RESUMEN Las infusiones de hojas de guanábana (Annona muricata L.) se han utilizado como medicina alternativa por su composición fitoquímica, actividad farmacológica y citotóxica, que les confieren actividad antibacteriana, antioxidante y anticancerígena. Las infusiones de hojas de guanábana se obtuvieron a 5, 10 y 15 min en muestras colectadas de las regiones de Chiapas y Nayarit en México; se evaluaron fenoles solubles totales (FST), flavonoides (F), taninos condensados (TC), antocianinas totales (AT), actividad antioxidante, reflectancia total atenuada por análisis de espectroscopia infrarroja transformada de Fourier (FTIR-ATR) y actividad citotóxica en líneas celulares MCF7 y HT-29. El contenido promedio de FST, F, TC y AT fue de 0.229±0.006 mg equivalentes de ácido gálico ml-1, 0.177±0.003 mg equivalentes de catequina ml-1, 0.298±0.012 mg equivalentes de cianidina 3-glucósido ml-1 y 0.189±0.003 mg equivalentes de catequina ml-1 respectivamente. El análisis FTIR-ATR determinó grupos carbonilo, hidroxilo, éster y ácidos carboxílicos. La actividad antioxidante por 2,2-difenil-1-picrilhidracilo (DPPH) y 2,2'-azino-bis-3-etilbenzotiazolina-6-ácido sulfónico (ABTS) fue de 0.446±0.014 y 3.53±0.515 mM equivalentes de Trolox ml-1 respectivamente. Los rendimientos de extracción de FST, F, TC y AT mediante infusión fueron 88.41, 66.12, 34.93 y 56.09 respectivamente. La actividad antioxidante fue 50.77% de ABTS y 21.44% de DPPH. Se presentó actividad citotóxica contra la línea celular MCF7 (80%). Las infusiones presentaron un alto contenido de polifenoles, actividad antioxidante y citotóxica.

ABSTRACT Infusions of soursop or graviola (Annona muricata L.) leaves have been used as alternative medicine for their phytochemical composition, pharmacological and cytotoxic activity that are related with antibacterial, antioxidant, and anticancer activities. Infusions of soursop leaves were obtained at 5, 10, and 15 min in samples collected from the Chiapas and Nayarit regions of Mexico. Total soluble phenols (TSP), flavonoids (FC), condensed tannins (CT), total anthocyanins (AC), antioxidant activity, attenuated total reflectance - Fourier transform infrared spectroscopy analysis (FTIR-TRA), cytotoxic activity in MCF7 and HT-29 cell lines were evaluated. The average contents of TSP, FC, CT and AC were as follows: 0.229±0.006 mg gallic acid equivalents ml-1, 0.177±0.003 mg catechin equivalents ml-1, 0.298±0.012 mg cyanidin 3-glucoside equivalents ml-1, and 0.189±0.003 mg catechin equivalents ml-1, respectively. The FTIR-ATR analysis determined carbonyl, hydroxyl, ester, and carboxylic acid groups. The antioxidant activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothia-zoline-6-sulfonic acid) (ABTS) were 0.446±0.014 and 3.53±0.515 mM Trolox equivalents ml-1, respectively. The extraction yields of TSP, FC, CT, and AC by infusion were 88.41, 66.12, 34.93, and 56.09%, respectively. The antioxidant activity was 50.77% for ABTS and 21.44% for DPPH. Cytotoxic activity was present against the MCF7 (80%) cell line. The infusions had high polyphenol contents, antioxidant and cytotoxic activities.

