Showing papers in "Spanish Journal of Agricultural Research in 2005"

Determination of the surplus that consumers are willing to pay for an organic wine.

Abstract: The aim of this study was to estimate the premium price that Spanish consumers are willing to pay for an organic wine with respect to the price of a conventional wine with similar characteristics. To accomplish this aim, contingent valuation has been used, which permits using a survey and a direct estimation of the premium price that consumers are willing to pay. The question format used is dichotomous choice valuation with follow-up questioning. Statistical analysis was carried out using descriptive statistical analysis and logistic regression, in such a way that the estimation for both methods has been compared. The premium price has been estimated in three segments of consumers, according to their life style (healthy, concern about environment and concern about food/diet). The main findings show that consumers with a healthy life style are those willing to pay a higher price for an organic wine.

Non-destructive fruit firmness sensors: a review

Abstract: The development of sensors to measure fruit internal quality variables is one of the challenges of post-harvest technology. Several variables can currently be measured, including sugar content, acid content, firmness and internal disorders. This article reviews the state of the art of non-destructive fruit firmness sensors. These include static and on-line sensors that use different technologies for determining force-deformation relationships, impact forces, the acoustic response to vibrations or impacts, and optical properties. The rebound technique and nuclear magnetic resonance is also used. Although many techniques are under development, some companies already market instruments that determine the internal quality of fruit.

Seasonal variations of rosmarinic and carnosic acids in rosemary extracts. Analysis of their in vitro antiradical activity.

Abstract: Rosemary plants were analysed using HPLC and eight different compounds (vanillic acid, caffeic acid, rosmarinic acid, naringin, hispidulin, cirsimaritin, carnosol and carnosic acid) were identified and quantified. The analysis of the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity revealed that rosmarinic and carnosic acids were the best rosemary scavengers with IC sun(50) values of 27 and 32 micro M, respectively. Environmental influences on rosmarinic and carnosic acids content in rosemary plants were studied over a period of one year under southern UK conditions. Carnosic acid reached the maximum concentrations in December, decreasing by 50% during the summer months, while rosmarinic acid showed a constant concentration during the year. The significance of these results has been discussed later in this paper.

Pre-sowing magnetic treatment of tomato seeds: effects on the growth and yield of plants cultivated late in the season

Abstract: The effects of pre-sowing magnetic treatments on the growth and yield of tomatoes (cv. Vyta), cultivated late in the season, were studied under field conditions. Tomato seeds were exposed either to a 120 mT dynamic magnetic field (induced by an experimental electromagnet) for 10 min or to a 80 mT field for 5 min. Non-treated seeds were used as controls. Plants were grown in experimental plots (20.2 square m) and cultivated according to standard agriculture practices. At physiological maturity, the plants were harvested from each plot and the number of fruits, mean fruit weight, fruit yield per plant and fruit yield per area determined. In the nursery stage, the treatments led to a significant increase in root length, fresh and dry root weight, stem length, fresh and dry stem weight, leaf area and foliole dry weight. During the vegetative stage, the leaf, stem and root relative growth rates of plants derived from magnetically-treated seeds were greater than those shown by control plants. In the generative stage, the relative growth rate of the fruits belonging to the "magnetically treated plants" was greater than that of control plant fruits. At the fruit maturity stage, the magnetically treated seeds produced plants with significantly more fruits (17.9-21.3%), with a significantly greater mean fruit weight (22.3-25.5%), and with a greater fruit yield per plant (47.3-51.7%) and per area (48.6-50.8%) than did the control plants. Pre-sowing magnetic treatments would appear to enhance the growth and yield of tomatoes cultivated late in the season.

Factors related to the adoption of organic farming in Spanish olive orchards

Abstract: The area given over to the cultivation of organic olive trees in Spain has greatly increased in the last ten years. The diffusion of organic farming is desirable since its principles are in line with the aim of the current EU Common Agricultural Policy to harmonise agrarian production and environmental protection, and to encourage the production of quality agricultural goods. This paper characterises organic olive growers and farms in the south of Spain and compares them to their conventional counterparts. Information was gathered in a survey of 322 olive growers. The organic growers differed from their conventional counterparts in that their orchards were less productive and in the more part-time nature of their dedication to agriculture. They were also younger, more involved in management and administration of the holding, attended more courses, were more commonly members of agricultural associations, received more information via the Andalusian Committee for Organic Agriculture (a control, certification and training organization), had a more negative opinion regarding the use of chemicals, and believed that organic agriculture required more time and effort but provided greater returns.

