Rodriguez-Navarro D.N.,Centro Las Torres Tomejil |
Margaret Oliver I.,University of Seville |
Albareda Contreras M.,Centro Las Torres Tomejil |
Ruiz-Sainz J.E.,University of Seville
Agronomy for Sustainable Development | Year: 2011
Soybean, Glycine max (L.) Merrill, is one of the most important food crops in the world. High soybean yields require large amounts of N fertilizers, which are expensive and can cause environmental problems. The industrial fixation of nitrogen accounts for about 50% of fossil fuel usage in agriculture. In contrast, biological fixation of N 2 is a low-cost source of N for soybean cropping through the symbiotic association between the plant and soil bacteria belonging to the genera Bradyrhizobium and Sinorhizobium, which are collectively called "soybean rhizobia". In general, symbiotic nitrogen fixation in crop legumes not only reduces fertilizer costs but also improves soil fertility through crop rotation and intercropping. Biological nitrogen fixation is due to symbioses between leguminous plants and species of Rhizobium bacteria. Replacing this natural N source by synthetic N fertilizers would cost around 10 billion dollars annually. Moreover, legume seed and foliage have a higher protein content than that of non-legumes, and this makes them desirable protein crops. There is a wide knowledge of the industrial elaboration and use of commercial soybean inoculants based on bradyrhizobia strains. At present, the technology to prepare different types of inoculants, either solid or liquid, is sufficiently developed to meet market requirements, although further research and investments are still required to improve the symbiotic efficacy of rhizobial inoculants. Inoculation of soybeans under field conditions has been successful in the USA, Brazil and Argentina, which are the world leaders in soybean cultivation in terms of acreage and grain yields. There are, however, limitations to a wider use of rhizobial inoculants: the size of indigenous soil rhizobial populations can prevent the successful use of inoculants in some particular areas. For example, many Chinese soils contain more than 10 5 soybean rhizobia per gram of soil, which imposes a serious barrier for nodule occupancy by the soybean rhizobia used as an inoculant. The use of inoculants based on soil bacteria other than rhizobia has also increased in the last decades. An example is the genus Azospirillum, which can be used for its capacity to increase plant growth and seed yields through different mechanisms, such as the production of plant hormones and the increase in phosphate uptake by roots. In addition, co-inoculation with Azospirillum and rhizobia enhances nodulation and nitrogen fixation. Although less developed, it is expected that inoculants based on mycorrhizal fungi will also play a relevant role in sustainable agriculture and forestry. In spite of any possible limitations, the use of inoculants appears compulsory in a frame of sustainable agriculture, which seeks to increase crop yields and nutrient-use efficiency while reducing the environmental costs associated with agriculture intensification. This review also summarizes some of the most relevant genetic aspects of soybean rhizobia in relation to their symbiosis with soybeans. They can be listed as follows: (1) legume roots exude flavonoids, which are able to activate the transcription of nodulation (nod, nol, noe) genes; (2) expression of nodulation genes results in the production and secretion of lipo-chitin oligosaccharide signal molecules, called LCOs or "Nod factors", which activate nodule organogenesis in the legume root; (3) LCOs induce numerous responses of the legume roots, such as hair curling and the formation of nodule primordia in the inner or outer cortex; (4) the function of many soybean rhizobia nod genes is known and the chemical structure of the LCOs produced has been determined; (5) in addition to LCOs, different soybean rhizobia surface polysaccharides are required for the formation of nitrogenfixing nodules; (6) surface polysaccharides might act as signal molecules or could prevent plant defense reactions. Cyclic glucans, capsular polysaccharides and lipopolysaccharides appear to play relevant roles in the soybean nodulation process since rhizobial mutants affected in any of these surface polysaccharides are symbiotically impaired. Present knowledge of the molecular bases determining cultivar-strain specificity and nodule occupancy by soybean rhizobia competitors is clearly insufficient. This lack of information is a serious barrier for developing strategies aimed at improving nodulation and symbiotic nitrogen fixation of commercial inoculants. In spite of these difficulties, recent studies have shown that the signaling pathway involved in triggering nodule organogenesis is independent of that operating in bacterial entry through infection thread formation. Theses facts might offer new insights for improving symbiotic nitrogen fixation and also for the feasibility of transferring nodule organogenesis, a first step in expanding this symbiotic interaction into other agriculturally important species. © INRA, EDP Sciences, 2010.
Daza A.,Centro Las Torres Tomejil |
Camacho M.,Centro Las Torres Tomejil |
Galindo I.,University of Seville |
Arroyo F.T.,Centro Las Torres Tomejil |
And 2 more authors.