ABSTRACT The Trichoderma harzianum fungus is one of the most widely used biological control agents in agriculture. A new T. harzianum THITR01 strain was isolated and their spores were mutagenized with ethyl methane sulfonate obtaining 174 mutants. M7, M14, M21 and M24 are mutant strains that showed 97.4%-100% antagonist effect against Sclerotium rolfsii, Rhizoctonia solani and Sclerotinia sclerotiorum compared to the wild strain. Under potato dextrose agar (PDA) medium with either NaCl, sorbitol or NaHCO3 there were nonsignificant growth rate differences between the mutants and the wild strain. M14 and M21 mutant strains were inoculated on ‘Jalapeño’ pepper plants (Capsicum annuum L. var. annuum) with unavailable P promoted a significant increase in root fresh weight (54% and 40%, respectively) and dry weight (28% in both strains), compared to plant inoculation with the wild strain. The M14 strain presented the highest P solubilization ability (13.4 μg g-1) in the substrate and promoted a change on root architecture. There was a higher relative water content (82.9%) in drought stressed plants inoculated with the M24 mutant than in plants that were inoculated with the wild type strain (76.3%), and also higher levels of proline in chili pepper plants inoculated with the M24 mutant (939.5 μg g-1 dry weight) than in plants inoculated with the wild type strain (419.8 μg g-1 dry weight). Therefore, M14, M21 and M24 mutant strains could potentially be used as biocontrol agents and plant protector from abiotic stress.

Resumo: A quitosana é um biopolímero obtido a partir da desacetilação da quitina, tem múltiplas aplicações na agricultura como antifúngico, condicionador de solo, indutor de mecanismos de defesa, revestimento pós-colheita de frutos, folhas e sementes, entre outros. O objetivo desta pesquisa foi avaliar o efeito de revestimentos de quitosana misturados com fungicida (ditiocarbamato) na germinação e velocidade de germinação de sementes de feijão e milho armazenadas e determinar a capacidade de retenção do fungicida nas sementes revestidas sob diferentes tempos de embebição. Dois tratamentos de revestimento usando quitosana nas concentrações de 0,1 e 0,5% de quitosana em agua, dois tratamentos de revestimento usando quitosana nas concentrações de 0,1 e 0,5% de quitosana suplementados com fungicida 0,5% e um revestimento usando apenas 0,5% de fungicida em água foram aplicados como recobrimento em sementes de feijão e milho; e como controle foram utilizadas sementes embebidas em água destilada; após os tratamentos, a porcentagem de germinação e a velocidade de germinação foram determinadas, também a liberação de fungicida foi determinada em 0, 1, 2 e 6 h de embebição, e o efeito do tempo de armazenamento na germinação e na velocidade de germinação foi determinado a 30, 60, 90, 120, 150 e 180 dias de armazenamento a 4 °C e 45% de umidade relativa. O efeito da liberação do fungicida foi determinado pela inibição da germinação de conídios de Fusarium oxysporum. Não houve efeitos negativos dos revestimentos na germinação da semente após o armazenamento. O tratamento que proporcionou maior retenção do agente fungicida e liberou-o gradativamente foi a concentração de 0,5% de quitosana misturada ao fungicida. O recobrimento de sementes com quitosana misturadas com fungicida não causam mudanças negativas na germinação das sementes ou na taxa de germinação.

Abstract: Chitosan is a biopolymer obtained from deacetylation of chitin; it has multiple applications in agriculture as an antifungal, soil conditioner, inducer of defense mechanisms, fruits postharvest coating, leaves and seeds, among others. The objective in this research was to evaluate the effect of chitosan coatings mixed with fungicide (dithiocarbamate) on the germination and germination speed of bean and maize seeds in storage and to determine the retention capacity of the fungicide in the coated seeds under different times of imbibition. Two coating treatments at concentrations of 0.1 and 0.5% chitosan in water, two coatings treatments at 0.1 and 0.5% chitosan supplemented with 0.5% fungicide and a coating without chitosan using only 0.5% fungicide in water were used in bean and maize seed; and as control seeds imbibed in distilled water were used; after treatments, germination percentage and germination speed were determined, also fungicide release were determined at 0, 1, 2 and 6 h of imbibition, and the effect of storage time on germination and germination speed was determined at 30, 60, 90, 120, 150 and 180 days of storage at 4 °C and 45% relative humidity. The fungicide release effect was determined by inhibiting Fusarium oxysporum conidia germination. There were no negative effects of coatings on seed germination after storage. The treatment that provided both greater retention of the fungicidal agent and released it gradually, was 0.5% chitosan mixed with fungicide concentration. Chitosan coating seeds mixed with fungicide do not cause negative changes in seed germination or germination rate.

