Traditional rice landraces disrupt Spodoptera litura reproduction: biochemical profiling and molecular docking

Abstract Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) is a major pest that causes great damage and loss economically in the cultivation of rice. To evaluate rice's potential for resistance to S. litura, fourth-instar larvae were fed to the traditional rice landraces: Karupu Kavuni, Mapillaisamba, Kattuyanam, Sreegasamba, Sonamasuri, Poongar, Attur Kichilisamba and Aruvatham Kuruvai. The results showed that most of the landraces reduced larval growth by prolonging the time to develop into pupae, lowering the weight of pupae and reducing the percentage of larvae that survived from egg to larval stage; therefore, these landraces have a natural resistance to S. litura. Karupu Kavuni contained the most myricetin at 142.75 µg g⁻1. Quercetin was effective at killing larvae based on results of the bioassay (i.e., 96.66% of larvae died). The biochemical analysis of resistant landraces showed that higher levels of total phenols, flavonoids, proline and tannins may be responsible for the antibiosis-based resistance to S. litura. This research provides evidence that the traditional rice landraces being tested can be used as genetic resources in breeding programs to produce rice varieties resistant to tobacco cutworm.