International Journal of Food Science and Technology | Year: 2012
The fruit quality parameters of several Japanese plum cultivars (Prunus salicina Lindl) were studied in two experimental orchards under organic and conventional management. The study was performed during 2008-2010 in the province of Seville (SW Spain). Colour, weight, size, firmness, soluble solid concentration and acidity were measured for fruit quality evaluation. Yield was also determined. In general, the organic fruit was of smaller size and weight. There was little difference in the colour of most of the varieties, but some varieties such as 'Friar' and 'Black Amber' were more colourful in the organic orchard. The soluble solid concentration and acidity were similar in the fruit from both orchards. The organic plums showed firmness equal to or slightly greater than conventional ones. Dry matter and nitrites were analysed in 2010, and no significant differences were observed in most of the varieties. The accumulated fruit yield was significantly superior in the conventionally managed orchard. © 2011 Institute of Food Science and Technology.
Dominguez P.,Centro Las Torres Tomejil |
Miranda L.,Centro Las Torres Tomejil
Journal of Berry Research | Year: 2015
BACKGROUND: Huelva (Spain) is the main region for strawberry production in Europe. Most fruit production is exported for fresh consumption to European countries, where consumers demand high fruit quality and appreciate its healthy properties. Strawberry intake is a valuable source of antioxidants compounds with important health benefits. The higher the antioxidant capacity of a cultivar, the better the enhancement of human health. OBJECTIVE: The comparative knowledge of fruit composition on antioxidant compounds and its variation along the cropping season, in ten strawberry cultivars cropped at Huelva. METHODS: Fruit yield and citric acid, ascorbic acid, total phenolics, anthocyanins content as well as antioxidant capacity of fruits were evaluated in ten strawberry cultivars at three harvesting times during the 2014 field campaign. RESULTS:Yield and fruit parameters analyzed were strongly influenced by the genotype and by the time of harvesting. Strawberry fruit quality and antioxidant properties were greater when harvested from mid-to late-season and were not associated with higher yields. CONCLUSIONS: Healthy properties of strawberry fruits depend on cultivar and harvest time. Knowledge of the nutritional properties of these strawberry cultivars might translate into benefits to growers and enhancement of health for consumers. © 2015-IOS Press and the authors. All rights reserved.
Duran Zuazo V.H.,Centro Las Torres Tomejil |
Rodriguez Pleguezuelo C.R.,Centro Camino Of Purchil |
Francia Martinez J.,Centro Camino Of Purchil |
Martin Peinado F.J.,University of Granada
Journal of Land Use Science | Year: 2013
Resource use and watershed management have become an increasingly important issue, stressing the need to find appropriate management approaches for improving agricultural landscapes. We analysed land-use changes from 1978 to 2007 in a representative watershed of Almuñécar (SE Spain). In 1978 the watershed consisted of 64.2% almond, 24.7% fallow land, 6.7% vineyard, 1.9% olive and 2.5% other uses. In 2007 much of the traditional orchards had disappeared, leaving only 17% almond and 0.6% vineyard. Not less than 29.8% had become shrubland and another 24.6% abandoned cropland. However, much of the land is now under subtropical crops: 19.2% avocado (Persea americana M.), 3.9% mango (Mangifera indica L.), 2.4% loquat (Eriobotrya japonica L.) and 1.1% cherimoya (Annona cherimola M.). This intensively irrigated agriculture with subtropical trees on terraces could exacerbate watershed degradation and could become a core problem with implications for sustainable resource use. The abandonment of traditional terraces with rainfed crops has led to the re-emergence of spontaneous native vegetation, promoting a denser plant cover and subsequent decrease in erosion. Therefore, highlighting the need for implementing sustainable conservation practices is crucial as part of future agricultural support. © 2013 Copyright Taylor and Francis Group, LLC.
