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Effects of simple and double grafting melon plants on mineral absorption, photosynthesis, biomass and yield
No full textThe Spanish type cultivar ‘Piel de Sapo’ (Cucumis melo L. var. saccharinus), has a limited compatibility with the Cucurbita maxima × Cucurbita moschata hybrids currently used as rootstocks. Double grafting can be used to improve compatibility between rootstock and scion by means of an intermediate rootstock compatible with both. Non-grafted, single, and double grafted melon plants of the cultivar Piel de Sapo were evaluated for water, nutrient absorption, photosynthesis activity, biomass production in early phases, as well as for yields and fruit quality in a long term trial. The hybrid ‘Shintoza’ (C. maxima × C. moschata) was used as rootstock, and the cantaloupe type melon cultivar ‘Sienne’ as an intermediate scion. Grafting did not affect net photosynthetic values, yet increased water use efficiency (35%). Double grafted plants increased aerial dry weights (66% and 31% with respect to non-grafted and simple graft plants, respectively), and also increased capacity for uptaking beneficial minerals (between 61% and 13% and particularly for NO3−, P, K, Ca, Mn, and Zn) with respect to non-grafted and single grafted plants. The quantum efficiency PSII photochemistry values increased in double grafted plants (12%) with respect to the control plants. Consequently, double grafting on a vigorous rootstock such as ‘Shintoza’, with an intermediate scion, results in improved mineral and water absorption and achieves an increase in ion influx to the scion – so enabling an increase in light photosynthetic reaction and biomass. Double grafted plants increased fruit yield when compared to simple grafted and non-grafted plants (12% and 56%, respectively) and did not affect fruit quality in terms of °Brix and colour. In conclusion, double grafting presents several beneficial aspects that are counter-balanced by the extra cost of the technique. The difference in yields reflects compatibility problems
Molecular insights into fungicide resistance in sensitive and resistant Penicillium digitatum strains infecting citrus
No full textThe continuous use of chemical fungicides on citrus postharvest has led to the development of resistant strains against the fungicides in use, representing a considerable threat because the control systems are no longer effective. Evaluation of the sensitivity of 75 Penicillium digitatum strains to seven different fungicides revealed the presence of a significant number of TBZ- (84%) and IMZ-resistant (77%) strains, i.e., those fungicides most used in citrus postharvest. Molecular characterization of different P. digitatum genes involved in fungicide resistance was carried out. All P. digitatum genes were selected based on particular mechanisms of resistance due to fungicide target or mode of action. TBZ-resistance was characterized by a unique point mutation in the beta-tubulin gene sequence corresponding to amino acid 200, confirming previous work on this subject. Moderate to low resistance to strobilurins did not reveal any mutation in the cytochrome 19 gene. DMI-resistance was evaluated by examining the CYP51 gene and four different ABC transporters PMR1. PMR3, PMR4 and PMR5. The CYP51 gene did not exhibit any mutation relating to DMI-resistance, but a five tandem repeat sequence previously described was found in the CYP51 promoter in 3 of the 75 isolates examined, whereas DMI-sensitive isolates and the other DMI-resistant isolates of P. digitatum had only one tandem repeat. Of all the ABC transporters studied, only PMR1 and PMR5 appear to be involved in fungicide resistance and several mutations were found in the promoter and the coding region for PMR5 in resistant strains compared to sensitive ones. In all cases, the resistance mechanism was consistent in both orchard or packing-house isolates and no differences conferred by either origin or fungicide pressure were observed. Consequently, since different processes have been described that confer fungicide resistance to the same compounds, such as DMIs, the hypothesis that multiple mechanisms could be acting simultaneously gains strength. (C) 2010 Elsevier B.V. All rights reserved
Agronomic comparison between organic rice and biodynamic rice. Short communication.
