Rice Varietal Manipulation to Reduce the Brown Planthopper Outbreak

Abstract

The study was conducted through detecting of differences of the brown planthopper (BPH). Nilaparvata lugen (Stal) virulence in damaging a differential set of BPH standard resistant rice varieties and a set of certified rice varieties in major irrigated rice growing areas. Eighty one BPH populations were caught from 80 districts (Amphurs) in 16 provinces of the lower northern, central, eastern and western regions of the country. BPH mass rearing was conducted to F₃-F₄ generations. The differential set of BPH standard resistant varieties carrying different resistant genes were Mudgo (Bph1), ASD7 (bph2), Rathu Heenati (Bph3), Babawee (bph4), ARC 10550 (bph5), Sawanalata (Bph6). T12 (bph7), Chin Saba (bph8), Pokkali (Bph9), and IR65482-4-136-22 (Bph 10). Seventy two BPH populations were tested with the differential set of BPH standard resistant varieties. The set of certified rice varieties were PTT1, CNT1, SPR1, SPR3, SPR90, PSL2, RD31, RD23 and RD7, with a susceptible check variety TN1. Seedling box screening techniques and Standard Evaluation System (SES) of IRRI were used to detect the resistant reaction. Differences in virulence of 72 BPH populations were analyzed by cluster analysis into group the similarity matrices. Results indicated that when testing with the differential set of standard resistant varieties, at coefficient 0.87, 72 BPH populations could be grouped into 11 different virulence BPH groups, and the differential set of BPH standard resistant varieties could be grouped into 6 different groups according to virulence reaction. Similarly, when testing with the set of certified rice varieties, at coefficient 0.84, 81 groups of BPH could be group into 20 different virulence BPH groups and the certified rice varieties were individually different. Reduction of BPH outbreak could be manipulated by recommendation farmers to plant certified rice varieties according to their resistant reactions in each district.