Perez-Guerrero S.,Centro Las Torres Tomejil |
Gelan-Begna A.,University of Cordoba, Spain |
Vargas-Osuna E.,University of Cordoba, Spain
BioControl | Year: 2015
Intraguild predation (IGP) among predatory arthropods can impair pest control efforts and endanger the joint-action compatibility of groups of natural enemies. The present study used plant microcosms to examine IGP of Cheiracanthium pelasgicum (C. L. Koch) (Araneae: Miturgidae) on minute pirate bugs Orius laevigatus (Fieber) (Hemiptera: Anthocoridae), two of the major lepidopteran-egg predators in southern Spanish cotton fields, and its effects on the control of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) eggs. Intensive unidirectional IGP of C. pelasgicum on O. laevigatus was observed under plant arena conditions: over 90 % of minute bugs were killed by spiders in the first 24 h. However, no negative interaction between C. pelasgicum and minute pirate bugs was found under different egg-density conditions with Orius alone, and the combination of two predator treatments displayed significantly higher predation rates than the spider-alone treatment after 24 h. Increased egg density did not affect control by predators, nor did it prompt a significant reduction in IGP. During a day–night bioassay, negative interaction between the two predators was found under night conditions, impacting on egg predation rates due to the combination of two predators. Predation of spiders on H. armigera eggs took place mainly at night, while predation by minute bugs was recorded both by day and by night. Finally, IGP by C. pelasgicum on minute pirate bugs was significantly higher by night. These outcomes demonstrate that diurnal and more intensive nocturnal IGP by spiders on minute pirate bugs had a moderate impact on the early control of H. armigera, with no negative effects after 24 h. © 2015 International Organization for Biological Control (IOBC)
Guzman G.,University of Cordoba, Spain |
Vanderlinden K.,Centro Las Torres Tomejil |
Giraldez J.V.,University of Cordoba, Spain |
Giraldez J.V.,CSIC - Institute for Sustainable Agriculture |
Gomez J.A.,CSIC - Institute for Sustainable Agriculture
Soil Science Society of America Journal | Year: 2013
The combination of runoff plot studies and soil tracking using a silt size magnetic sediment tracer, allowed a better understanding of the relative contribution of different zones in olive (Olea europaea L.) orchard plots to total soil losses. The average erosion rates were different in the tree rows (tr) (0.8 kg m-2 mo-1) and in the inter-tree rows (itr) (1.4 kg m-2mo-1), inter-tree rills (r) being the most eroded areas (4 kg m-2 mo-1) from October 2008 to April 2010. Since soil under the olive canopies has a high infiltration capacity, splash is a major erosion process in this area, while, in the itr, sheet and rill erosion are the dominant processes. The proposed magnetic tracer technology was an effective tool for determining the cumulative soil losses at the plots for a 17 mo period (average 141 Mg ha-1) with an accuracy of 7.2 Mg ha-1. To achieve this accuracy, determination of bulk density, selectiveness in the transport process, tracer distribution in the soil profile and field calibration of the magnetic susceptibility probe were required. The evolution of tracer distribution provided insight into soil displacement within the runoff plots due to erosion processes. The tracer distribution maps also indicate a high coefficient of variability of the incorporation of tagged soil into the plot, which should be improved in future research to increase the usefulness of this approach in water erosion studies. Copyright © 2013 by the Soil Science Society of America, Inc.
Garcia-Tejero I.,Centro Las Torres Tomejil |
Romero-Vicente R.,Centro Las Torres Tomejil |
Jimenez-Bocanegra J.A.,Centro Las Torres Tomejil |
Martinez-Garcia G.,Centro Las Torres Tomejil |
And 2 more authors.
Agricultural Water Management | Year: 2010
Four strategies of deficit irrigation based on a different water-stress ratio (WSR) applied in each phenological stage, and a control treatment were implemented in 11-year-old citrus trees (Citrus sinensis L. Osb. Cv. Navelina) grafted onto carrizo citrange (C. sinensis L. Osb. × Poncirus Trifoliata L. Osb.). The midday stem-water potential and stomatal conductance were measured during the periods considered, and these parameters were used to estimate the plant-water status. Integrated stem-water potential (ΨInt) and integrated stomatal conductance (gInt) were calculated for all treatments and used as a water-stress indicator for the crop. Reference equations were formulated to quantify the relations between water-stress indicators (WSR, ΨInt, gInt) and the crop response, expressed as yield, yield components, and fruit-quality parameters under limited seasonal water availability. Significant differences in yield were found in the second year of experiment between the stressed treatments and control, although these differences were evident during the first year. The main effects were detected in treatments with a water-sever stress applied during the flowering and fruit-growth phases. When this degree of stress was applied during the maturity phase, it was reflected mainly in fruit-quality parameters (total soluble solids, and titrable acidity). These results lead to the conclusion that, in mature orange trees, deficit irrigation affects yield and fruit quality, while enabling water savings of up to 1000 m3 ha-1. Therefore, yield declined on average 10-12% but boosted water productivity 24% with respect to the fully irrigated treatment. Regarding the water-stress indicators used, ΨInt and gInt showed highly significant correlations with the yield and fruit-quality parameters. © 2009 Elsevier B.V. All rights reserved.
