Moral F.J.,University of Extremadura |
Terron J.M.,Research Center La Orden Valdesequera |
Silva J.R.M.d.,University of Évora
Soil and Tillage Research | Year: 2010
Site-specific management promotes the identification and management of areas within the field, which represent subfield regions with homogeneous characteristics (management zones). However, determination of subfield areas is difficult because of the complex combination of factors which could affect crop yield. One possibility to capture yield variability is the use of soil physical properties to define the management zones as they are related to plant available water. With the aim of characterizing the spatial variability of the main soil physical variables and using this information to determine potential management zones, soil samples were taken from 70 locations in a 33-ha field in Badajoz, southwestern Spain. Firstly, accurate spatial distribution maps of the soil attributes were generated by using regression kriging as the most suitable algorithm in which exhaustive secondary information on soil apparent electrical conductivity (ECa) was incorporated. ECa measurements were carried out with a Veris 3100 operating in both shallow (0-30 cm), ECs, and deep (0-90 cm), ECd, mode. Clay, coarse sand and fine sand were the soil physical properties which exhibited higher correlation with ECa (positively correlated with the finer texture component, clay, and negatively correlated with the coarser ones, coarse and fine sands), particularly with ECs. Thus, this was the secondary variable used to obtain the kriged maps. Later, principal component analysis and fuzzy cluster classification were performed to delineate management zones, resulting in two subfields to be managed separately. This number of subfields was determined using the fuzzy performance index and normalized classification entropy as the way to optimize the classification algorithm. © 2009 Elsevier B.V. All rights reserved.
Perez E.A.,University of Extremadura |
Tellez T.R.,University of Extremadura |
Maqueda S.R.,University of Extremadura |
Linares P.J.C.,University of Extremadura |
And 6 more authors.
Acta Botanica Gallica | Year: 2015
Water hyacinth (Eichhornia crassipes (Mart.) Solms-Laub.) is an invasive aquatic weed that has one of the highest growth indices of vascular plants, producing large amounts of biomass. Its use for composting, livestock feed and biogas production has been proposed as a management strategy for its control. The work presented here is an assessment of the potential spread of water hyacinth due to the release of seeds from the by-products of some of these manufacturing processes. We tested experimentally if the seeds were destroyed or did not lose germinability when they had passed through the gut of sheep, remained in compost piles or been used in biogas bioreactors. We made optical and electronic microscopic observations, and calculated retrieval and germination percentages of the seeds subjected to these treatments. After having passed through the gut of sheep, the anatomical organization of the seed was completely destroyed, only 30.50 ± 5.83% of the seeds were retrieved and the germinability was null (0 ± 0%). The biogas production and compost-treated seeds both had retrieval percentages of 100 ± 0% and germination values of 1.00 ± 0.57 and 3.50 ± 0.96% respectively, with several anatomical damages. The use for compost or biogas production as a management strategy to control this pest is not completely safe from an environmental perspective and the selected management option should focus on sheep fodder production. © 2015 Société botanique de France.
Lukas V.,Mendel University in Brno |
Moreno F.R.,Research Center la Orden Valdesequera |
Neudert L.,Mendel University in Brno |
Dryslova T.,Mendel University in Brno
Precision Agriculture 2011 - Papers Presented at the 8th European Conference on Precision Agriculture 2011, ECPA 2011 | Year: 2011
The knowledge of spatial variability of nutritional status in plants is important for adequate variable rate application of fertilizers. In this paper are presented initial results of an ongoing study which verify using of multispectral imagery to estimate a continuous image of nutritional status in winter wheat. Verification was carried out in 2010 at two different locations with areas of 53 and 38 ha in the Czech Republic. Plant inorganic analysis (content of N, P, K, Mg, Ca and S) and ground measurement of LAI were carried out in winter wheat at BBCH 30 in regular sampling grid 150 × 150 m. Results were related with the broadband multispectral images (G, R, NIR bands, NDVI index) from an aerial survey using two techniques, multiple linear regression and decision trees. Both methods shown promising results, reaching values of 0.83 for the R square with the multiple linear regression and a hit rate of 57.8% with the decision trees.
Vazquez F.M.,Research Center La Orden Valdesequera |
Jarvis C.E.,Natural History Museum in London
Taxon | Year: 2010
The typification of ten Linnaean names of taxa belonging to the Valerianaceae is discussed. Lectotypes are designated from the Linnaean herbarium at LINN (Valeriana dioica, V. locusta var. discoidea, V. phu, V. tripteris), the Burser Herbarium at UPS (V. montana, V. tuberosa), and from the Clifford Herbarium at BM (V. rubra). An illustration in a pre-Linnaean work is designated as the lectotype of both V. locusta var. mutica and V. locusta var. pumila. Valeriana mixta, often treated as ambiguous, is discussed and will be proposed for formal rejection. Each type choice made here maintains the present usage of the corresponding Linnaean name.
Rodriguez-Molina M.C.,Research Center La Orden Valdesequera |
Morales-Rodriguez M.C.,Research Center La Orden Valdesequera |
Palo C.,Research Center La Orden Valdesequera |
Osuna M.D.,Research Center La Orden Valdesequera |
And 2 more authors.
