ReDivia - Repositorio Digital de l'Instit Valencià d'Investigacions Agràries
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Trifoliata hybrids rootstocks for 'Lane Late' navel orange in Spain
Get PDFCarrizo citrange [Citrus sinensis (L.) Osb. × Poncirus trifoliata (L.) Raf.] and Cleopatra mandarin (C. reshni Hort. ex Tan.) are the most important rootstocks used in Spain, but they are problematic and it is necessary to search for new rootstocks with better all-round performance. The performance of 'Lane Late' navel orange [Citrus sinensis (L.) Osb] on ten rootstocks was determined in the South of the province of Alicante (Spain). They are Carrizo citrange, Cleopatra mandarin and eight new hybrids obtained at the Instituto Valenciano de Investigaciones Agrarias in Valencia (Spain): 020324 [Troyer citrange (C. sinensis × P. trifoliata) × Cleopatra mandarin], Forner-Alcaide 418 (F&A 418) [Troyer citrange × common mandarin (C. deliciosa Ten.)], Forner-Alcaide 13 (F&A 13), 030118, 030127 and 030131 (Cleopatra mandarin × P. trifoliata) and 030212 and 030230 (Cleopatra mandarin × Troyer citrange). Soil is clay loam, with pH 8.5 and electric conductivity in the saturation extract at 25ºC of 5.79 mS cm-1. Yield was weighed during the first nine harvests, fruit quality was determined in the last three. Pre-harvest fruit-drop was controlled for the 4th until 9th harvests. The trees of 'Lane Late' navel budded on Cleopatra mandarin were the tallest (2.5 m) and F&A 418 (1.6 m) the shortest of all rootstocks tested. Trees on 030131 hybrid and Carrizo citrange rootstocks had the highest mean yield (81.2 and 80.3 kg per tree per year respectively), while trees on F&A 418 produced the lowest mean yield (22.3 kg per tree per year). Trees on 030131, 020324 and 030212 had the highest yield efficiency as total cumulative yield per cubic meter of canopy volume (62.1, 58.7 and 55.9 kg m-3 respectively) whereas trees on 030127, F&A 418 and Cleopatra mandarin had lower yield efficiencies (45.0, 44.4 and 38.6 kg m-3, respectively). Pre-harvest fruit-drop was lower in trees grafted on Cleopatra mandarin (24.62 %) and on 030212 (26.61 %), and was also low on F&A 418 (27.76 %), 020324 (28.14 %) and 030230 (29.18 %) rootstocks. Trees on Carrizo citrange and 030127 experienced important fruit-drop (40.24 % and 38.27 % respectively). Trees on F&A 418 had the highest fruit weight and fruit size whereas trees on 030118 induced the lowest ones. The ripeness index was the highest on F&A 13 (18.3) and lowest on F&A 418 (15.3), 030212 (15.3)
Spatio-temporal patterns and interactions with honeydew-producing Hemiptera of ants in a Mediterranean citrus orchard
No full textThe role of ants in the citrus agro-ecosystem is controversial and understanding their ecology may help to clarify their function. The present study determined the daily and seasonal foraging patterns, the spatial distribution, the feeding sources and the associations with honeydew-producing Hemiptera of three ant species that forage in citrus canopies. The dominant ants Pheidole pallidula (Nylander) (Myrmicinae) and Lasius grandis Forel (Formicinae) foraged in mutually exclusive territories within the field, although they both shared their territory with the subordinate Plagiolepis schmitzii Forel (Formicinae), a distribution pattern known as 'ant mosaic'. The observed mean overlap for the spatial distribution was significantly lower than the generated by null models, providing strong evidence of spatial interspecific competition, especially between the two dominants. Ants ascended to the canopies from April until November. Colony nutritional requirements and temperature probably shape their seasonal foraging patterns. The daily activity pattern of P. schmitzii was strictly diurnal, whereas L. grandis and P. pallidula were active during the entire day. The ants' diet in the canopies consisted principally of hemipteran honeydew, whereas citrus nectar and predation/scavenging did not represent important food sources. More than 60% of the total honeydew sources and 100% of the citrus mealybug Planococcus citri colonies were tended by ants during spring and summer
Response of Clementina de Nules citrus trees to summer deficit irrigation. Yield components and fruit composition
No full textThe effects of mid-summer regulated deficit irrigation (RDI) treatments were investigated on Clementina de Nules citrus trees over three seasons. Water restrictions applied from July, once the June physiological fruit drop had finished, until mid September were compared with a Control treatment irrigated during all the season to match full crop evapotranspiration (ET(c)). Two degrees of water restrictions were imposed based on previous results also obtained in Clementina de Nules trees (Ginestar and Castel, 1996; Gonzalez-Altozano and Castel, 1999). During the RDI period, deficit irrigation was applied based on given reductions over the ET(c), but also taking into account threshold values of midday stem water potential (Psi(s)) of -1.3 to -1.5 MPa for RDI-1 and of -1.5 to -1.7 MPa for RDI-2. Results showed that water savings achieved in the RDI-2 treatment impaired yield by reducing fruit size. On the contrary, the RDI-1 strategy allowed for 20% water savings, with a reduction in tree growth but without any significant reduction in yield, fruit size nor in the economic return when irrigation was resumed to normal dose about three months before harvest. Water use efficiency (WUE) in the RDI trees was similar or even higher than in Control trees. RDI improved fruit quality increasing total soluble solids (TSS) and titratable acidity (TA). In conclusion, we suggest that the RDI-1 strategy here evaluated can be applied in commercial orchards not only in case of water scarcity, but also as a tool to control vegetative growth improving fruit composition and reducing costs associated with the crop management. (C) 2011 Elsevier B.V. All rights reserved
