Uso correcto del análisis clúster en la caracterización de germoplasma vegetal.

El presente trabajo tuvo como objetivo hacer una recopilación de información básica para poder realizar de forma apropiada el análisis clúster. Este método multivariado permite hacer agrupaciones y es muy utilizado en estudios de caracterización de recursos genéticos. Se mencionan los tipos de datos a utilizar, los índices de similitud y disimilitud, los métodos de aglomeración y la forma correcta de establecer el número de grupos en un dendrograma

Distribuição e caracterização agroclimática de regiões potenciais para cultivo de pinhão-manso no México

The purposes of this study were to determine the distribution and climatic patterns of current and future physic nut (Jatropha curcas) cultivation regions in Mexico, and to identify possible locations for in vivo germplasm banks establishment, using geographic information systems. Current climatic data were processed by Floramap software to obtain distribution maps and climatic patterns of regions where wild physic nuts could be found. DIVA-GIS software analyzed current climatic data (Worldclim model) and climatic data generated by CCM3 model to identify current and future physic nut cultivation regions, respectively. The distribution map showed that physic nut was present in most of the tropical and subtropical areas of Mexico, which corresponded to three agroclimatic regions. Climate types were Aw2, Aw1, and Bs1, for regions 1, 2 and 3, respectively. Nontoxic genotypes were associated with region 2, and toxic genotypes were associated with regions 1 and 3. According to the current and future cultivation regions identified, the best suitable ones to establish in vivo germplasm collections were the coast of Michoacán and the Isthmus of Tehuantepec, located among the states of Veracruz, Oaxaca and Chiapas.Physic nut (Jatropha curcas) is a Mexican native plant that has recently acquired strong importance for biodiesel production. The purposes of this study were to determine the distribution, climatic patterns, and the location of germplasm banks based on current and future cultivation regions of physic nut in Mexico using Geographic Information Systems. First, current climatic data were processed by Floramap software version 1.02 to obtain distribution maps and climatic patterns where wild physic nuts could be found. Second, DIVA-GIS software version 5.4 analyzed current climatic data (Worldclim model) and climatic data generated by CCM3 model to obtain current and future cultivation regions, respectively. The distribution map showed that physic nut was distributed in most of the tropical and subtropical areas of Mexico. These areas corresponded to three agro-climatic regions. Region 1 had Aw2 climate, region 2 had Aw1, and region 3 had Bs1 climate. Besides, non-toxic genotypes were associated with region 2, and toxic genotypes were associated with regions 1 and 3. According to the current and future cultivation regions obtained, the best suitable regions to establish in vivo germplasm collections were the coast of Michoacan and the Isthmus of Tehuantepec, located among the states of Veracruz, Oaxaca, and ChiapasOs objetivos deste estudo foram determinar a distribuição e os padrões climáticos de regiões de cultivo, atuais e futuras, do pinhão-manso no México, e identificar possíveis locais para o estabelecimento de bancos ativos de germoplasma, com uso de sistemas de informação geográfica. Os dados climáticos atuais foram processados pelo software Floramap, para obter mapas de distribuição e padrões climáticos de regiões onde plantas de pinhão-manso selvagens poderiam ser encontradas. Foi utilizado o software DIVA-GIS para análise dos dados climáticos atuais (modelo Worldclim) e dos dados climáticos gerados pelo modelo CCM3, para identificar regiões de cultivo atuais e futuras de pinhão-manso, respectivamente. O pinhão-manso está distribuído na maioria das zonas tropicais e subtropicais do México, que correspondem a três regiões agroclimáticas. Os tipos climáticos foram Aw2, Aw1 e Bs1 para as regiões 1, 2 e 3 respectivamente. Genótipos não tóxicos foram associados à região 2, e genótipos tóxicos foram associados às regiões 1 e 3. De acordo com as regiões de cultivo atuais e futuras identificadas, as mais adequadas para o estabelecimento de coleções in vivo de germoplasma são a costa de Michoacán e o Istmo de Tehuantepec, localizadas entre os estados de Veracruz, Oaxaca e Chiapas

Variabilidad anatómica de los sistemas de conducción y estomático de genotipos de Prunus spp. de diferentes orígenes

