Strawberry genotypes with resistance to Tetranychus urticae mediated by leaf trichomes

Abstract

ABSTRACT The two-spotted spider mite (Tetranychus urticae) is the main pest encountered in strawberry cultivation in protected environments, causing damage and increasing the cost of production associated with chemical control. Breeding programs are essential for obtaining new cultivars that are more tolerant to two-spotted spider mites. The objective was to evaluate whether the leaf trichomes mediatethe resistance of intraspecific strawberry hybrids to two-spotted spider mites. Preselected hybrids were subjected to infestation by two-spotted spider mites and evaluated via the no-choice assay and the travel test. Resistance was correlated with the density of trichomes, both glandular and non-glandular, present on the surface of the leaflets of strawberry genotypes. The results indicated that there is an influence of hybrids and cultivars on the behavior of the pest, allowing the verification of the existence of resistant genotypes (RVDA#16, RVCS#44 and Camino Real). These treatments resulted in low numbers of eggs deposited and hatched compared with the other treatments and shorter distances traveled by two-spotted spider mites on the surface of leaflets. It was also verified that the glandular trichomes presented a significant negative correlation with the average distance traveled by two-spotted spider mites on the surface of the leaf discs, indicating that these structures alter the behavior of these arthropods. Genotype resistance was associated with the presence of glandular trichomes. In addition to the superiority of the agronomic and postharvest attributes of the preselected hybrids (RVDA#16 and RVCS#44) identified in the previous selection efforts, they proved to be promising materials for achieving resistance to the spider mite, revealing important genotypes for use as cultivars and particularly as parents in breeding programs.