Parasitoid community of Protopulvinaria pyriformis (Hemiptera: Coccidae) on laurel: Influence of host size, seasonal trend and aggregation on its main parasitoid
No full textThe phenology of Protopulvinaria pyriformis (Cockerell) (Hemiptera: Coccidae) and its parasitoid complex were studied on laurel Laurus nobilis L. in urban green spaces of Eastern Spain from March 2008 to January 2010. P. pyriformis is bivoltine, gravid females peaked on spring and fall and the 2nd and 3rd instars were present throughout the year. The natural parasitoid community of P. pyriformis consisted of three primary parasitoids and four facultative hyperparasitoid species. Metaphycus helvolus (Compere) (Hymenoptera: Encyrtidae) accounted for 98% of the parasitoids recovered. Although M. helvolus parasitized all the scale instars, it attacked P. pyriformis mostly at the end of the spring, when scales were larger. M. helvolus behaved as a solitary parasitoid and its secondary sex ratio was male biased when it parasitized the 2nd instar. Its secondary sex ratio became female biased when it parasitized scales larger than 1.1 mm. M. helvolus behaved as a facultative gregarious parasitoid and its secondary sex ratio was always female biased (0.3 males per scale) when it parasitized the 3rd instar and the adults. The number of eggs allocated per host, as well as the number of parasitoids that emerged, increased with scale size. Mostly, broods of two to four parasitoids emerged from these scales. M. helvolus showed inverse host density dependence, parasitism decreased as the number of scales per leaf increased. The implications of these results on the biological control of this and other soft scales are discussed. (C) 2011 Elsevier Inc. All rights reserved
Concentration, spatial and size distribution of airborne aerobic mesophilic bacteria in broiler farms
Get PDFIn livestock houses, particulate matter (PM) and airborne microorganism are two of the most relevant air pollutants. Particulate matter may carry microorganisms, the inhalation of which can cause detrimental health effects. The aim of this study was to study the spatial distribution of airborne aerobic mesophilic bacteria in the air of a broiler farm (rearing poultry for meat production), to quantify the concentration of airborne aerobic mesophilic bacteria and PM in the air and to study their evolution in time, as well as to evaluate the relationship between particle size and airborne aerobic mesophilic bacteria, and to correlate the evolution of PM concentrations and aerobic mesophilic bacteria concentrations. For this purpose, the air of two broiler rooms in an experimental broiler farm was sampled weekly using different methods during 42 days. There was a spatial gradient (p<0.001) in aerobic mesophilic bacteria concentrations between animal height and higher heights, at the beginning of the production cycle (day 3). The concentration of aerobic mesophilic bacteria in the air ranged from 3 to 6.53 log CFU/m(3). Between 42% and 96% of aerobic mesophilic bacteria in the air were found in the particle size ranges between 3.3 to more than 7 mu m. The PM concentration in the air was equal to 0.019 mg/m(3) for PM2.5 and equal to 0.189 mg/m(3) for PM10. The PM and bacteria concentrations followed a similar evolution during the production cycle (correlation coefficient between 0.78 and 0.89), showing a maximum concentration on day 24 and decreasing thereafter, coinciding with an increase in the ventilation rate
Composition of Oregano Essential Oil (Origanum vulgare) as Affected by the Use of Winery-Distillery Composts
No full textThree different windy-distillery composts were used as binary components with peat-perlite mix (PP) in growing media for oregano cultivation. These composts were prepared using exhausted grape mare as principal component combined with several co-composting wastes, such as citrus juice waste (C1), tomato soup waste (C2) and cattle manure (C3). Three treatments were established for each compost type, with increasing compost quantities to traditional PP mix (0%, 25% and 50%). Physical and physico-chemical analyses of the different mixtures of winery-distillery composts and PP were carried out. The volatile compounds of oregano samples were extracted by steam-hydrodistillation and analyzed by GC/MS. Twenty-seven compounds were tentatively identified, with terpinen-4-ol, carvacrol, thymol and gamma-terpinene being the major compounds. The total yield of volatile compounds (mg plant(-1)) was always increased by the use of the compost materials as ingredients of the growing media. However, the total volatile concentration of control samples, 16.3 g kg(-1), was only increased by the compost-mixtures containing 50% of Cl and 25% of C2 or C3. The final recommendation is to use grape mare together with citrus juice or tomato soup wastes at ratios of 1:1 as growing media for the cultivation of aromatic herbs, including oregano
