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Curvas de desprendimiento en la recolección mecanizada de oliva mediante el análisis de las imágenes de las ramas en movimiento
Get PDFEn la recolección mecanizada de oliva mediante vibrador de troncos, la frecuencia de vibrado, el
tiempo de vibrado y el número de vibraciones son parámetros fundamentales para el correcto
funcionamiento del equipo. El objetivo del presente trabajo fue la evaluación del derribo de olivas
en función del tiempo mediante el análisis de los videos de desprendimiento. Olivos de la
variedad ‘Villalonga’, en una parcela en Moncada (Valencia) fueron vibrados con un tractor
frutero con un vibrador orbital Topavi. De los árboles vibrados, 14 grabaciones a alta velocidad
de una rama superior vertical, fueron seleccionadas, 7 de árboles vibrados a 20 Hz durante 3 s
(B) y 7 vibrados a 15 Hz durante 5 s (C), realizando 1, 2 o 3 vibraciones consecutivas con un
descanso de 3 s. Debido a la situación y ángulo de las ramas solo en dos casos fue necesaria
una segunda vibración para el desprendimiento de todos los frutos. En ambos casos la fruta no
desprendida, cayó rápidamente al inicio de la segunda vibración. En todos los casos, menos en
uno, se produjo el desprendimiento del 80% de los frutos antes de 1 s, con una media de 0,77 s.
Y una media de 1,28 s para el desprendimiento del 100%. No se encontraron diferencias
significativas entre los valores de los dos tipos de vibración, B y C. La evolución del porcentaje de
desprendimiento en función del tiempo se ajustó a una curva multiplicativa del tipo y=k·xa, con un
R2 medio de 99,4 %. No se encontraron diferencias significativas entre los coeficientes k y a de
los dos tipos de vibración. El desprendimiento de las olivas de las ramas verticales de la parte
superior del árbol se produce de forma no lineal en un tiempo bastante inferior al tiempo total de
vibrado
Browning inhibition and microbial control in fresh-cut persimmon (Diospyros kaki Thunb. cv. Rojo Brillante) by apple pectin-based edible coatings
Get PDFThe aim of this study was to develop new edible coatings based on apple pectin with a combination of antioxidants and antimicrobial agents to control enzymatic browning and microbial growth of fresh-cut ‘Rojo Brillante’ persimmon. The survival of important food-borne human pathogens artificially inoculated on fresh-cut fruit was also assessed. Potassium sorbate (PS) at 2 or 4 g kg−1, sodium benzoate (SB) at 4 g kg−1, or nisin (NI) at 500 IU mL−1, were added to apple pectin coatings containing 10 g kg−1 citric acid and 10 g kg−1 calcium chloride as antioxidants. Persimmon slices were dipped in the coatings, the aqueous antioxidant solution (citric acid and calcium chloride) or water (control), packed in an ambient atmosphere and stored at 5 °C for up to 9 days. Microbial growth, colour, firmness, polyphenol oxidase (PPO) activity, visual quality and overall sensory flavour were measured during storage. Coated samples and those dipped in the antioxidant aqueous solution presented lower a* values than control samples, which indicated effective browning inhibition. Persimmon slices treated with coatings containing PS and SB reached the limit of marketability after 7 days of storage. At the end of storage, the overall fruit flavour was ranked above the limit of acceptability. Antimicrobial coatings inhibited growth of mesophilic aerobic bacteria, and those containing SB and NI were the most effective. No growth of moulds, yeasts and psychrophilic aerobic bacteria was detected during storage. All the treatments effectively reduced the populations of Escherichia coli and Salmonella enteritidis, NI-coating being the most effective. For Listeria monocytogenes, only the NI-coating effectively reduced the bacterial population
Physiological Basis and Transcriptional Profiling of Three Salt-Tolerant Mutant Lines of Rice
Get PDFSalinity is a complex trait that affects growth and productivity in many crops, including rice. Mutation induction, a useful tool to generate salt tolerant plants, enables the analysis of plants with similar genetic background, facilitating the understanding of the salt tolerance mechanisms. In this work, we generated three salt tolerant mutant lines by irradiation of a salt-sensitive cultivar plants and screened M2 plants at seedling stage in the presence of high salinity. These three lines, SaT20, SaS62, and SaT58, showed different responses to salinity, but exhibited similar phenotype to wild type plants, except SaT20 that displayed shorter height when grown in the absence of salt. Under salt conditions, all three mutants and the parental line showed similar reduction in yield, although relevant differences in other physiological parameters, such as Na+ accumulation in healthy leaves of SaT20, were registered. Microarray analyses of gene expression profiles in roots revealed the occurrence of common and specific responses in the mutants. The three mutants showed up-regulation of responsive genes, the activation of oxido-reduction process and the inhibition of ion transport. The participation of jasmonate in the plant response to salt was evident by down-regulation of a gene coding for a jasmonate O-methyltransferase. Genes dealing with lipid transport and