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Dipti S.S.,International Rice Research Institute | Dipti S.S.,A+ Network | Bergman C.,University of Nevada, Las Vegas | Bergman C.,A+ Network | And 19 more authors.
Rice | Year: 2012

It is internationally accepted that malnutrition and chronic diseases in developing countries are key limitations to achieving the Millennium Development Goals. In many developing countries, rice is the primary source of nutrition. In those countries, the major forms of malnutrition are Fe-induced anaemia, Zn deficiency and Vitamin A deficiency, whereas the major chronic disease challenges are Type II diabetes, cardiovascular disease and some cancers. There is a growing corpus of evidence regarding both limitations and opportunities as to how rice could be an effective vehicle by which to tackle key nutrition and health related problems in countries with limited resources. Rice breeding programs are able to focus on developing new varieties carrying enhanced amounts of either Fe, Zn or betacarotene because of large public investment, and the intuitive link between providing a mineral/vitamin to cure a deficiency in that mineral/vitamin. By contrast, there has been little investment in progressing the development of particular varieties for potential impact on chronic diseases. In this review article we focus on the broad battery of evidence linking ricerelated nutritional limitations to their impact on a variety of human health issues. We discuss how rice might offer sometimes even simple solutions to rectifying key problems through targeted biofortification strategies and finally, we draw attention to how recent technological (-omics) developments may facilitate untold new opportunities for more rapidly generating improved rice varieties specifically designed to meet the current and future nutritional needs of a rapidly expanding global population. © 2012 Dipti et al.

Medina A.,University Centroccidental Lisandro Alvarado | Gonzalez-Vera A.,Fundacion para la Investigacion Agricola Danac | Pineda J.,University Centroccidental Lisandro Alvarado | Hernandez A.,University Centroccidental Lisandro Alvarado
Bioagro | Year: 2012

The banded leaf of maize is the primarily disease in corn fields in Portuguesa State, Venezuela. The objectives of this study were to determine the incidence and carry out cultural and pathogenic characterization of binucleate Rhizoctonia strains isolated from typical symptoms of the banded leaf of maize. From samples collected in 2006, fungus strains were isolated in semi selective media and they were purified by growing hyphae tips. Nuclear staining was used to verify the number of nuclei per cell, and it allowed to find that 39.68 % of the isolates belonged to binucleate Rhizoctonia. Isolates were characterized by measuring the formation of sclerotia and growth velocity in PDA medium. Two pathogenicity tests were performed: a) in greenhouse, where agar-mycelium discs were inoculated in basal leaves of healthy maize plants, and b) in laboratory, where a grain of rice colonized by the fungus was placed on the adaxial part of healthy leaves in 2 ppm kinetin solution. The results in greenhouse indicated that the 16 tested strains caused symptoms in 100 % of the inoculated seedlings, being a response similar of the control Rhizoctonia solani AG1 IA. Only 31.2% of strains and isolates formed sclerotia, and the most aggressive isolates (M2C1, M4G4, M5B1, and M1F3) showed an average growth rate of 1.1 cm per day, under laboratory conditions. We conclude that Ceratobasidium (= binucleate Rhizoctonia) emerges as a pathogen of the complex banded leaf of maize, in Portuguesa State, Venezuela.

Bastidas Y.,University Centroccidental Lisandro Alvarado | Chassaigne A.,Fundacion para la Investigacion Agricola Danac | Alezones J.,Fundacion para la Investigacion Agricola Danac | Hernandez A.,University Centroccidental Lisandro Alvarado
Bioagro | Year: 2015