ABSTRACT Plant biodiversity provides a natural source of several compounds with biological activity, such as antioxidant and antifungal properties; such effects are related with the concentrations of phenols and flavonoids and different organs of the plants. In this research, aqueous (W) and 70% ethanol (Et70) extracts from flowers (F), leaves (L), stems (S) and roots (R) of Barkleyanthus salicifolius (Kunth) H. Rob. & Brettell were used to test antioxidant and antifungal activities and also the total concentration of phenols and flavonoids were analyzed; and types of phenolic acids and flavonoids were determined for each plant organ extract by HPLC. The Et70 enhance the extraction process of phenols and flavonoids, also showed higher antifungal and antioxidant activities. The obtained extract of the Et70 × F interaction showed the higher concentration of total phenols (57.90 mg GAE), flavonoids (91.03 mg QE) and antioxidant activity (285.07 Μm Trolox) per gram of dry extract. In addition, this extract shows an antifungal inhibition interval of 66.17% (Fusarium oxysporum) to 92.89% (Colletotrichum gloeosporioides). The phenol ferulic acid (35.57 mg g-1) and the flavonoid naringenina (206.60 mg g-1) were the compounds with the highest values founded in Et70-R, both of them compounds had been tested against fungal pathogens. Data indicate that antifungal and antioxidant activities are in function of phenolic acids and flavonoids concentration, as well as solvent used to extraction. Therefore, B. salicifolius species growing on wild form have the ability of accumulate several compounds with biological activity.

Mexico is the center of origin, domestication and diversity of maize. This cereal is the main constituent of the Mexican diet, especially for low-income families. In this research, 10 maize accessions derived from a large landrace collection, with the 'INIFAP-QPM' accession and a 'regional landrace' as controls, were studied to identify the accessions with the best biochemical and physiological characteristics showing good adaptation to 'El Bajío' (regional center in Mexico) conditions. The accessions were statistically superior to the two controls in the germination and accelerated aging tests. In the assessment of variable plumule length, variability was observed among the accessions, but the controls showed the lowest values. Protein contents in different fractions (albumins, globulins, prolamins and glutelins) showed variability as did oil and fiber contents. The 'HRH2015' accession showed high contents of albumins and globulins and low contents of prolamins and glutelins. The 'regional landrace' accession exhibited the highest contents of glutelins and prolamins but the lowests content of globulins and albumins. The total percentage of proteins showed variability among the accessions, but the values were within those reported in the literature. The 'RQ2015' accession presented the highest oil content (5.25%). The electrophoretic patterns of prolamins were obtained, and some differences were observed between them. The 'regional landrace' presented the lowest protein content, which was significantly different from those of the other evaluated accessions. This research demonstrates biochemical, germination and vigor variability among the studied maize accessions.