Green S.R.,Plant and Food Research |
Romero R.,Centro Las Torres Tomejil
Acta Horticulturae | Year: 2012
Thermal methods, including heat-pulse, have been used to measure sap flow for many decades. In most cases, analysis and interpretation of the temperature signals has remained largely unchanged since the pioneering work of Marshall (1958) and the theoretical calibrations of Swanson and Whitfield (1983). Two recent advances to heat-pulse have been developed to improve measurements at low flows; the 'Average Gradient' method (CAG) of Villalobos and Testi (2008), which modified the 'compensation method' (CHP) to improve sensitivity at low flows (i.e. < 10 cm h-1), and the 'Heat Ratio Method' (HRM) of Burgess et al. (2001) which employs temperature ratios measured at equal distances either side of the heater source. Preliminary results from CHP, CAG and HRM are compared against lysimeter data from potted trees to demonstrate the performance of these methods across a range of flows. We also propose and test two new methods to resolve low sap flow. The first method we will call the Symmetrical Gradient method (SGM). It consists of averaging the temperature-difference signal (δT) of two probes that are equidistant from the heater. The second method we will call the Maximum Derivative Method (MDM). The analysis of MDM is based on the maximum rate of change of the temperature difference curve (i.e. the derivative, δT'max). We have applied this derivative approach to temperature data collected using both symmetrical and assymetrical probe arrangements. Our measurements suggest these two indicators (δT and δT'max) are proportional to the sap flow across a wide range of flows. Data suggests our new 'calibrated maximum derivative' CMD method (CMD), is a simple and practical means to extend CHP over the low-flow regime.
Perez-Guerrero S.,Centro Las Torres Tomejil |
Molina J.M.,Centro Las Torres Tomejil
Spanish Journal of Agricultural Research | Year: 2016
Drosophila suzukii (Matsumura, 1931) is an invasive pest from South East Asia that was detected for the first time in Southern Europe in 2008. This species can damage a wide range of soft-skinned fruits crops affecting ripening fruits and causing important economic losses. Since the exclusive use of chemical insecticides for controlling D. suzukii may prompt the appearance of resistance and environmental pollution, alternative methods compatible with sustainable management are required. In this study, commercial formulations of powdered sulphur and kaolin were tested as a preventive method applied to blueberry fruits under laboratory conditions. In no-choice assay, powdered sulphur had a significant effect on oviposition and adult emergency with reductions of 76% and 77%, respectively. In addition, sulphur displayed a significant toxicity on males and lethal effect with over 40% adult mortality seven days after exposure. The choice assay confirmed and improved the powdered sulphur effects, with reductions of 98% and 96% in oviposition and adult emergence, respectively. In contrast, kaolin produced no significant reduction in infestation and adult mortality during no-choice and choice assays. These outcomes suggest that preventive use of powdered sulphur could be considered for sustainable control of D. suzukii in some berry crops. © 2016 INIA.
PubMed | University of Abderrahmane Mira de Béjaïa, Technical University of Madrid and Centro Las Torres Tomejil
Type: Journal Article | Journal: Systematic and applied microbiology | Year: 2016
Lupinus micranthus is a lupine distributed in the Mediterranean basin whose nitrogen fixing symbiosis has not been described in detail. In this study, 101 slow-growing nodule isolates were obtained from L. micranthus thriving in soils on both sides of the Western Mediterranean. The diversity of the isolates, 60 from Algeria and 41 from Spain, was addressed by multilocus sequence analysis of housekeeping genes (16S rRNA, atpD, glnII and recA) and one symbiotic gene (nodC). Using genomic fingerprints from BOX elements, 37 different profiles were obtained (22 from Algeria and 15 from Spain). Phylogenetic analysis based on 16S rRNA and concatenated atpD, glnII and recA sequences of a representative isolate of each BOX profile displayed a homogeneous distribution of profiles in six different phylogenetic clusters. All isolates were taxonomically ascribed to the genus Bradyrhizobium. Three clusters comprising 24, 6, and 4 isolates, respectively, accounted for most of the profiles. The largest cluster was close to the Bradyrhizobium canariense lineage, while the other two were related to B. cytisi/B. rifense. The three remaining clusters included only one isolate each, and were close to B. canariense, B. japonicum and B. elkanii species, respectively. In contrast, phylogenetic clustering of BOX profiles based on nodC sequences yielded only two phylogenetic groups. One of them included all the profiles except one, and belonged to symbiovar genistearum. The remaining profile, constituted by a strain related to B. elkanii, was not related to any well-defined symbiotic lineage, and may constitute both a new symbiovar and a new genospecies.