Instituto Nacional Of Investigaciones Agropecuarias

Quito, Ecuador

Instituto Nacional Of Investigaciones Agropecuarias

Quito, Ecuador
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Ortiz-Olivas M.E.,Universidad Juárez del Estado de Durango | Hernandez-Diaz J.C.,Universidad Juárez del Estado de Durango | Fladung M.,Thunen Institute of Forest Genetics | Canadas-Lopez A.,Instituto Nacional Of Investigaciones Agropecuarias | And 2 more authors.
Forests | Year: 2017

Studies of spatial genetic structure (SGS) are important because they offer detailed insights into historical demographic and evolutionary processes and provide important information regarding species conservation and management. Pinus engelmannii and P. leiophylla var. leiophylla are two important timber tree species in Mexico, covering about 2.5 and 1.9 million hectares, respectively. However, studies in relation to population genetics are unfortunately scant. The aim of this research was to use amplified fragment length polymorphisms (AFLP) analysis to identify potential differences in spatial genetic structure within and among seven Pinus engelmannii and nine P. leiophylla var. leiophylla seed stands in Durango, Mexico. Within the 16 seed stands of the two tested pine species, no significant SGS was detected, although SGS was detected among the seed stands. We concluded that the collection of seed in only some seed stands should not significantly alter the degree of genetic differentiation within the (collected) seed. Distances between seed orchards and pollen propagators of more than 24 km for P. engelmannii and 7 km for P. leiophylla may be sufficient to limit contamination. Finally, local seeds should be used for (re)forestation. © 2017 by the authors.

Ordonez M.E.,Pontifical Catholic University of Ecuador | Barnes C.W.,Instituto Nacional Of Investigaciones Agropecuarias
Mycotaxon | Year: 2017

The full macrocyclic autoecious life cycle of five spore stages was confirmed for Edythea quitensis on Berberis hallii in the highlands of Ecuador. The spermogonial and aecial stages had not previously been recorded. Spore descriptions and DNA sequence analysis are included.

Rodriguez-Hidalgo R.,Central University of Ecuador | Perez-Otanez X.,Central University of Ecuador | Garces-Carrera S.,Instituto Nacional Of Investigaciones Agropecuarias | Vanwambeke S.O.,Catholic University of Louvain | And 3 more authors.
PLoS ONE | Year: 2017

Rhipicephalus microplus is widely distributed in tropical and subtropical areas of the world where livestock is a principal activity with great veterinary and economic importance. In Ecuador, this hematophagous ectoparasite has been observed between 0 and 2600 masl. One of the main tick control measures is the use of acaricides, which have been indiscriminately used worldwide and in Ecuador. In this country, no studies on acaricide resistance in Rhipicephalus microplus have been published. The current study aims to characterise the level of resistance of R. microplus against three main acaricides commonly used in Ecuador i.e. amitraz, alpha-cypermethrin and ivermectin to determine the level and pattern of dose-responses for R. microplus in 12 field populations (farms). The level of acaricide resistance was evaluated using three different bioassays: adult immersion test (AIT), larval package test (LPT) and larval immersion test (LIT), as recommended by the FAO. The predictive dose-responses were analysed by binomial logistics regression of the larval survival rate (resistance). In general, we found resistance of 67% for amitraz; 50% for alpha-cypermethrin and from 25 to 42% for ivermectin in the twelve field populations analysed. Resistance levels were studied in larval and adult bioassays, respectively, which were slightly modified for this study. For larval bioassays based on corrected mortality i.e. high (above 51%), medium (21-50%) and low (11-20%) resistance, percentages less than 10% were considered as susceptible. For the adult test, two resistance levels were used i.e. high (more than 76%) and medium (51 to 75%) resistance. Percentages lower than 50% were considered as susceptible. In this context, for larval bioassays, amitraz showed 21%, 38% and 8% for high, medium and low resistance, respectively. Alpha-cypermethrin presented 8%, 4 and 38% for high, medium and low resistance, respectively. Ivermectin presented 8%, 25% and 8% for high, medium and low resistance, respectively. For adult tests with amitraz 50% and 17% of the field populations showed average and high resistance, with evidences of average resistance to alpha-cypermethrin in 50% of the samples and average resistance against ivermectin in 25% of the farms. No statistical difference amongst the three bioassays was found and acaricide resistance was confirmed by logistic regression analysis; hence resistance (dose-responses) in each field populations differed, depending on the choice of the acaricide, frequent usage, frequency of treatment and farm management. The effective estimated dose needed to eliminate 99% of ticks is higher than dose recommended by the manufacturer. In conclusion, amitraz showed the highest resistance followed by ivermectin and alpha-cypermethrin and reveals differences on resistance in each individual field population. This information is important in order to establish the monitoring of resistance on each farm individually, contributing to the rational use of acaricides included in an integrated control program for R. microplus. © 2017 Rodríguez-Hidalgo et al.This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Riquelme A.,Center for Advances Studies in Fruit Science | Alvarez P.,Instituto Nacional Of Investigaciones Agropecuarias | Pinto M.,Center for Advances Studies in Fruit Science | Pinto M.,Instituto Nacional Of Investigaciones Agropecuarias
Acta Horticulturae | Year: 2017

