Battling against Brown Planthopper in Rice: Genomic Selection in Backcross Breeding to Produce Resistant Cultivars - A Review

Brown Planthopper (BPH), Nilaparvata lugens Stal, imposes a significant threat to the rice cultivation in Sri Lanka, generating 5–10% of annual yield losses. Rice farmers mainly adopt chemical methods to control the BPH attacks. The intensive use of insecticides is a crucial trigger for the development of resistance and hence continuous BPH outbreaks. Thus, the chemical methods of control do not provide a permanent solution to the BPH. The most recommended strategy of resolving the BPH crisis in rice is the development of resistant cultivars. Most of the Sri Lankan rice germplasm has already been screened for BPH resistance; however, reliable molecular breeding strategies must be implemented to acieve this target. Development of BPH resistant cultivars relies on utilizing appropriate genomic selection protocols in breeding schemes such as marker-assisted backcrossing. Therefore, a literature survey was carried out to evaluate BPH control methods and to emphasize the employment of backcross breeding with the genomic selection approach as a precise tool to develop BPH resistant rice varieties. The genetic basis of BPH resistance has been unravelled for many rice cultivars however, further screening is required to identify locally available resistant sources. The polymorphic markers for the foreground and background selection must be developed for the introgression of the BPH resistant genes and recovery of the recurrent parent genome. The validation of the markers developed in the international breeding and genetics programmes for the local germplasm is also an essential step prior to the genomic selection of BPH resistant rice varieties.