Shade nets effect on canopy light distribution and quality of fruit and spur leaf on apple cv. Fuji

Abstract: The upper region of the Rio Negro and Neuquen valley, Argentina (latitude: 38o 55’ South) experiences high temperatures and light intensities before the apple harvest. This hinders these fruits turning red and increases the risks of them becoming sunburnt. In the December of two growing seasons (when the fruits were about 43 mm in diameter), still some 80 days before harvest, 15% and 55% density shade nets were placed over ‘Fuji’ apple trees. At harvest time, light distribution was determined at two canopy heights (1 and 3 m) on either side of the trees. Fruiting spurs were examined, and colour, sunburn damage, weight, soluble solid content and flesh firmness of the fruits determined. Specific leaf weight (SLW) was also established. Shade nets notably decreased the amount of photosynthetically active radiation (PAR) available; they also reduced fruit colour (redness), soluble solid content and flesh firmness, and the SLW. The 55% density net decreased fruit sunburn, but no differences were found between the 15% density net and control treatments. Spurs at the bottom of the canopy received less light, and the SLW, as well as the colour and soluble solid content of their fruit, was lower than observed for the higher spurs. The impossibility of exporting fruits damaged by high temperatures and intense solar radiation during ripening requires shade nets be used, their density depending on the conditions experienced. Additional key words: photosynthetically active radiation, specific leaf weight, sunburn.

Economic valuation of water and «willingness to pay» analysis with repect to tropical fruit production in southeastern Spain

Abstract: This paper reports a survey of how 64 tropical fruit growers from the Granada coast of Spain use and value their water resources. This area produces crops of high added value. The agricultural demand for water is ever increasing and is much greater than the actual supply. This problem is worsened by the infiltration of seawater into the aquifers that provide most of the irrigation water for the area. Moreover, the population increases five-fold in the summer due to tourism, further aggravating the problem of water scarcity. Technical innovations, especially the reuse of urban wastewater, and economic solutions, namely increasing the price of water, have been proposed under the European Union Water Framework Directive. The main questions in the survey are described and the responses analysed. The productive, technological and resource management characteristics that determine the growers’ expressed willingness to pay for the water they use, as well as their attitude towards the use of alternative sources (such as residual water) are examined. Finally, the marginal product value of irrigation water in the area is calculated. Additional key words: economic value of water, tropical fruit production, willingness to pay for water.

Effect of moderate irrigation on grape composition during ripening

Abstract: The effect of moderate irrigation on berry composition during the ripening of Monastrell grapes and the quality of wines produced from these grapes in a very dry area of southeastern Spain have been studied. The results showed that irrigated grapes reached higher weights but this did not impair sugar accumulation. Titratable acidity and pH were only slightly affected by irrigation, titratable acidity was higher in only one year in the most irrigated grapes at the end of ripening, mainly due to a higher malic acid content. Anthocyanin content in must was slightly lower in irrigated grapes. The results of the sensory analysis of the wines showed that wines made from non irrigated grapes usually obtained the highest scores for quality and intensity of color and aroma although differences were small.

