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Efecto de diferentes abonos orgánicos en el arrozal ecológico en la Albufera de Valencia
Get PDFEn una parcela de arrozal ecológico, variedad Montsianell, localizada en el Tancat
de Zacarés en La Albufera (El Palmar, Valencia), se ha realizado durante la campaña de
2009 un ensayo con la finalidad de evaluar la eficacia de dos abonos orgánicos
comerciales: Naturgan y Labinor. Los tratamientos incluidos en el experimento fueron: T1,
testigo (sin fertilización), T2, T3 y T4, Naturgan a dosis de 29, 44 y 59 kg N/ha, y T5, T6 y T7,
Labinor a 55, 83 y 110 kg N/ha, respectivamente. Los resultados obtenidos pusieron de
manifiesto una respuesta significativa del cultivo a la fertilización orgánica, tanto en
desarrollo vegetativo como en la producción. Los rendimientos obtenidos con el abono
Labinor fueron superiores a los generados con Naturgan en todas las dosis comparadas.
El rendimiento más alto se logró con la dosis alta de Labinor (110 kg N/ha). Asimismo la
eficiencia del nitrógeno, evaluada como porcentaje del nitrógeno recuperado por el cultivo,
registró con el producto Labinor unos valores entre 28 y 30%, mientras que con Naturgan
se obtuvieron unas cifras más bajas (entre 10 y 20%). El contenido de nitrógeno en las
hojas bandera dio unos valores subóptimos en todos los tratamientos de Naturgan, en
cambio, las tres dosis de Labinor originaron niveles adecuados. Los contenidos de macro
y micronutrientes en el grano y la paja de arroz no resultaron afectados de forma
significativa por los tratamientos de fertilización. Las mayores cantidades de nutrientes
extraídas por las plantas (grano y paja) correspondieron al tratamiento dosis alta de
Labinor (110 kg N/ha)
Abundancia de depredadores en setos de frutales en el Parc Agrari del Baix Llobregat
Get PDFSe ha estudiado la abundancia de la entomofauna auxiliar asociada a los setos de un
arboretum de frutales ecológicos perteneciente al "Parc Agrari del Baix Llobregat", cuya
gestión técnica está realizada por la "ADV de Fruita del Baix Llobregat. Las especies
vegetales estudiadas fueron lentisco (Pistacia Lentiscus L.), genista (Genista sp.), durillo
(Viburnum tinus L.), adelfa (Nerium oleander L.), madroño (Arbutus unedo L.), salvia
(Salvia sp.), romero (Rosmarinus oficinalis L.), así como tres tipos de macizos de
aromáticas con salvia, romero, espliego (Lavandula sp.) o tomillo (Thymus oficinalis L.)
como principales especies. El muestreo se ha efectuado con aspiración (soplador ECHO
PB 46-LN,+ kit aspirador).
El análisis de las aspiraciones muestran como resultado un total de 67.717 artrópodos, de
los cuales 14.236 pueden considerarse depredadores generalistas (un 21% del total).
Arácnidos y hormigas son con mucho los más habituales, con una población identificada
de 6.934 y 4.999 individuos, respectivamente. Del resto de depredadores, los más
numerosos fueron los coccinélidos con 618 individuos, seguidos de heterópteros con 557
(nábidos, míridos y antocóridos, por este orden), dípteros con 290 (de los cuáles 283 eran
cecidómidos) y neurópteros con 224 (fundamentalmente crisópidos, con 199).
Existen variaciones notables de la abundancia entre las especies de setos estudiadas.
Así, contando el conjunto de depredadores, salvia, madroño y aromáticas destacan del resto, mientras que baladre y genista son las de menor cantidad de depredadores. Si
dejamos aparte hormigas, serían salvia, aromáticas y durillo los mejores. En neurópteros
destacan lentisco y madroño, mientras que en coccinélidos, dípteros, heterópteros y
arácnidos depredadores salvia y aromáticas
Efecto de cubiertas vegetales permanentes en la fertilidad del cultivo de cítricos ecológicos
Get PDFSe han estudiado diferentes cubiertas vegetales permanentes en mandarinos
ecológicos y convencionales de Alzira, en suelo arenoso, para comprobar su
comportamiento fertilizante y su crecimiento. En plantación joven, con aspersión, se
sembró alfalfa (Medicago sativa), sola y junto a ray-grass inglés (Lolium perenne),
trévoles (Trifolium subterraneum+T. repens) y mielgas (Medicago rugosa+M.
truncatula+M. polymorpha). En Clemenules adultos a goteo se estudiaron las silvestres en
la conducción ecológica, y el no laboreo con herbicidas en la convencional. La evolución
muestra como trévoles y mielgas degeraron muy deprisa, dando paso a silvestres (grama
-Cynodon dactylon- en verano, y Bromus spp. y otras en invierno), descartándolos como
coberturas en estas condiciones.
