Molecular characterization of intraspecific variations in Helicoverpa armigera (Hübner) populations across India

Abstract

Aim: The present study was undertaken to explore the genetic diversity among Helicoverpa armigera populations from varied geographic regions of India using mitochondrial cytochrome c oxidase I (COI) gene fragments. Methodology: The larval specimens of H. armigera collected from 20 locations were subjected to DNA extraction, PCR amplification of target gene, sequencing and then multiple sequence alignments. Results: Based on COI sequence data, high levels of genetic differentiation among some H. armigera populations were detected, but divergence existing was not high enough to delineate them as separate species. The Indian population as a whole exhibited similarity with global genetic assemblage. Significant negative neutrality test indices and unimodal mismatch distribution further supported that this insect experienced a demographic expansion in the past. The phylogenetic tree and median-joining haplotype network indicated that genetic similarity was not related with geographic proximity of populations. Interpretation: Differences based on genetic analyses indicate considerable subspecific level variations among H. armigera populations of India. However, there is no existence of any unidentified cryptic species of H. armigera in the country.