45 research outputs found
Bee honey color variation throughout the year in Hejotitán, Jalisco, México.
Bee honey is a highly valued food whose international marketing is controlled by quality standards that are based on its physicochemical properties. One of them is color, which does not reflect a high or low quality, but rather the preferences of certain consumer markets. Color in honey is mostly determined by its floral sources that constantly change throughout the year. This study was intended to record color variations of the honey collected by Apis mellifera. For this purpose, honey was sampled from three selected hives, in an apiary in the town of Huejotitan, state of Jalisco, in western Mexico, on a monthly basis for a year. Color was measured according to the Pfund scale. Humidity was also measured since fermentation due to excessive moisture could spoil the samples. Two additional samples were collected, as well, from the bulk of honey at the time of the harvests, directly from the extractor: one from the spring harvest in May 2012, and the other from the fall harvest in December 2012. A total of 23 samples were obtained from December 2011 to December 2012. Color ranged from 0 mm Pfund (water white) to 85 mm Pfund (light amber) and humidity from 17% to 24%. It was discovered that the samples collected during the peak of the nectar flow, October - November, were contrastingly whiter than the rest. Although requiring more work, since consumers prefer clearer honeys, it is concluded that honey harvested at intervals during the high flow in the hives, with careful consideration of the moisture and making sure to keep honeys from different hives, apiaries and producers separate, a wider variety of honeys would be obtained, with different shades of color and different properties, better targeting the more specialized and demanding markets of today
Maternal genetic inheritance of red pericarp in the grain of maize
The diversity of colors in the grain of corn is wide, from whites to blacks and including a continuum of various shades of yellows, pinks, reds, purples and blues. The most abundant commercial colors are yellow and white, however other colors have become more important because of the presence of pigments to which are attributed favorable effects as a food. The pigments are also considered natural barriers of the grain against the invasion of pests and diseases in the production fields. The colors of the grain of corn occur in three different parts of the seed: the cover of the grain or pericarp, derived from the maternal tissue, with a diploid genetic content; the endo-sperm, including the aleurone layers that are cells in the grain immediately below the pericarp with a chromosome content of 3n; and the embryo, with a genetic content of 2n. The red color considered in this study is present in the pericarp ignoring possible effects in other tissues of grain and other organs of the plant. In this study, we used materials with colorless or red pericarp, and white or yellow endosperm; with the purpose of describing the type of inheritance of this character in the grain of corn. The results indicated a maternal genetic inheritance with classical complete dominance of the red color of pericarp over the clear or transparent phenotype, where the red color of the grains on ear is determined by the genotype of the mother grain but not by the seed embryo genotypes, which is characterized by uniformity of grain color of the ear. This type of inheritance could be useful in the development of pigmented varieties of higher food quality for humans
Identification of teosinte populations (Zea spp.) useful for grain yielding improvement in maize (Zea mays L.)
The great phenotypic and genotypic diversity of Genus Zea can be inherited within and between populations. Teosinte (Zea spp.) is the closest wild relative to maize, distributed in Mexico and Central America from Chihuahua to Costa Rica through several environmental conditions. The potential ability of exotic germplasm to incorporatetraits on maize (Zea mays L.) domesticated crops has been demonstrated. Among traits of economic interest that can be transferred from teosinte to maize, the following stand out: higher grain yield, resistance to pests and diseases, and product quality. 180 crosses between BC2F1 (maize-teosinte families) and LUG282 were evaluated to test introgressed teosinte germplasm potential on CIMMYT line CML311 background. The 180 F1 with teosinte introgressions were evaluated at three environments and compared to a reference control LUG282xCML311 and to some other experimental and some commercial hybrids as controls also. Main variables evaluated were days to anthesis and silking, plant and ear height, root and stalk lodging and grain yield. The results of the combined ANOVA by teosinte families showed that hybrids with introgressions of a teosinte population from La Lima, Tolimán, Jalisco, (Zea mays ssp. parviglumis landrace Balsas) averaged higher in grain yield, but they were notstatistically superior to the reference control LUG282xCML311 (α = 0.05); while in the combined ANOVA by treatments only the hybrid with teosinte T100 (T = treatment number) was statistically superior to reference control for grain yield (α = 0.05). Among other traits, hybrids with Zea diploperennis introgressions (San Andres Milpillas, Nayarit) appeared to be a reliable source for resistance to foliar diseases