La alfalfa es la que mejor ha resistido la competencia de las hierbas en
condiciones de insolación alta y aspersión. En biomasa y cobertura no se han encontrado
diferencias entre alfalfa y grama, mientras que las demás eran menores, sobre todo en los
adultos, por su sombreado
Manual básico de horticultura ecológica
Get PDFLa horticultura ecológica tiene como finalidad la obtención de alimentos de la máxima calidad y sanidad, utilizando técnicas que no impliquen el uso de fitosanitarios ni de fertilizantes que procedan de síntesis química, siguiendo en el cultivo los ciclos de la naturaleza y garantizando como modelo de producción su sostenibilidad ecológica y social. La horticultura ecológica es parte de la agricultura ecológica, está relacionada con los cultivos extensivos, la fruticultura, la ganadería y los aprovechamientos forestales;
aporta su parte a los diseños de la explotación ecológica más amplia, donde cada uno de los componentes tiene su responsabilidad para garantizar la funcionalidad del sistema
Shifting from Seedling Mandarin Trees to Grafted Trees and Controlling Huanglongbing and Viroids: a Biotechnological Revolution in Nepal
Get PDFPoverty in Nepal, largely a rural phenomenon, is widespread, with 30.8% of the population living below the poverty line. Agriculture is the main source of livelihood of the Nepalese people who are living below poverty. Citrus, the first cash crop, is grown in small to very small orchards producing less than 10 tons/ha. More than 90% of the trees are seedlings of a local mandarin and therefore they are essentially free of most graft-transmissible diseases. Huanglongbing (HLB) and the Asian psyllid vector, Diaphorina citri, were reported in Nepal in the mid-1960s and, in the absence of any control measures, have continued to spread ever since. Here we report the information available regarding the presence of HLB in several important citrus-growing areas (Armalakur, Bandipur, Dhankuta/Karmitar, Kathmandu, Lamjung, Paripatle, Pokhara, Sindulimadi and Syangja) and the identification of four citrus viroids (Citrus exocortis viroid, Hop stunt viroid, Citrus viroid-III, and Citrus viroid-V) in the experimental citrus station of Pokhara. Citrus rehabilitation, as part of a program to improve food security for the Nepalese population, was started in 2004, and is based on (I) producing disease-free citrus trees, grafted on adequate rootstocks, in covered, insect-proof nursery facilities, (II) demonstration orchards with grafted trees, (III) control of HLB by trunk applications of systemic insecticides and/or guava interplants, (IV) selection of viroid-free budwood sources, and (V) transfer of technology to the farmers
Performance of 'Clausellina' mandarin on four rootstocks
No full textThis study, carried out in Almeria (Spain), evaluates the performance of 'Clausellina' mandarin on four rootstocks: Carrizo citrange [Citrus sinensis (L.) Osb. x Poncirus trifoliata (L.) Raft C. volkameriana Ten. and Pasq.; and, the two new hybrids 'C-13' (C. depressa Hay. x P trifoliata) obtained at the University of California Citrus Research Center and '020326' [Troyer citrange (C. sinensis x P trifoliata) x Cleopatra mandarin] obtained at the Instituto Valenciano de Investigaciones Agrarias in Valencia (Spain). Soil was sandy, with pH>8 and electric conductivity below 4.5 mmhos cm(-1) in the saturation extract. Yield was weighed during the first nine harvests, fruit quality was determined in the 5(th) and 9(th) harvests and tree size was evaluated annually from 3 to 11 years after planting. Trees on C. volkameriana rootstock were biggest and produced the highest yield, followed by trees on Carrizo citrange. Trees on the C-13 hybrid selection were most efficient in yield m(-3) of canopy volume. There were few differences between rootstocks in terms of fruit quality
Annotation and overview of the Pseudomonas savastanoi pv. savastanoi NCPPB 3335 draft genome reveals the virulence gene complement of a tumour-inducing pathogen of woody hosts
No full textPseudomonas savastanoi pv. savastanoi is a tumour-inducing pathogen of Olea europaea L. causing oliveknot disease. Bioinformatic analysis of the draftgenome sequence of strain NCPPB 3335, whichencodes 5232 predicted coding genes on a totallength of 5856 998 bp and a 57.12% G + C, revealed alarge degree of conservation with Pseudomonassyringae pv. phaseolicola 1448A and P. syringae pv.tabaci 11528. However, NCPPB 3335 contains twelvevariable genomic regions, which are absent in all pre-viously sequenced P. syringae strains. Various fea-tures that could contribute to the ability of this strainto survive in a woody host were identified, includingbroad catabolic and transport capabilities for degrad-ing plant-derived aromatic compounds, the duplica-tion of sequences related to the biosynthesis of thephytohormone indoleacetic acid (iaaM, iaaH) and itsamino acid conjugate indoleacetic acid-lysine (iaaLgene), and the repertoire of strain-specific putativetype III secretion system effectors. Access to thisseventh genome sequence belonging to the ‘P. syrin-gae complex’ allowed us to identify 73 predictedcoding genes that are NCPPB 3335-specific. Resultsshown here provide the basis for detailed functionalanalysis of a tumour-inducing pathogen of woodyhosts and for the study of specific adaptations of a P.savastanoi pathovar
