ABSTRACT In Mexico, Creole corn has presented problems related to seed rot. Therefore, the objective of this study was to determine the frequency of fungi associated with Creole corn seeds. From January to February 2019, 13 Creole corn samples were collected from several localities in Guerrero, Mexico. The samples were processed in PDA culture medium and the frequency of each fungus was estimated based on cultural characteristics and taxonomic keys. Considering symptomatic corn seed samples, Fusarium oxysporum was recorded in eight samples at 97.2%, followed by F. graminearum, isolated from race “Olotillo 1” at 94.4% and from race “Cónico pepitilla” at 58.3%. Phomopsis sp. was isolated at 100% from race “Olotillo 2”. Gibberella moniliformis was isolated from “Elotes Occidental 1” at 83.3%, while the least frequent isolate (19.4%) from “Pepitilla” was Sarocladium strictum, which was recorded in three samples at the low values of 11.1% and 2.8% for races “Arrocillo 2” and “Pepitilla”, respectively; Talaromyces variabilis was found in two samples at 11.1% and 2.8% from “Arrocillo 2” and “Cónico pepitilla”, respectively; Stenocarpella macrospora was isolated at 72.2% from “Pepitilla”. Aspergillus flavus was obtained from “Cónico Pepitilla” at 16.7%, while Setosphaeria turcica and Emericella sp. were less frequently isolated. Considering asymptomatic seeds of race “Cónico pepitilla”, F. oxysporum was isolated at 8.3%, Fusarium acuminatum at 8.3% and Gibberella moniliformis at 41.7%; from asymptomatic seeds of “Olotillo 1” and “Olotillo 2”, Phomopsis sp. was isolated at 50% and Rhizoctonia solani at 50%, respectively. In the present study, the fungi F. oxysporum, Phomopsis sp., G. moniliformis and F. graminearum were most frequently associated with Creole corn seeds.

RESUMO No México, o milho crioulo apresenta problemas de podridão das sementes. Portanto, o objetivo desta pesquisa foi determinar a frequência de fungos associados a sementes de milho crioulo. De janeiro e fevereiro de 2019, 13 amostras de milho crioulo foram coletadas em localidades de Guerrero, México. As amostras foram processadas em meio de cultura BDA e a frequência de cada fungo foi estimada com base nas características culturais e chaves taxonômicas. Nas amostras sintomáticas de sementes de milho, Fusarium oxysporum foi registrado em oito amostras com 97,2%, seguido por F. graminearum isolado na raça de milho “Olotillo 1” com 94,4% e na raça “Cónico pepitilla” com 58,3%. Phomopsis sp., foi isolado 100% na raça “Olotillo 2”. Gibberella moniliformis, foran isolados de “Elotes Occidental 1” com 83,3% e o menos frequente (19,4%) em “Pepitilla” foi Sarocladium strictum registrado em três amostras com valores baixos de 11,1% e 2,8% na raça de milho “Arrocillo 2” e “Pepitilla”, Talaromyces variabilis em duas amostras com 11,1% e 2,8% em “Arrocillo 2” e “Cónico pepitilla”. Stenocarpella macrospora foi isolado em 72,2% da raça de milho “Pepitilla”. Aspergillus flavus em “Cónico Pepitilla” com 16,7%, Setosphaeria turcica e Emericella sp., foi isolado com menor frequência. Em sementes assintomáticas da raça “Cónico pepitilla” foi isolado F. oxysporum com 8,3%, Fusarium acuminatum 8,3%, Gibberella moniliformis em 41,7%, em sementes assintomáticas de “Olotillo 1” e “Olotillo 2” Phomopsis sp., foi isolado em 50% e Rhizoctonia solani com 50%. Neste estudo, os fungos F. oxysporum, Phomopsis sp., G. moniliformis e F. graminearum foram os mais frequentemente associados às sementes de milho crioulo.

Resumen La especie Solanum lycopersicum L. muestra variación en intensidad de color, forma y tamaño de fruto, hábitos de crecimiento, por lo que es importante identificar variedades sobresalientes en características agronómicas y someterlos a un proceso de mejoramiento genético. El objetivo del presente estudio fue evaluar el efecto de la inoculación con Klebsiella variicola, K. quasipneumoniae y K. pneumoniae en plantas de 19 ecotipos de tomate. Se estableció un experimento en un diseño de bloques completos al azar bajo un arreglo factorial generalizado con cinco repeticiones en condiciones de bioespacio. Las variables evaluadas fueron días a floración, peso fresco de fruto, longitud de raíz, peso fresco de raíz, volumen de raíz, peso seco de raíz y número de semillas. El análisis de varianza mostró diferencias significativas en las fuentes de variación cepas de bacteria y ecotipos de tomate. Los resultados indicaron variación en el sistema radicular, características agronómicas y componentes de rendimiento de fruto con la aplicación de bacterias promotoras de crecimiento vegetal en ecotipos nativos de tomate. Las cepas bacterianas favorecen la producción de frutos de tomate con atributos para ser comercializados.