Corbicular pollen spectrum (Apis mellifera) of samples from Huejotitan, Jalisco, Mexico
Las abejas melíferas (Apis mellifera L.) dependen completamente de los recursos que las rodean. Estos afectan su supervivencia, producción de miel y la calidad de ésta. Muy poca información está disponible sobre los recursos que utilizan las abejas melíferas en México. Se hizo un estudio para identificar los recursos florales utilizados por las abejas melíferas por medio de un análisis del polen corbicular colectado de un colmenar en la población de Huejotitan, municipio de Jocotepec, estado de Jalisco, México. Se utilizaron trampas de polen tipo Ontario modificadas para colectar muestras de polen de manera mensual de tres colmenas a través de un periodo de cuatro meses (agosto – noviembre, 2012). Se etiquetaron y congelaron las muestras para luego procesarlas mediante la técnica de acetólisis para eliminar la exina. Se prepararon portaobjetos permanentes de glicerina para conservar y analizar las muestras. La identificación, el recuento de los granos de polen, así como la medición de cada grano se realizaron por medio de un microscopio vertical equipado con un micrómetro ocular de 100X y utilizando aceite de inmersión. Se hizo una colección de referencia como medio auxiliar de identificación y como referencia estacional de las especies florecientes en el área del colmenar muestreado. Una vez al mes se recolectaron, se marcaron, y se prensaron flores de todas las plantas en flor, y se llevaron al herbario para su identificación. El polen fue extraído de estas flores, procesado e identificado. En las muestras de polen corbicular se identificaron 23 tipos de plantas pertenecientes a 17 familias de plantas. Trece de ellas se identificaron a nivel de especie, cinco a nivel de género y cinco más a nivel familia. Myrtaceae fue la familia representada con mayor frecuencia en las muestras, seguida por Asteraceae, Fabaceae y Lamiaceae.This study examines the different plants visited by the honeybee (Apis mellifera L.) during the honey harvest season (August to November) 2012. The work consisted in identifying the corbicular pollen pellets collected by the bees in one apiary in the village of Huejotitan, municipality of Jocotepec, state of Jalisco, Mexico. Three hives were selected and sampled monthly by means of Ontario modified pollen traps. The samples were tagged and frozen and later processed by acetolysis technique to remove the exine; permanent glycerine slides were made for the preservation and analysis. Identification and counting of pollen grains was performed using an Olympus BH-2® upright microscope equipped with a 100X ocular micrometer to measure each individual species pollen grain, using immersion oil. Wild plants in bloom were also collected monthly, tagged, pressed and taken to the herbarium for identification; the pollen was extracted, processed and identified for a reference collection that served as an ancillary means of identification and as a seasonal reference to the blooming species. In the corbicular pollen, 23 types of plants were identified: 13 at species level, five at genus level and five at family level belonging to 17 plant families. Myrtaceae resulted the most frequently represented family followed by Asteraceae, Fabaceae and Lamiaceae
Travaillez ou mariez-vous !:La régulation sexuée de la pauvreté en France et aux États-Unis
L’article présente une analyse sexuée de l’évolution des droits et devoirs qui lient les personnes percevant l’aide sociale et l’Etat en France et aux Etats-Unis. Dans les deux pays, la contrepartie exigée en retour de la solidarité nationale a longtemps reposé pour les femmes sur leur rôle de « mère », pour les hommes sur celui de « pourvoyeur de ressources de la famille ». Les réformes successives des programmes de lutte contre la pauvreté aux Etats-Unis et en France ont modifié la nature de ces obligations, renforçant dans les deux cas la logique du mérite via une exigence d’insertion dans l’emploi, ceci de façon plus marquée aux Etats-Unis qu’en France. L’injonction à l’autonomie concerne désormais femmes et hommes, mais épargne les femmes mariées, dont l’inactivité est acceptée voire encouragée dans les dispositifs sociaux ou fiscaux
Extinction risk of Mesoamerican crop wild relatives
Ensuring food security is one of the world's most critical issues as agricultural systems are already being impacted by global change. Crop wild relatives (CWR)—wild plants related to crops—possess genetic variability that can help adapt agriculture to a changing environment and sustainably increase crop yields to meet the food security challenge.