Nitric oxide (NO) has the ability to emulate dependent effects of light on plants. In particular, this molecule can inhibit the degradation of chlorophyll and promote the accumulation of this pigment in greening tissues. On the other hand, early lightinduced proteins (ELIPs) are known to bind chlorophyll molecules, thus protecting them from degradation. NO, in turn, can also increase the expression of ELIPs. The aim of this study was to evaluate the effect of exogenous applications of nitric oxide on the chlorophyll content and on the expression of ELIPs-like proteins in greening young leaves of grapevines. Buds of grapevine 'Sultanina' were kept in the dark for two weeks to obtain aetiolated shoots. A nitric oxide treatment was obtained by spraying 100 μM S-nitroso-N-acetylpenicillamine solution onto shoots. Distilled water was sprayed onto control plants. The total chlorophyll content was measured by Arnon's method and ELIPs expression was detected by western blots, using pea-ELIPs antibodies. The results indicate that if the shoots were kept in dark after treatment, NO was unable to affect the chlorophyll content and the ELIP expression. However, if the greening young leaves were irradiated for two hours after NO treatment with 475 μmol PAR m-2 s-1, NO was very effective for increasing the chlorophyll content and the ELIPs expression. This effect was greater as the light intensity increased.

Ginocchio R.,University of Santiago de Chile | Leon-Lobos P.,Instituto Nacional Of Investigaciones Agropecuarias | Arellano E.C.,University of Santiago de Chile | Anic V.,University of Chile | And 2 more authors.
Environmental Science and Pollution Research | Year: 2017

Abandoned tailing dumps (ATDs) offer an opportunity to identify the main physicochemical filters that determine colonization of vegetation in solid mine wastes. The current study determined the soil physicochemical factors that explain the compositional variation of pioneer vegetal species on ATDs from surrounding areas in semiarid Mediterranean-climate type ecosystems of north-central Chile (Coquimbo Region). Geobotanical surveys—including physicochemical parameters of substrates (0–20 cm depth), plant richness, and coverage of plant species—were performed on 73 ATDs and surrounding areas. A total of 112 plant species were identified from which endemic/native species (67%) were more abundant than exotic species (33%) on ATDs. The distribution of sampling sites and plant species in canonical correspondence analysis (CCA) ordination diagrams indicated a gradual and progressive variation in species composition and abundance from surrounding areas to ATDs because of variations in total Cu concentration (1.3%) and the percentage of soil particles <2 μm (1.8%). According to the CCA, there were 10 plant species with greater abundance on sites with high total Cu concentrations and fine-textured substrates, which could be useful for developing plant-based stabilization programs of ATDs in semiarid Mediterranean-climate type ecosystems of north-central Chile. © 2017 Springer-Verlag Berlin Heidelberg

Paruelo J.M.,University of Buenos Aires | Pineiro G.,University of Buenos Aires | Baldi G.,National University of San Luis | Baeza S.,University of Montevideo | And 3 more authors.
Rangeland Ecology and Management | Year: 2010