Summary The species Solanum lycopersicum L. shows variation in intensity of color, fruit shape and size, growth habits, so it is important to identify outstanding varieties in agronomic characteristics and subject them to a genetic improvement process. The objective of this study was to evaluate the effect of inoculation with Klebsiella variicola, K. quasipneumoniae and K. pneumoniae in plants of 19 tomato ecotypes. An experiment was established in a randomized complete block design under a generalized factorial arrangement with five replications under biospace conditions. The variables evaluated were days to flowering, fresh fruit weight, root length, fresh root weight, root volume, dry root weight and number of seeds. The analysis of variance showed significant differences in the sources of variation bacterial strains and tomato ecotypes. Results indicated variation in the root system, agronomic characteristics and fruit yield components with the application of plant growth promoting bacteria in native tomato ecotypes. Bacterial strains favor the production of tomato fruits with attributes to be commercialized.

Abstract The objective of this research work was to model the preparation of a syrup formulation based on plant extracts of bougainvillea, eucalyptus, cinnamon, marigold and itamo to inhibit the growth of S. aureus and S. pyogenes, bacteria associated with respiratory infections. The presence of secondary metabolites in the methanolic extracts of each species was determined by chromatography, as well as the antibacterial activity of the extracts and syrups and their antioxidant capacity were evaluated. Eucalyptus extract was found, to be the best at inhibiting bacteria, just like its syrup form, and cinnamon extract is the best antioxidant.

Resumen El presente trabajo de investigación tuvo como objetivo el modelaje para la elaboración de la formulación de un jarabe a base de extractos vegetales de bugambilia, eucalipto, canela, caléndula e ítamo para inhbir el crecimientio de S. aureus y S. pyogenes, bacterias asociadas con las infecciones respiratorias. Se determinó por cromatografía la presencia los metabolitos secundarios en los extractos metanólicos de cada especie, así como también se evalúo la actividad antibacteriana de los extractos y de los jarabes y su capacidad antioxidante. Se encontró que el extracto de eucalipto es el mejor para inhibir a las bacterias, al igual que en su forma de jarabe y el extracto de canela es el mejor antioxidante.

Abstract: Physico-chemical and microbiological parameters were analyzed during dry and rainy season to verify the water quality of the lower Papagayo river basin and its tributaries. The analyzed parameters were compared with the Ecological Water Quality Criteria and Mexican Official Standards. Some values of the physico-chemical and microbiological analyses were outside of the maximum permissible levels in the rainy season (fecal coliforms, sedimentary solids, total suspended solids and turbidity), and which were significantly different with respect to dry season, whose values of the total hardness and dissolved oxygen increased in some sampling sites during this season. Metal concentrations showed values according to the official regulations, as well as the fats and oils. Physico-chemical and water quality of the Papagayo river basin show that Omitlán river was the station with the highest contamination level. Despite the considerable contributions of pollutants into the principal stream of the Papagayo river, in the two sampling stations located in the lower portion of the basin, termed Bellavista Papagayo and Lomas de Chapultepec, it is appreciated that the river has a good capacity of autopurification, even when in these localities there is an important contribution of pollutants. Based on the results obtained and the application of those rules, it was determined that the water in the downstream basin of the Papagayo river should not be used directly as a source of drinking water for the population centers. This is because they contain dangerous pollutants that cause adverse effects to humans.

Resumen: Se realizaron análisis físico-químicos y microbiológicos durante la temporada de secas y lluvias para conocer la calidad del agua de la cuenca baja del río Papagayo y sus afluentes. Los parámetros analizados se compararon con los criterios ecológicos de calidad del agua y las Normas Oficiales Mexicanas. Algunos valores de los análisis físico-químicos y microbiológicos se encuentran fuera de los límites máximos permisibles en la época de lluvias (coliformes fecales, sólidos sedimentables, sólidos suspendidos totales y turbiedad), los cuales difieren de forma significativa con respecto a la época de secas, la dureza total y el oxígeno disuelto aumentaron en algunos sitios de mu est reo. La concentración de metales, grasas y aceites presenta valores permitidos en las normas oficiales. La calidad fisicoquímica y microbiològica del agua de la cuenca del río Papagayo muestra que la estación con mayor grado de contaminación es la del río Omitlán. A pesar de los aportes considerables de materia contaminante al cauce principal del río Papagayo, en las estaciones de mu est reo Bellavista Papagayo y Lomas de Chapultepec, se aprecia que tiene capacidad de autopurificación, aun cuando en dichos puntos hay contribuciones importantes de contaminantes. Los resultados revelan que la cuenca baja del río Papagayo presenta contaminantes que causan efectos nocivos al ser humano, como la mayoría de los ríos en México, no puede considerarse como fuente de abastecimiento de agua potable.

