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Effect of ethylene degreening on the development of postharvest penicillium molds and fruit quality of early season citrus fruit
Get PDFThe effect of commercial degreening with ethylene gas on fruit susceptibility and quality and development of postharvest green (GM) and blue (BM) molds on early season citrus fruit was investigated. Each cultivar was harvested with different peel color indexes (CI). Fruit were exposed for 3 d to 2 μL L−1 ethylene at 21 °C and 95–100% RH before or after artificial inoculation with Penicillium digitatum or Penicillium italicum. Control fruit were kept at the same environmental conditions without ethylene. Fruit were stored at either 20 °C for 7 d or 5 °C for 14 d and disease incidence (%) and severity (lesion diameter) were assessed. No significant effect of commercial degreening was observed on fruit susceptibility to both GM and BM on citrus cultivars inoculated after degreening. Likewise, no significant effect was observed on disease incidence on citrus cultivars inoculated before degreening and stored at either 20 °C for 7 d or 5 °C for 14 d. In contrast, in cultivars like ‘Clemenules’ mandarins and ‘Navelina’ oranges, degreening significantly increased the severity on fruit with higher initial CI (−3.6 and 1.7, respectively). GM and BM severity on degreened and control ‘Clemenules’ mandarins incubated at 20 °C for 7 d was 146 and 118 mm and 56 and 46 mm, respectively. In general, commercial degreening did not significantly affect external and internal quality attributes of citrus cultivars. Commercial degreening after inoculation of less green (more mature) fruit showed a trend to increase mold severity, presumably through an aging effect (acceleration of peel senescence)
Tiempo óptimo de vibrado para el derribo de aceitunas Villalonga con un vibrador de masas de inercia
Get PDFLa recolección mecánica de aceitunas mediante vibradores de troncos es una técnica ampliamente extendida en
la actualidad, sin embargo, esta actividad sigue creando controversias entre los agricultores porque en ocasiones
se causan daños a los árboles, principalmente descortezado del tronco y deshojado. El primer problema suele ser
debido a equipos en mal estado de conservación y el segundo a tiempos de vibrado excesivos.
Se ha estudiado el tiempo óptimo de derribo de algunas variedades como ‘Picual’ y ‘Hojiblanca’ muy extendidas
en Andalucía, pero es conveniente analizar lo que ocurre con otras variedades y estructura de los árboles. En este
sentido, se planteó una experiencia con olivos de la variedad ‘Villalonga’, la más extendida en la Comunidad
Valencia.
Se utilizó un vibrador de masas de inercia orbital, con una frecuencia de 15,4 Hz y unos desplazamientos picopico,
medidos a la altura de la cruz (0,9 m de altura) de 2,6 cm. Los tratamientos experimentales consistieron en
aplicar vibraciones con las siguientes duraciones: T1, 5 s; T2 5 + 5 s; T3, 5 + 5 + 5 s y T4, 5 + 5 + 5 +5 s, a 10
árboles por repetición, recogiendo los frutos derribados tras cada vibración.
En la primera vibración de 5 s se desprendieron el 87% de los frutos presentes en el árbol, la segunda vibración,
derribó un 9%, mientras que la tercera y cuarta vibración tan sólo desprendieron un 2 % y un 1%
respectivamente.
