Diverse sources of resistance to Thrips palmi (Thysanoptera: Thripidae) in chili (Capsicum annuum and C. chinense).

Abstract

Thrips are the most devastating pests globally and significantly reduce productivity and quality of chili plants and fruits. Thrips infest chili crops, causing direct damage by feeding on leaves, fruits, and flowers and indirect damage as vectors for tospoviruses. Enhancing host plant resistance is a sustainable and eco-friendly approach to managing pests. Twenty-three entries, previously identified as resistant to the twospotted spider mite (Tetranychus urticae Koch), along with thrips-resistant entries identified through field-based observations, were evaluated against Thrips palmi Karny under controlled environmental conditions. Three Capsicum annuum and 6 C. chinense entries were identified as resistant to thrips. Validation screening confirmed these 9 entries as being resistant to T. palmi. A total of 7,072 single nucleotide polymorphisms (SNPs) identified through ddRAD sequencing of the 9 resistant entries were used for phylogenetic analysis. The entries clustered by species, with C. chinense forming a distinct clade separate from C. annuum; however, within each clade, the highly resistant entries were genetically divergent, suggesting the presence of diverse resistance genes. The diverse sources of host resistance to T. palmi identified provide a basis for future research in understanding host-arthropod interactions and breeding schemes to achieve higher levels of resistance in chili peppers.