European Journal of Plant Pathology | Year: 2013
Fusarium wilt of tobacco could be caused by Fusarium oxysporum f. sp. batatas or f. sp. vasinfectum since f. sp. nicotianae was rejected because there was no evidence of isolates specific to tobacco. Forty isolates of F. oxysporum from soil and plants from tobacco fields in Extremadura (south-western Spain) were characterized by pathogenicity on burley and flue-cured tobacco, for vegetative compatibility group (VCG), and by random amplified polymorphic DNA (RAPD). Isolates from burley were identified as race 1 of F. oxysporum f. sp. batatas based on pathogenicity on tobacco, sweet potato and cotton, and those from flue-cured as race 2. Most isolates from soil were heterokaryon self-incompatible (HSI) and the remaining isolates from soil and tobacco were grouped into four VCGs: VCG 1 (5 isolates from burley), VCG 2 (17 isolates from flue-cured and 4 from soil), VCG 3 (2 isolates from flue-cured) and VCG 4 (2 isolates from soil). This is the first report of the two races and VCGs of F. oxysporum f. sp. batatas in Spain. Analysis of RAPD revealed two clusters (C-I and C-II) related to race and VCGs. C-I included race 1 (VCG 1) isolates from burley and nonpathogenic (VCG 4 or HSI) isolates from soils. C-II included nonpathogenic (VCG 2) and race 2 (VCG 2 or VCG 3) isolates from flue-cured. VCG and RAPD markers were effective in distinguishing race 2 from race 1, suggesting that there are two genetically differentiated groups of F. oxysporum f. sp. batatas on tobacco in Extremadura. © 2013 KNPV.
Munoz-Costa A.,Research Center La Orden Valdesequera |
Calleja-Alarcon J.A.,Autonomous University of Barcelona
Forest Systems | Year: 2013
Aim of study: The present work provides novel insights on factors (either intrinsic or extrinsic) that trigger sprouting in woody species living at range margins. We aim to explain the inter-individual variability in the multi-stemmed architecture of Prunus lusitanica L., an Iberian evergreen relict tree related to the Tertiary flora. Area of study: Northeastern Mediterranean mountains of the Iberian Peninsula, the Northeast limit of the global distribution of the species. Material and methods: We gathered data on two modes of vegetative reproduction, basal and layering sprouts, in 288 clumps of Prunus lusitanica from four populations. We modeled and analyzed the effect of environmental factors (topography, canopy cover, soil moisture and disturbances) and plant size (diameter at breast height) on sprouting by means of Generalized Linear Model and other statistical approaches. Main results: Plant size arises as the principal factor to explain the variability of the numbers of both types of sprouts yet it is not a trigger factor. Natural and anthropogenic disturbances promote basal and layering shoots, while tree canopy is mainly relevant for basal shoots, and slope and soil moisture are significant factors for layering shoots. Research highlights: The multi-stemmed architecture of P. lusitanica at the Northeastern limit of its worldwide distribution is triggered by local environmental factors and disturbances. Each external factor shows different levels of influence on the variability and type of vegetative reproduction yet the intensity of the response is driven by the size of the largest trunk of each clump.
Lopez-Corrales M.,Research Center La Orden Valdesequera |
Mateos J.R.,Research Center La Orden Valdesequera |
Alarcon M.V.,Research Center La Orden Valdesequera |
Banuls P.,Research Center La Orden Valdesequera |
And 3 more authors.
Acta Horticulturae | Year: 2014
The breeding program carried out at Centro de Investigación La Orden-Vadesequera began in 2006 with the aim of obtaining new varieties adapted to soil and climatic conditions of the Jerte Valley (Spain). The main objectives of this research are, firstly, to improve certain physicochemical properties of native varieties cultivated in the valley and, secondly, to diversify this product with modern varieties with new features such as both early and late ripening, and improved organoleptic quality. Different varieties from the Jerte Valley germplasm bank and breeding programs in the USA and Canada, with interesting traits such as earliness, high productive potential, self-fertility, tolerance to rain-cracking, large size, firmness of flesh and good organoleptic quality, were used as parentals. In relation to fruit-set, varying percentages were obtained depending on year and crossing, being the highest value obtained using cv 'Hudson' as a female parent. The influence of cold storage in seed germination was also studied, showing that a 60 days cold storage period followed by stratification improves embryo viability and plant survival in greenhouse, shortening germination time and increasing the efficiency of field establishment. In some crossings the number of established seedling is over 200 and, currently, there are 1,828 plants (seedlings) in field. The selection process based on fruit quality traits will begin in 2010.
Ramos S.,University of Extremadura |
Rincon S.,Junta de Extremadura |
Vazquez F.M.,Research Center La Orden Valdesequera
Annales Botanici Fennici | Year: 2010
Astragalus gines-lopezii is a perennial herb, endemic to the south of the Iberian Peninsula. It has been classified as 'Endangered' by the Extremadura Regional Catalogue and placed in the equivalent category (EN D) of the National Red List because only one population in the world is known. Conservation of A. gines-lopezii requires a greater understanding of its population size, seed ecology and germinationconditions. The latter issues are particularly important when establishing a reintroduction programme. This species was observed in nine colonies on the same mountainside, the largest of which consists of 60plants. In this study, we compare the ability of the seeds to germinate under various conditions. Unlike most other members of the Fabaceae, the seeds of A. gines-lopezii do not need physical or chemical pre-treatment in order to germinate; instead they require a photoperiod for optimal germination. This study will facilitate a more in-depthunderstanding of this rare and poorly known species. © Finnish Zoological and Botanical Publishing Board 2010.