México es el centro de origen, domesticación y diversidad del maíz. Este cereal ocupa el primer lugar como constituyente de la dieta de los mexicanos, sobre todo de las familias de bajos recursos. En esta investigación se estudiaron 10 accesiones de maíz derivadas de una colecta amplia de Criollos y como testigos INIFAP-QPM y un criollo de la región, con el objetivo de identificar las accesiones con mejores características bioquímicas y fisiológicas con buena adaptación a las condiciones de El Bajío. Las accesiones fueron estadísticamente superiores a los dos testigos en las pruebas de germinación y envejecimiento acelerado; en la variable longitud de plúmula se observó variabilidad entre las accesiones, pero los testigos siguieron mostrando los valores más bajos. El contenido de proteína en sus diferentes fracciones (albúminas, globulinas, prolaminas y glutelinas) mostró variabilidad, así como el contenido de aceite y fibra. Se encontró una accesión (HRH2015) con alto contenido de albúminas y globulinas y bajo contenido de prolaminas y glutelinas; el 'genotipo criollo' presentó el mayor contenido de glutelinas y prolaminas pero el menor en globulinas y albúminas. El porcentaje total de proteínas presentó variabilidad entre las accesiones, pero los valores están dentro de los reportados en la literatura. El genotipo 'RQ2015' presentó el más alto contenido de aceite (5,25%). Se obtuvieron los patrones electroforéticos de las prolaminas y se observaron algunas diferencias entre ellas. El criollo de la región, tomado como referencia, presentó el menor contenido de proteína estadísticamente diferente al resto de las accesiones evaluadas. Esta investigación demuestra la variabilidad existente a nivel bioquímico, germinación y vigor entre las accesiones de maíz estudiadas.

Abstract Seeds are an indispensable element in agricultural production and represent one of the means to improve crop yield and fertilization is essential for the production of high quality seeds. In the present work, the quality of the wheat seed was evaluated when the fertilizer-N is divided into different percentages. The varieties used were Gema C2004, Nana F2007 and Urbina S2007. The recommended N-P-K fertilization dose in the The Bajio region is 240-60-00. The fertilization-N divisions (FFN) were at planting, 45 days after sowing (dds) and 75 dds in the following percentages: 1) 00-00-00, 2) 100-00-00, 3) 00-100-00, 4) 50-50-00, 5) 00-50-50, 6) 70-30-00, 7) 30-70-00, 8) 00-30-70, 9) 00-70-30 and 10) 33-33-33. In the field the yield was evaluated, in the laboratory the physiological quality of the seed and in the greenhouse the vigor of the seedling in a sand bed. By fractionating the fertilizer-N at 30-70-00 and 33-33-33 the amount of m2 seeds increased, observing higher yields in wheat production compared to the recommended fertilization-N of 50-50-00 that currently used. The best emergency percentages were presented in the subdivisions 33-33-33, 30-70-00 and 70-30-00. Regarding vigor indexes IV-I and IV-II, the treatment that showed the highest values was 30-70-00. The FFN in which the best results were observed in the variables of yield, physiological seed quality and seedling vigor was 30-70-00.

Resumen Las semillas son un elemento indispensable en la producción agrícola y representan uno de los medios para mejorar el rendimiento en los cultivos y la fertilización es indispensable para la producción de semillas de alta calidad. En el presente trabajo se evaluó la calidad de la semilla de trigo cuando el fertilizante-N se fracciona en diferentes porcentajes. Las variedades utilizadas fueron Gema C2004, Nana F2007 y Urbina S2007. La dosis de fertilización N-P-K recomendada en la región de El Bajío es de 240-60-00. Los fraccionamientos de la fertilización-N (FFN) fueron a la siembra, 45 días después de la siembra (dds) y 75 dds en los siguientes porcentajes: 1) 00-00-00, 2) 100-00-00, 3) 00-100-00, 4) 50-50-00, 5) 00-50-50, 6) 70-30-00, 7) 30-70-00, 8) 00-30-70, 9) 00-70-30 y 10) 33-33-33. En campo se evaluó el rendimiento, en laboratorio la calidad fisiológica de semilla y en invernadero el vigor de plántula en cama de arena. Al fraccionar el fertilizante-N en 30-70-00 y 33-33-33 se incrementó la cantidad de semillas m2, observando mayores rendimientos en la producción de trigo en comparación con la fertilización-N recomendada de 50-50-00 que actualmente se utiliza. Los mejores porcentajes de emergencia se presentaron en los fraccionamientos 33-33-33, 30-70-00 y 70-30-00. Con relación a los índices de vigor IV-I y IV-II, el tratamiento que mostro los valores mayores fue 30-70-00. El FFN en el que se observaron los mejores resultados tanto en las variables de rendimiento, calidad fisiológica de semilla y vigor de plántula fue 30-70-00.