No full textBiodynamic agriculture is a type of organic agriculture which has been applied successfully to different crops, including rice. Due to the lack of published studies comparing biodynamic and organic rice, the objective of the present study was to compare the performance of rice (Oryza sativa L.) under these two agronomical methods. Two varieties
were transplanted mechanically in Pego-Oliva Natural Park (Alicante, Spain) under continuous flooding, without fertilization or rotation. Grain yield was not significantly different between methods of culture (4,188 vs 4,237 kg ha–1 under organic and biodynamic agriculture, respectively). In our study, grain yield was not significantly different between varieties either (4,228 vs 4,199 kg ha–1 for ‘Bomba’ and ‘Albufera’, respectively), but whole grain milling
yield was higher in ‘Albufera’ than in ‘Bomba’ (66% vs 55.4%). It is concluded that in these conditions and with these varieties, both methods yield equally
Efficacy and economics of ground cover management as a conservation biological control strategy against Tetranychus urticae in clementine mandarin orchards
No full textConservation biological control by means of ground cover offers an interesting alternative to chemical control of the twospotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae), a key pest of clementine mandarins. The aim of this study was to investigate whether this tactic could actually achieve significant reductions in crop losses caused by this pest. The three most common cover practices used in citrus in Spain were compared: wild cover, a cover of Festuca arundinacea Scherb. (Poaceae), and bare soil. The action threshold was more often exceeded in wild cover than in bare soil or F. arundinacea. When expenditures and revenues were balanced, the most favorable cover was F. arundinacea (between 44.4 and 74.5% cost reduction relative to the most expensive one). F. arundinacea as a cover crop is a conservation biological control strategy highly recommendable for clementine producers. Although its use did not reduce mite populations below the action threshold, the population decreases obtained made the adoption of this tactic a beneficial alternative both ecologically and economically. (C) 2011 Elsevier Ltd. All rights reserved
Pathogenic and non-pathogenic Agrobacterium tumefaciens, A-rhizogenes and A-vitis strains form biofilms on abiotic as well as on root surfaces
No full textPathogenic and non-pathogenic Agrobacterium tumefaciens, A. rhizogenes and A. vitis strains growing in minimal liquid medium adhered to different abiotic surfaces, forming biofilms at initial stages of development. Agrobacterium tumefaciens and A. vitis strains were able to attach to both polystyrene and polypropylene materials, whereas the A. rhizogenes strains only bound to polystyrene surfaces. Strains of the three species were also able to form biofilms on borosilicate coverslips. It is concluded that their ability to adhere to and form nascent biofilms on abiotic surfaces is dependent on the Agrobacterium species (biovar), surface material and growth conditions. Furthermore, tumorigenic A. tumefaciens and A. vitis strains, and the biological control agent A. rhizogenes strain K84, bound tightly to and formed complex biofilms on the surface of tomato root tips ex planta. More importantly, in planta assays confirmed that all three Agrobacterium spp. strains efficiently colonized tomato seedlings and also formed biofilms on roots. These complex structures, as revealed by scanning electron microscopy, were composed of numerous bacterial cells arranged in different ways: either dense and continuous carpets, large aggregates embedded in extra-cellular material or globular mushrooms traversed internally by channels. Confocal laser scanning microscopy, using GFP-marked derivative strains, corroborated the presence of live, three-dimensional and thick green fluorescent structures attached to plant material. This study illustrates that besides A. tumefaciens, strains of the species A. rhizogenes and A. vitis are also able to build biofilms on abiotic as well as on root surfaces
Evolutionary genomics of Staphylococcus aureus reveals insights into the origin and molecular basis of ruminant host adaptation
No full textStaphylococcus aureus is an important human pathogen that also causes economically important infections of livestock. In a recent paper, we employed a population genomic approach to investigate the molecular basis of ruminant host adaptation by S. aureus. The data suggest that the common pathogenic clone associated with small ruminants originated in humans but has since adapted to its adopted host through a combination of allelic diversification, gene loss and acquisition of mobile genetic elements. In particular, a new subfamily of staphylococcal pathogenicity islands (SaPI) was identified encoding a novel von Willebrand factor-binding protein (vWBP) with ruminant-specific coagulase activity. The wide distribution of vWBP-encoding SaPIs among ruminant strains implies an important role in host-adaptation. In the current article we summarize the findings of the paper and comment on the implications of the study for our understanding of the molecular basis of bacterial host adaptation
Tetraploidization events by chromosome doubling of nucellar cells are frequent in apomictic citrus and are dependent on genotype and environment
No full text† Background and Aims Polyploidy is a major component of plant evolution. The citrus gene pool is essentially
diploid but tetraploid plants are frequently encountered in seedlings of diploid apomictic genotypes. The main
objectives of the present study were to establish the origin of these tetraploid plants and to ascertain the importance of genotypic and environmental factors on tetraploid formation.