Here we report the results of an extinction risk assessment of 224 wild relatives of some of the world's most important crops (i.e. chilli pepper, maize, common bean, avocado, cotton, potato, squash, vanilla and husk tomato) in Mesoamerica—an area of global significance as a centre of crop origin, domestication and of high CWR diversity.
We show that 35% of the selected CWR taxa are threatened with extinction according to The International Union for Conservation of Nature (IUCN) Red List demonstrates that these valuable genetic resources are under high anthropogenic threat. The dominant threat processes are land use change for agriculture and farming, invasive and other problematic species (e.g. pests, genetically modified organisms) and use of biological resources, including overcollection and logging. The most significant drivers of extinction relate to smallholder agriculture—given its high incidence and ongoing shifts from traditional agriculture to modern practices (e.g. use of herbicides)—smallholder ranching and housing and urban development and introduced genetic material.
There is an urgent need to increase knowledge and research around different aspects of CWR. Policies that support in situ and ex situ conservation of CWR and promote sustainable agriculture are pivotal to secure these resources for the benefit of current and future generations
Bee Honey Color Variation throughout the Year
Bee honey is a highly valued food whose international marketing is controlled by quality standards that are based on its physicochemical properties. One of them is color, which does not reflect a high or low quality, but rather the preferences of certain consumer markets. Color in honey is mostly determined by its floral sources that constantly change throughout the year. This study was intended to record color variations of the honey collected by Apis mellifera. For this purpose, honey was sampled from three selected hives, in an apiary in the town of Huejotitan, state of Jalisco, in western Mexico, on a monthly basis for a year. Color was measured according to the Pfund scale. Humidity was also measured since fermentation due to excessive moisture could spoil the samples. Two additional samples were collected, as well, from the bulk of honey at the time of the harvests, directly from the extractor: one from the spring harvest in May 2012, and the other from the fall harvest in December 2012. A total of 23 samples were obtained from December 2011 to December 2012. Color ranged from 0 mm Pfund (water white) to 85 mm Pfund (light amber) and humidity from 17% to 24%. It was discovered that the samples collected during the peak of the nectar flow, October - November, were contrastingly whiter than the rest. Although requiring more work, since consumers prefer clearer honeys, it is concluded that honey harvested at intervals during the high flow in the hives, with careful consideration of the moisture and making sure to keep honeys from different hives, apiaries and producers separate, a wider variety of honeys would be obtained, with different shades of color and different properties, better targeting the more specialized and demanding markets of today
EVALUATING THE CORRELATION OF PLOIDY LEVEL, LEAF SIZE, STOMATA CHARACTERISTICS AND TUBER WEIGHT IN Dioscorea spp. POPULATIONS FROM JALISCO, MÉXICO
Background. “Camote de cerro” (Dioscorea spp.) is a plant of great importance in West rural areas of Mexico as food source and alternative medicine. Dioscorea is an important crop around the world for its carbohydrate contribution to diets. Yams are polyploid plants, and species with modifications at ploidy level also present changes in leaf size and stomata characteristics. These variations can favor resistance to adverse conditions. Objective. In the present study, evaluation and correlation of ploidy levels, leaf size, stomata characteristics and tuber weight were carried out for Dioscorea remotiflora Kunth and Dioscorea sparsiflora Hemsley in accessions obtained from 11 localities in México. Methodology. Chromosome counting was carried out in root meristems. Measuring and counting stomata were carried out. Productivity rate (PR) was calculated dividing harvested tuber weight over seed tuber weight, for each experimental unit. Leaves width and length were measured. Results. Show that variation is higher among different localities than among specimens from the same locality. Significant differences were observed for, ploidy levels (P), stomata dimensions and number of chloroplasts in stomata. Differences in chloroplast numbers present in occlusive cells were also significant for different species. Implications. Ploidy level showed a relation with chloroplasts numbers in stomata and stomata width. Leaf size presented a relation with stomata dimensions, and leaf width showed a relation with tuber weight. Conclusions. These observations allowed us to determine that there are variation among populations; stomata width and chloroplast number in a population can help to determine ploidy levels, and leaf width is a response variable that allows to predict tuber weight