ReDivia - Repositorio Digital de l'Instit Valencià d'Investigacions Agràries
Not a member yet
2747 research outputs found
Sort by
Application of modulated chlorophyll fluorescence and modulated chlorophyll fluorescence imaging to study the environmental stresses effect
Get PDFChlorophyll (Chl) a fluorescence is a widely used tool to monitor the photosynthetic process in plants subjected to environmental stresses.
this review reports the theoretical bases of Chl fluorescence, and the significance of the most important Chl fluorescence parameters. it also reports
how these parameters can be utilised to estimate changes in photosystem ii (Psii) photochemistry, linear electron flux and energy dissipation
mechanisms. the relation between actual Psii photochemistry and Co2 assimilation is discussed, as is the role of photochemical and
non-photochemical quenching in inducing changes in Psii activity. the application of Chl fluorescence imaging to study heterogeneity on leaf
lamina is also considered. this review summarises only some of the results obtained by this methodology to study the effects of different
environmental stresses, namely water and nutrients availability, pollutants, temperature and salinity
Importance of feeding behaviour on life cycle in the zoophytophagous bug Dicyphus geniculatus
Get PDFDicyphus geniculatus (Fieber) (Heteroptera Miridae) is a Mediterranean mirid that has been observed in public green areas in
towns of eastern and western provinces of Spain feeding on whiteflies and thrips on Dianthus caryophyllus L. carnations. In this
article, the relative importance of feeding behaviour with respect to the duration of nymphal development and nymphal survival,
as well as reproduction, was investigated. Nymphs of Bemisia tabaci (Gennadius), larvae of Frankliniella occidentalis (Pergande)
and carnation plants introduced into a 50 × 50 × 50 cm methacrylate box, together with adults mirids, in a climate-controlled
chamber (25 ± 1 °C, 60 ± 5% HR, 16:8 h L:D photoperiod) were used to analyse feeding behaviour. In particular, data on realised
fecundity, sex ratio and adult longevity were analysed. Realised fecundity differed significantly with respect to prey availability
(F1, 267 = 44504.92; p ≤ 0.001). The sex ratio did not differ from 1(♂♂):2(♀♀+♂♂) with respect to feeding regimes [“with
B. tabaci prey” (37/53+37 = 0.41), χ2 = 1.434, df 1, p = 0.231, “with F. occidentalis prey” (42/50+42 = 0.46), χ2 = 0.200, df 1,
p = 0.655] or prey type (B. tabaci or F. occidentalis, χ2 = 0.564, df 1, p = 0.453). Adult longevity differed significantly in terms of
prey availability (F2, 534 = 58.89, p ≤ 0.001) and longevity differed for each sex within each feeding regime (F1, 534 = 14.13;
p ≤ 0.001). D. geniculatus can survive on a host plant diet exclusively but could not complete its development in the absence of
supplemental prey food, indicating that D. geniculatus requires an animal component in its diet. Other zoophytophagous dicyphines
are successfully used as beneficials in integrated pest management in horticultural crops. Thus, D. geniculatus has a potential
role in the biological control of carnation pests, and therefore may be a promising pest biological control agent, thus contributing
to urban area sustainability
Estimación del Índice de Color de los Cítricos utilizando dispositivos móviles
Get PDFLos primeros cítricos se recolectan en España antes de que hayan alcanzado su típico color
naranja. Sin embargo, para su llegada al mercado es necesario que alcancen un cierto color
comercial, por lo que la fruta se somete a ciertos tratamientos de desverdizado cuya duración
depende de su color en el momento de recolección medido según estándar Índice de Color de
los Cítricos (ICC). Para estimar este índice, las frutas se comparan con unas tarjetas de colores
que representan la piel de cítricos con diferentes índices o se utilizan colorímetros. Para facilitar
la medida de este índice, se ha desarrollado una aplicación gratuita para dispositivos móviles
basados en Android que utiliza técnicas de procesamiento de imágenes utilizando la cámara
incorporada en el dispositivo. Las imágenes de un fruto se analizan en vivo para obtener su ICC.