Growth and nitrogen use efficiency of irrigated maize in a semiarid region as affected by nitrogen fertilization

Abstract: The main groundwater pollution factor in irrigated maize production areas is leaching of nitrogen below the root zone. During the years 1999-2001, experiments were carried out on irrigated maize in the semiarid region of CastillaLa Mancha to evaluate the effect of nitrogen in the growth and yield of maize. Three rates of nitrogen were tested: No (0 kg N ha -1 ), Nop (175, 150 and 130 kg N ha -1 in 1999, 2000 and 2001, respectively), and Nc (300 kg N ha -1 ). A high initial level of residual soil NO3 - was found in the spring of 1999 as a consequence of fertilization carryover from the previous years. Although there was no plant response to N fertilization in 1999, significant responses were obtained during the following two years. Moreover, in 2000, the grain production did not show significant differences between Nop and Nc. However, in 2001, maize yield was slightly decreased due to an attempt to decrease the Nop to 130 kg N ha -1 , showing significant differences with regard to Nc. The differences in grain yield among nitrogen levels were mainly due to a significant variation in maximum leaf area index, leaf area duration and crop growth rate. There was a decreasing pattern in nitrogen use efficiency values with increasing fertilizer rates, indicating that crop production could be sustained with lower fertilizer applications. Fertilizer practices must be revised in order to control and prevent insofar as possible water pollution in «La-Mancha Oriental» aquifer.

Resistance of pepper germplasm to Phytophthora capsici isolates collected in Northwest Spain

Abstract: One single pathotype (race 0) was identified among eight tested isolates of Phytophthora capsici (Leonian) collected in northwest Spain, after inoculation tests using pepper cultivars of different origin, including the well known reference resistant cultivar Serrano Criollo de Morelos 334. Complete resistance to P. capsici was not found after the inoculation of 23 local genotypes of Capsicum annuum with three different isolates of this oomycete, collected in northwest Spain. However significant differences in virulence were found for the three P. capsici isolates inoculated into the local pepper germplasm, using disease data based on results of genotype-isolate interactions. Virulence test as well as breeding methods for resistance to the pathogen are also discussed. Additional key words: Blight, Capsicum annuum, pathogenic variation, races.

Water use in three rice flooding management systems under Mediterranean climatic conditions

Abstract: Andalusia is the main rice producing region in Spain (40,000 ha). During the last decade it has suffered several years of water shortage leading to a decrease in crop area. In this work, studies have been performed to optimise water delivery and energy costs, comparing three flooding management systems: 1) irrigating seven days a week (control system: traditional continuous flooding system), 2) five days a week and 3) four days a week (maintaining the traditional irrigation management until 55 days after seeding in both tested systems). Total water used (water delivery) in 2000 corresponded to 44,917 cubic m haE–1 (traditional), 34,445 cubic m haE–1 (five days a week) and 29,209 cubic m haE–1 (four days a week). In 2001 these values were 45,607, 34,271 and 28,958 cubic m haE–1 respectively. No significant differences (LSD > 0.05) were found among the three flooding management systems in rice growth and yield. In 2000, irrigating five days a week, 23.31% of pumping energy was saved, and 34.97% when irrigating four days a week. In 2001 these values were 24.86% and 36.51%, respectively. These improvements, combined with the generalisation of integrated production procedures, will render Andalusian rice production more sustainable.

Quality perception and consumer attitudes to «specific quality beef» in Aragón, Spain

Abstract: Over the last decade, beef consumption has decreased in most European countries, including Spain Along with other factors that have contributed towards greater competition in agricultural markets, this has led to an increase in the offer of high-added-value beef products - a strategy the sector also follows to help it deal with the crisis caused by a number of health scandals The aim of the present study was to analyse consumer attitudes towards "specific quality beef" (SQB; beef with quality specifications as indicated by labels or public quality denominations) A relationship was seen with respect to the level of consumer knowledge and the purchase of this type of product Those with a higher average income and higher level of education had a more favourable attitude towards them The butcher was the most important source of consumer information on SQB Price was the factor that most limited the consumption of these products

Short communication. Effects of type and level of supplementation with dietary n-3 fatty acids on yolk fat composition and n-3 fatty acid retention in hen eggs

Abstract: A marine algal oil (MAO) with a high docosahexaenoic acid content (46.7%) was evaluated for the production of n-3 fatty acid (FA) enriched eggs. To determine its effects, laying hens were fed one of two diets containing different amounts of MAO, or a control diet containing marine fish oil (MFO). The efficiency of retention of total n-3 FA in the yolk fat depended both on the type and level of dietary n-3 substrate. Per unit weight of dietary oil added, MAO was better than MFO in terms of total n-3 FA retention by the yolk fat. However, the efficiency of retention of total n-3 FA, expressed as g FA retained per g of FA intake, was higher for MFO than for MAO. Additional key words: layers, n-3 retention efficiency, n-3 sources, yolk fatty acid composition.

