Diversity and bioclimatic profiles of Vanilla spp. (Orchidaceae) in Mexico. The genus Vanilla comprises around 110 species distributed throughout Earth's tropical regions, with the largest number of reported species growing in the American continent. Vanilla farming is associated with many Mexican cultures such as the Totonac, Mayan, Chinantec, and Mazatec, among others. Currently, this crop is threatened by technical, social, ecological, and climatic conditioning factors, limiting its production and the preservation of wild and cultivated species. It is therefore necessary to ascertain the current diversity status of each of these species, as well as some of their main bioclimatic profile indicators, in order to help decision-making, aimed at preserving and genetically improve these species. During 2008, we gathered data from IPN, MEXU, and XAL herbaria, as well as from CONABIO's World Information Network on Biodiversity (REMIB), the Global Biodiversity and Information Facility (GBIF), and we also used data from live access to BUAP's vanilla germplasm bank, obtained between 2008 and 2014. Distribution maps were generated using a geographical information system. Bioclimatic profiles for each species were obtained considering 19 WorldClim variables and altitude at a spatial resolution of approximately 1 Km 2 . Variance, Mean, and standard deviation for each of the 19 variables were calculated at each of the registered points. Extreme environmental condition intervals (minimum, average, and maximum) were also obtained. In order to determine the most important distribution variables of the species, we performed a principal component analysis and carried out Kruskal-Wallis and Dunn's tests on the variables identified as significant. Results indicated records for V. planifolia, V. pompona, V. insignis, V. inodora V. odorata, V. cribbiana, and V. sprucei in Mexico, distributed throughout nine states in the country. V. planifolia presented wide intervals of temperature and rain precipitation, while V. pompona, V. odorata, V. insignis and V. inodora presented intermediate intervals. The amplitudes of extreme data for each species can be considered in locating areas where ex situ regional preservation strategies could be put in place, as well as in establishing areas for cultivation. The bioclimatic profile we found, allows for an indirect inference of each species' genetic condition, which could be used in genetic improvement programs; for instance, V. odorata grows at high altitudes and tolerates low temperatures, while V. inodora tolerates high temperatures, and V. odorata, V. pompona and V. planifolia tolerate low rain precipitation. Rev. Biol. Trop. 65 (3): 975-987. Epub 2017 September 01.
Los problemas y limitaciones del control de enfermedades fúngicas mediante el uso de fungicidas hacen que el control biológico de hongos fitopatógenos se presente como un método de control alternativo en la producción de tomate (Lycopersicon esculentum M.) en invernadero, la cual está limitada por la incidencia del oomycete Phytophthora capsici, siendo una de las enfermedades más destructivas a nivel mundial. El objetivo de este trabajo fue evaluar el efecto de cuatro bio-fungicidas elaborados a base de cepas nativas del genero Trichoderma contra P. capsici en la producción de tomate, denominado en la región "jitomate" variedad Ramses, en condiciones de invernadero en sistema de camas. El biofungicida a base de T. harzianum presentó los mejores resultados promedios con una supervivencia de 76,4% y un rendimiento promedio de 27% mayor al grupo control. Todos los tratamientos con biopreparados presentaron mayor altura de la planta y biomasa final que el tratamiento control. Así, el tratamiento control mostró una mortalidad del 54%, con un rendimiento promedio de 11% menor al de los biopreparados con cepas nativas de Trichoderma spp. y mayor al tratamiento inoculado con P. capsici, que presentó la mayor incidencia "enfermedad" (40%), la menor supervivencia (26,3%) y un descenso de rendimiento de fruto del 64% respecto al control.
A field survey for insects associated with amaranth Amaranthus hypocondriacus L. (Amaranthaceae) was conducted in the semiarid Region Mixteca of Puebla State in Mexico. Also, the losses to the crop caused by the phytophagous species were assessed. Samples were collected every fifteen days during one year in five plots to obtain a representation of the phytophagous and beneficial insects, and of the percentages of plants infested with the principal phytophagous insects. The species that were observed causing considerable damage to the crop were Hypolixus truncatulus Fab. (Coleoptera: Curculionidae), Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), Pholisora catullus (Fab.) (Lepidoptera: Hesperiidae) and Phyllophaga ilhuicaminai Morón (Coleoptera: Melolonthidae). Borers infested 92% of the crop, while the white grubs group 45%. Yield losses by general insects without pest control program were 65.5%. Foliage and soil insects reduced the yield to 44.2 and 39.1%, respectively. This is the first report of quantification of losses due to pest insects in the amaranth crop.
The problems and limitations of the control of diseases caused by phytopathogens through the use of fungicides, make the biological control present as an alternative method in the production of tomato plants in greenhouse, which is limited by the incidence of Fusarium oxysporum Schlechtend.:Fr., being the most worldwide destructive disease. The objective of the present investigation was to evaluate the effect of three Mexican strains of the genus Trichoderma against F. oxysporum on the production of tomato seedlings under greenhouse conditions, as well as to determine the antagonistic effect of the strains used. The Trichoderma harzianum strain had the highest antagonistic activity (81.50%) and the highest growth rate (1.25 cm/day), proving to be the most aggressive strain to control F. oxysporum. in addition the results of the interaction of the dual cultures paired, presented a visible overgrowth zone with hyphae of Trichoderma spp. Seeds inoculated with T. harzianum showed a survival of 84% and a mortality of 16%, lower than the control group, which present a mortality of 58%; however, the treatment inoculated with F. oxysporum had the highest incidence of "disease" with 83%, the lowest survival (17%) and a decrease of the green biomass with respect to the control.
Para producir plantas de calidad en vivero, se utilizan sustratos comerciales como el Peat Moss, agrolita y vermiculita, cuyo costo es eleva- do y reduce significativamente los márgenes de utilidad; por lo anterior, se necesita buscar sustratos alternativos. La cáscara de nuez (Juglans regia L.) es un residuo sin aprovechamiento en producción; sin embargo, cuenta con importantes elementos nutritivos para ser aprovechados por los organismos vegetales. Se evaluó el crecimiento inicial de Pinus patula producido en vivero, con composta de cáscara de nuez con agrolita y vermiculita, mediante sustitución paulatina del Peat Moss. Con un diseño experimental completamente al azar, se estudiaron 4 tratamientos a base de cáscara de nuez + agrolita y vermiculita, en proporciones que variaron desde 0% hasta 80% de cáscara de nuez, y la mezcla de sustratos comerciales. A los 7 meses y medio, las plántulas que se desarrollaron en el tratamiento 1, mezcla testigo (Peat Moss 33% + vermiculita 33% + agrolita 33%) y el tratamiento 4 (Cáscara de nuez 33% + vermiculita 33% + agrolita 33%) presentaron valores más altos en las variables: altura, diámetro, peso seco aéreo, peso seco radicular y peso seco total. La relación aérea/raíz y el índice de esbeltez no presentaron diferencias entre los 4 tratamientos. El valor más alto del índice de calidad de Dickson fue para el testigo (0,25 g.cm-1), seguido por el tratamiento 4 (0,24 g.cm-1), sin diferencias estadísticas. La cáscara de nuez permite producir plántulas sanas, por lo que es útil como sustrato alternativo para la producción de plantas en vivero, lo que reduce los costos de producción además de contribuir con el sector productivo forestal.
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