Zaragoza, Spain
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Herrero M.,EEAD CSIC
Environmental and Experimental Botany | Year: 2014

In temperate woody plants, flowering time is adjusted to the environmental temperature, and survival to cold winter temperatures is achieved through dormancy. But also chilling temperatures during dormancy are required for proper flower bud development and flowering. The time the flower bud remains dormant is both genetically and environmentally controlled, and is a major factor determining the adaptation of species and cultivars to particular ecological conditions because chilling requirements vary greatly among genotypes. Recently this adaptation is jeopardised with climate changing conditions. However, little is known on the biological milestones underpinning these events, and when differences in flowering time are established. In this work we evaluate the hypothesis that anther meiosis time is related to winter cold temperatures, and that differences in flowering time are set up by differences in the time when pollen meiosis occurs. For this purpose, anther development has been characterised in five apricot cultivars with different chilling requirements. The work was done over two years with different weather conditions, a cold and a mild winter. The sporogenous tissues differentiated prior to dormancy and remained in this apparently quiescent stage during the winter. Once chilling requirements were fulfilled, meiosis closely followed and was highly correlated to breaking of endodormancy. Meiosis was completed within one week and was followed by a change in the colour of the anthers from green to yellowish, which could be a useful visual indicator to know that breaking of endodormancy had already occurred. The fact that this sequence of events was consistent in all the cultivars, and different climatic years analysed, supports the hypothesis that winter cold temperatures are related to the time of pollen meiosis, which in turn reflects in different flowering times. © 2013 Elsevier B.V.

Situations of high flower bud drop and low fruit set without apparent causes are common in fruit trees. The term flower quality has been coined to explain differences among flowers in their capacity to set fruit, but the causes underpinning these differences are largely unknown. This lack of knowledge is based on the fact that these differences are established a posteriori and there are no criteria to determine a priori what will make a flower to set a fruit or to drop. In this work, we profit from the empirical knowledge that there are fruiting and non-fruiting shoots to explore to which extent flower bud differentiation and bud development will affect the subsequent fruit set. For this purpose, the processes from flower bud differentiation to fruit set were sequentially analyzed in both types of shoots, over 2 years. More than half of the buds from long shoots aborted development and dropped before flowering. At anthesis, most of the remaining flowers showed underdeveloped pistils that failed to sustain pollen germination or pollen tube growth along the pistil. This unsuccessful development resulted in clear differences in fruit set between both types of branches. These results highlight that flower bud differentiation and development play an important role for fruit set and that developmental timing appears critical to reach anthesis with a fully developed pistil. © 2010 Springer-Verlag.

Zapata N.,EEAD CSIC | Salvador R.,EEAD CSIC | Cavero J.,EEAD CSIC | Lopez C.,EEAD CSIC | And 3 more authors.
Irrigation Science | Year: 2013

The application of new technologies to the control and automation of irrigation processes is becoming very important, and the automatic generation and execution of irrigation schedules is receiving growing attention. In this paper, a prototype automatic irrigation controller for solid-set systems is presented. The device is composed by software and hardware developments. The software was named Ador-Control and it integrates five modules: the first four modules simulate drop trajectories, water distribution, crop growth and yield, and the last module ensures bidirectional communication between software and hardware. Decision variables based on soil, crop, and irrigation performance indexes were used to make real-time irrigation decisions. A randomized experimental design was designed to validate the automatic controller over a corn crop during two seasons. Three treatments were analyzed: T0) manual programmer or advanced farmer; T1) automatic scheduling controlled by indexes based on soil simulated water content and irrigation performance; and T2) advanced automatic scheduling controlled by simulated thresholds of crop and irrigation indexes. Experimental results in 2009 and 2010 indicated that automatic irrigation treatments resulted in similar maize yield but using less water than manual irrigation (10 % between T0 and T1, and 18 % between T0 and T2). © 2012 Springer-Verlag Berlin Heidelberg.

Malosetti M.,Wageningen University | van Eeuwijk F.A.,Wageningen University | van Eeuwijk F.A.,Center for BioSystems Genomics | Boer M.P.,Wageningen University | And 6 more authors.
Theoretical and Applied Genetics | Year: 2011

Quantitative trait locus (QTL) detection is commonly performed by analysis of designed segregating populations derived from two inbred parental lines, where absence of selection, mutation and genetic drift is assumed. Even for designed populations, selection cannot always be avoided, with as consequence varying correlation between genotypes instead of uniform correlation. Akin to linkage disequilibrium mapping, ignoring this type of genetic relatedness will increase the rate of false-positives. In this paper, we advocate using mixed models including genetic relatedness, or 'kinship' information for QTL detection in populations where selection forces operated. We demonstrate our case with a three-way barley cross, designed to segregate for dwarfing, vernalization and spike morphology genes, in which selection occurred. The population of 161 inbred lines was screened with 1,536 single nucleotide polymorphisms (SNPs), and used for gene and QTL detection. The coefficient of coancestry matrix was estimated based on the SNPs and imposed to structure the distribution of random genotypic effects. The model incorporating kinship, coancestry, information was consistently superior to the one without kinship (according to the Akaike information criterion). We show, for three traits, that ignoring the coancestry information results in an unrealistically high number of marker-trait associations, without providing clear conclusions about QTL locations. We used a number of widely recognized dwarfing and vernalization genes known to segregate in the studied population as landmarks or references to assess the agreement of the mapping results with a priori candidate gene expectations. Additional QTLs to the major genes were detected for all traits as well. © 2011 The Author(s).