An application of the analytic hierarchy process method in farmland appraisal

Abstract: This paper applies a multi-criteria methodology to farmland appraisal known as the analytic hierarchy process (AHP). This methodology is especially useful when there is partial information and/or qualitative variables are used or when quantitative variables are used but the professional does not have access to their quantification. This context presents difficulties when applying conventional farmland appraisal methods. Likewise, the application of the analytic hierarchy process to the field of farmland appraisal is an advance with respect to previous studies on the application of multi-criteria methods in which only quantitative variables have been used.

Short communication. Inhibition of Paenibacillus larvae subsp. larvae by the essential oils of two wild plants and their emulsifying agents

Abstract: In honey bees (Apis mellifera L.), American foulbrood (AFB) is caused by the infection of the larvae and pupae with the bacterium Paenibacillus larvae subsp. larvae. The antibacterial effects of the essential oils of wild camomile (Tagetes minuta L.) and Andean thyme (Acantholippia seriphioides A. Gray) against different strains of P. larvae subsp. larvae were evaluated in vitro. The possible inhibitory effects of two emulsifiers of these oils (propylene glycol and soybean lecithin) were also assessed. Significant differences in antibacterial action were seen between the oils and emulsifiers (P < 0.01). Andean thyme had the strongest antibacterial effect; the minimum inhibitory and minimum bactericide concentrations were 200-250 mg l -1 and 300 mg l -1 respectively. An additional inhibitory effect was seen when propylene glycol was used as an emulsifier; no such extra effect was seen when soybean lecithin was employed. Additional key words: Acantholippia seriphioides, bacteria, honey bee, propylene glycol, soybean lecithin, Tagetes minuta. Resumen

Effluent particle removal by microirrigation system filters

Abstract: The aim of this work was to determine whether the filters used in microirrigation systems can remove potentially emitter-clogging particles. The particle size and volume distributions of different effluents and their filtrates were established, and the efficiency of the removal of these particles and total suspended solids by screen, disc and sand filters determined. In most of the effluents and filtrates, the number of particles with a diameter > 20 micro m was minimal. By analysing the particle volume distribution it was found that particles larger than the disc and screen filter pores appeared in the filtrates. However, the sand filter was able to retain particles larger than the pore size. The filtration efficiency depended more on the type of effluent than on the filter. It was also found that the particle size distribution followed a potential law. Analysis of the beta exponents showed that the filters did not significantly modify the particle size distribution of the effluents.

Induction of fruit calcium assimilation and its influence on the quality of table grapes.

Abstract: Sprays containing soluble Ca, polypeptidic N and Ti ascorbate in several combinations were applied to cv. Crimson table grape vines (Vitis vinifera L.). Foliar spraying resulted in the accumulation of N, P, K, Ca, Mg, Fe, Zn, Cu and Ti in the leaves, but not of Na, Cl or Mn. In the berries, Ca, Fe, Zn and Cu concentrations increased in the skin and flesh. These berries were also larger than controls, firmer, had a deeper external red colour, and their weight loss during postharvest storage was reduced. The increase in the Ca and micronutrient content of the fruit is explained as a consequence of the beneficial effect of Ti on absorption, translocation and assimilation processes. In turn, improved Ca assimilation by the fruit was responsible for the beneficial effects seen on firmness and storage life.

