Quantification of antibiosis levels in nine different rice genotypes against Nilaparvata lugens (Homoptera: Delphacidae)

Studies on different parameters of antibiosis to simultaneously compare diverse genotypes with different resistance levels are lacking. Such studies are necessary to identify the genetic variability among resistant genotypes, which, ultimately, can lead to the identification of resistance genes with diverse mechanisms. The current study was undertaken to quantify antibiosis levels in nine rice genotypes against the brown planthopper (BPH), Nilaparvata lugens (Stål), under glasshouse conditions using nine parameters. Among these genotypes, RP2068-18-3-5 and Ptb33 displayed significantly better performance as compared to other genotypes in most of the parameters studied and did not differ from each other. Rathu Heenati was the best in unfertilised eggs laid and similar to the above two genotypes regarding percent of nymphal survival. All the test genotypes performed significantly better than the susceptible check TN1, though INRC3021 did not differentiate from the former in some tests. The overall damage score was positively and significantly correlated with the amount of honeydew excretion, percent nymphal survival and emergence, the proportion of brachypterous females, female population, and growth index, and were negatively and significantly correlated with percent unfertilised eggs laid and nymphal development period. Regression analysis revealed a significant linear relationship between damage score and nymphal emergence, nymphal survival percentage, and proportion of brachypterous females. RP2068-18-3-5 is the new source of BPH resistance identified through this study, which breeders can further use in resistance breeding.