Se analizaron las posibles relaciones entre el índice de madurez de las aceitunas y el porcentaje de frutos caídos
antes de las vibraciones, con el porcentaje de derribo en la primera vibración de 5 s, observándose una ligerísima
relación positiva entre ambas variables
Influencia de diferentes tratamientos de riego sobre la composición volátil de vinos elaborados con las variedades blancas “Cigüente” y “Verdejo”
Get PDFEn este trabajo se han estudiado los efectos de diferentes tratamientos de
régimen hídrico sobre la composición aromática de los vinos elaborados con uva de
las variedades blancas Cigüente (en Badajoz) y Verdejo (en Valladolid). Los
tratamientos de riego estudiados para Cigüente fueron: CiNR (no regado), CiPR
(déficit preenvero, regado al 25% hasta envero y después al 75%), CIPO (déficit
postenvero. 75% hasta envero y después al 25%) y CiT (riego máximo durante toda
la temporada). Para Verdejo los tratamientos de riego fueron VeNR (no regado),
VeRS (riego al 50% del testigo hasta vendimia) y VeT (testigo, 50% ETo, riego
máximo). Los mostos obtenidos de las diferentes variedades y tratamientos se
sulfitaron con 50 mg/L de SO2, se inocularon con la levadura neutra EC1118
(Lallemand) y su fermentación se llevó a cabo a temperatura controlada. La
composición volátil de los vinos elaborados a partir de cada tratamiento fue
analizada mediante GC-MS. Se identificaron y cuantificaron 42 compuestos en
Verdejo y 36 en Cigüente, que se agruparon en ocho familias aromáticas: alcoholes
superiores, alcoholes en C6, ésteres, acetatos, ácidos, fenoles, lactonas y compuestos
carbonilados. A nivel global no se encontraron diferencias significativas entre
tratamientos de riego en ninguna de las variedades de estudio, sin embargo se
observó una tendencia al aumento de concentración en los tratamientos no regados
(NR). En el análisis por familias de compuestos volátiles, se hallaron pocas
diferencias significativas entre tratamientos. En el caso de Cigüente, se observó un
efecto significativo del riego sobre las familias de lactonas y compuestos
carbonilados, ambas familias representadas por un único compuesto volátil (γ-
butirolactona y acetoina respectivamente). Por otra parte, en Verdejo los
tratamientos de riego únicamente tuvieron influencia significativa sobre la familia
de fenoles volátiles, representada por dos compuestos (4-vinilgüaiacol y 4-vinilfenol).
En ambos casos, Verdejo y Cigüente, la mayor concentración de estas familias de
compuestos volátiles fue observada en los tratamientos no regados (NR). En general,
en el resto de las familias de compuestos volátiles analizadas no se observaron
diferencias significativas, aunque se observó una tendencia hacia una mayor
concentración en los tratamientos no regados (NR)
The peach volatilome modularity is reflected at the genetic and environmental response levels in a QTL mapping population
Get PDFBackground: The improvement of fruit aroma is currently one of the most sought-after objectives in peach breeding programs. To better characterize and assess the genetic potential for increasing aroma quality by breeding, a quantity trait locus (QTL) analysis approach was carried out in an F-1 population segregating largely for fruit traits. Results: Linkage maps were constructed using the IPSC peach 9 K Infinium (R) II array, rendering dense genetic maps, except in the case of certain chromosomes, probably due to identity-by-descent of those chromosomes in the parental genotypes. The variability in compounds associated with aroma was analyzed by a metabolomic approach based on GC-MS to profile 81 volatiles across the population from two locations. Quality-related traits were also studied to assess possible pleiotropic effects. Correlation-based analysis of the volatile dataset revealed that the peach volatilome is organized into modules formed by compounds from the same biosynthetic origin or which share similar chemical structures. QTL mapping showed clustering of volatile QTL included in the same volatile modules, indicating that some are subjected to joint genetic control. The monoterpene module is controlled by a unique locus at the top of LG4, a locus previously shown to affect the levels of two terpenoid compounds. At the bottom of LG4, a locus controlling several volatiles but also melting/non-melting and maturity-related traits was found, suggesting putative pleiotropic effects. In addition, two novel loci controlling lactones and esters in linkage groups 5 and 6 were discovered. Conclusions: The results presented here give light on the mode of inheritance of the peach volatilome confirming previously loci controlling the aroma of peach but also identifying novel ones
Analysis of the detachment of citrus fruits by vibration using artificial vision
