Resumen La resistencia al daño por Spodoptera frugiperda (Lepidoptera: Noctuidae) se ha documentado para algunas razas mexicanas de maíz y teocintles. En el Estado de Oaxaca hay aproximadamente 31 razas de maíz y tres razas de teocintle, pero se conoce poco sobre su resistencia al daño por insectos. Este estudio comparó el desarrollo y fecundidad de S. frugiperda al alimentarse con maíz nativo y teocintle Z. luxurians de Oaxaca, México. No se determinaron diferencias significativas en los parámetros de desarrollo de machos y hembras de acuerdo con el tipo de planta hospedera, excepto en el peso de la pupa de machos, el cual fue mayor en teocintle (0,189 g) que en maíz nativo (0,174 g). El tiempo transcurrido desde eclosión a emergencia del adulto fue de 28,96 a 30,17 d en maíz nativo y de 28,51 a 30,34 d en teocintle. Las hembras emergieron antes que los machos en ambos tipos de planta hospedera. La proporción sexual fue de aproximadamente 0,5 para ambos sexos. El peso larval fue mayor en teocintle (0,451 a 0,459 g) que en maíz nativo (0,442 a 0,454 g). Respecto a los parámetros de fecundidad, no se determinaron diferencias significativas en el período de oviposición, número de huevos por masa de huevo, huevos por hembra, y huevos por tipo de planta hospedera. El Índice de Adecuación se correlacionó positivamente con el peso de la pupa en ambos sexos y con los parámetros de fecundidad de las hembras de S. frugiperda. Nuestros resultados demostraron que la alimentación larval en maíz nativo y en teocintle no afectaron los parámetros de desarrollo y fecundidad de S. frugiperda. Las defensas constitutivas de las hojas del maíz fueron similares a las de teocintle.

Abstract Resistance to Spodoptera frugiperda (Lepidoptera: Noctuidae) damage has been documented in some Mexican maize races and teosintes. There are approximately 31 races of native maize and three races of teosinte in Oaxaca state, but little is known about their resistance to insect damage. This study compared the development and fecundity of S. frugiperda fed on native maize and the teosinte Zea luxurians, from Oaxaca, Mexico. No significant differences were determined in the development parameters of males and females according to the host plant types, except the pupal weight of males, which was higher on teosinte (0.189 g) than on native maize (0.174 g). Duration from hatching to adult emergence was 28.96 to 30.17 d on native maize and 28.51 to 30.34 d on teosinte. Females emerged before males in both host plant types. The sex ratio was approximately 0.5 for both sexes. Larval weight was higher on teosinte (0.451 to 0.459 g) than on native maize (0.442 to 0.454 g). According to the fecundity parameters, no significant differences in the duration of oviposition, the number of eggs per egg mass, eggs per female, and eggs per host plant types were determined. Fitness Index was positively correlated with the pupal weight of both sexes and the fecundity parameters of S. frugiperda females. Our results demonstrated that larval feeding on native maize and teosinte did not affect the development parameters and fecundity of S. frugiperda. Constitutive defenses in native maize leaves were similar to those of teosinte.

ABSTRACT Genomic selection is considered to be an important tool in plant breeding programs. However, its application in the earliness of tomato (Solanum lycopersicum L.) has not been studied. The objective of the present study was to evaluate the prediction performance of six statistical models for six quantitative characteristics related to earliness in tomato. The study used phenotypic and genotypic data belonging to an F2 population consisting of 172 tomato plants. Simple sequence repeat (SSR) markers were obtained using genotypic information, and the genomic values were estimated by the following six different statistical models: Bayesian Lasso (BL), Bayesian ridge regression (BRR), BayesA, BayesB, BayesCπ, and reproducing kernel Hilbert spaces (RKHS) regression. The correlation values ranged from 0.17 to 0.57. The highest association values were found in days to flowering of the third inflorescence and 1000-seed weight, which were greater than 0.5. In general, all the models performed in a similar manner because only slight differences were observed among the correlation values. Specifically, BL, BayesB, and RKHS exhibited the highest Pearson correlation values for most traits. According to the results, genomic selection could be a useful tool to support tomato breeding focused on earliness.

