Airborne multi-spectral imagery for mapping cruciferous weeds in cereal and legume crops

Cruciferous weeds are competitive broad-leaved species that cause losses in winter crops. In the present study, research on remote sensing was conducted on seven naturally infested fields located in Córdoba and Seville, southern Spain. Multi-spectral aerial images (four bands, including blue (B), green (G), red (R) and near-infrared bands) taken in April 2007 were used to evaluate the feasibility of mapping cruciferous patches (Diplotaxis spp. and Sinapis spp.) in winter crops (wheat, broad bean and pea) and compare the accuracy of different supervised classification methods (vegetation indices, maximum likelihood and spectral angle mapper). The best classification method was selected to develop site-specific cruciferous treatment maps. Cruciferous patches were efficiently discriminated with red/blue (R/B) and blue/green (B/G) vegetation indices and the maximum likelihood classifier. At all of the locations, the accuracy of the results obtained from the spectral angler mapper was relatively low. The cruciferous weed-classified imagery of each location were created according to the method that provided the best discrimination results and were used to obtain site-specific treatment maps for in-season post-emergence control measures or herbicide applications for subsequent years. By applying the site-specific treatment maps, herbicide savings from 71.7 to 95.4% for the no-treatment areas and from 4.3 to 12% for the low-dose herbicide were obtained.     

Development of the teleomorph of Ascochyta rabiei on culture media

Ascochyta blight caused by Didymella rabiei (anamorph: Ascochyta rabiei) is an important foliar disease of chickpea in many countries. The fungus is heterothallic and requires the pairing of two compatible mating types for the teleomorph to develop. In nature, the teleomorph only develops on chickpea debris that overwinters on the soil surface in the presence of both mating types. When natural and synthetic agar media were seeded with conidial suspensions of compatible isolates of D. rabiei from Spain and the United States and incubated under favourable conditions for teleomorph development, the teleomorph only developed on 2?% water agar amended with powdered chickpea stems or hot water extracts of chickpea stems, but not on 14 other natural or synthetic media. Ascospore isolates of D. rabiei from pseudothecia that developed on agar media were indistinguishable in cultural and morphological characteristics from isolates of the fungus from chickpea. Production of pseudothecia and ascospores on the best culture medium was always lower than on stem pieces of chickpea straw used as a control treatment. Ascospores discharged from pseudothecia that developed on powdered chickpea stem media onto chickpea seedlings were pathogenic, inducing symptoms identical to those caused by ascospores from chickpea stem pieces or conidia from a chickpea isolate of the fungus. This is the first report of the teleomorph of D. rabiei developing on culture media.     

Dual Benefits of Whey Protein Concentrate in a Microencapsulated Diet for Larval White Shrimp, Litopenaeus vannamei

Abstract— In this work a larval shrimp diet was spray-dried using a ratio of 75% whey protein concentrate and 25% mesquite gum as wall material, where the sole protein contribution to the diet was the whey protein concentrate. The microencapsulated diet exhibited the following physical properties: mean volumetric particle size of 49.3 om, characteristic floatability time 225.3 min, and density of 606 g/L. Its outer morphology was characterized by a dimpled spherical shape with no evident surface pores or cracks. Inner microstructure showed a central void, with the feed components finely embedded in the wall matrix. Two bioassays were performed with zoea of white shrimp Litopenaeus vannamei . In the first study, microencapsulated diet, and microencapsulated diet plus a single dose of live algae, were compared with a live algae control diet; in the second study, three co-feeding regimes consisting of microencapsulated diet + 10,30 and 60C. muellericellaL, respectively, were compared with the live algae control diet. In overall terms, the co-feeding regime with 30 cells/ OL produced larvae with carapace length (0.74-mm CL) and development index (4.5 DI) significantly superior to that of the live algae treatment (0.70-mm CL, 4.1 DI; respectively), and yielded similar individual dry weight (34-Og DW) and survival rate (58%). These results indicate that microencapsulated diets supplemented with live algae can produce responses similar to those of live feed. These results     

Comparing taxonomic levels of epigeal insects under different farming systems in Andalusian olive agroecosystems