† Methods Tetraploid seedlings from 30 diploid apomictic genotypes were selected by flow cytometry and genotyped with 24 single sequence repeat (SSR) markers to analyse their genetic origin. Embryo rescue was used to
grow all embryos contained in polyembryonic seeds of ‘Tardivo di Ciaculli’ mandarin, followed by characterization of the plantlets obtained by flow cytometry and SSR markers to accurately establish the rate of tetraploidization events and their potential tissue location. Inter-annual variations in tetraploid seedling rates were analysed
for seven genotypes. Variation in tetraploid plantlet rates was analysed between different seedlings of the same
genotype (‘Carrizo’ citrange; Citrus sinensis × Poncirus trifoliata) from seeds collected in different tropical, subtropical and Mediterranean countries.
†Key Results Tetraploid plants were obtained for all the studied diploid genotypes, except for four mandarins. All
tetraploid plants were identical to their diploid maternal line for SSR markers and were not cytochimeric.
Significant genotypic and environmental effects were observed, as well as negative correlation between mean
temperature during the flowering period and tetraploidy seedling rates. The higher frequencies (20 %) of tetraploids were observed for citranges cultivated in the Mediterranean area.
†Conclusions Tetraploidization by chromosome doubling of nucellar cells are frequent events in apomictic
citrus, and are affected by both genotypic and environmental factors. Colder conditions in marginal climatic
areas appear to favour the expression of tetraploidization. Tetraploid genotypes arising from chromosome doubling of apomictic citrus are extensively being used as parents in breeding programmes to develop seedless triploid cultivars and have potential direct use as new rootstocks
Comparative analysis of proteome changes induced by the two spotted spider mite Tetranychus urticae and methyl jasmonate in citrus leaves
No full textCitrus plants are currently facing biotic and abiotic stresses. Therefore, the characterization of molecular traits involved in the response mechanisms to stress could facilitate selection of resistant varieties. Although large cDNA microarray profiling has been generated in citrus tissues, the available protein expression data are scarce, in this study, to identify differentially expressed proteins in Citrus clementina leaves after infestation by the two-spotted spider mite Tetranychus urticae, a proteome comparison was undertaken using two-dimensional gel electrophoresis. The citrus leaf proteome profile was also compared with that of leaves treated over 0-72 h with methyl jasmonate, a compound playing a key role in the defense mechanisms of plants to insect/arthropod attack. Significant variations were observed for 110 protein spots after spider mite infestation and 67 protein spots after MeJA treatments. Of these, 50 proteins were successfully identified by liquid chromatography-mass spectrometry-tandem mass spectrometry. The majority constituted photosynthesis- and metabolism-related proteins. Five were oxidative stress associated enzymes, including phospholipid glutathione peroxidase, a salt stressed associated protein, ascorbate peroxidase and Mn-superoxide dismutase. Seven were defense-related proteins, such as the pathogenesis-related acidic chitinase, the protease inhibitor miraculin-like protein, and a lectin-like protein. This is the first report of differentially regulated proteins after T. urticae attack and exogenous MeJA application in citrus leaves. (C) 2010 Elsevier GmbH. All rights reserved
Guía de agricultura ecológica de almendro
Get PDFLa Federación de Cooperativas Agrarias de la Comunidad Valenciana (FECOAV) tiene
atribuidas las funciones de representación, coordinación y promoción del cooperativismo
agrario en dicho ámbito territorial, lo que la faculta para liderar proyectos
de la magnitud del que se presenta en estas líneas.