ABSTRACT The Mesoamerican region is a center of domestication and high genetic diversity of Phaseolus vulgaris L., which continues to evolve on-farm as part of multi-cropping systems (milpa) and is commonly associated with maize. The genetic resources of the common bean provide knowledge of its agronomic potential. However, there is also a need to document the biochemical composition of the seed in the genetic resources preserved by Mesoamerican farmers. To assess the genotypic and environmental effects on the polyphenol, flavonoid and monomeric anthocyanin contents, and antioxidant activity (DPPH) in seed coats and cotyledons of the common bean, 54 native populations and five improved varieties were evaluated from seed samples that were cultivated in two cropping seasons under a randomized complete block design with four replicates. In addition, seed color parameters were evaluated. At harvest time, a dry sample of grain was obtained from each population, and after a soaking treatment of 12 h, seed coats were separated from cotyledons. The evaluated populations and varieties of common beans showed significant differences (P < 0.05) in polyphenol, flavonoid and anthocyanin compositions, antioxidant activity, and seed color parameters. The geographical origins of the populations and cropping season significantly affected the compositions of the seed coats and cotyledons, and the regions of origin and populations had significant interactions with the cropping season. Among populations, phenolic compound concentrations and antioxidant activities were higher in dark or pigmented seed coats than in the cotyledons. The genotype-environment interaction effects in bioactive compounds provide insights into options for genetic improvement of the common bean to promote their consumption.

ABSTRACT The flowering time is regarded as an important factor that affects yield in various crops. In order to understand how the molecular basis controlling main components of earliness in tomato (Solanum lycopersicum L.), and to deduce whether the correlation between fruit weight, days to flowering and seed weight, is caused by pleiotropic effects or genetic linkage, a QTLs analysis was carried out using an F2 interspecific population derived from the cross of S. lycopersicum and S. pimpinellifolium. The analysis revealed that most of the components related to earliness were independent due to the absence of phenotypic correlation and lack of co-localization of their QTLs. QTLs affecting the flowering time showed considerable variation over time in values of explained phenotypic variation and average effects, which suggested dominance becomes more evident over time. The path analysis showed that traits such as days to flowering, seed weight, and length of the first leaf had a significant effect on the expression of fruit weight, confirming that their correlations were due to linkage. This result was also confirmed in two genomic regions located on chromosomes 1 and 4, where despite showing high co-localization of QTLs associated to days to flowering, seed weight and fruit weight, the presence and absence of epistasis in dfft1.1 × dftt4.1 and fw1.1 × fw4.1, suggested that the linkage was the main cause of the co-localization.

En este trabajo se describió y clasificó la agrobiodiversidad del sistema milpa en la región tropical de San Felipe Usila, México, a partir de la percepción de agricultores sobre la diversidad fenotípica y usos de la variabilidad intra-específica y biodiversidad recolectada a nivel de parcela. Bajo un enfoque de agroecosistemas, se obtuvo información de tres sistemas de producción, denominados: laderas pedregosas (> 18° de pendiente), lomeríos irregulares y pedregosos con pendientes entre 6 y 18°, y terrenos planos (< 6°) de zonas ribereñas. Así, con el objetivo de registrar la percepción de diversidad y usos de la agrobiodiversidad, se aplicaron entrevistas a 200 agricultores de once comunidades indígenas Chinantecas de San Felipe Usila, mediante un cuestionario semiestructurado. En el análisis de ji-cuadrada, se determinaron relaciones significativas (P < 0.05) entre agroecosistemas y variantes fenotípicas de frijol y maíz, cultivos intercalados, regímenes de humedad para la siembra, superficie sembrada y fechas de siembra, floración y cosecha de maíz. En el análisis de correspondencia múltiple, se distinguen patrones de diversidad, uso y manejo en relación a regiones geográfico-culturales de localización de los agroecosistemas y parcelas. En las parcelas de producción se siembran, cultivan y recolectan hasta 26 especies, las principales son: maíz (cinco variantes fenotípicas), frijol (21 variedades y poblaciones nativas), calabaza (cuatro variantes) y yuca (tres variantes). También fue notorio el alto uso de pesticidas y fertilizantes químicos, hasta 22 productos diferentes.

