Zingiberene-mediated resistance to the South American tomato pinworm derived from Lycopersicon hirsutum var. hirsutum

The Lycopersicon hirsutum var. hirsutum accession PI 127826 is recognized as a good source of resistance to arthropod pests due to the action of the allelochemical zimgiberene, a sesquiterpene present in its glandular trichomes. Five genotypes were selected from the F-2 generation of the interspecific cross Lycopersicon esculentum 'TOM-556' x Lycopersicon hirsutum var. hirsutum 'PI 127826', based on their low levels (BPX-368-clone#56) or high levels (BPX-368-clone#92, BPX-368-clone#105, BPX-368-clone#179, BPX-368-clone#250) of zingiberene. The five F2 genotypes were tested for resistance to the South American tomato pinworm Tuta absoluta along with accession L. esculentum 'TOM-556' (pinworm susceptible), and the accessions L. hirsutum var. hirsutum 'PI 127826' and L. pennellii 'LA 716' (resistant). The F2 clones selected for high foliar zingiberene levels showed lower scores for leaflet lesion type (LLT), percent leaflets attacked (PLA) and overall plant damage (OPD) than the low zingiberene genotypes. The results indicated that zingiberene mediates resistance to the South American pinworm, based on feeding and on ovipositing deterrence, in populations derived from the interspecific cross between Lycopersicon. esculentum and Lycopersicon hirsutum var. hirsutum. Indirect selection for high foliar zingiberene content is suggested as an efficient technique for breeding tomatoes for resistance to the South American tomato pinworm.