Molecular diversity of Nilaparvata lugens (Stål.) (Hemiptera: Delphacidae) from India based on internal transcribed spacer 1 gene

Brown planthopper, Nilaparvata lugens, is the major pest of rice in India and causes significant yield loss. It causes damage by sucking the plant sap leading to a characteristic symptom called ‘hopper burn’. The present study was undertaken to assess the genetic variability of N. lugens populations from different rice ecologies in India, to comprehend and assist in planning proper management strategies. We evaluated the molecular diversity in 17 N. lugens populations based on internal transcribed spacer 1 (ITSI) gene sequences. In all, 53 unique haplotypes were identified and their numbers varied from 1 to 10 in the sampled populations. Genetic diversity indices like nucleotide diversity, haplotype number, haplotype diversity and average number of nucleotide differences revealed low to high levels of genetic diversity among the populations. A highly significant negative relation of Fu’s F and Tajima’s D tests with insignificant sum of square deviation (SSD) values indicated possible recent expansion of N. lugens in different Indian regions with a population expansion time of 3.9 million years. A non-significant correlation in isolation pattern by distance indicated that geographic barriers present in India are inadequate to bring genetic differentiation among N. lugens from different migratory populations. In the present study, the ITSI gene sequence was used to analyse genetic structure among N. lugens in India.