In this research, the agrobiodiversity from the milpa system, in the tropical region of San Felipe Usila, Mexico, was described and classified on base to farmers' perception about phenotypic diversity and use of variability intra-specific, and gathered biodiversity at parcel level. So, under an agroecosystem approach, varied information was completed on three production systems, named as: abrupt hills (> 18° of inclination), rolling hills with irregular and stony zones but slopes from 6 to 18°, and lands of alluvial plains (< 6°) near to riverine zones. Therefore, in order to obtain the perception of diversity and uses on the agrobiodiversity, 200 semistructured questionnaire were applied to equal number of farmers from twelve Chinantec indigenous communities from San Felipe Usila. In the chi-square tests were detected significant relations (P < 0.05) between agroecosystems and its relationships with phenotypic variants of common bean and maize, intercropped crops, moisture regimens for planting, sown area and months of sowing, flowering and harvesting in maize cultivation. As result of the multiple correspondence analysis was detected that, managing and use patterns of the diversity are directly related with geographic-cultural regions, which are located the agroecosystems and farmers' plots. Commonly, in the production plots are planted, cultivated and/or recollected until 26 species, and the main planted crops are: maize (five phenotypic variants), common bean (21 commercial varieties and native populations), squash (four variants) and cassava (three variants). In addition, it was evident a high use of pesticides and chemical fertilizers, until 22 different products.

Yield is a complex trait that is affected by several genetic and environmental factors. Yield is defined as the amount of the part of interest that is harvested from a crop plant in a given area. We investigated the genetic basis of yield in an F2 population derived from a cross between Solatium lycopersicum L. and its most closely related wild species S. pimpinellifolium L. We found that average fruit weight, fruit diameter, and fruit length had a strong effect on yield. In addition, small effects on yield due to soluble solids content and locule number were also observed. A total of 25 different significant quantitative trait locus (QTLs) were detected for six traits (fruit length and diameter, fruit weight, yield, locule number, and Brix degrees). The percentage of phenotypic variation associated with single QTLs ranged from 4.19% to 12.67%. A strong co-location of QTLs among yield and fruit size traits was observed, suggesting that these QTLs play a role in the same expression process controlling yield. We also realized that the effects of soluble solids content on yield could be due to direct effects of fruit size QTLs linked to genes controlling soluble solids content. This result then may suggest that yield in tomato is mainly formed by fruit size QTLs, whereas the remaining factors may play a complementary role in the expression of tomato yield.

Diversity among native maize populations in the highlands of the state of Puebla, Mexico has been studied through the association of those populations with some of the reported maize races; however, population variation within races has been little studied. The aim of the study was to characterize morphologically populations of native maize from the highlands of the state of Puebla and to define relationships among and within races to which they belong. In 2012, 41 native maize populations from the valleys of Serdan, Libres-Huamantla and Puebla were evaluated; 19 representative-race populations, two commercial and two experimental populations were included as controls in the trials. Forty morphological variables were recorded and an analysis of variance was applied, as well as multivariate techniques such as discriminant stepwise, principal component and cluster analyses. Statistical differences among populations for most of the variables were detected and it is considered as an indicator of diversity. Native populations were associated with Chalqueño, Conico, and Elotes Conicos races and with sub-race Elotes Chalqueños. Variation among and within groups was identified, suggesting that the environment and the dynamic process of selection from the farmers on native maize populations in the highlands of the state of Puebla, support an important variation among and within groups representative of the maize races in this area. On the basis of the identified variation, breeding and conservation in situ of maize races can be carried out.