Developmental rates of the Lappet Moth "Streblote panda" Hübner (1820) (Lepidoptera: Lasiocampidae) at constant temperatures

Abstract: Streblote panda Hubner [1820] (Lepidoptera: Lasiocampidae) is a potential pest of forest, floricultural and horticultural plants. This paper reports the rate of development of this species at six constant temperatures between 16.0 and 31.0 C( 3C increments). Individuals were monitored daily and egg, larval and pupal development times recorded. The development rate was calculated as the reciprocal of the median number of days required to complete development. Linear regression methods were used to estimate lower temperature thresholds and the number of degree-days (DDs) needed for the development of each stage (and total development) under these laboratory conditions. The average hatching time was 18.0 days at 16C and 7.2 days at 31C; the average larval development time was 131.8 days at 16C and 31.7 days at 31C. The egg-to-adult development time ranged from 189.0 days at 16C to 48.5 days at 31C. The threshold temperatures were 7.9, 11.9, 12.5 and 11.3C for egg, larval, pupal and egg-to-adult development respectively. Differences between larval instars were found; threshold temperatures were lower for late instars. The number of degree days (DDs) for egg-to-adult development was estimated at 1000.0 above 11.9C. The results suggest three full generations are possible per year in SW Spain.

Evaluation of local onion lines from northwest Spain.

Abstract: Traditional onion (Allium cepa L.) varieties are still produced in certain regions of Spain due to their high quality and acceptance in local markets. The evaluation of morphological traits for 18 local northwestern Spanish onion lines showed the existence of three different groups attending exclusively to bulb shape traits and six classes if we consider bulb shape traits as well as skin and flesh colours. There was a positive correlation between storage quality and percentage of dry matter content. The importance of considering well defined descriptors in order to characterize correctly onion germplasm is also discussed in this paper. Additional key words: Allium cepa, characterization, dry matter, germplasm, storage quality. Resumen Evaluacion de lineas locales de cebolla del noroeste espanol En determinadas regiones espanolas todavia se cultivan variedades tradicionales de cebolla (Allium cepa L.) debido a su elevada calidad organoleptica que hace que tengan una buena aceptacion en determinados mercados locales. La evaluacion morfologica de 18 cultivares de cebolla recopilados en el noroeste espanol ha permitido la caracterizacion de las mismas en tres grupos bien diferenciados si se consideran los caracteres relacionados con la forma del bulbo exclusivamente y seis clases si se tienen en consideracion tanto la forma del bulbo como el color de la piel y de la carne. En las lineas estudiadas existe, asimismo, una correlacion positiva entre la calidad de conservacion y el porcentaje de materia seca. En el articulo se discute tambien la importancia del uso de descriptores bien definidos en las caracterizaciones de germoplasma de cebolla. Palabras clave adicionales: Allium cepa, calidad de almacenamiento, caracterizacion, germoplasma, materia seca.

Inheritance of seed physical traits in upland cotton under different temperature regimes

Abstract: Physical seed traits such as seed weight, volume and density are determinants of seed vigour in cotton, while seed surface area is of prime importance in lint production. Two Pak-upland cotton crosses, plus their parental, F2 and back cross generations were evaluated over two years to determine the inheritance pattern of their seed physical traits under heat stress and non-stress field regimes. The heat stress regime suppressed the average expression of seed traits in all generations. The results showed there to be low genetic variability with respect to physical seed traits, particularly seed volume, seed density and seed surface area, among several generations of the two cotton crosses. The inheritance of seed physical traits was complex in both crosses due to the presence of substantial non-allelic interactions (digenic epistatic effects) and the influence of generation × temperature regime interaction. The two crosses expressed different patterns of inheritance for seed physical traits. Those governing seed volume and seed surface area were highly sensitive to the temperature regime in both crosses and were controlled by additive genetic effects under heat stress conditions, and by dominant genetic effects under non-stress regime. The non-stress regime favoured the expression of dominant genetic effects. From a breeding point of view, the heat stress regime could be a more favourable environment for enhancing selection efficiency.

Vibrational analysis of seedless watermelons: use in the detection of internal hollows

Abstract: The internal quality of fruit can be non-invasively tested using systems based on vibrational characteristics. In this work, acoustic impulses were used to detect internal hollows in watermelons; the change in the signal revealing the problem. Frequency spectrum variables were analysed for their potential as non-destructive predictors of this defect. The band magnitude variables, obtained from the integral of the spectrum magnitudes between two frequencies, best predicted internal disorders. Experimental modal analysis was used to investigate the vibrational performance of watermelons and to determine the best positions for the impact point and response measurement microphone. A firsttype spherical mode and its resonant frequency was the best indicator of internal quality problems. Finite element modal analysis was performed to establish a watermelon shape/characteristics model and to compare theoretical and experimental results.

