CHARACTERIZATION OF RESISTANCE EXPRESSION IN GENOTYPES OF SOLANUM SECTION LYCOPERSICON AGAINST Tuta absoluta (LEPIDOPTERA: GELECHIIDAE)

Two studies were conducted with the aim of characterizing the antixenosis and antibiosis resistance expression of genotypes in the Solanum section Lycopersicon against Tuta absoluta (Meyrick). The species used were S. lycopersicum (Fiorentino, Naomi and Belle), S. habrochaites (RCAT030597, PI126446), S. chilense (INIABB79), S. peruvianum (RCAT031296, RCAT039874 and RCAT030403) and S. pimpinellifolium (PI390739). For the antixenosis bioassay, a leaf was removed from plants of each genotype and placed in a cup with a floral foam soaked in water. The cups were stored in cages covered with anti-aphid mesh. The number of eggs per plant was determined seven days after releasing the adults. For the antibiosis bioassay, one leaf per genotype and replication was placed in a plastic cup with floral foam soaked in water, and first-stage tomato leaf miner larvae were placed individually on the leaves. Larval survival, total average male and female pupal weight and consumed foliar area were assessed for each genotype. It was determined that most wild species showed resistance to Tuta absoluta by antixenosis and antibiosis mechanisms. The genotype S. habrochaites (RCAT030597) presented more resistance by antibiosis based on larval survival. Nonetheless, the resistance-level characterization depended on the insect response that was considered because S. chilense was less preferred for oviposition; however, in this genotype, the larval survival in the no-choice assays was among the highest observed. Thus, this study provides comprehensive information on the resistance level of several Solanum genotypes that could be used in further efforts to understand the complex mechanisms underlying Solanum resistance to the tomato leaf miner. Se condujeron dos estudios para caracterizar los mecanismos de resistencia por antixenosis y antibiosis de genotipos de Solanum seccion Lycopersicon a Tuta absoluta (Meyrick). Las especies utilizadas fueron Solanum lycopersicum (Fiorentino, Naomi y Belle), S. habrochaites (RCAT030597, PI126446), S. chilense (INIABB79), S. peruvianum (RCAT031296, RCAT039874, RCAT030403) y S. pimpinellifolium (PI390739). Para la evaluacion de antixenosis, se retiro una hoja de cada planta y se coloco en un recipiente con espuma floral embebida en agua. Los recipientes se introdujeron en jaulas cubiertas de malla anti-afidos. Se determino el numero de huevos por planta a los siete dias despues de la liberacion de los adultos. Similarmente, pero en forma independiente, cada hoja se inoculo con una larva de primer estado, evaluandose su sobrevivencia, peso final de pupas hembras y machos y el area foliar consumida. Se determino que la mayoria de los genotipos silvestres expresaron mecanismos de resistencia a Tuta absoluta por antixenosis y/o antibiosis. El genotipo S. habrochaites (RCAT030597) presento mayor resistencia por antibiosis basado en la sobrevivencia de las larvas y dano foliar. No obstante, la caracterizacion del nivel de resistencia dependio de la respuesta considerada, ya que S. chilense fue menos preferido para oviposicion pero en este genotipo la sobrevivencia de las larvas estuvo entre las mas altas. Asi, este estudio proporciona informacion adicional del nivel de resistencia de varios genotipos de Solanum , la que podria ser utilizada en futuros esfuerzos para comprender los complejos mecanismos que subyacen la expresion de resistencia de Solanum a la polilla del tomate.