En el altiplano del estado de Puebla, México, se ha estudiado la diversidad existente en poblaciones nativas de maíz a través de la asociación de éstas con alguna de las razas reportadas para valles altos; sin embargo, la variación de las poblaciones dentro de esas razas ha sido poco estudiada. El objetivo del estudio fue caracterizar morfológicamente a poblaciones de maíces nativos del altiplano del estado de Puebla y definir las relaciones existentes entre y dentro de las razas a las que pertenecen. En 2012 se evaluaron 41 poblaciones nativas de maíz procedentes de las regiones de los valles de Serdán, Libres-Huamantla y Puebla; se incluyeron 19 testigos raciales, dos testigos comerciales y dos variedades experimentales. Se registraron 40 variables morfológicas y se aplicó un análisis de varianza, además de técnicas multivariadas como el análisis discriminante stepwise, componentes principales y de conglomerados. Se detectaron diferencias estadísticas entre poblaciones para la mayoría de las variables, lo que se considera un indicador de diversidad. Las poblaciones nativas se asociaron con las razas Chalqueño, Cónico, Elotes Cónicos y con la sub-raza Elotes Chalqueños. Se identificó variación dentro de los grupos resultantes, lo que sugiere que el ambiente y el proceso dinámico de selección de los agricultores sobre las poblaciones nativas de maíz en el altiplano del estado de Puebla, favorecen una variación entre y dentro de grupos representativos de las razas en esta zona. La variación identificada puede ser la base para el mejoramiento y conservación in situ de razas de maíz.

El objetivo del presente estudio fue evaluar la respuesta a la infección natural por Fusarium spp. en las mazorcas de 55 poblaciones nativas de maíz. Las poblaciones evaluadas procedían de cinco estados de México, estas se sembraron en tres localidades en 2010 y 2011 bajo condiciones de secano (temporal). El porcentaje promedio de pudrición de mazorca fue significativamente diferente entre las poblaciones de maíz, localidades y poblaciones dentro de cada localidad y entre años. Las agrupaciones de poblaciones por color de grano también mostraron diferencias, ya que los grupos de color amarillo y rojo mostraron el menor porcentaje de infección. Por la procedencia geográfica, los maíces de Oaxaca presentaron menor daño que los de los estados de México, Puebla, Tlaxcala y Guerrero. En rendimiento de grano hubo diferencias entre localidades, poblaciones y años. Los efectos significativos en la interacción de grupos de poblaciones por localidad indican que las poblaciones de maíz de origen local tienden a presentar menor porcentaje de pudrición y mayor rendimiento, lo que sugiere un proceso de coevolución y coadaptación. El mayor rendimiento de mazorca se obtuvo en 2011, en donde también destacaron las poblaciones de Oaxaca, por lo que se infiere que las poblaciones nativas de maíz de esta entidad son una fuente potencial de resistencia/tolerancia a pudrición de mazorca por Fusarium spp.

The objective of this study was to evaluate the response to natural infection of Fusarium spp. on 55 native maize populations. The populations evaluated were collected in five states of Mexico, and planted in three locations in 2010 and 2011 under rainfed conditions. The average percentage of ear rot was significantly different among maize populations, locations and among populations within locations and years. The population groups of kernel color showed differences among them, where yellow and red groups presented the lower infection percentages. In the relation to geographic provenance, maize populations of Oaxaca presented less damage than those from Mexico, Puebla, Tlaxcala and Guerrero states. In grain yield, there were differences among locations, populations and years. In the significant interaction between population groups and locations showed that populations with local origin presented low ear rot percentage and major yield, which suggest a coevolution and coadaptation process. The higher ear weight was obtained in 2011, where the Oaxaca populations were outstanding. It is possible to infer that native maize populations from Oaxaca are a potential source of resistance or tolerance to ear rot caused by Fusarium spp.