Grasslands are one of the most modified biomes on Earth. Land use changes had a large impact on carbon (C) stocks of grasslands. Understanding the impact of land use/land cover changes on C stocks and fluxes is critical to evaluate the potential of rangeland ecosystem as C sinks. In this article we analyze C stocks and fluxes across the environmental gradients of one of the most extensive temperate rangeland areas: the RÃ-o de la Plata Grasslands (RPG) in South America. The analysis summarizes information provided by field studies, remote sensing estimates, and modeling exercises. Average estimates of aboveground net primary production (ANPP) ranged from 240 to 316 g C·m-2·yr-1. Estimates of belowground NPP (BNPP) were more variable than ANPP and ranged from 264 to 568 g C·-2·yr-1. Total Carbon ranged from 5004 to 15008 g C·-2. Plant biomass contribution to Total Carbon averaged 13% and varied from 9.5% to 27% among sites. The largest plant C stock corresponded to belowground biomass. Aboveground green biomass represented less than 7% of the plant C. Soil organic carbon (SOC) was concentrated in the slow and passive compartments of the organic matter. Active soil pool represented only 6.7% of the SOC. The understanding of C dynamics and stocks in the RPG grasslands is still partial and incomplete. Field estimates of ANPP and BNPP are scarce, and they are not based on a common measurement protocol. Remotely sensed techniques have the potential to generate a coherent and spatially explicit database on ANPP. However, more work is needed to improve estimates of the spatial and temporal variability of radiation use efficiency. The absence of a flux tower network restricts the ability to track seasonal changes in C uptake and to understand fine-scale controls of C dynamics. © 2010 Society for Range Management.

Sotomayor-Ramirez D.,University of Puerto Rico at Mayaguez | Espinoza Y.,Instituto Nacional Of Investigaciones Agropecuarias
Journal of Agriculture of the University of Puerto Rico | Year: 2010

Cultivation affects soil organic matter loss through decreased soil structural stability. Sparse information is available for highly weathered soils. The objective of this study was to evaluate the effects of soil order (Ultisols and Inceptisols) and land use (agriculture and forest) on the formation of water stable aggregates, concentration of aggregate-associated C, and quality of C In aggregates from selected soils in a humid tropical watershed. Ultisols and soils under forest had increased soil C as a result of increased C concentrations in aggregates. Nearly 90% of the soil C was found in macroaggregates of soils under forest and In Ultisols. In forest and agriculture land use, soil silt+clay content was an important determinant for C storage in the bulk soil but not in aggregates. Cultivation reduced the percentage of soil mass in large macroaggregates (>2,000 μm) relative to that in forest soils, whereas Ultisols had greater soil mass percentage in large macroaggregates than Inceptisols. Overall, macroaggregates have higher labile and stable C than microaggregates. Ultisols had greater amounts of labile C but similar proportions of stable C. As has been found in other soils dominated by mixed-mineralogy and 1:1 clays and oxides, aggregate-associated C is not the sole determinant for the formation of macroaggregates.

Stewart R.D.,Virginia Polytechnic Institute and State University | Stewart R.D.,Oregon State University | Abou Najm M.R.,American University of Beirut | Rupp D.E.,Oregon State University | And 4 more authors.
Hydrological Processes | Year: 2015

Irrigation experiments on 12 instrumented field plots were used to assess the impact of dynamic soil crack networks on infiltration and run-off. During applications of intensity similar to a heavy rainstorm, water was seen being preferentially delivered within the soil profile. However, run-off was not observed until soil water content of the profile reached field capacity, and the apertures of surface-connected cracks had closed >60%. Electrical resistivity measurements suggested that subsurface cracks persisted and enhanced lateral transport, even in wet conditions. Likewise, single-ring infiltration measurements taken before and after irrigation indicated that infiltration remained an important component of the water budget at high soil water content values, despite apparent surface sealing. Overall, although the wetting and sealing of the soil profile showed considerable complexity, an emergent property at the hillslope scale was observed: all of the plots demonstrated a strikingly similar threshold run-off response to the cumulative precipitation amount. © 2014 John Wiley & Sons, Ltd.