RESUMO. A eficiência do uso da água (UEA) foi proposta como uma alternativa para mitigar os efeitos das mudanças climáticas na agricultura e reduzir a pressão sobre os recursos hídricos, principalmente em espécies com altos requerimentos de água que são cultivadas sob condições de sequeiro. O objetivo deste estudo foi caracterizar o UEA instantâneo, integral e molecular de quatro cultivares de feijão, contrastando sua resposta em condições de água limitadas para comparar os mecanismos componentes desta característica entre cultivares tolerantes à seca. Os resultados indicaram que os cultivares tolerantes aumentaram seu UEA instantâneo em comparação aos suscetíveis; entretanto, houve diferença entre as cultivares, uma vez que Pinto Villa apresentou maior condutância estomática e taxa de transpiração, levando a um custo maior de água para produção de sementes do que Pinto Saltillo. Além disso, os genes EUA de ycf2, rrn16, rpoC2, hardy, ndhK, erecta e ycf1 foram apenas sobreexpressos em Pinto Saltillo sob condições de água limitadas, o que se revelou ser a cultivar mais eficiente do UEA. Portanto, os mecanismos componentes da UEA são diferentes mesmo entre as cultivares tolerantes à seca e os mecanismos pelos quais as cultivares tolerantes aumentaram sua UEA instantânea e integral foram diferentes.

ABSTRACT. The water-use efficiency (WUE) has been proposed as an alternative to mitigate the effects of climate change in agriculture and to reduce pressure on water resources, mainly in species with high water requirements which are grown under rainfed conditions. The aim of this study was to characterize the instantaneous, integral and molecular WUE of four bean cultivars contrasting in their response under limiting water conditions to compare the component mechanisms of this trait between drought tolerant and susceptible cultivars. Results indicated that tolerant cultivars increased their instantaneous WUE in comparison to susceptible ones; however, there was a difference between cultivars since Pinto Villa had a higher stomatal conductance and transpiration rate, leading to a higher water cost to produce seed than Pinto Saltillo. Furthermore, ycf2, rrn16, rpoC2, hardy, ndhK, erecta and ycf1 WUE genes were only overexpressed in Pinto Saltillo under limited water conditions, which turned out to be the most WUE efficient cultivar. Therefore, the component mechanisms of WUE are different even between drought tolerant cultivars and the mechanisms by which the tolerant cultivars increased their instantaneous and integral WUE were different.

Abstract The chinese melon seed has been used traditionally to make horchata; however, it has lost the habit of consuming it. To expand the knowledge of this plant resource reservation soluble proteins were extracted from the seed. The total protein content was 27.34% for cantaloupe and 24.9% for honeydew (smooth). The globulins constitute the majority faction and prolamins, the minority. In the electrophoretic pattern shows globulin fraction abundant and well-defined bands. The precipitated proteins with hydrochloric acid or cold showed an electrophoretic pattern similar in both varieties. Proteins were extracted at pH values best between 5 and 12, but not values of 2 to 4. The treatment with trypsin and chymotrypsin showed accumulation of bands on the front of the gel, demonstrating the presence of digested peptides. The inhibitory activity against trypsin is greater at the albumins fraction with 741 UI mL-1 and globulin fraction with 587 UI mL-1. The mineral content was 0.5% for phosphorus and magnesium 0.28 for cantaloupe; for honeydew was 0.36% for potassium and 0.28% for phosphorus. The oil content was 35.8% in seed cantaloupe and 23.2% in the honeydew, which is known to 67.5% are unsaturated fatty acids; oil was amber color, pleasant odor. The use of melon seed is a plant resource to be promoted for its high content of protein and oil, as it is valuable for human consumption. It can also be used in the formulation of livestock feed or cultured insect larvae in the laboratory.

