Role of 2-tridecanone and type VI glandular trichome on tomato resistance to Tuta absoluta

The secondary metabolite 2-tridecanone, secreted by the type VI glandular t richomes present in the leaves of Lycopersicon hirsutum L., make it resista nt to a great variety of insects, including the tomato pinworm, Tuta absolu ta (Meyrick). The 2-tridecanone concentration, the type VI glandular tricho me densities and the pinworm infestation degree were evaluated on the Lycop ersicon esculentum Mill. susceptible cultivar 'Uco Plata', on the Lycopersi con hirsutum f. glabratum resistant accession PI 134417 and on their F-1 an d F-2. The mean infestation degree with pinworm larvae was significantly hi gher in 'Uco Plata' than in PI 134417. The 2-tridecanone concentration was significantly higher in the resistant parent, but the presence of this meta bolite could only partially account for the resistance (R-2 = 8.17%). No si gnificant differences were detected in the type VI glandular trichomes dens ities between the susceptible and resistant parents. This trait was indepen dent of the 2-tridecanone level and the pinworm infestation degree.