The aim of this research was to study the relationships between environmental humidity availability and the anatomical characteristics of water conduction and stomatal systems, in five Mexican peach genotypes with different origins (Jalatzingo and Misantla, Veracruz; Temascaltepec, México; Tulancingo, Oaxaca; Sombrerete, Zacatecas), one almond and Nemaguard rootstock. Shoots, leaves and stomata of six months old plants were anatomically characterized by means of 25 characters. The almond tree and the rootstock Nemaguard showed differences in relation to the peaches, which had higher similarity, although they maintained a separation according to their origin. Groups were differentiated by the following characters: stomatal density; width of the leaf upper epidermis; number, frequency and perimeter of xylem vessels; and the index of vulnerability of the leaf central vein, pith, xylem and phloem percentage of the shoot. The conditions of humidity availability of their origin showed strong association with the studied anatomical characteristics, because the environment with more deficit of humidity (Tulancingo and Sombrerete) showed plants with bigger size and smaller frequency of vessels of xylem, as well as low xylem and phloem percentage in shoot, which can be interpreted as resistance adaptations to drought. The area where the occurrence of drought (Jalatzingo) is rare showed the opposite characteristics.The aim of this research was to study the relationships between environmental humidity availability and the anatomical characteristics of water conduction and stomatal systems, in five Mexican peach genotypes with different origins (Jalatzingo and Misantla, Veracruz; Temascaltepec, México; Tulancingo, Oaxaca; Sombrerete, Zacatecas), one almond and Nemaguard rootstock. Shoots, leaves and stomata of six months old plants were anatomically characterized by means of 25 characters. The almond tree and the rootstock Nemaguard showed differences in relation to the peaches, which had higher similarity, although they maintained a separation according to their origin. Groups were differentiated by the following characters: stomatal density; width of the leaf upper epidermis; number, frequency and perimeter of xylem vessels; and the index of vulnerability of the leaf central vein, pith, xylem and phloem percentage of the shoot. The conditions of humidity availability of their origin showed strong association with the studied anatomical characteristics, because the environment with more deficit of humidity (Tulancingo and Sombrerete) showed plants with bigger size and smaller frequency of vessels of xylem, as well as low xylem and phloem percentage in shoot, which can be interpreted as resistance adaptations to drought. The area where the occurrence of drought (Jalatzingo) is rare showed the opposite characteristics.El propósito de esta investigación fue estudiar las relaciones ambientales de disponibilidad de humedad, con las características anatómicas del sistema de conducción de agua y estomático, en cinco genotipos de duraznos mexicanos con diferentes orígenes (Jalatzingo y Misantla, Veracruz; Temascaltepec, México; Tulancingo, Oaxaca; Sombrerete, Zacatecas), un almendro y el portainjerto Nemaguard. Fueron caracterizados anatómicamente brotes, hojas y estomas de plántulas de seis meses de edad, mediante 25 caracteres. El almendro y el portainjerto Nemaguard presentaron diferencias con respecto a los duraznos, los cuales tuvieron mayor similitud, aunque mantuvieron una separación acorde con su origen. Los caracteres que diferenciaron los grupos fueron: densidad estomática, grosor de la epidermis superior, número, frecuencia y perímetro de vasos, el índice de vulnerabilidad de la nervadura central, y el porcentaje de médula, xilema y floema del brote. Las condiciones de disponibilidad de humedad del origen presentaron fuerte asociación con las características anatómicas estudiadas, debido a que los ambientes con mayor déficit de humedad (Tulancingo y Sombrerete) presentaron mayor tamaño y menor frecuencia de vasos de xilema, así como bajo porcentaje de xilema y floema en brote, lo que puede interpretarse como adaptaciones de resistencia a sequía. La zona donde es rara la ocurrencia de sequía (Jalatzingo) presentó características opuestas

Compromising between European and US allergen immunotherapy schools: Discussions from GUIMIT, the Mexican immunotherapy guidelines