metabolism were, in general, up-regulated except in SaS62, that also exhibited down-regulation of genes involved in ion transport and Ca2+ signal transduction. The two most tolerant varieties, SaS62 and SaT20, displayed lower levels of transcripts involved in K+ uptake. The physiological study and the description of the expression analysis evidenced that the three lines showed different responses to salt: SaT20 showed a high Na+ content in leaves, SaS62 presented an inhibition of lipid metabolism and ion transport and SaT58 differs in both features in the response to salinity. The analysis of these salt tolerant mutants illustrates the complexity of this trait evidencing the breadth of the plant responses to salinity including simultaneous cooperation of alternative or complementary mechanisms
The influence of plant spacing in the early stages of selection of rice (Oryza sativa L.) varieties
Get PDFThe cultural practices of the early generations in a pedigree breeding programme may influence its success. The main objective of this study was to compare two selection environments in rice: Widely spaced planting in the field and dense planting in concrete basins. Both methods had yielded commercial varieties in the past. Two F2 populations (J and MS), derived from two crosses sharing the same female parent, were transplanted to both environments. Phenotypic traits were evaluated and their narrow sense heritabilities (h2) estimated
in the F3 and in the F4 progenies of selected plants, all grown in the field. Growth potential was more apparent in the field for most traits, especially those related to yield, but broad sense heritabilities were higher in the basins for ten traits, being higher in the
field for the other five. In population F2MS, field selection resulted in F3 plants which retained a higher tillering ability than those derived from basins selection. Most traits showed low h2 values: Additive variance was only relevant in panicle length (in both populations), plant height and mean panicle weight (in the J population). However, response to one generation of selection (from F3 to F4) also showed fixable variation in panicle number. In addition, this selection reduced plant height, increased culm diameter and internode length (in both populations), and improved pulling resistance (against lodging) in population J. It may be concluded that both practices
can be used for selection in the F2, although different responses might be expected in yield related traits
Medición del porcentaje de madurez en ramas de café mediante dispositivos móviles y visión por computador
Get PDFActualmente, la cosecha de café en Colombia se realiza de manera manual, tiene un alto
requerimiento de mano de obra y es responsable del 40% de los costos de producción. Para
determinar las necesidades de mano de obra, los productores realizan estimaciones de la
producción mediante métodos destructivos o subjetivos. Este trabajo investiga el desarrollo de
una estrategia, basada en el análisis de imágenes, para planificar la cosecha del café a través de
la estimación no destructiva del porcentaje de frutos maduros (PM) en las ramas. Para la puesta
a punto de la metodología, se adquirieron imágenes utilizando un teléfono móvil en diferentes
condiciones de campo a un total de 69 ramas de café variedad Castillo®, con un PM entre el 10%
y el 70%. Debido a la longitud de las ramas (entre 40 y 60 cm), se capturaron varias imágenes de
cada rama, obteniendo un total de 280 imágenes. Para segmentar las imágenes se utilizó la
aplicación Food-ColorInspector (http://www.cofilab.com) y para cada rama se obtuvo mediante
esta aplicación el área correspondiente a tres estados de madurez de los frutos (inmaduro,
semimaduro y maduro), que se asoció al PM. Adicionalmente, se realizó el conteo manual de los
frutos en los distintos estados de maduración. Se utilizaron 23 ramas escogidas al azar para
crear un modelo lineal de estimación entre los porcentajes de madurez obtenidos mediante el
análisis de las imágenes y el análisis manual. El modelo obtuvo un coeficiente de determinación
R2=88%, con un error promedio absoluto del 3,9% entre el PM estimado a mano y mediante
análisis de imagen. Posteriormente, este modelo se validó con 46 ramas restantes, obteniendo
un R2=75% y un error promedio de 5,5%. Los resultados son prometedores para la creación de
herramientas que automaticen la actual estimación manual de cosecha del café mediante el uso
dispositivos móviles, como teléfonos inteligentes, al alcance de cualquier caficulto
Segmentation techniques in image analysis: A comparative study
Get PDFNowadays, the detection, localization, and quantification of different kinds of features in an RGB image (segmentation) is extremely helpful for, e.g., process monitoring or customer product acceptance. In this article, some of the most commonly used RGB image segmentation approaches are compared in an orange quality control case study. Analysis of variance and correspondence analysis are combined for determining their most relevant differences and highlighting their pros and cons
Enzyme activity in soil after different procedures for managing rice straw
Get PDFSevere problems are caused by site burning of
rice straw in Valencia, the third largest Spanish city.