PubMed | Instituto Nacional Of Investigaciones Agropecuarias, University of Greenwich and Pontifical Catholic University of Ecuador
Type: | Journal: Journal of economic entomology | Year: 2016

Delia platura Meigen is an important pest in crops around the world. Its host range includes almost 50 species, and it can develop in soil organic matter. In Ecuador, D. platura is a serious problem for the crop, Lupinus mutabilis Sweet (Chocho), and it also attacks broccoli (Brassica oleracea L.). After broccoli is harvested, crop residue is mixed with soil or collected and stored close to Chocho fields. The objectives of this study were to determine the adaptive responses of larvae reared on different hosts and whether D. platura females are preferentially attracted to germinating L. mutabilis seeds or broccoli residue. Accordingly, larval performance and attraction of female D. platura reared on broccoli residue and L. mutabilis seeds were evaluated. The number of larvae, pupae, and adults were higher when reared on broccoli. Conversely, pupal weight was higher and time from larva to pupa, pupa to adult, and total life cycle were longer in flies reared on L. mutabilis. Although D. platura developed more quickly on broccoli, L. mutabilis was also a good host since pupae were heavier compared with flies reared on broccoli. Delia platura females reared on broccoli preferred broccoli residue to L. mutabilis in an olfactometer. Volatiles from broccoli residue in soil may attract D. platura females and stimulate oviposition on L. mutabilis seeds. Environmentally benign production of L. mutabilis crops with minimal insecticide applications may require the elimination of fresh broccoli residue as fertilizer in soils where L. mutabilis is cultivated.

PubMed | Santa Catarina State University, Proterra, University of Reunion Island, Box 2312 and 31 more.
Type: | Journal: Persoonia | Year: 2016

Novel species of fungi described in the present study include the following from Australia: Neoseptorioides eucalypti gen. & sp. nov. from Eucalyptus radiata leaves, Phytophthora gondwanensis from soil, Diaporthe tulliensis from rotted stem ends of Theobroma cacao fruit, Diaporthe vawdreyi from fruit rot of Psidium guajava, Magnaporthiopsis agrostidis from rotted roots of Agrostis stolonifera and Semifissispora natalis from Eucalyptus leaf litter. Furthermore, Neopestalotiopsis egyptiaca is described from Mangifera indica leaves (Egypt), Roussoella mexicana from Coffea arabica leaves (Mexico), Calonectria monticola from soil (Thailand), Hygrocybe jackmanii from littoral sand dunes (Canada), Lindgomyces madisonensis from submerged decorticated wood (USA), Neofabraea brasiliensis from Malus domestica (Brazil), Geastrum diosiae from litter (Argentina), Ganoderma wiiroense on angiosperms (Ghana), Arthrinium gutiae from the gut of a grasshopper (India), Pyrenochaeta telephoni from the screen of a mobile phone (India) and Xenoleptographium phialoconidium gen. & sp. nov. on exposed xylem tissues of Gmelina arborea (Indonesia). Several novelties are introduced from Spain, namely Psathyrella complutensis on loamy soil, Chlorophyllum lusitanicum on nitrified grasslands (incl. Chlorophyllum arizonicum comb. nov.), Aspergillus citocrescens from cave sediment and Lotinia verna gen. & sp. nov. from muddy soil. Novel foliicolous taxa from South Africa include Phyllosticta carissicola from Carissa macrocarpa, Pseudopyricularia hagahagae from Cyperaceae and Zeloasperisporium searsiae from Searsia chirindensis. Furthermore, Neophaeococcomyces is introduced as a novel genus, with two new combinations, N. aloes and N. catenatus. Several foliicolous novelties are recorded from La Runion, France, namely Ochroconis pandanicola from Pandanus utilis, Neosulcatispora agaves gen. & sp. nov. from Agave vera-cruz, Pilidium eucalyptorum from Eucalyptus robusta, Strelitziana syzygii from Syzygium jambos (incl. Strelitzianaceae fam. nov.) and Pseudobeltrania ocoteae from Ocotea obtusata (Beltraniaceae emend.). Morphological and culture characteristics along with ITS DNA barcodes are provided for all taxa.

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