Telluric pathogens isolated from blighted pepper (Capsicum annuum L.) plants in northwestern Spain.

Abstract: A survey of blighted pepper (Capsicum annuum L.) plants covering 120 farms in northwestern Spain was performed between 2001 and 2004 with the aim of identifying the main telluric pathogens associated with the disease in this part of the country. The following potential telluric pathogens were isolated from the 755 diseased plants inspected: Phytophthora capsici Leonian, P. nicotianae Breda de Haan, Verticillium dahliae Kleb., Rhizoctonia solani Kuhn, Sclerotium rolfsii Sacc., Fusarium solani Mart. (Sacc.) and Botrytis cinerea Pers. R. solani was the most commonly isolated pathogen; this was detected on 38% of the farms and isolated from 16% of the plants analysed. Inoculation tests were performed with isolates of P. capsici, P. nicotianae and F. solani on C. annuum cv. Yolo Wonder. These confirmed P. nicotianae as a pepper pathogen, but with weaker pathogenic behaviour than P. capsici. F. solani was confirmed as a secondary pathogen.

Influence of earthworms on organic waste composting and characterisation of vermicompost end products

Abstract: The aim of this work was to study the influence of earthworms on the composting process. Selected waste mixtures —pine sawdust + poultry litter (M1), cotton industry waste + poultry litter (M2), shredded paper + horse manure (M3), and cotton industry waste + horse manure (M4)— were composted for 85, 64, 60 and 60 days respectively in plastic boxes. The temperature variations during this process followed the typical three-phase pattern. At the end of this process 95, 80, 75 and 95 g of Eisenia andrei were added to each treatment respectively to initiate vermicomposting. Together, the composting and vermicomposting processes took between 105 and 175 days. Earthworm biomass decreased in M1 and M2, and increased in M3 and M4. The physical, chemical and biological variables measured, such as time to compost maturity, the changes in earthworm population, the C/N ratio, and the availability of nutrients, showed that M3 was the best medium for earthworm activity, and that M4 had the best chemical and physical properties as an organic manure. Mixtures containing poultry litter were not suitable for vermicomposting. However, M1 was the best mixture in a test involving the growth of ryegrass (Lolium perenne cv. Weterwald); compared to controls, a 120% dry weight yield was obtained.

Effect of feeding level during the period previous to free-range fattening on growth and carcass characteristics in Iberian pigs.

Abstract: This study was principally undertaken to provide information of the influence of feeding level during the period prior to fattening on growth and carcass traits of Iberian pigs finished under free-range conditions with acorns and grass. During the period prior to fattening, a group of 11 pigs (high feeding level, H) was fed with 70 g feed kgE–1 LW sup(0.75) (live weight) and another group of 11 pigs (low feeding level, L) was fed with 50 g feed kgE–1 LW sup(0.75). The pigs average daily gain for prior to fattening, free-range and whole periods were: 385.4 and 168.9 (P<0.001), 508.4 and 582.1 (P<0.05) and 430.5 and 320.5 (P<0.05) g day–1in H and L pigs respectively. The H and L pigs' slaughter weights were 166.2 and 138.4 kg (P<0.01). Feeding level during the period prior to the fattening period had no significant effect on backfat thickness and Longissimus dorsi (LD) area measured at the level of the last rib, LD intramuscular fat percentage and carcass hams, forelegs, loins, sirloin and total cut amounts. The correlation coefficients between pig growth rate during the whole period and carcass hams, forelegs and total cut amount were 0.95, 0.92 and 0.95 respectively. The interaction between the feeding level prior to the free-range period and carcass weight was studied for carcass traits.