The intensification of olive production methods in southern Spain, has involved a widespread use of chemicals and the progressive loss of many Mediterranean forest patches, natural landscapes and semi-natural vegetation. Species level inventories require an enormous amount of time and financial resources, mainly due to the necessity of employing taxonomists in the early stages of a study. The use of a higher taxonomic level is particularly useful when rapid biodiversity surveys are required. This survey investigates the reliability of a rapid method to detect which high taxonomic level of epigeal insects could best distinguish different farming systems in olive agroecosystems, taking into account three higher taxonomic categories as surrogate measures of insect diversity: orders for all the insects, families of Coleoptera and carabid morphospecies. Insects were collected in pitfall traps in olive orchards under organic, integrated and conventional farming systems in two provinces in Andalusia (Córdoba and Granada) with different surrounding landscapes over three different years. In 1999 and 2000 a study of trends over time was undertaken between March and October of both years in Granada, and in 2003 a geographically extended study was conducted in 18 different orchards during pre-blooming and post-blooming periods in Granada and Córdoba. To rapidly assess biodiversity in olive agroecosystems by examining soil communities, in order to classify farming systems on a regional scale, the taxonomic level of order seems to be a more reliable approach than a lower taxonomic level in insects. This methodology could be used as a possible useful short-cut to assess biodiversity in olive orchards at a local scale, the order surrogacy being useful when results are required rapidly and in a context of limited financial resources.     

Supercritical Fluid Extraction of Fucoxanthin from the Diatom Phaeodactylum tricornutum and Biogas Production through Anaerobic Digestion

Phaeodactylum tricornutum is the marine diatom best known for high-value compounds that are useful in aquaculture and food area. In this study, fucoxanthin was first extracted from the diatom using supercritical fluid extraction (SFE) and then using the extracted diatom-like substrate to produce bioenergy through anaerobic digestion (AD) processes. Factors such as temperature (30 °C and 50 °C), pressure (20, 30, and 40 MPa), and ethanol (co-solvent concentration from 10% to 50% v/v) were optimized for improving the yield, purity, and recovery of fucoxanthin extracted using SFE. The highest yield (24.41% w/w) was obtained at 30 MPa, 30 °C, and 30% ethanol but the highest fucoxanthin purity and recovery (85.03mg/g extract and 66.60% w/w, respectively) were obtained at 30 MPa, 30 °C, and 40%ethanol. Furthermore, ethanol as a factor had the most significant effect on the overall process of SFE. Subsequently, P.tricornutum biomass and SFE-extracted diatom were used as substrates for biogas production through AD. The effect of fucoxanthin was studied on the yield of AD, which resulted in 77.15 ± 3.85 LSTP CH₄/kg volatile solids (VS) and 56.66 ± 1.90 LSTP CH₄/kg VS for the whole diatom and the extracted P.tricornutum, respectively. Therefore, P.tricornutuman can be considered a potential source of fucoxanthin and methane and both productions will contribute to the sustainability of the algae-biorefinery processes.     

Antioxidant systems and their relationship with the response of pepper fruits to storage at 20 degrees C

Fresh peppers (Capsicum annuum L., variety California) in their green and red ripe stages were stored at 20 degrees C for 7 and 19 days to determine the effects of storage on whole fruit antioxidant capacity (TAA) and ascorbate (ASC) content, as well as on some antioxidant enzyme activities, such as catalase (CAT), superoxide dismutase (SOD), and those of the ASC-glutathione cycle. At least one Mn-SOD, two Fe-SODs, and three CuZn-SODs were detected in the fruit extract after native polyacrylamide gel electrophoresis. All of the SOD isozymes and glutathione reductase had higher activity levels in the red control fruits than in the green fruits, whereas the activities of monodehydroascorbate and dehydroascorbate reductase were higher in green fruits. Ascorbate peroxidase (APX) was found to be similar in both fruits. SODs, CAT, and APX seem to be involved in pepper fruit ripening and senescence during storage at 20 degrees C, perhaps influencing the active oxygen species levels in the fruit. TAA, as well as the ASC content, was higher in red peppers than in green, and storage increased the ASC in both green and red fruits.     

Seaweed Blends as a Valuable Source of Polyunsaturated and Healthy Fats for Nutritional and Food Applications

Seaweeds are considered healthy and sustainable food. Although their consumption is modest in Western countries, the demand for seaweed in food markets is increasing in Europe. Each seaweed species has unique nutritional and functional features. The preparation of blends, obtained by mixing several seaweeds species, allows the obtaining of maximum benefits and ingredients with single characteristics. In this work, five seaweed blends, commercially available and produced under organic conditions in Europe, were characterized. The proximal composition included contents of ash (20.28–28.68% DW), proteins (17.79–26.61% DW), lipids (0.55–1.50% DW), and total carbohydrates (39.47–47.37% DW). Fatty acid profiles were determined by gas chromatography–mass spectrometry (GC–MS), allowing quantification of healthy fatty acids, namely n-3 and n-6 polyunsaturated fatty acids (PUFA), and calculation of lipid quality indices. Each blend showed a characteristic PUFA content in the lipid pool (35.77–49.43% of total fatty acids) and the content in essential and healthy n-3 PUFA is highlighted. The atherogenicity (0.54–0.72) and thrombogenicity (0.23–0.45) indices evidenced a good nutritional value of lipid fractions. As nutritional and environmentally attractive products, the consumption of the studied seaweed blends can contribute to a healthy lifestyle.