Inheritance of Type IV Glandular Trichomes and Two-Spotted Spider Mite Resistance in an Interspecific Cross of Lycopersicon esculentum × L. pennellii  LA2580

An experiment was conducted to study the inheritance of type IV glandular trichomes and its relation to two-spotted spider mite (TSSM) resistance in cross Lycopersicon esculentum Mill × L. pennellii ‘LA 2580’. Parents and their F1 and F2 progenies were raised under natural conditions. Five weeks after transplanting, fully expanded young leaves were collected and used for estimating density of type IV glandular trichomes and TSSM resistance. Subsequently, two-month-old plants were challenged with TSSM (50 adults and 150 eggs). After two weeks, they were scored for damage index (0 to 6 scale). The estimated heritability in broad sense was high (93%) for density of type IV glandular trichomes. Statistical analyze showed that two dominant unlinked genes control the presence of type IV trichomes in the hybrids. There was an over expression of type IV glandular trichomes in F1 plants. Density of type IV trichomes in F2 individuals showed a broad range of variability (0 to 35 trichomes/mm²). There was a significant positive relationship between density of type IV glandular trichomes and resistance to TSSM.