Get PDFThe vibratory behaviour of citrus fruits is studied using slow-motion cameras in order to gain a better understanding of the parameters involved in fruit detachment when mechanical harvesting is done using shakers. Single citrus fruits with a small portion of stem were vibrated using strokes from 60 mm to 180 mm and frequencies from 3 Hz to 18 Hz. The movement was recorded at 300 fps and the main parameters considered for fruit detachment were determined through the analysis of the video sequences. Image-processing algorithms created for this purpose were applied to the automated estimation of the centroid of the fruit, the angle of the stem pistil axis, and the position of some selected points in the fruit in each frame of the video sequences to obtain dynamic parameters such as the position, speed and acceleration of the fruit during the movement until it is detached. The signals obtained from the image processing were filtered, providing results in accordance with the calibration systems. In general, results suggest that the inertial forces transmitted to the fruit were lower than the tensile forces required to detach the fruit by pulling it in the stem pistil direction. The largest peaks were observed using long strokes that required fewer cycles for detachment. On the other hand, short strokes combined with high frequencies needed more cycles, and thus a fatigue phenomenon was present. Short strokes and low frequencies were unable to detach some fruit
Genetic Variation and Possible Mechanisms Driving the Evolution of Worldwide Fig mosaic virus Isolates
No full textFig mosaic virus (FMV) is a multipartite negative-sense RNA virus infecting fig trees worldwide. FMV is transmitted by vegetative propagation and grafting of plant materials, and by the eriophyid mite Aceria ficus. In this work, the genetic variation and evolutionary mechanisms shaping FMV populations were characterized. Nucleotide sequences from four genomic regions (each within the genomic RNAs 1, 2, 3, and 4) from FMV isolates from different countries were determined and analyzed. FMV genetic variation was low, as is seen for many other plant viruses. Phylogenetic analysis showed some geographically distant FMV isolates which clustered together, suggesting long-distance migration. The extent of migration was limited, although varied, between countries, such that FMV populations of different countries were genetically differentiated. Analysis using several recombination algorithms suggests that genomes of some FMV isolates originated by reassortment of genomic RNAs from different genetically similar isolates. Comparison between nonsynonymous and synonymous substitutions showed selection acting on some amino acids; however, most evolved neutrally. This and neutrality tests together with the limited gene flow suggest that genetic drift plays an important role in shaping FMV populations
Inoculum Sources, Infection Periods, and Effects of Environmental Factors on Alternaria Brown Spot of Mandarin in Mediterranean Climate Conditions
Get PDFAlternaria brown spot (ABS), caused by Alternaria alternata, is a serious disease affecting mandarin in humid and in semi-arid regions. The information available from Florida cannot be easily extrapolated to Mediterranean regions; thus, epidemiological studies were conducted during two consecutive years in Spain. Pathogenic isolates were found in the canopy and leaf litter and on weeds of the genus Sonchus. The pathogen survived in fallen immature leaves for up to 76 days, until complete leaf decay. Conidia of Alternaria spp. were captured continuously and pathogenic isolates were detected in all sampling dates. However, the number of pathogenic isolates was not correlated with the total captured, indicating that morphological identification is not sufficient for airborne inoculum monitoring. In contrast to humid areas, infections occurred mainly in spring and autumn. Classification tree analysis indicated that virtually all infections occurred on weeks with rainfall ≥2.5 mm and average temperature ≥12.5°C. Based on regression quantiles, the amount of rainfall, number of rain days, and total wetness duration were considered important factors increasing ABS incidence during infection periods. The development of decision support systems for ABS control in Mediterranean conditions may benefit from the restricted periods of infection and the strong influence of weather factors in disease onset
Comparative performance of three sampling techniques to detect airborne Salmonella species in poultry farms