The red prickly pear Opuntia ficus-indica (L.) Mill. (Cactaceae) is an important source of bioactive and functional compounds, but has problems for its storage and commercialization. Therefore a study was done about controlled atmospheres effect upon the minimally processed fruit to conserve the antioxidant compounds at 5 °C during 16 days of storage. At the end of the storage period, we registered that the treatments with 5% O2 + 95% N2 and 10% CO2 + 5% O2 + 85% N2 maintained the level of betalains (125.6 mg l-1, 126.16 mg l-1) and antioxidant activity (263.7 μmol Eq Trolox 100 ml-1, 267.6 μmol Eq trolox 100 ml-1) compared to the initial evaluated content (116.1 mg 1-1, 270.4 μmol Eq Trolox 100 ml mg 1-1). The polyphenols content did not change over treatment 5% O2 + 95% N2 (d0-16 ≈ 65.6 - 57.7 mg EAG 100 ml-1). The results show that even after 16 days of storage, with using controlled atmospheres, minimally processed prickly pear has high antioxidant activity because it keeps the betalains and polyphenols content.

La tuna roja de Opuntia ficus-indica (L.) Mill. (Cactaceae) es una fuente importante de compuestos biactivos y funcionales, pero tiene dificultades para su almacenamiento y comercialización. Por lo tanto se realizó un estudio del efecto de las atmósferas controladas sobre los frutos mínimamente procesados para conservar los compuestos antioxidantes a temperatura de 5 °C y durante 16 días de almacenamiento en atmósferas controladas. Al final del mismo se registró que los tratamientos con 5% O2 + 95% N2 y 10% CO2 + 5% O2 + 85% N2 mantuvieron el nivel de betalaínas (125,6 mg l-1, 126,16 mg l-1) y actividad antioxidante (263,7 μmol Eq Trolox 100 ml-1, 267,6 μmol Eq Trolox 100 ml-1), respecto al contenido inicial evaluado (116,1 mg l-1, 270,4 μmol Eq Trolox 100 ml-1). Mientras que el contenido de polifenoles no varió en el tratamiento con 5% O2 + 95% N2 (d0-16 ≈ 65,6 - 57,7 mg EAG 100 ml-1). Los resultados indican que aún después de 16 días de almacenamiento con el uso de atmósferas controladas, la tuna roja mínimamente procesada tiene alta actividad antioxidante puesto que conserva el contenido de betalaínas y polifenoles.

Agromorphological phenotypic variation and postharvest biophysical changes in fruits after 10 days of storage at room temperature were evaluated in a collection of tomatoes from Oaxaca, Mexico. The collection of 57 accessions were planted and characterized under greenhouse. During postharvest the pH, degrees Brix (°Brix), weight loss and color parameters (L*, a*, b*, chromaticity and Hue angle) were evaluated at 0 and 10 days after harvest. The accession showed significant differences (P < 0.01) over all agromorphological traits, and there were differences among genepools classified a priori as cultivated, ruderal, and intermediate populations between cultivated and ruderal. Nine groups of phenotypic diversity were determined. The storage times (0 and 10 days) presented significant differences at all biophysical traits. After 10 days of storage at room temperature (20.6±5°C and 34±10% RH) the °Brix increased from 4.1 to 4.6 and similarly pH from 3.7 to 4.3. Among phenotypic groups and interaction storage times-groups, significant differences were found for °Brix, color coordinates L* and b*, and Hue angle. The differential postharvest changes indicate phenotypic divergences among and within genepools, which can be exploited in the plant breeding programs with regional objectives.