Effect of feeding level during the period previous to free range fattening on growth and carcass characteristics

Abstract: El objetivo principal de este estudio fue analizar el efecto del nivel de alimentacion de premontanera sobre el crecimiento y caracteristicas de la canal de cerdos ibericos cebados en montanera exclusiva. Un grupo de 11 cerdos fue diariamente alimentado con 70 g de pienso por kg de peso metabolico durante la premontanera (nivel de alimentacion alto, A) y otro grupo de 11 cerdos con 50 g de pienso por kg de peso metabolico (nivel de alimentacion bajo, B) durante el mismo periodo. La ganancias medias diarias durante la premontanera, montanera y periodo total fueron: 385,4 vs 168,9 g (P < 0,001), 508,4 vs 582,1 g (P < 0,05) y 430,5 vs 320,5 g (P < 0,05), respectivamente, en los cerdos A frente a los B. Los pesos al sacrificio de los cerdos alimentados con el nivel A y B fueron 166,2 y 138,4 kg respectivamente. El nivel de alimentacion de premontanera no tuvo influencia significativa sobre el espesor de grasa dorsal, area del musculo Longissimus dorsi (LD), medidos a nivel de la ultima costilla, porcentaje de grasa intramuscular del LD y cantidades de jamon, paleta, lomo, solomillo y total de partes nobles de la canal. Los coeficientes de correlacion entre la ganancia media diaria durante el periodo total experimental y las cantidades de jamon, paleta y total de partes nobles de la canal fueron 0,95, 0,92 y 0,95, respectivamente. Este trabajo estudia la interaccion entre el nivel de alimentacion de premontanera y el peso canal para las caracteristicas de la canal.

Influence of arbuscular mycorrhizas on the growth rate of mist-propagated olive plantlets

Abstract: The aim of this work was to determine the influence of early inoculation of semi-woody olive cuttings (cv. Cornicabra), cultivated under mist propagation conditions, with arbuscular mycorrhizal fungi. A strongly positive response was seen to root inoculation with the three fungal species tested —Glomus mosseae, G. intraradices and G. claroideum— both in nursery phase plantlets, and in older plants grown in 5 L pots. Additional key words: Glomus, mist propagation, mycorrhizal fungi, Olea europaea, plantlets. Resumen Influencia de las micorrizas arbusculares en el desarrollo de plantones de olivos propagados bajo nebulizacion

Comparison of the pesticide coverage achieved in a trellised vineyard by a prototype tunnel sprayer, a hydraulic sprayer, an air-assisted sprayer and a pneumatic sprayer

Abstract: La pulverizacion es el principal metodo usado en Castilla-La Mancha para aplicar productos fitosanitarios a la vina en espaldera. Si la eficiencia de las aplicaciones se incrementa, la cantidad de pesticida empleado se reduce y el rendimiento de las maquinas existentes y de las nuevas tecnologias aumenta. Para ello, debe conocerse el recubrimiento alcanzado en las hojas y desarrollarse un sistema que pueda determinarlo rapidamente. Con estos objetivos se construyo y ensayo un prototipo de pulverizador tipo tunel, y se comparo su eficiencia con los tres tipos de maquinas de aplicacion de productos fitosanitarios mas utilizados en esta region: pulverizadores, atomizadores y nebulizadores. Para determinar el porcentaje de recubrimiento logrado por las maquinas, se desarrollo un sistema rapido que combina el uso de cartulinas de papel hidrosensible con la vision artificial. Con todos los pulverizadores se uso el mismo fungicida comercial (200 L ha-1) y se ensayaron, a tres presiones diferentes (0,1 MPa, 0,3 MPa y 0,6 MPa), en un vinedo en espaldera. Se demostro que en los cuatro modelos la calidad de la aplicacion mejora con la presion de la pulverizacion, y que el mejor recubrimiento se obtuvo con el prototipo de pulverizador tipo tunel. Aunque los resultados obtenidos no fueron optimos (formacion de una pelicula uniforme de fungicida), el valor medio alcanzado por el prototipo fue del 54%, y en ocasiones supero el 79%.

