Resistência à Helicoverpa armigera (Lepidoptera: Noctuidae) e a Myzus persicae (Hemiptera: Aphididae) em genótipos de tomateiro obtidos do cruzamento com Solanum galapagense

Abstract

The wild species Solanum galapagense is promising for use in tomato breeding programs because it has high levels of insect resistance, associated with glandular trichomes, and other favorable characteristics. The objective of this study was to determine the resistance to caterpillar Helicoverpa armigera and the aphid Myzus persicae in tomato genotypes obtained from crosses with S. galapagense and its possible association with the presence of glandular trichomes. To that end, it made the quantification of leaf trichomes of plants of the F2 population, derived from interspecific cross Solanum lycopersicum 'TOM- 684' x S. galapagense 'LA-1401'. Based on the results of this evaluation, we selected five plants with high density of glandular trichomes (BPX-486-17, 486- 62-BPX, BPX-486-10, 486-46 and BPX-BPX-486-08) and two with low (BPX- 486-313 and BPX-486-383). These genotypes were cloned via stem cuttings and together with LA-1401 parent and commercial checks TOM-584 and Santa Clara, submitted to two resistance tests to H. armigera in laboratory, a survival and other preference. The same genotypes were also used to perform two tests of preference of M. persicae, a free choice and the other no choice. The selected genotypes, five which, together with LA-1401 showed high densities of type IV trichomes, also showed lower survival of H. armigera caterpillar and less preferred for food and nymphs production/reproduction of the aphid M. persicae compared the two BPX-486-313 genotypes BPX-486-383; and commercial controls with low density of glandular trichomes. The genotypes with high density of glandular trichomes type IV (BPX-486-17, 486-10-BPX, BPX-486- 46) and the LA-1401 also showed less preference and smaller note food consumption of the H. armigera in compared to genotypes with low density of glandular trichomes (BPX-486-313, Santa Clara and TOM-584). Negative signicant correlations between the density of glandular trichomes type IV and survival, and food preference of H. armigera, and also between the trichomes type IV and the food preference and production of nymphs/reproduction of the M. persicae were found. These results indicate the occurrence of association between type IV trichomes with resistance to H. armigera by antibiosis and nonpreference and M. persicae by the non-preference mechanism.