Se evaluó la variación fenotípica agromorfológica y cambios biofísicos de frutos después de 10 días de almacenamiento a temperatura ambiente, en una colección de tomate de Oaxaca, México. La colección de 57 colectas fue sembrada y caracterizada bajo invernadero. En poscosecha se evaluó pH, grados Brix, pérdida de peso y parámetros de color (L*, a*, b*, cromaticidad y ángulo Hue) a 0 y 10 días después de la cosecha. Las colectas mostraron diferencias significativas (P < 0,01) en todos los caracteres agromorfológicos y también hubo diferencias significativas entre acervos genéticos preclasificados como cultivados, ruderales e intermedios entre cultivados y ruderales. Nueve grupos de diversidad fenotípica fueron conformados. Se determinaron diferencias significativas entre tiempos de almacenamiento (0 y 10 días) para todas las características biofísicas. Después de 10 días de almacenamiento a temperatura ambiente (20,6±5°C y 34±10% HR), se incrementaron los °Brix de 4,1 a 4,6 y pH de 3,7 a 4,3. Entre grupos fenotípicos e interacción tiempo de almacenamiento-grupos, se determinaron diferencias significativas en °Brix, coordenadas de color L* y b*, y ángulo Hue. Los cambios diferenciales poscosecha indican divergencias fenotípicas entre y dentro de acervos genéticos que pueden explotarse en programas de mejoramiento con objetivos regionales.

Wild and cultivated populations of tomatoes spread across Mexico generally are heterogeneous with wide variability in phenological traits, plant, fruit and yield. However, it is necessary to quantify its genotypic variation and how is influenced by the environment, for the purpose of using such information for their conservation, direct use and in breeding programs. In this study was evaluated the variation of agronomic traits of interest into three gene pools, in two consecutive cycles of greenhouse production, from August to December 2009 and from February to July 2010; in a randomized block design with three replications, were transplanted 29 populations grouped by type of fruit: tomatillo (12), globe (15) and saladette (2). There were significant differences (p < 0.05) between and within groups of populations in phenological, morphological and agronomic traits of interest. Populations of fruit with tomatillo form were early at beginning of flowering, fruiting and fruit ripening (17 to 68.5 days after transplantation, ddt) the group of globe fruits and saladette (20 to 82.3 ddt). The gene pools evaluated interact with the growing season; in the spring season 2010 had higher plant vigor and high in agronomic traits. In particular, populations of globe fruit type and tomatillo showed wide variability that can be used in breeding programs towards local interest objectives.

Las poblaciones silvestres y cultivadas de jitomate que se distribuyen en México, generalmente son heterogéneas con amplia variabilidad en caracteres fenológicos, de planta, fruto y rendimiento. No obstante, es necesario cuantificar su variación genotípica y como se ve influenciada por el ambiente, con el propósito de utilizar esa información para su conservación, aprovechamiento directo y en programas de mejoramiento genético. En este trabajo se evaluó la variación de caracteres de interés agronómico en tres acervos genéticos, en dos ciclos consecutivos de producción en invernadero, agosto-diciembre de 2009 y febrero-julio de 2010. En un diseño de bloques al azar con tres repeticiones, se trasplantaron 29 poblaciones agrupadas por forma de fruto en: tomatillo (12), riñón (15) y saladette (2). Se determinaron diferencias significativas (p< 0.05) entre y dentro de grupos de poblaciones en caracteres fenológicos, morfológicos y de interés agronómico. Las poblaciones con formas de fruto tomatillo fueron más precoces al inicio de floración, fructificación y maduración de frutos (17 a 68.5 días después del trasplante, ddt) que el grupo de frutos riñón y saladette (20 a 82.3 ddt). Los acervos genéticos evaluados interaccionan con el ciclo de cultivo, en la estación de primavera 2010 presentaron mayor vigor de planta y altos en caracteres agronómicos. En particular, las poblaciones de frutos tipo costilla o riñón y tomatillo presentaron amplia variabilidad que puede aprovecharse en programas de mejoramiento hacia objetivos de interés local.