PubMed | EEAD CSIC, Wageningen University, Technical University of Madrid, University of Gloucestershire and Scotland’s Rural College
Type: | Journal: Journal of environmental management | Year: 2016

A portfolio of agricultural practices is now available that can contribute to reaching European mitigation targets. Among them, the management of agricultural soils has a large potential for reducing GHG emissions or sequestering carbon. Many of the practices are based on well tested agronomic and technical know-how, with proven benefits for farmers and the environment. A suite of practices has to be used since none of the practices can provide a unique solution. However, there are limitations in the process of policy development: (a) agricultural activities are based on biological processes and thus, these practices are location specific and climate, soils and crops determine their agronomic potential; (b) since agriculture sustains rural communities, the costs and potential for implementation have also to be regionally evaluated and (c) the aggregated regional potential of the combination of practices has to be defined in order to inform abatement targets. We believe that, when implementing mitigation practices, three questions are important: Are they cost-effective for farmers? Do they reduce GHG emissions? What policies favour their implementation? This study addressed these questions in three sequential steps. First, mapping the use of representative soil management practices in the European regions to provide a spatial context to upscale the local results. Second, using a Marginal Abatement Cost Curve (MACC) in a Mediterranean case study (NE Spain) for ranking soil management practices in terms of their cost-effectiveness. Finally, using a wedge approach of the practices as a complementary tool to link science to mitigation policy. A set of soil management practices was found to be financially attractive for Mediterranean farmers, which in turn could achieve significant abatements (e.g., 1.34 MtCO2e in the case study region). The quantitative analysis was completed by a discussion of potential farming and policy choices to shape realistic mitigation policy at European regional level.

Lopez-Vicente M.,EEAD CSIC | Lana-Renault N.,University of La Rioja | Garcia-Ruiz J.M.,IPE CSIC | Navas A.,EEAD CSIC
Journal of Soils and Sediments | Year: 2011

Purpose: Sediment delivery from headwater catchments to reservoirs is a serious threat to reservoir sustainability and is a critical issue in Mediterranean environments where water resources are scarce. In this study we assessed the consequences of two landscape management scenarios (natural vegetation recovery and scrub clearance) on soil erosion and sediment yield. The results were analyzed in relation to predicted and measured rates of soil erosion and sediment yield, with the aim of promoting better management practices. Materials and methods: The study area was the Arnás River catchment (284 ha), which is located in the central Spanish Pyrenees; the area includes abandoned and poorly managed fields. The combination of the RUSLE and SEDD models of soil erosion and sediment delivery was evaluated in terms of its ability to predict annual rates of sediment yield, using field measurement data for seven water years at the gauging station. The consequences of natural plant succession in other areas of the Spanish Pyrenees and scrub clearance practices implemented by certain regional governments to increase grazing meadow areas and reduce the incidence of wildfires were spatially analyzed using GIS. The main sediment source areas were identified, and their specific and total sediment yields were calculated. Results and discussion: The predicted soil loss under existing conditions was 2.6 Mg ha-1 year-1, with 5% of the surface area affected by rates greater than 2 Mg. The measured sediment yield range was 69-534 Mg year-1. The maximum sediment yield detected was associated with an extraordinary debris flow. The predicted rates were strongly correlated to measured rates (Nash-Sutcliffe coefficient = 0.72). The main sources were alluvial deposits [specific sediment yield (SSY) = 51 Mg ha-1 year-1], bare soil (SSY = 12), unpaved trails (SSY = 11), lots (SSY = 4), and pastures (SSY = 1). Under a scenario of vegetation recovery, decreases of 3%, 17%, and 16% in soil loss and sediment delivery and yield (respectively) are predicted, whereas increases of 15%, 5%, and 2% are predicted following scrub clearance practices. Conclusions: Coupling the RUSLE and SEDD models enabled estimation of annual values of soil erosion and sediment delivery in monitored and unmonitored catchments of small and medium size, making this approach a useful tool for risk analysis. Management practices that combine fire-risk control, by the implementation of scrub clearance practices, with the effects of plant succession on sediment production are suggested as the best management strategy. © 2011 Springer-Verlag.