Background: Allergen immunotherapy (AIT) has a longstanding history and still remains the only disease-changing treatment for allergic rhinitis and asthma. Over the years 2 different schools have developed their strategies: the United States (US) and the European. Allergen extracts available in these regions are adapted to local practice. In other parts of the world, extracts from both regions and local ones are commercialized, as in Mexico. Here, local experts developed a national AIT guideline (GUIMIT 2019) searching for compromises between both schools. Methods: Using ADAPTE methodology for transculturizing guidelines and AGREE-II for evaluating guideline quality, GUIMIT selected 3 high-quality Main Reference Guidelines (MRGs): the European Academy of Allergy, Asthma and Immunology (EAACI) guideines, the S2k guideline of various German-speaking medical societies (2014), and the US Practice Parameters on Allergen Immunotherapy 2011. We formulated clinical questions and based responses on the fused evidence available in the MRGs, combined with local possibilities, patient's preference, and costs. We came across several issues on which the MRGs disagreed. These are presented here along with arguments of GUIMIT members to resolve them. GUIMIT (for a complete English version, see Supplementary data) concluded the following: Results: Related to the diagnosis of IgE-mediated respiratory allergy, apart from skin prick testing complementary tests (challenges, in vitro testing and molecular such as species-specific allergens) might be useful in selected cases to inform AIT composition. AIT is indicated in allergic rhinitis and suggested in allergic asthma (once controlled) and IgE-mediated atopic dermatitis. Concerning the correct subcutaneous AIT dose for compounding vials according to the US school: dosing tables and formula are given; up to 4 non-related allergens can be mixed, refraining from mixing high with low protease extracts. When using European extracts: the manufacturer's indications should be followed; in multi-allergic patients 2 simultaneous injections can be given (100% consensus); mixing is discouraged. In Mexico only allergoid tablets are available; based on doses used in all sublingual immunotherapy (SLIT) publications referenced in MRGs, GUIMIT suggests a probable effective dose related to subcutaneous immunotherapy (SCIT) might be: 50–200% of the monthly SCIT dose given daily, maximum mixing 4 allergens. Also, a table with practical suggestions on non-evidence-existing issues, developed with a simplified Delphi method, is added. Finally, dissemination and implementation of guidelines is briefly discussed, explaining how we used online tools for this in Mexico. Conclusions: Countries where European and American AIT extracts are available should adjust AIT according to which school is followed

Distribution and agroclimatic characterization of potential cultivation regions of physic nut in Mexico

The purposes of this study were to determine the distribution and climatic patterns of current and future physic nut (Jatropha curcas) cultivation regions in Mexico, and to identify possible locations for in vivo germplasm banks establishment, using geographic information systems. Current climatic data were processed by Floramap software to obtain distribution maps and climatic patterns of regions where wild physic nuts could be found. DIVA-GIS software analyzed current climatic data (Worldclim model) and climatic data generated by CCM3 model to identify current and future physic nut cultivation regions, respectively. The distribution map showed that physic nut was present in most of the tropical and subtropical areas of Mexico, which corresponded to three agroclimatic regions. Climate types were Aw2, Aw1, and Bs1, for regions 1, 2 and 3, respectively. Nontoxic genotypes were associated with region 2, and toxic genotypes were associated with regions 1 and 3. According to the current and future cultivation regions identified, the best suitable ones to establish in vivo germplasm collections were the coast of Michoacán and the Isthmus of Tehuantepec, located among the states of Veracruz, Oaxaca and Chiapas

Modelos de las zonas adecuadas de adaptación del tejocote (Crataegus mexicana DC.) por efecto del cambio climático.

The objective of this research was to determine the possible displacement of Crataegus mexicana DC from its current adaptation zones due to the influence of climate change. Two models of suitable growing areas were constructed, one using current climate data and the second using data of the CCM3 model, which predicted the possible climate change to 2050. The model with current climatic data showed that the current growing areas of central Mexico have high to excellent growing conditions, as similar areas of the Transmexican Volcanic Axis, Mexican Plateau, Sierra Madre Oriental, and Sierra Madre del Sur. This model also showed limited adaptation areas on the northeast, northwest and south of the country. In contrast, with the CCM3 model the Transmexican Volcanic Axis, including the current growing areas, improved the conditions from very high to excellent, and improved conditions for cultivation in this and other regions of the country. Therefore, the tejocote will be positively affected by the change in temperature and rainfall to 2050, which could result in an increase in the area dedicated to this crop.El objetivo de este trabajo fue determinar el posible desplazamiento de Crataegus mexicana DC. de las actuales zonas de adaptación, por efecto del cambio climático. Se hicieron dos modelos de zonas adecuadas de adaptación con los datos climáticos actuales y los del modelo CCM3, que predice el posible cambio climático al 2050. La mode- lación con los datos climáticos actuales muestra condiciones de adaptación que van de buenas a excelentes en las zonas de cultivo en el centro de México, así como condiciones similares para zonas del Eje Volcánico Transmexicano, Altiplano Mexicano, Sierra Madre Oriental y Sierra Madre del Sur. También presentó zonas con adaptación limitada en el noreste, noroeste y sur del país. En contraste, con el modelo CCM3 se mejoran las condiciones de muy buenas a excelentes, del Eje Volcánico Transmexicano incluyendo las actuales zonas de cultivo y en otras regiones del país. Por lo tanto, el tejocote se verá afectado de manera positiva por el cambio de la temperatura y la lluvia hacia el 2050, lo que podría ocasionar que se incremente su superficie cultivada