Does melatonin treatment during lactation influence milk production in Lacaune and Assaf ewes

Abstract: To determine whether treatment with melatonin during lactation harms milk production, two experiments were performed. In Experiment 1, 188 Lacaune ewes, lambed between September 12 and November 1 were used, and in Experiment 2, 124 Assaf ewes that lambed between November 14 and January 11. In Experiment 1, a first milk record was obtained on February 11, which was used to divide the animals into two groups, M and C. On March 11, a subcutaneous melatonin implant was administered to M animals (n = 93), and the rest (n = 95) corresponded to the Control Group (C). In Experiment 2, the first milk record was at weaning (January 5) and, on February 15, ewes were divided into M (n = 90) and C (n = 34). From that date until dry-off, monthly milk records were obtained. In both experiments, melatonin treatment significantly increased the number of lambs produced, and no detrimental effects on milk production were detected. In conclusion, the use of melatonin to improve reproduction in dairy sheep does not interfere with milk production. Moreover, an increase in the number of lambs produced, and the greater number of ewes that can be milked in the following period because of exogenous melatonin can provide economical benefits to farms.

Effect of conjugated linoleic acid, high-oleic sunflower oil and fish oil dietary supplementation on laying hen egg quality

Abstract: An experiment was performed to determine the effect of supplementing the diet of laying hens with conjugated linoleic acid (CLA), fish oil (FO) and high-oleic sunflower oil (HOSO) on hen performance, egg yolk fatty acid (FA) concentrations, and egg sensorial quality and firmness. Four treatments were factorially designed involving two levels of supplementation of FO (0 and 17 g kg -1 ) and HOSO (30 and 35 g kg -1 ) for diets containing 3 g kg -1 of CLA. A control diet was also designed, with 30 g kg -1 HOSO but with no CLA or FO. Twenty five 38 week-old Warren laying hens were randomly assigned to 28 d dietary treatments with the above diets, following a pre-experimental period of 21 d. The type of diet did not affect egg production characteristics. The addition of CLA increased the yolk fat concentrations of CLA, saturated FA and C22:5 n-3, but reduced those of monounsaturated FA and C20:4 n-6. Supplementation with FO increased long-chain n-3 FA concentrations but reduced those of long-chain n-6 FAs, t10,c12 and tt-CLA. Supplementation with HOSO had little influence on yolk fat composition. Supplementation with CLA and FO impaired egg sensorial quality in an additive fashion, although yolk firmness was not affected. Eggs from hens fed diets with 3 g CLA kg -1 and 30 g HOSO kg -1 —but no added FO— contained 9 g CLA kg -1 yolk fat and were of acceptable sensorial quality to trained panellists. However, no eggs double-enriched in CLA and n-3 FA were obtained that were also sensorially acceptable.

Genetics of panicle-related traits of agronomic importance in rice through triple test cross analysis

Abstract: Se ha llevado a cabo un analisis mediante cruzamientos prueba para estudiar la genetica de algunos caracteres de importancia agronomica relacionados con la panicula del arroz tipo ?Basmati?. La separacion de la epistasia total en dos tipos, i (aditivo ? aditivo) y j + l (aditivo ? dominancia y dominancia ? dominancia), revelo que las interacciones de tipo j + l eran estadisticamente significativas para el numero de paniculas por planta y para el rendimiento de la planta. Los efectos genicos aditivos y dominantes fueron importantes para la longitud de la panicula, el n.o de ramas secundarias, el n.o de granos llenos y esteriles por panicula, asi como para la densidad de panicula. Sin embargo, los efectos aditivos fueron la unica fuente de variacion para el n.o de ramas primarias por planta y para el porcentaje de fertilidad. La varianza aditiva fue mayor para todos los caracteres y el grado de dominancia fue menor que la unidad, lo que indica una dominancia parcial. La correlacion no significativa entre sumas y diferencias no mostro ninguna evidencia de dominancia direccional. Estos resultados indican que las interacciones epistaticas de tipo j + l pueden ser manipuladas para la mejora de los caracteres n.o de paniculas por planta y rendimiento por planta mediante seleccion recurrente. El hecho de que predominen los efectos genicos aditivos sugiere la ocurrencia de seleccion en poblaciones tardias en segregacion. Por ello, para la mejora del rendimiento de arroz se propone una seleccion temprana para el n.o de ramas primarias por panicula y para el porcentaje de fertilidad.