Maize in Venezuela is affected by several pathogenic fungi that cause yield reduction and damaged grain. The small and medium farmers demand affordable cultivars with high yield potential and good agronomic performance. The maize breeding program of DANAC Foundation offers open pollinated varieties (OPV) as an alternative for low income producers. In 2011 trials were conducted in order to characterize two new DANAC OPV and compare them with four commercially available varieties. Trials for agronomic performance evaluation were planted in two farms located in Tucupido (Guárico State) and San Javier (Yaracuy State). Simultaneously, these cultivars were evaluated in laboratory conditions for resistance to Fusarium verticilloides (FV) and Aspergillus flavus (AF) through seed inoculation, and Rhizoctonia solani (RS) through plant inoculation. No interactions cultivars by location were detected, except for the flowering time. The highest yields were observed in Tucupido. The new variety DANAC-5021 had the highest value for days to anthesis at both locations, and in the pooled analysis showed the highest grain yield (4708 kg·ha-1), endosperm fraction (78.2%) and specific gravity (0,804 kg·L-1), and the lowest value for lodging (less than 4%). The new variety DANAC-5023 was more resistant than any other cultivar against AF and FV grain colonization and against RS plant infection. The superior performance of these new varieties evidence the positive effect of selecting parents of OPVs for high per se yield and enhanced resistance to pathogens. © 2015, Universidad Centroccidental Lisandro Alvarado (UCLA). All rights reserved.

Gonzalez-Vera A.,Fundacion para la Investigacion Agricola Danac | Graterol E.,Fundacion para la Investigacion Agricola Danac | Borges B.,Fundacion para la Investigacion Agricola Danac | Hernandez F.,Fundacion para la Investigacion Agricola Danac
Bioagro | Year: 2011

The rice (Oryza sativa L.), in Venezuela, is affected by sheath blight caused by Rhizoctonia solani (teleomorph = Thanatephorus cucumeris). No complete resistance has been found in the world. In consequence, breeding programs should evaluate many cultivars for selecting those with the best quantitative level of resistance. The objectives were to compare methods of evaluation and cultivars reaction for resistance to the sheath blight caused by R. solani AG-1 IA. The evaluation methods were microchamber and mycelium ball in greenhouse conditions, kinetin test in laboratory and colonized rice infestation under field conditions. The cultivars were 23 genotypes of rice, including control varieties. Three haplotypes of R. solani, previously characterized, were used for the inoculations. The experimental designs were randomized complete block with three replications. The effectiveness of the trials was determined based on the discrimination of controls with well-known reaction and the best correlation of the laboratory and greenhouse methods with the field results. The method of microchamber using the isolate A5B4 (64) had the best correlation with field results (r = 0.50 on average), followed by the method of ball mycelium (r = 0.49, on average). The control cultivars 'Tetep' (resistant) and 'Lemont' (susceptible) were consistent across the experiments. The principal component analysis identified the genotypes CT15150-M-11-4-3-2-M (derived from a cross with O. glaberrima), 'SD20A' and 'DSativa' with the best levels of resistance. These results indicate the existence of reliable methods to evaluate this disease and adapted cultivars with resistance to rice sheath blight.

Alezones J.,Fundacion para la Investigacion Agricola Danac | Avila M.,Fundacion para la Investigacion Agricola Danac | Chassaigne A.,Fundacion para la Investigacion Agricola Danac | Barrientos V.,Fundacion para la Investigacion Agricola Danac
Archivos Latinoamericanos de Nutricion | Year: 2010

In Venezuela, white corn is the most important crop regarding production, harvest area and consumption. One of its main by-products is corn oil, whose positive effect on health caused by the high content of unsaturated fatty acids has been widely recognized. In order to characterize the fatty acids profile of twelve white grained maize hybrids extensively grown in Venezuela, and the effect that divergent localities has on this profile, three semi commercial scale trials where established in Portuguesa, Yaracuy and Guárico states. Proportions of the main fatty acids in the raw oil of the different grain samples were determined using gas chromatography. Significant differences (p<0,01) between hybrids were found for arachidic, palmitic, stearic, oleic, gadoleic and linoleic acids; non significant differences were found for linolenic acid. Significant differences between localities were found for all the fatty acids evaluated. High and significant correlations between fatty acids content were found; the most important relations were: linoleic-oleic (Rho= -0,98**), arachidic-palmitic (Rho= -0,61**), linoleic-stearic (Rho= -0,61**) and oleic-stearic (Rho= 0,58**). Corn produced in Venezuela presents lower levels of linoleic and higher levels of palmitic, stearic and oleic acids than the levels found in temperate corn. These differences involve significant changes in the nutritional properties of Venezuelan corn oil that should be considered in the development of new cultivars and industrial processes for oil production.

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