rice-growing countries. DV85 is a BPH-resistant indica variety. A single dominance gene conferring resistance in DV85 was previously mapped on the long arm of chromosome 11. The objectives of this study were to investigate feeding behaviors of BPH on DV85 plants and fine-map the BPH resistance gene, here designated Bph28(t). A seedling bulk test was conducted to identify resistant plant reactionsvg to BPH feeding. The results showed that the resistance of DV85 functions by means of tolerance during BPH attack, rather than non-preference and antibiosis. For fine mapping, two F2 populations were developed by crossing DV85 with the susceptible japonica variety Kinmaze and indica 9311. A high-resolution genetic map harboring Bph28(t) was constructed and Bph28(t) was finally physically defined to an interval of 64.8 kb between markers Indel55 and Indel66. The fine- mapped Bph28(t) gene will facilitate marker-assisted gene pyramiding for BPH resistance.