Burillo G.S.,EEAD CSIC | Delirhasannia R.,University of Tabriz | Playan E.,EEAD CSIC | Paniagua P.,EEAD CSIC | And 3 more authors.
Journal of Irrigation and Drainage Engineering | Year: 2013

Ballistic simulation has been successfully applied to impact sprinklers. However, ballistic simulation of center pivot sprinkler irrigation has been limited by the difficulty in estimating the initial drop velocity vector in fixed and rotating spray plate sprinklers. Initial velocity is severely affected by the impact of the jet on the sprinkler deflecting plate (or plates). In this work, experimental techniques based on drop photography have been used to obtain the droplet velocity and angle in the vicinity of a fixed spray plate sprinkler by using three different nozzle diameters. Furthermore, simulation techniques based on the inverse solution of drop trajectory were combined to determine the initial velocity vector and energy loss at the spray. Our analysis suggests that the ballistic model can be used to simulate drop inverse trajectory in these sprinklers, although the ballistic model can benefit from 5 to 10% effective drag-force screening. The ratio of initial drop velocity to jet velocity was between 0.67 and 0.82, whereas the kinetic energy losses in the spray sprinklers amounted to 33-55%. © 2013 American Society of Civil Engineers.

Playan E.,EEAD CSIC | Salvador R.,EEAD CSIC | Lopez C.,EEAD CSIC | Lecina S.,CITA DGA | And 2 more authors.
Journal of Irrigation and Drainage Engineering | Year: 2014

Farmers continue to show great differences in irrigation water use, even for a given location and crop. Irrigation advisory services have narrowed the gap between scientific knowledge and on-farm scheduling, but their success has been limited. The performance of sprinkler irrigation is greatly affected by factors such as wind speed, whose short-time variability requires tactical adjustments of the irrigation schedule. Mounting energy costs often require the consideration of interday and intraday tariff evolution. Opportunities have arisen that allow these challenges to be addressed through irrigation controllers guided by irrigation and crop simulation models. Remote control systems are often installed in collective pressurized irrigation networks. Agrometeorological information networks are available in regions worldwide. Water users' associations use specialized databases for water management. Different configurations of irrigation controllers based on simulation models can develop, continuously update, and execute irrigation schedules aiming at maximizing irrigation adequacy and water productivity. Bottlenecks requiring action in the fields of research, development, and innovation are analyzed, with the goal of establishing agendas leading to the implementation and commercial deployment of advanced controllers for solid-set irrigation. © 2013 American Society of Civil Engineers.

Zapata N.,EEAD CSIC | Nerilli E.,Instituto Agronomico Mediterraneo Of Bari | Martinez-Cob A.,EEAD CSIC | Chalghaf I.,CITA DGA | And 3 more authors.
Spanish Journal of Agricultural Research | Year: 2013

Fruit production development is resulting in large commercial orchards with improved water management standards. While the agronomic and economic benefits of regulated deficit irrigation (RDI) have long been established, the local variability in soils and climate and the irrigation system design limits its practical applications. This paper uses a case study approach (a 225 ha stone fruit orchard) to unveil limitations derived from environmental spatial variability and irrigation performance. The spatial variability of soil physical parameters and meteorology in the orchard was characterized, and its implication on crop water requirements was established. Irrigation depths applied during 2004- 2009 were analysed and compared with crop water requirements under standard and RDI strategies. Plant water status was also measured during two irrigation seasons using stem water potential measurements. On-farm wind speed variability amounted to 55%, representing differences of 17% in reference evapotranspiration. During the study seasons, irrigation scheduling evolved towards deficit irrigation; however, the specific traits of RDI in stone fruits were not implemented. RDI implementation was limited by: 1) poor correspondence between environmental variability and irrigation system design; 2) insufficient information on RDI crop water requirements and its on-farm spatial variability within the farm; and 3) low control of the water distribution network.

Julian C.,CSIC - Centro de Investigación y Tecnología Agroalimentaria | Rodrigo J.,CSIC - Centro de Investigación y Tecnología Agroalimentaria | Herrero M.,EEAD CSIC
Annals of Botany | Year: 2011

Background and Aims In temperate woody perennials, flower bud development is halted during the winter, when the buds enter dormancy. This dormant period is a prerequisite for adequate flowering, is genetically regulated, and plays a clear role in possibly adapting species and cultivars to climatic areas. However, information on the biological events underpinning dormancy is lacking. Stamen development, with clear differentiated stages, appears as a good framework to put dormancy in a developmental context. Here, stamen developmental changes are characterized in apricot (Prunus armeniaca) and are related to dormancy. MethodsStamen development was characterized cytochemically from the end of August to March, over 4 years. Developmental changes were related to dormancy, using the existing empirical information on chilling requirements. Key Results Stamen development continued during the autumn, and the flower buds entered dormancy with a fully developed sporogenous tissue. Although no anatomical changes were observed during dormancy, breaking of dormancy occurred following a clear sequence of events. Starch accumulated in particular places, pre-empting further development in those areas. Vascular bundles developed and pollen mother cells underwent meiosis followed by microspore development. ConclusionsDormancy appears to mark a boundary between the development of the sporogenous tissue and the occurrence of meiosis for further microspore development. Breaking of dormancy occurs following a clear sequence of events, providing a developmental context in which to study winter dormancy and to evaluate differences in chilling requirements among genotypes. © The Author 2011. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved.

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