Physical and chemical characterization of wild tomato Solanum habrochaites accessions for resistance to the sweetpotato whitefly

Abstract

Sweetpotato whitefly Bemisia tabaci is a significant worldwide insect pest affecting tomato production, causing direct damage during feeding and transmitting multiple plant viruses to this crop. Continuing research to improve integrated pest management (IPM) of sweetpotato whitefly is required to maintain profitable tomato production for growers. This study evaluated the resistance of eight wild tomato accessions of Solanum habrochaites and four commercial tomato cultivars of Solanum lycopersicum to sweetpotato whitefly infestation. Field experiments were conducted at the Wiregrass Research and Extension Center at Auburn University, where whitefly populations were reported in vegetable crops. Accessions and cultivars were evaluated for resistance to whiteflies through the ability to reduce the insect population, analysis of the presence of glandular trichomes, and the profile and quantification of terpenes of each tomato species. Results indicated significant variations in whitefly population dynamics among the wild tomato accessions and commercial tomato cultivars. Wild tomato accessions of S. habrochaites had higher numbers of glandular trichomes and distinct terpene profiles, particularly sesquiterpenes, known for their pest-repellent properties. Multivariate analysis identified three clusters based on terpene profiles and trichome types correlating with whitefly resistance. Accessions of S. habrochaites PI127826, PI134418, and G29258 had prominent results. They significantly reduced whitefly nymph development compared to cultivars of S. lycopersicum. The GC–MS analysis of leaflet extracts revealed that accessions of S. habrochaites had higher levels of sesquiterpenes, including α-zingiberene, β-caryophyllene, and α-humulene, with PI127826 uniquely producing Ar-curcumene and 9‑hydroxy-zingiberene. Results highlight the potential of wild tomato accessions of S. habrochaites in breeding programs to enhance whitefly resistance in tomatoes, which can support a sustainable IPM program.