2-tridecanone content and resistence to Tuta absoluta Meyrick and Tetranychus urticae Koch in tomato.

The South American tomato pinworm and the two spotted spider mite are two important pests of the tomato crop in Argentina. The wild accession PI 134417 of Lycopersicon hirsutum f. glabratum is resistant to both pests. The resistance to insects in the wild tomato accessions has been associated to the presence of secondary metabolites as 2-tridecanone, 2-undecanone, alpha-tomatine, etc. In this work the concentration of 2-tridecanone was colorimetrically quantified and the tomato pinworm and two spotted spider mite degrees of infestation were evaluated in the susceptible cultivar Uco Plata INTA (L. esculentum), the resistant accession PI 134417 (L. hirsutum f. glabratum) and their F1 and F2, grown in the greenhouse and in the field. In the field essay the 2-tridecanone concentration in PI 134417 was 36 times higher than in Uco Plata; in the greenhouse it was 15 times higher. The high 2-tridecanone concentration would be controlled by several genes of recessive effect. The mean infestation degree of the tomato pinworm was significantly higher in the cv. Uco Plata than in PI 134417 in both environments. The F1 and F2 means suggest a mean genic additive effect for this trait. The estimated broad heritability was 70% in the greenhouse and 56 % in the field. PI 134417 was highly resistant to the two spotted spider mite in both environments. The F1 and F2 means suggest that the resistance to this pest would be a recessive trait. No correlation was found between the 2-tridecanone concentration and the two spotted spider mite degree of infestation, so the 2-tridecanone would not be involved in the resistance. A significative negative correlation was found between the 2-tridecanone concentration and the tomato pinworm degree of infestation in the greenhouse but not in the field. The 2-tridecanone could account only partially for the tomato pinworm resistance in the greenhouse. In the field another resistance mechanism could be involved independently of the 2-tridecanone.

Key words: 2-tridecanone, genetic resistance, Lycopersicon spp, South American tomato pinworm, two spotted spider mite.