En FECOAV estamos convencidos que el Proyecto mayas (Medio Ambiente Y
Agricultura Sostenible) está llamado a ser el embrión de los cambios que se deben
producir en la agricultura de la Comunidad Valenciana, reorientando parte de sus
producciones hacia modelos más sostenibles, hacia modelos agroecológicos. Por
ello y para ello, aprovechando la oportunidad que brinda el Programa empleaverde
de la Fundación Biodiversidad, en el marco del Programa Operativo de Adaptabilidad
y Empleo del Fondo Social Europeo para el periodo 2007/2013, hemos programado
diversas actuaciones orientadas al incremento de la formación de los
agentes implicados.
Desde la perspectiva y el firme compromiso de FECOAV con sus asociados, con
la actividad agraria, el medio ambiente y la sociedad en general, la agricultura
ecológica se vislumbra como una apuesta de futuro. Una apuesta que debe evidenciar
lo mejor de todos y cada uno de nosotros, lo mejor de nuestro territorio; y
que debe poner en valor el buen hacer de los agricultores, no sólo por la excelente
calidad de los productos que obtengan, sino por el respeto y cuidado del entorno
en el que desarrollan la actividad productiva.
Para ampliar la formación de los agricultores y trabajadores del medio agrario
en materia de agricultura ecológica se van a impartir dieciocho cursos específicos
en distintos puntos de la geografía de la Comunidad Valenciana que abarcan los
cultivos más representativos. Para desarrollar este programa de trabajo se cuenta
con la participación de profesionales de alta cualificación y contrastada solvencia.
Además, se facilita a los alumnos el material didáctico adecuado y elaborado ex
profeso: Guía de Agricultura Ecológica del cultivo de que se trate en cada curso,
Guía de Exigencias de la Condicionalidad y Tríptico Informativo sobre el Empleo de
Subproductos de la Ganadería (Campaña de Sensibilización)
Treating boar sperm with cholesterol-loaded cyclodextrins widens the sperm osmotic tolerance limits and enhances the in vitro sperm fertilising ability
No full textTreating sperm with cholesterol-loaded cyclodextrins (CLC) improves the cryosurvival of the sperm of different cold-shock sensitive species. However, the response of boar sperm to this treatment is not fully understood. The aim of this study was to determine how CLC and methyl-beta-cyclodextrin (M beta CD, not loaded with cholesterol) affect the parameters for boar sperm functionality, including sperm osmotic resistance, and the ability of the sperm to capacitate and to penetrate the sow's immature oocytes in vitro. Samples treated with CLC or M beta CD prior to freezing exhibited similar percentages of motile sperm, live sperm and sperm with intact acrosomes as the control samples (P > 0.05). In addition, these treatments did not alter the response of the boar sperm to capacitating conditions. However, when compared to the controls and the M beta CD-treated samples, the CLC-treated sperm maintained greater percentages of motile sperm and live sperm in a wide range of osmotic solutions including hypo- (50.75 and 150 mOsm/kg) and hyper-osmotic (600, 800 mOsm/kg) conditions (P < 0.05). In addition, the CLC-treated sperm exhibited greater oocyte penetration ability than the control and the M beta CD-treated sperm (P < 0.0001). In conclusion, the pre-freezing treatment of boar sperm with CLC does not alter the ability of the sperm to respond to capacitating conditions. Despite not increasing the cryosurvival of the sperm, this treatment widens the sperm osmotic tolerance limits and enhances the in vitro sperm fertilising ability. (C) 2011 Elsevier B.V. All rights reserved