The biomass expansion factors (BEF) allow estimating the amount of biomass set per tree based on inventory variables; useful information for climate change projects. The objective was to estimate BEF variables per tree, through the generation of regression models for volume and aboveground biomass in Pinus chiapensis (Mart.) Andresen, in a community in the northern highlands of Oaxaca. Destructive sampling of 70 trees was made during 2012, randomly selecting individuals in proportion to the diametric frequency. The stem was cubed by the overlapping bolt method. The volume of wood with bark was transformed to biomass by the specific gravity and for the rest of the aboveground component were used conversion factors of biomass (dry weight / fresh weight). Nonlinear models of total volume and trade volume with and without bark and total aboveground biomass were obtained. Allometric variables were used from inventory like normal diameter (ND, cm) and total height (TH, m). For the elaboration of volumetric rates, adjusted models showed determination coefficients between 0.94 and 0.98. The Schumacher-Hall model showed the best fit for total aboveground biomass R²= 0.95, using the same independent variables from volume. The BEF was obtained by the quotient of the model from biomass and total tree volume with bark (BEFvtcc= 1040.771 x ND015073 x TH042946). With this equation, it is possible to estimate reliably, the total aboveground biomass (kg) in trees of Pinus chiapensis from of inventory variables or volume.

Los factores de expansión de biomasa (FEB) permiten estimar la cantidad de biomasa fijada por árbol con base en variables de inventario; información útil para proyectos sobre cambio climático. El objetivo fue estimar FEB variables por árbol a través de la generación de modelos de regresión para volumen y biomasa aérea en Pinus chiapensis (Mart.) Andresen, en una comunidad de la Sierra Norte de Oaxaca. Se empleó muestreo destructivo de 70 árboles realizado durante 2012, seleccionando aleatoriamente individuos de forma proporcional a la frecuencia diamétrica. El tallo se cubicó por el método de trozas traslapadas. El volumen de madera con corteza se transformó a biomasa mediante la gravedad específica y para el resto del componente aéreo se usaron factores de conversión de biomasa (peso seco/ peso verde). Se obtuvieron modelos no lineales de volumen total y comercial con y sin corteza y de biomasa total aérea. Se emplearon variables alométricas de inventario como diámetro normal (DN, cm) y altura total (AT, m). Para la elaboración de tarifas volumétricas, los modelos ajustados mostraron coeficientes de determinación entre 0.94 y 0.98. El modelo de Schumacher-Hall mostró el mejor ajuste para biomasa total aérea con R²= 0.95, utilizando las mismas variables independientes que en el volumen. El FEB se obtuvo mediante el cociente de los modelos de biomasa y de volumen total árbol con corteza (FEBvtcc= 1040.771 x DN0 15073 x AT-042946). Con ésta ecuación, es posible estimar confiablemente la biomasa total aérea (kg) en árboles de Pinus chiapensis a partir de variables de inventario o de volumen.

Genetic diversity of the maize populations in Mexico is very dynamic and depends on biological, agroecological, and socio-economic factors and familiar needs. In this study, the morphological variability of a collection of 60 population samples of maize were described and classified, such samples were collected in 44 communities from Low Mixtec-Oaxaca region (846 masl to 1842 masl). The samples were sown and cultivated during crop cycle Sprig-Summer 2010 at Santo Domingo Tonala, Oaxaca, under a randomized complete design with four replications. Nineteen morphological traits of plant, ear, kernel and tassel were evaluated and significant differences among maize populations were determined in these characters. The traits height plant and ear, number of kernels per row were determinants to describe the total morphological variability. Morphological and phenological variation of the maize populations was associated with patterns of altitudinal and geographic variation of the sample origin. Six phenotypic groups with significant differences among them but with similar ear, kernel and plant traits to describes for races Celaya, Bolita, Pepitilla, Ancho and some racial complexes among Ancho, Mixteco, Celaya and Bolita.