Resumen La semilla de melón chino se ha usado de manera tradicional para elaborar horchata; sin embargo, se ha perdido la costumbre de consumirla. A fin de ampliar el conocimiento sobre este recurso vegetal se extrajeron las proteínas de reserva solubles de la semilla. El contenido total de proteína fue de 27.34% para el melón chino y de 24.9% para el melón verde (liso). Las globulinas constituyen la fracción mayoritaria y las prolaminas, la minoritaria. En el patrón electroforético, la fracción globulina muestra bandas abundantes y bien definidas. Las proteínas precipitadas con ácido clorhídrico o frío mostraron un patrón electroforético semejante en ambas variedades. Las proteínas se extrajeron mejor a valores de pH entre 5 y 12, pero no a valores de 2 a 4. El tratamiento con tripsina y quimotripsina mostró acumulación de bandas en el frente del gel, lo cual demuestra la presencia de péptidos digeridos. La actividad inhibitoria contra tripsina es mayor en la fracción albúminas con 741 UI mL-1 y fracción globulina con 587 UI mL-1. El contenido mineral fue de 0.5% para fósforo y de 0.28 para magnesio en melón chino; para el verde fue de 0.36% para potasio y de 0.28% para fósforo. El contenido de aceite fue de 35.8% en semilla de melón chino y de 23.2% en el verde, del cual se sabe que 67.5% son ácidos grasos insaturados; el aceite fue de color ámbar, de olor agradable. El uso de la semilla de melón es un recurso vegetal que debe promoverse por su alto contenido de proteína y aceite, ya que es valioso para la alimentación humana. También puede usarse en la formulación de alimento para ganado o de larvas de insecto cultivadas en laboratorio.

Este trabajo provee una visión general de la actividad proteolítica en el intestino de adultos de Moneilema armatum (Coleoptera: Cerambycidae) y la inhibición de dichas enzimas por proteínas obtenidas de los cladodios de Opuntia ficus-indica . Las proteasas intestinales activas fueron detectadas de pH neutral a ligeramente alcalino a través de zimografía y ensayos espectrofotométricos usando sustratos sintéticos. Estas enzimas fueron susceptibles a un inhibidor específico para serin proteasas (PMSF) y también se demostró que las actividades proteolíticas presentes correspondieron a actividades tipo tripsina, quimotripsina y elastasa. Aunque los cladodios de O. ficus-indica poseen inhibidores de serin proteasas endógenos, parece ser que no todas las proteasas de M. armatum fueron afectadas, particularmente la actividad de tipo elastasa. Estos resultados indican que M. armatum exhibe una variedad de actividades de serin proteasas y que algunas de estas actividades podrían haberse vuelto insensibles a la presencia de dichos inhibidores endógenos.

This work provides an overview of proteolytic activity in the intestine of Moneilema armatum (Coleoptera: Cerambycidae) adults and inhibition of such enzymes by proteins obtained from the cladodes of Opuntia ficus-indica. Active intestinal proteases were detected at a neutral and slightly alkaline pH through zymography and spectrophotometric assays using synthetic substrates. These enzymes were susceptible to a specific serine protease inhibitor (PMSF). It was also demonstrated that trypsin-, chymotrypsin-, and elastase-like activities were present. Although the cladodes of O. ficus-indica possess endogenous inhibitors of serine proteases, it appears that not all proteases of M. armatum were affected, particularly those with elastase-like activity. The results indicated that M. armatum exhibits a variety of serine protease activities, and some of these proteolytic activities were insensitive to endogenous O. ficus-indica protease inhibitors.

