Rice productivity is greatly affected by various biotic and abiotic stresses. Insect-pests are one of the major biotic constraints to cause significant losses in rice production. Brown planthopper (BPH), Nilaparvata lugens Stål, is the most serious insect-pest of rice in Asia where most of the world rice is produced. Controlling insects using chemicals is already proven detrimental not only to environment but also to human health. Integrated Pest Management (IPM) is the best approach to control

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... insect pests. Host plant resistance is the principal component of IPM along with biological, cultural and physical methods. Use of varietal resistance is the best option to control BPH. Many BPH resistant rice varieties with natural BPH resistance have been developed and widely used against BPH. However, frequent breakdown of monogenic resistance by new BPH biotypes has been a serious threat to control BPH. To overcome such difficulty in the use of monogenic resistance, development of durable resistance is needed as the sustainable means to control BPH. To develop durable resistance, pyramiding of BPH resistance genes and quantitative trait loci (QTLs), through marker-assisted method, is needed. For this, many BPH resistance genes and QTLs have already been identified and mapped on rice chromosomes. This article reviews identification, mapping and pyramiding toward successful cloning of BPH resistance genes/QTLs and provides the basis/ guidelines to work on natural insect resistance genes using molecular markers in Nepal.