Removal, incorporation or composting are being tested as
alternatives to burning, and the changes they produce in
selected soil biological properties have been studied in two
field trials. One compares removal, burning and
incorporation the straw, and a second evaluates the
application of straw-derived compost for rice production. No
statistically-significant effects on the measured indicators of
biological activity were found in either experiment, indicating
that management-induced changes are small.
Unexpectedly, burning did not affect negatively enzyme
activities or microbial biomass contents since there were no
differences between treatments, or usual levels were
recovered in a few months. The changes induced by straw
removal or incorporation were also not statistically
significant. When straw-derived compost applications were
assayed, dehydrogenase activity was slightly variable and
apparently unaffected by N and compost rates or
compost/mineral N combinations, but phosphomonosterase
activity seems to increase parallel to compost to mineral N
ratio
Mejora del aroma y flavor en variedades tradicionales de pimiento y especies relacionadas (capsicum sp.): diversidad intra e interespecífica
Get PDFPimientos, chiles y ajíes son términos para denominar especies del género Capsicum, destacando el pimiento común (Capsicum annuum) por su amplia distribución, diversidad varietal, importancia económica y ser la predominante en España (Nuez et al., 2003). Es una de las hortícolas más importantes y se emplea en innumerables recetas, contribuyendo con su particular pungencia y/o flavor (DeWitt y Bosland, 2009). Si bien el conocimiento sobre factores relativos a la pungencia es muy amplio, los estudios sobre volátiles responsables del flavor son muy escasos y nulos en materiales tradicionales. Así, los primeros estudios sobre diversidad en volátiles de Capsicum, realizados por el Grupo de Mejora del pimiento del COMAV, permitieron identificar más de 300 compuestos (Rodríguez-Berruezo et al., 2010; Kolmannsberger et al., 2011). Se presentan avances sobre estudios de diversidad y premejora de la fracción volátil en variedades tradicionales de pimiento y se discuten las diferencias con sus formas modernas
Non-Polluting Chemical Approaches to Control Citrus Postharvest Diseases
Get PDFCommercial cultivars of Citrus spp. (Rutaceae), including oranges, mandarins or tangerines, grapefruits, lemons, and limes are the most widely produced fruits in the world. China, Brazil, and the United States (USA) lead the global production, which is mainly devoted to juice extraction, but Spain is the leading country for exports of fresh entire fruit for direct consumption. Among postharvest losses of fresh fruit, those of pathological origin are especially important because whole export shipments are often rejected by wholesale buyers when they find rotten fruits, even at low proportions. In these cases, the producer is also charged for the transport and handling costs [1]
Influence of natal host on parasitism by Spalangia cameroni (Hymenoptera: Pteromalidae)
Get PDFSpalangia cameroni Perkins (Hymenoptera: Pteromalidae) is sold commercially as a biocontrol agent of fi lth fl ies,
including the house fl y, Musca domestica L. (Diptera: Muscidae). For this reason, S. cameroni is mass-reared for inundative
releases to control harmful fl ies. However, the mass-rearing protocols include very little information on the infl uence of natal host
on subsequent host selection by parasitoids with more than one potential host as in the genus Spalangia. Here, we report on the
use of S. cameroni against M. domestica. The S. cameroni were reared using Ceratitis capitata Wiedemann (Diptera: Tephritidae)
(natal host) pupae for several generations. Freeze-killed fl y pupae were used in assays to determine the fecundity, number of
adult progeny and sex-ratio of this parasitoid. Realized fecundity and number of adult progeny were greater when provided with
house fl y pupae than Mediterranean fruit fl y pupae. Thus S. cameroni parasitized more house fl y pupae than C. capitata pupae,
even though the parasitoid was reared on Mediterranean fruit fl y for many generations. These results indicate that S. cameroni
reared on C. capitata can be successfully used in inundative releases against both fruit fl ies (agriculture) and house fl ies (livestock
farming)