A enxertia de Cucurbita maxima x Cucurbita moschata tem sido usada para prevenir problemas com Fusarium oxysporum f. sp. niveum na produção de melancia embora não seja efetivo contra ataque de nematóides. Em razão de seu vigor, plantas enxertadas podem ser plantadas em densidade mais baixa do que as plantas não enxertadas. A tolerância a Fusarium oxysporum f. sp. niveum e Meloidogyne incognita foi avaliada em plantas de melancia enxertadas em híbridos de Citrullus lanatus cv Robusta e em Cucurbita maxima x Cucurbita moschata cv Super Shintoza. Foram usadas densidades de plantas de 2.083 e 4.166 plantas ha-1. Como testemunhas usou-se plantas não enxertadas. Os cultivares de melancia Crocantes vermelhas e Sangria foram usados como polinizador. O experimento foi realizado em dois ciclos, sendo instalado em solo infestado com Fusarium oxysporum f. sp. niveum e Meloidogyne incognita. A incidência de Fusarium oxysporum f. sp. niveum foi, significativamente, maior em plantas não enxertadas. Plantas enxertadas apresentaram resistência semelhante ao Fusarium independentemente do porta-enxerto. O índice de galhas de Meloidogyne incognita foi significativamente menor em plantas enxertadas em Citrullus lanatus cv Robusta. As maiores diferenças significativas em relação aos demais tratamentos foram observadas em ambas as densidades de plantas enxertadas pela produtividade das plantas enxertadas em Citrullus lanatus cv Robusta.

Cucurbita maxima x Cucurbita moschata rootstock are used to prevent infection with Fusarium oxysporum f. sp. niveum in watermelon production; however, this rootstock is not effective against nematode attack. Because of their vigor, the grafted plants can be planted at lower plant densities than the non-grafted plants. The tolerance to Fusarium oxysporum f. sp. niveum and Meloidogyne incognita was assessed in watermelon plants grafted onto a hybrid of Citrullus lanatus cv Robusta or the Cucurbita maxima x Cucurbita moschata cv Super Shintoza rootstocks. The densities of plants were 2083 and 4166 plants ha-1. Non-grafted watermelons were the controls. The Crunchy Red and Sangría watermelon cultivars were used as the scions, it the latter as a pollinator. The experiments were performed for two production cycles in soils infested with Fusarium oxysporum f. sp. niveum and Meloidogyne incognita. The incidence of Fusarium oxysporum f. sp. niveum was significantly greater in the non-grafted than in the grafted plants. The grafted plants presented similar resistance to Fusarium regardless of the rootstock. The root-knot galling index for Meloidogyne incognita was significantly lower in plants grafted onto Citrullus lanatus cv Robusta than onto the other rootstock. The yields of plants grafted onto Citrullus lanatus cv Robusta grown at both plant densities were significantly higher than in the other treatments.

El objetivo de este trabajo fue caracterizar a nivel bioquímico la semilla de dos variedades mexicanas de frijol, Bayo Berrendo y Patzcuareño. En el año 2011, en Celaya, México, se extrajeron proteínas de reserva de las dos variedades criollas de frijol (Phaseolus vulgaris), con el fin de obtener sus perfiles electroforéticos. El contenido de proteína soluble en el caso de Bayo Berrendo fue de 16,47% y 14,53% para el Patzcuareño. Se detectaron diferencias en el patrón electroforético, sobre todo en la fracción de albúminas, que permitió diferenciar las variedades. La harina presentó alta actividad inhibitoria contra tripsina, principalmente en la fracción de faseolinas, 355 unidades en el Bayo Berrendo y 507 unidades en el Patzcuareño. Se determinó la composición elemental de la harina observándose diferencias en cuanto al contenido mineral. El Bayo Berrendo tiene un contenido de 0,15% de Ca, 5,53% de K y 0,60% de Mg. Los valores respectivos para el Patzcuareño fueron: 0,17%, 3,52% y 0,67%. El Bayo posee 18,8 ppm de Fe y el Patzcuareño 3,63 ppm. Se midieron otras variables relacionadas con su utilización con fines alimenticios, como capacidad de absorción de agua, con valores cercanos al 100% y tiempos de cocción menores a 110 min. Fenotípicamente las dos variedades se distinguen fácilmente, tanto en tamaño de semilla como en color. El peso de 100 semillas del Bayo Berrendo fue de 14,6 g y del Patzcuareño 32,6 g.

