Identificación y evaluación de antagonista del tizón temprano Alternaria Soleni en tomate Lycopersicon esculentum mill
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2010
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Facultad de Ciencias Agrarias Universidad de Guayaquil
Resumen
El tizón temprano Alternaria solani en el cultivo de tomate es uno de los problemas fitosanitarios de importancia, para su manejo los productores utilizan productos químicos cuyos efectos repercuten en la salud de las personas y del ecosistema, por lo que la búsqueda de agentes biocontroladores eficaces es necesaria. El presente estudio tuvo los siguientes objetivos: 1) Identificar microorganismos antagonistas que actúen en forma natural sobre fitopatógenos foliares en el cultivo de tomate y 2) realizar pruebas de eficacia de él o los antagonistas sobre fitopatógenos foliares en condiciones de laboratorio e invernadero.
El muestreo se realizó en campos de productores de las provincias de Guayas y Santa Elena. La identificación de los antagonistas se realizó mediante el método de CTAB modificado para la extracción del ADN, se emplearon secuencias espaciadoras interna transcritas del ADN ribosomal (ITS 1 e ITS2). Se identificó a Trichoderma asperellum en las cepas Isidro Ayora, Río Verde y El Azúcar; Hypocrea lixii en la Km 20, las cepas Pedro Carbo y EELS no fueron identificadas.
La prueba de patogenicidad consistió en confrontar micelio de A. solani y las cepas de antagonistas, se evaluaron cada 24 horas hasta 120 horas. Las seis cepas mostraron su máximo crecimientos a las 48 horas de iniciado el estudio, se destacaron El Azúcar y EELS como las de mayor crecimiento.
Para determinar el efecto de las seis cepas de hongos antagonistas se utilizaron las dosis 1x106, 1x108 y 1x1010 conidios/ml sobre la germinación de conidios de A. solani, los tratamientos fueron tres dosis y seis cepas y dos testigos (químico y absoluto) lo que totalizó 20, para el análisis de varianza se uso un DCA con arreglo factorial A X B + 2. Se usaron cinco unidades experimentales. Las cepas EELS y Río Verde tuvieron el mejor efecto sobre la germinación de A. solani, igualmente los muestra la interacción; mientras que la inhibición de los tubos germinativos y deshidratación de esporas fue con la cepa Río Verde.
En invernadero se usaron seis y cuatro cepas de antagonistas y dos testigos en los cultivares Floradade y Miramar, totalizando ocho y seis tratamientos en su orden. En Floradade los menores porcentajes de foliolos infectados por A. solani fueron con las cepas Pedro Carbo y EELS y en Miramar la cepa EELS y testigo comercial. La temperatura y humedad relativa favorable para el
The early blight of tomatoes Alternaria solani is one of the main phytosanitarian problems, for its management the producers use chemical products that affect people’s and ecosystem’s health, so the search of biocontrol agents is necessary. The present research had the following objectives: 1) Identify microorganisms’ antagonists that will act in a natural form on phytopathogens of leaves in the tomato crop and 2) Testing the efficacy of it or the antagonists on phytopathogens of leaves in a laboratory or greenhouse conditions. The sampling was performed in producing fields of Guayas and Santa Elena province. The identification of the antagonists was realized through CTAB method modified for the extraction of DNA, were used internal transcribed spacer sequences of ribosomal DNA (ITS 1 e ITS2). Trichoderma asperellum in the Isidro Ayora, Río Verde and El Azúcar strains was identified; Hypocrea lixii in the 20km, the Pedro Carbo and EELS strains were not identified. The pathogenicity test consisted in confront mycelium of A. solani and the antagonists strains; they were evaluated every 24 hours to 120 hours. The six strains showed their maximum growths on the 48 hours and El Azúcar and EELS were highlighted as the fastest. To determine the effect of the six antagonist strains, the doses 1x106, 1x108, 1x1010 conidia/ml on the conidia germination of A. solani were used, the treatments were three doses, six strains, and two controls (chemical and absolute) that totalized 20, for the variance analysis was used an DCA with A X B + 2 factorial arrangement. There were used five experimental units. The EELS and Rio Verde strains had the best effect on the A. solani germination, also shows the interaction, whereas inhibition of germ tubes and spore dehydration was with the Rio Verde strain. In the greenhouse were used six and four antagonist strains and two controls in the Floradade and Miramar crops, totalizing eight and six treatments in their order. In Floradade the minor percentages of infested leaves by A. solani were Pedro Carbo and EELS strains, and in Miramar the EELS strain and the comercial control. The
The early blight of tomatoes Alternaria solani is one of the main phytosanitarian problems, for its management the producers use chemical products that affect people’s and ecosystem’s health, so the search of biocontrol agents is necessary. The present research had the following objectives: 1) Identify microorganisms’ antagonists that will act in a natural form on phytopathogens of leaves in the tomato crop and 2) Testing the efficacy of it or the antagonists on phytopathogens of leaves in a laboratory or greenhouse conditions. The sampling was performed in producing fields of Guayas and Santa Elena province. The identification of the antagonists was realized through CTAB method modified for the extraction of DNA, were used internal transcribed spacer sequences of ribosomal DNA (ITS 1 e ITS2). Trichoderma asperellum in the Isidro Ayora, Río Verde and El Azúcar strains was identified; Hypocrea lixii in the 20km, the Pedro Carbo and EELS strains were not identified. The pathogenicity test consisted in confront mycelium of A. solani and the antagonists strains; they were evaluated every 24 hours to 120 hours. The six strains showed their maximum growths on the 48 hours and El Azúcar and EELS were highlighted as the fastest. To determine the effect of the six antagonist strains, the doses 1x106, 1x108, 1x1010 conidia/ml on the conidia germination of A. solani were used, the treatments were three doses, six strains, and two controls (chemical and absolute) that totalized 20, for the variance analysis was used an DCA with A X B + 2 factorial arrangement. There were used five experimental units. The EELS and Rio Verde strains had the best effect on the A. solani germination, also shows the interaction, whereas inhibition of germ tubes and spore dehydration was with the Rio Verde strain. In the greenhouse were used six and four antagonist strains and two controls in the Floradade and Miramar crops, totalizing eight and six treatments in their order. In Floradade the minor percentages of infested leaves by A. solani were Pedro Carbo and EELS strains, and in Miramar the EELS strain and the comercial control. The
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CULTIVO DE TOMATE, TIZON TEMPRANO, ENFERMEDAD DEL TOMATE