La diversidad genética poblacional de maíz en México es muy dinámica y depende de factores biológicos, agroecológicos y socio-económicos, y necesidades familiares. En este trabajo se describió y clasificó la variabilidad morfológica de una colección de 60 muestras poblacionales de maíz, colectadas en 44 municipios de la Mixteca Baja Oaxaqueña (846 msnm a 1842 msnm). Las muestras se sembraron y cultivaron durante el ciclo primavera-verano de 2010, en Santo Domingo Tonala, Oaxaca, bajo un diseño de bloques completos al azar con cuatro repeticiones. Se evaluaron 19 caracteres morfológicos de planta, mazorca, grano y espiga (panoja), y se determinaron diferencias significativas entre poblacionales en estos caracteres. Los caracteres altura de planta y mazorca, días a floración masculina y femenina, y número de granos por hilera en la mazorca fueron determinantes para describir la variabilidad morfológica total. La variación morfológica y fenológica de las poblaciones de maíz se asocia con los patrones altitudinales y geográficos de donde proceden. Se determinaron seis grupos fenotípicos significativamente diferentes con características de mazorca, grano y planta semejantes a las descritas para las razas Celaya, Bolita, Pepitilla, Ancho, y ciertos complejos raciales entre Ancho, Mixteco, Celaya y Bolita.

Reports of the last decade show that some types of food and spices included in the human diet, such as pepper (Capsicum annuum L.) can have a positive effect on human health. The Mexican pepper germplasm is poorly documented with regard to variety and the amount of phytochemical compounds that it contains. In the present study, the variation of phytochemical compounds was evaluated in nine fruit variants (morphotypes) of wild and cultivated pepper grown in Oaxaca. ANOVA detected significant differences among pepper morphotypes and ripeness stages of fruits; vitamin C, total phenols, flavonoids, P-carotene, coordinated chromatic of color, and capsaicinoids. The highest values of vitamin C were found in ’Tabaquero’, ’Guero’ and ’Costeño’ morphotypes (151.6 to 183.2 mg 100 g-1). With regard to total phenols and flavonoids, ’Piquín’ and ’Solterito’ had the highest levels. Coordinates of color a* and b*, and chroma presented a positive correlation with phenol and flavonoid contents. The evaluated morphotypes differed in capsaicin and dihydrocapsaicin; C. annuum had higher capsaicin content (4.9 to 142 /<g mL¹) than dihydrocapsaicin (1.5 to 65.5 /<g mL¹) and C. pubescens Ruiz & Pav. showed the opposite pattern.

En la última década, se reportó que el consumo de ciertos alimentos y especias, como el chile (Capsicum annuum L.), pueden tener un efecto positivo en la salud. Particularmente, los acervos genéticos mexicanos de chile están poco documentados en relación a la diversidad desde la perspectiva fitoquímica. En este trabajo se evaluó la variación de compuestos fitoquímicos en nueve morfotipos de chile silvestres y cultivados de Oaxaca. El ANDEVA detectó diferencias significativas entre morfotipos y estados de madurez en vitamina C, fenoles, flavonoides, P-caroteno, color, y capsaicinoides. Los valores más altos de vitamina C se determinaron en ’Tabaquero’, ’Guero’ y ’Costeño’ (151.6 a 183.2 mg 100 g-1). En fenoles y flavonoides sobresalieron los tipos ’Piquin’ y ’Solterito’. Las coordenadas cromáticas a* y b*, y los tonos (C*) se correlacionaron positivamente con el contenido de fenoles totales y flavonoides. Los morfotipos evaluados difieren en el contenido de capsaicina y dihidrocapsaicina, en C. annuum fue mayor la cantidad de capsaicina (4.9 a 142 pig mL-1) que de dihidrocapsaicina (1.5 a 65.5 pg mL-1) y en C. pubescens Ruiz & Pav. el patrón fue inverso.