Effect of temperature on RNA silencing of a negative-stranded RNA plant virus: Citrus psorosis virus
No full textCitrus psorosis virus (CPsV), genus Ophiovirus, causes a bark scaling disease of citrus. CPsV virions are kinked filaments with three negative-stranded RNA molecules (vRNA) and a 48 kDa coat protein. The effect of temperature on symptom expression, virus accumulation and RNA silencing was examined in sweet orange seedlings (Citrus sinensis) graft-inoculated with three different CPsV isolates and grown in a glasshouse at 26/18 degrees C or 32/26 degrees C (day/night). Most plants kept in the cooler glasshouse showed a shock reaction in the first flush with shoot necrosis, and then moderate to intense chlorotic flecking and spotting in young leaves, whereas plants incubated at 32/26 degrees C did not exhibit shoot necrosis, and young leaf symptoms were milder. Virus titre estimated by ELISA and by northern and dot blot hybridization paralleled symptom intensity, with significantly higher virus accumulation in plants incubated at 26/18 degrees C. The amount of CPsV-derived small RNAs (CPsV-sRNAs) slightly increased at 32/26 degrees C, with the ratio of CPsV-sRNA/vRNA being higher at 32/26 degrees C than at 26/18 degrees C. These results suggest that (i) CPsV infection induces RNA silencing in citrus plants, (ii) symptom intensity is associated with virus accumulation, and (iii) temperature increase enhances the RNA silencing response of citrus plants and decreases virus accumulation
Cryoprotectant and freezing-process alter the ability of chicken sperm to acrosome react
No full textSperm surviving after freezing-thawing is usually 40-50% of the initial population. Damage during this process affects both fertilizing ability and its duration in avian species. However, the effect of cryopreservation on the sperm ability to undergo the acrosome reaction, the initial event of fertilization, is still in question in birds. In this paper, the influence of cryoprotectant (glycerol and dimethylacetamide-DMA) and of two different cryopreservation processes (pellets or straws) on the ability of rooster sperm to acrosome react (AR measured with PNA-FITC) was studied. Motility parameters (CASA) and plasma membrane integrity (propidium iodide exclusion) were also measured. The addition of cryoprotectants (CPA) immediately provoked a dramatic decrease in the ability of sperm to undergo the acrosome reaction, glycerol being more harmful than DMA. The cryoprotectant removal was also harmful. The other parts of the freezing process further decreased the ability to AR. Motility was affected to a lesser extent by CPA presence although plasma membrane integrity was not altered. The DMA/rapid freezing procedure was the most harmful for plasma membrane integrity. Taken together, these results show that AR is more dramatically altered by CPA presence than motility and membrane integrity and CPA provokes a more pronounced effect than the freezing-thawing process especially in the case of using glycerol/slow freezing process. (C) 2010 Elsevier B.V. All rights reserved
Effect of Cooling Rate to 5 degrees C, Straw Size and Farm on Fertilizing Ability of Cryopreserved Rabbit Sperm
No full textHigh fertility and prolificacy in rabbits are currently only achieved using fresh sperm. This study was conducted to determine if the cooling rate to 5 degrees C, the straw size and the farm where artificial inseminations are performed have an impact on the fertilizing ability of rabbit sperm cryopreserved with an extender containing dimethyl sulphoxide (DMSO; 1.75 M) and sucrose (0.05 M). Slow cooling to 5 degrees C improved neither fertility rate (58 vs 56% kindling rate for fast and slow cooling, respectively) nor prolificacy (6.5 vs 8.7 total born for slow and fast cooling, respectively; p < 0.05) compared to fast cooling rate to 5 degrees C. The straw size did not have an effect on either fertility or prolificacy (47 vs 57% kindling rate and 6.3 vs 6.8 total born for sperm loaded into 0.25 and 0.5 ml straws, respectively). In addition, similar results were obtained between farms (46-57% kindling rate and 4.9-6.7 total born), although this effect should be studied further. In conclusion, with this extender, slow cooling does not present a beneficial effect on sperm fertilizing ability and either 0.25 or 0.5 ml straws can be used to freeze the sperm, obtaining similar results after artificial insemination. In addition, similar results were obtained between farms when using cryopreserved sperm, and these results were lower than those obtained after artificial insemination with fresh semen. Therefore, new approaches are needed to improve the results obtained when cryopreserved sperms are used before this type of sperm can be used for commercial purposes