Effect of ground-cover management on spider mites and their phytoseiid natural enemies in clementine mandarin orchards (I): Bottom-up regulation mechanisms
No full textTetranychus urticae Koch (Acari: Tetranychidae) is an important pest of citrus that can also feed on most plant species occurring in the ground cover associated with this crop. To determine the effect of managing the ground cover on the biological control of this mite, we have studied the dynamics of both tetranychid and phytoseiid mites in four commercial citrus orchards under three different ground cover management strategies: (1) bare soil, (2) resident wild cover and (3) a sown cover of Festuca arundinacea Schreb. (Poaceae). The results obtained provide evidence that both bottom-up and top-down regulation processes related to the nature of the ground cover affected the tetranychid mite populations in citrus orchards (Panonychus citri (McGregor), Tetranychus evansi Baker & Pritchard and T. urticae). Best results were obtained with the ground cover of F. arundinacea, which did not allow the establishment of T. evansi, and offered a better regulation of both P. citri and T. urticae than either bare soil or the resident wild cover. We hypothesize that the selection of a host race of T. urticae specialized in F. arundinacea when this plant was used as a cover crop could partly explain the results obtained. Further trap cropping effects could also be relevant (bottom-up regulation)
Clp-dependent proteolysis of the LexA N-terminal domain in Staphylococcus aureus
No full textThe SOS response is governed by the transcriptional regulator LexA and is elicited in many bacterial species in response to DNA damaging conditions. Induction of the SOS response is mediated by autocleavage of the LexA repressor resulting in a C-terminal dimerization domain (CTD) and an N-terminal DNA-binding domain (NTD) known to retain some DNA-binding activity. The proteases responsible for degrading the LexA domains have been identified in Escherichia coli as ClpXP and Lon. Here, we show that in the human and animal pathogen Staphylococcus aureus, the ClpXP and ClpCP proteases contribute to degradation of the NTD and to a lesser degree the CTD. In the absence of the proteolytic subunit, ClpP, or one or both of the Clp ATPases, ClpX and ClpC, the LexA domains were stabilized after autocleavage. Production of a stabilized variant of the NTD interfered with mitomycin-mediated induction of sosA expression while leaving lexA unaffected, and also significantly reduced SOS-induced mutagenesis. Our results show that sequential proteolysis of LexA is conserved in S. aureus and that the NTD may differentially regulate a subset of genes in the SOS regulon
Advances in Machine Vision Applications for Automatic Inspection and Quality Evaluation of Fruits and Vegetables
No full textArtificial vision systems are powerful tools for the automatic inspection of fruits and vegetables. Typical target applications of such systems include grading, quality estimation from external parameters or internal features, monitoring of fruit processes during storage or evaluation of experimental treatments. The capabilities of an artificial vision system go beyond the limited human capacity to evaluate long-term processes objectively or to appreciate events that take place outside the visible electromagnetic spectrum. Use of the ultraviolet or near-infrared spectra makes it possible to explore defects or features that the human eye is unable to see. Hyperspectral systems provide information about individual components or damage that can be perceived only at particular wavelengths and can be used as a tool to develop new computer vision systems adapted to particular objectives. In-line grading systems allow huge amounts of fruit or vegetables to be inspected individually and provide statistics about the batch. In general, artificial systems not only substitute human inspection but also improve on its capabilities. This work presents the latest developments in the application of this technology to the inspection of the internal and external quality of fruits and vegetables
Mineralization and Nutrient Release of an Organic Fertilizer Made by Flour, Meat, and Crop Residues in Two Vineyard Soils with Different pH Levels
No full textThe mineralization and nutrient evolution of an organic fertilizer compost of flour, meat, and crop residues was evaluated in two vineyard soils. A lysimetric testing, using 2.2-L Buchner funnels, was carried out to study the evolution of pH, electrical conductivity, and nutrients during the 400-day experiment. The net mineralization for two different doses of the fertilizer mixed with the soils was compared with an unfertilized control. The pH value of the acidic soil decreased to values less than 4.5 because of the yield of hydrogen (H+) in the organic fertilizer mineralization, whereas the soluble aluminium (Al3+) increased quickly in the leachates. The mineralization process was quicker in the alkaline soil (with a maximum mineralization rate of 0.83 mg nitrogen (N) kg(-1) day(-1) for the 8 Mg ha(-1) dose and 0.43 mg N kg(-1) day(-1) for the 4 Mg ha(-1) dose) in comparison with the acidic soil, which reduced these rates up to 50%. The N-nitrate (NO3) amounts yielded in a year were 150 and 79 kg N ha(-1) for the 8 and 4 Mg ha(-1) doses respectively in the alkaline soil, enough to cover the vineyard N demand. These values were reduced to 50% and 60% of N-NO3 for the acidic soil, indicating the important effect of pH in the mineralization