Variabilidad anatómica de los sistemas de conducción y estomático de genotipos de Prunus spp. de diferentes orígenes Anatomical variability of water conduction and stomatal systems in genotypes of Prunus spp. of different origins

El propósito de esta investigación fue estudiar las relaciones ambientales de disponibilidad de humedad, con las características anatómicas del sistema de conducción de agua y estomático, en cinco genotipos de duraznos mexicanos con diferentes orígenes (Jalatzingo y Misantla, Veracruz; Temascaltepec, México; Tulancingo, Oaxaca; Sombrerete, Zacatecas), un almendro y el portainjerto Nemaguard. Fueron caracterizados anatómicamente brotes, hojas y estomas de plántulas de seis meses de edad, mediante 25 caracteres. El almendro y el portainjerto Nemaguard presentaron diferencias con respecto a los duraznos, los cuales tuvieron mayor similitud, aunque mantuvieron una separación acorde con su origen. Los caracteres que diferenciaron los grupos fueron: densidad estomática, grosor de la epidermis superior, número, frecuencia y perímetro de vasos, el índice de vulnerabilidad de la nervadura central, y el porcentaje de médula, xilema y floema del brote. Las condiciones de disponibilidad de humedad del origen presentaron fuerte asociación con las características anatómicas estudiadas, debido a que los ambientes con mayor déficit de humedad (Tulancingo y Sombrerete) presentaron mayor tamaño y menor frecuencia de vasos de xilema, así como bajo porcentaje de xilema y floema en brote, lo que puede interpretarse como adaptaciones de resistencia a sequía. La zona donde es rara la ocurrencia de sequía (Jalatzingo) presentó características opuestas.The aim of this research was to study the relationships between environmental humidity availability and the anatomical characteristics of water conduction and stomatal systems, in five Mexican peach genotypes with different origins (Jalatzingo and Misantla, Veracruz; Temascaltepec, México; Tulancingo, Oaxaca; Sombrerete, Zacatecas), one almond and Nemaguard rootstock. Shoots, leaves and stomata of six months old plants were anatomically characterized by means of 25 characters. The almond tree and the rootstock Nemaguard showed differences in relation to the peaches, which had higher similarity, although they maintained a separation according to their origin. Groups were differentiated by the following characters: stomatal density; width of the leaf upper epidermis; number, frequency and perimeter of xylem vessels; and the index of vulnerability of the leaf central vein, pith, xylem and phloem percentage of the shoot. The conditions of humidity availability of their origin showed strong association with the studied anatomical characteristics, because the environment with more deficit of humidity (Tulancingo and Sombrerete) showed plants with bigger size and smaller frequency of vessels of xylem, as well as low xylem and phloem percentage in shoot, which can be interpreted as resistance adaptations to drought. The area where the occurrence of drought (Jalatzingo) is rare showed the opposite characteristics

Variación de la región ribosómica nuclear en Crataegus L. del centro y sur de México.

This study was conducted at the Universidad Autónoma de Chapingo and concluded in October 2008, to determine the genetic relationships among species of Crataegus fromcentral and southern Mexico. The variation in the sequences of the nuclear ribosomal region was low in all accessions of germplasm of Mexican Crataegus, and the phylogramonly showed separation of the species used as positive controls, but did not show a clear separation of groups of species. However, all accessions had the same pattern of nucleotide substitution and very low values of the distanceof nucleotide composition; thus, Mexican Crataegus species have high genetic relationship among them, but there is alack of evidence to conclude that they are variants of the same taxonomic species. C. nelsoni and C. stipulosa could be a source of genes for C. mexicana because both species,from Chiapas, have the closest relationship with this species,which has the best agronomic characteristics.Este estudio fuerealizado en la Universidad Autónoma Chapingo y concluido en octubre de 2008 y tuvo como objetivo determinar las relaciones genéticas entre especies de Crataegus del centro y sur de México. La variación en las secuencias de la región ribosómica nuclear fue baja en todas las accesiones de germoplasma de Crataegus mexicanos, y el filograma sólomostró separación de las especies usadas como controles positivos, pero no mostró una clara separación de gruposde especies. Sin embargo, todas las accesiones tuvieron un mismo patrón de sustitución de nucleótidos y muy bajos valores en la distancia de composición de nucleótidos; porlo que las especie s mexicanas de Crataegus mostraron altarelación genética, pero falta evidencia para concluir que son variantes de una misma especie taxonómica. C nelsoni y C.stipulosa pueden ser una fuente de genes para C. mexicana porque ambas especies, originarias de Chiapas, tienen la másestrecha relación con esta especie , que es la que presenta las mejores características agronómicas