Abstract The study was conducted in the village of Filo de Caballos, municipality of Leonardo Bravo, Guerrero, Mexico, from November 2011 to October 2012, in an orchard of Hass avocado, 5 years old. The objective was to evaluate the treatment of chemical and organic nutrition of avocado trees; fertilizers used were: 50 kg tree of cattle dung (manure); 200-100-200 kg ha-1 of N-P-K (edaphic) and 30-10-15.30 kg ha-1 of Ca-Mg-B (foliar). We found that in buds, treatment manure + edaphic + foliar (41 shoots/branch) was better than treatments manure + edaphic (19 shoots/branch), leaf (9 shoots/branch) and the control (21 shoots/branch). And with 17 fruits, manure + treatment + foliar edaphic significantly exceeded the edaphic + foliar treatments (6 fruits), leaf (1 fruit) and the control (3 fruits). The manure + foliar treatment had the highest length (16 cm) of the main shoot, beating the treatment of manure + edaphic (7 cm) and leaf (9 cm). The edaphic + foliar treatment (75 cm2) had higher leaf area than control (65 cm2) and had the highest fruit weight 2.62 kg with 10 fruits, which was significantly higher than the control (1.51 kg 10 fruits).

Resumen El estudio se realizó en la localidad de Filo de Caballos, municipio de Leonardo Bravo, Guerrero, México, durante noviembre de 2011 a octubre de 2012 en un huerto de aguacate Hass, de 5 años de edad. El objetivo fue evaluar tratamientos de nutrición química y orgánica en árboles de aguacate; los abonos usados fueron: estiércol bovino 50 kg árbol (estiercol); 200-100-200 kg ha-1 de N-P-K (edáfico) y 30-10-15 kg ha-1 de Ca-Mg-B (foliar). Se encontró que en brotes florales, el tratamiento estiércol + edáfico + foliar (41 brotes/rama) fue mejor que los tratamientos estiércol + edáfico (19 brotes/rama), foliar (9 brotes/rama) y el testigo (21 brotes/rama). Además, con 17 frutos, el tratamiento estiércol + edáfico + foliar superó de manera significativa a los tratamientos de Edáfico + foliar (6 frutos), foliar (1 fruto) y al testigo (3 frutos). El tratamiento de estiércol + foliar tuvo la mayor longitud (16 cm) del brote principal, superando a los tratamientos de estiércol + edáfico (7 cm) y foliar (9 cm). El tratamiento edáfico + foliar (75 cm2) presentó mayor área foliar que el testigo (65 cm2) y tuvo el mayor peso de fruto con 2.62 kg 10 frutos, el cual fue significativamente mayor que el testigo (1.51 kg 10 frutos).

Agronomic traits and genetic components are indicators of quality; additional factors are important to study the traits of germplasm in a breeding program. The effects of general (GCA) and specific (SCA) combining adequacy and the type of gene action for agronomic traits of regular maize (Zea mays L.) seeds and high-quality protein were analysed. The genetic material consisted of 10 maize inbred lines: four of regular grain and six high-quality protein. The variables analysed were: days to male and female flowering, plant and ear height, plant and ear score, and grain yield. The results showed significant variation among genotypes (p≤ 0.01) on the effects of GCA and SCA for all agronomic variables. Lines were identified as: T-44, B-41, LT-155, T-45 and CML-144 C, with higher values of GCA, being 0.6379, 0.4592, 0.3286, 0.2945 and 0.3382 t ha-1, respectively, for grain yield. Furthermore, outstanding materials based on its identified SCA crosses 4 * 8 (B-41 * CML-144), 1 * 5 (T-45 * CLQ-6203), and 2 * 7 (T-44 * CML- 142), with SCA estimated values for grain yield of 1.0875, 0.9544 and 0.7591 t ha-1, respectively. The type of additive gene action was the predominant in agronomic characters.

Los caracteres agronómicos y sus componentes genéticos son indicadores de la calidad de semillas; además, son factores importantes para estudiar las características del germoplasma en un programa de mejoramiento. Se analizaron los efectos de aptitud combinatoria general (ACG) y específica (ACE) y el tipo de acción génica de caracteres agronómicos de la semilla de maíz (Zea mays L.) normal y de alta calidad de proteína. El material genético consistió de 10 líneas endogámicas de maíz: cuatro de grano normal y seis de alta calidad de proteína. Se analizaron las variables: días a floración masculina y femenina, altura de planta y mazorca, calificación de planta y mazorca, y rendimiento de grano. Los resultados mostraron variación significativa entre genotipos (p≤ 0.01) en los efectos de ACG y ACE para todas las variables agronómicas. Se identificaron líneas como: T-44, B-41, LT-155, T-45 y CML-144 C, con valores mayores de ACG, siendo 0.6379, 0.4592, 0.3286, 0.2945 y 0.3382 t ha-1, respectivamente, para rendimiento de grano. Además, se identificaron materiales sobresalientes con base a su ACE las cruzas 4 * 8 (B-41 * CML-144), 1 * 5 (T-45 * CLQ-6203), y 2 * 7 (T-44 * CML-142), con valores estimados de ACE para rendimiento de grano de 1.0875, 0.9544 y 0.7591 t ha-1, respectivamente. El tipo de acción génica aditiva fue la que predominó en los caracteres agronómicos.