Get PDFSampling techniques to detect airborne Salmonella species (spp.) in two pilot scale broiler houses were compared. Broilers were inoculated at seven days of age with a marked strain of Salmonella enteritidis. The rearing cycle lasted 42 days during the summer. Airborne Salmonella spp. were sampled weekly using impaction, gravitational settling, and impingement techniques. Additionally,Salmonella spp. were sampled on feeders, drinkers, walls, and in the litter. Environmental conditions (temperature, relative humidity, and airborne particulate matter (PM) concentration) were monitored during the rearing cycle. The presence of Salmonella spp. was determined by culture-dependent and molecular methods. No cultivable Salmonella spp. were recovered from the poultry houses' surfaces, the litter, or the air before inoculation. After inoculation, cultivable Salmonella spp. were recovered from the surfaces and in the litter. Airborne cultivable Salmonella spp. were detected using impaction and gravitational settling one or two weeks after the detection of Salmonella spp. in the litter. No cultivable Salmonella spp. were recovered using impingement based on culture-dependent techniques. At low airborne concentrations, the use of impingement for the quantification or detection of cultivable airborne Salmonella spp. is not recommended. In these cases, a combination of culture-dependent and culture-independent methods is recommended. These data are valuable to improve current measures to control the transmission of pathogens in livestock environments and for optimising the sampling and detection of airborne Salmonella spp. in practical conditions
Economic Weights in Rabbit Meat Production
Get PDFA profit function was designed for an industrial commercial rabbitry with the most common management in industrial rabbit production. The incomes, costs, and profit function were calculated and economic weights of the traits were estimated. The variable costs (feeding, artificial insemination, health and replacement) represented 62% of the total costs, and the fixed costs (labour, utilities, amortisation and administration) represented 38% of the total costs. Major costs were feeding of fattening kits and labour cost, at 26% and 18% of the total cost, respectively. The economic weights were feed conversion rate during fattening (-20.2 (sic)/[g feed/g liveweight]), number of kits born alive (15.7 (sic)/kit), pregnancy rate (1.7 (sic)/percentage unit), weaning survival (1.7 (sic)/percentage unit), fattening survival (2.0 (sic)/percentage unit), daily feed intake (-0.50 (sic)/(g feed/d)), daily gain during fattening (1.33 (sic)/(g weight/d)), and replacement rate (-0.29 (sic)/percentage unit). When varying the prices of kg of fattening feed and kg of liveweight, only the economic weights of feed conversion rate during fattening in the first case and the number of kits born alive in the second case changed considerably. Changes in labour cost produced appreciable changes in the whole production cost. Although economic weights are robust to changes in prices, these weights should be recalculated after some generations of selection, because changes in the mean of the traits due to selection can also change economic weights
The role of traditional varieties of tomato as sources of functional compounds
No full textBACKGROUND: Traditional varieties of tomato, usually associated with excellent organoleptic quality, are increasingly appreciated in European quality markets. A collection of 126 populations of 16 traditional varieties from the east of Spain (a secondary diversity center for tomato) have been evaluated over 2 years in order to determine their potential value as sources of functional compounds, including ascorbic acid, lycopene, beta-carotene and total phenolic content. RESULTS: Population and population x year interaction significantly affected lycopene and ascorbic acid contents, while year effect was also significant for beta-carotene. Despite finding some global trends in certain varieties concerning their functional value, high levels of variation have been found at the intra-varietal level. Populations with high levels of the compounds analysed have been found, as well as different levels of intra-population and inter-year variation. Maximum mean contents for both years have reached 308 mg kg(-1) ascorbic acid, 130 mg kg(-1) lycopene, 30 mg kg(-1) beta-carotene and 89 mg caffeic acid 100 g(-1) total phenolic contents, though it is difficult to identify accessions with joint high values of the three compounds. CONCLUSION: These results open the possibility to promote traditional materials as sources of functional compounds, thus strengthening their quality niches and consolidating their price premium. Additionally, these materials could also be used in breeding programs for quality. (C) 2014 Society of Chemical Industr