The objective of this work was to characterize, at the biochemical level, two Mexican native landraces Bayo Berrendo and Patzcuareño of common bean. Storage protein from seeds was extracted from two common bean (Phaseolus vulgaris) varieties (Bayo Berrendo and Patzcuareño), and their respective electrophoretic patterns were compared. Total soluble protein was 16,47% for Bayo Berrendo, and 14,53% for Patzcuareño. Differences were also detected in the albumin fraction. Moreover their flour showed high inhibitory activity against trypsin mainly in the phaseolin fraction, which corresponded to 355 units in the Bayo Berrendo and 507 units in the Patzcuareño variety. The elemental composition of the flour was also determined and showed differences. The Bayo Berrendo seed flour has a composition of 0,15% Ca, 5,53% K and 0,60% Mg. While values for the Patzcuareño flour were 0,17%, 3,52 and 0,67% respectively. Interestingly the Bayo variety contained 18,8 ppm iron, while Patzcuareño contains only 3,63 ppm. Other variables related to food usage were analyzed such as water absorption capacity, which showed values near 100% for both landraces, and cooking time which took less than 110 minutes. Phenotypically, the two landraces are different in both size and color. The weight for 100 seeds of the Bayo Berrendo variety was 14,6 g and for Patzcuareño 32,6 g.

Population density affects some agronomic traits in varieties such as physical and physiological quality of the seed. In order to assess this effect, two female genotypes were grown of two commercial hybrids of maize (Zea mays L.); the evaluated densities were 52 630,65 789,78 789,92 013 and 105 263 plants ha-1 in the experimental field of Roque Institute of Technology, Guanajuato. A factorial experiment was chosen, using arandomized complete block design with four replications. We evaluated plant height, ear size, days to silking, photosynthetically active leaves, tillering, attack of Fusarium spp., stalk lodging, plant ''horras'' and grain yield; seed quality was evaluated by volumetric weight, purity analysis, weight of 1000 seeds and seed classes. The physiological quality, through the standard germination and vigor. The results show that, the density of population had statistically significant effects on the following agronomic traits: plant height and ear size, photosynthetically active leaf number, tillering, percentage of plants ''horras'' and grain yield; so, at least one density is higher or allow to see differences between them; in none of the variables of this group, showed interaction effects between genotypes and densities, indicating independence among these factors.

La densidad de población afecta algunos caracteres agronómicos en las variedades, como la calidad física y fisiológica de la semilla. Con el objetivo de evaluar este efecto, se sembraron dos genotipos hembra de dos híbridos comerciales de maíz (Zea mays L.); las densidades evaluadas fueron 52 630, 65 789, 78 789, 92 013 y 105 263 plantas ha-1 en el campo experimental del Instituto Tecnológico de Roque, Guanajuato. Se eligió un experimento factorial con diseño de bloques completos al azar con cuatro repeticiones. Se evaluó altura de planta, de mazorca, días a floración femenina, hojas fotosintéticamente activas, amacollamiento, ataque de Fusarium spp., acame de tallo, plantas ''horras'' y rendimiento de grano; la calidad de la semilla fue evaluada mediante peso volumétrico, análisis de pureza, peso de 1 000 semillas y clases de semilla. La calidad fisiológica, a través de la germinación estándar y el vigor. Los resultados obtenidos muestran que la densidad de población tuvo efectos estadísticamente significativos en las siguientes variables agronómicas: altura de planta y de mazorca, número de hojas fotosintéticamente activas, amacollamiento, porcentaje de plantas ''horras'' y rendimiento de grano; así, al menos una densidad es superior o permite observar diferencias entre ellas; en ninguna variable de este grupo se presentó efectos de interacción entre genotipos y densidades, indicando independencia entre estos factores.