Para ello, se calcula el valor promedio de las coordenadas de color RGB (rojo, verde, azul) de un
área circular preseleccionada en la imagen y se transforma al espacio de color HunterLab para
finalmente calcular el ICC. Para validar este método, se realizaron varias pruebas tanto en
campo como en condiciones de laboratorio con diferentes variedades de naranjas (Navel,
Bonanza, Cram y Navelina) en diferentes estados de madurez, y se utilizaron diferentes
dispositivos Android con diversas características. Las mediciones obtenidas se compararon con
los resultados proporcionados por un colorímetro ampliamente utilizado en la industria para esta
tarea. Los valores de R2 obtenidos oscilaron entre el 0,96 y el 0,98 dependiendo de las cámaras
de los dispositivos móviles probados, lo que muestra la robustez y fiabilidad de la aplicación
móvil desarrollada para ser utilizada como ayuda en la toma de decisiones sobre la recolección o
desverdización de estas frutas
GRAS, plant- and animal-derived compounds as alternatives to conventional fungicides for the control of postharvest diseases of fresh horticultural produce
Get PDFPostharvest decay caused by fungal pathogens is one of the most important factors causing economic losses for the worldwide industry of fresh horticultural produce. Despite the positive results of the use of conventional chemical fungicides, alternatives for decay control are needed because of increasing concerns related to their widespread and continued use. Low-toxicity chemical alternatives evaluated for control of postharvest diseases of temperate, subtropical and tropical fruit, and fruit-like vegetables are reviewed. These compounds should have acceptable antifungal activity with known and very low toxicological effects on mammals and minimal impact on the environment. In addition, they should be exempt from residue tolerances on agricultural commodities. Authorities confirm these characteristics by approving them as food additives or preservatives or as generally regarded as safe (GRAS) substances. Among these, the most important are inorganic or organic salts, e.g. carbonates, sorbates, benzoates, paraben salts, etc., and composite edible coatings formulated with antifungal ingredients. Hydrocolloids (polysaccharides such as cellulose derivatives, alginates, pectins, or gums, and various plant proteins) and food-grade lipids are the main components of the matrix of composite coatings. Interesting antifungal ingredients for edible coatings include GRAS salts, essential oils, and antagonistic microorganisms. Low-toxicity chemicals of natural origin include plant extracts and essential oils, antifungal peptides and small proteins, and coatings based on chitosan or plant gels like those from Aloe spp. Efficacy and overall performance, advantages, disadvantages, limitations, and potential combinations of these alternatives in hurdle technologies for postharvest decay control are discusse
Efecto del tamaño de baya en Tempranillo bajo diferentes prácticas culturales
Get PDFEste trabajo tiene como objetivo determinar la influencia del tamaño de baya
sobre la composición de la misma para la variedad Tempranillo sometida a
diferentes prácticas culturales. En un viñedo situado en Requena (Valencia) se
realizaron ensayos sobre riego y carga productiva (2004 y 2005) y fecha de
deshojado (2008). Se obtuvo la distribución de peso fresco de baya por tratamiento y
se dividió en cuatro categorías; para cada una de ellas se determinó el peso de piel y
semillas así como el contenido en sólidos solubles, acidez total, pH, índice de
polifenoles totales (IPT) y concentración de antocianos. El tamaño de baya tuvo un
efecto significativo en la composición de la uva, siendo las más pequeñas las que, en
general, presentaron mayores concentraciones de azúcares y antocianos. Asimismo,
el riego incrementó la proporción de semillas en las bayas así como la acidez total.
Una menor carga productiva aumentó el contenido de sólidos solubles en las bayas,
el peso específico de la piel y la concentración de antocianos de las bayas más
grandes, lo que sugiere que ajustar la carga productiva podría permitir al viticultor
obtener bayas de mayor tamaño con una composición adecuada para elaborar vinos
de alta calidad. El deshojado mejoró la composición química de las bayas debido a
una mejor exposición de los racimos a la radiación solar. Por lo tanto, la calidad de
la baya puede modularse mediante estas prácticas con el fin de alcanzar los objetivos
de la bodega
Acta Horticulturae
No full textTurkey is the most important producer and exporter country of apricot, Prunus armeniaca. Production of apricots for fresh market relies on foreign cultivars grown on Mediterranean and Aegean regions while Malatya is the most important region for production of dry apricots based on local cultivars. Plum pox virus (PPV) in Turkey has been known since 1968, but it was not widespread until recent years. Malatya region has been free of sharka disease so far, but the disease has already been reported from many different provinces since 2006. Because of that, introgression of resistance to PPV in the local cultivars with good pomological characteristics became an important objective for the apricot crop. In the current breeding program, obtaining new cultivars resistant to PPV, selection of resistant seedlings by using molecular markers linked to PPV resistance was aimed at. Nineteen local apricot genitors and progenies obtained from the crosses between the PPV resistant cultivar ‘Stark Early Orange’ (SEO), ‘Harcot’ and local cultivars such as ‘Hacıhaliloğlu’, ‘Kabaaşı’, ‘Hasanbey’, ‘Çöloğlu’, ‘Adilcevaz5’, ‘Şekerpare’, ‘MahmudunEriği’, ‘Soğancı’ and ‘Çataloğlu’ were screened with markers. The markers PGS1.21 and PGS2.23 co-segregating with resistance to PPV were used to screen a total of 189 apricot progenies. None of the local genitors had alleles linked to PPV resistance. Among the progenies screened, 15 seedlings from ‘Şekerpare’ by SEO, 12 from ‘Adilcevaz5’ by SEO, 7 from ‘Hacıhaliloğlu’ by SEO, 9 from ‘Kabaaşı’ by SEO, 5 from ‘Çöloğlu’ by SEO, 9 from ‘Çataloğlu’ by SEO, 4 from ‘Hasanbey’ by SEO, and 1 from ‘MahmudunEriği’ by SEO and none of the ‘Harcot’ by ‘Soğancı’ presented resistant alleles and were selected for further studies
Determination of Enzyme Activity in Rabbit Seminal Plasma and its Relationship with Quality Semen Parameters
Get PDFThe objective of this study was to determine rabbit seminal plasma enzyme activity. Furthermore, correlations between semen parameters and enzyme activity and male age were examined. The study was performed using 17 New Zealand White males from 5 to 9 mo old. Overall, 252 semen samples were collected from bucks from May to September. Semen characteristics were analysed and the seminal plasma was obtained by centrifugation. The activities of alanyl aminopeptidase (APN), aspartate transaminase (AST), alanine aminotransferase (ALT), gamma-glutamyl transpeptidase (GOT), lactate dehydrogenase (LDH) and alkaline phosphatase (ALKP) in the seminal plasma fluid were measured. Significant differences between males were found in APN, GGT, LDH, ALKP and ALT activities (P<0.05). No significant differences between enzyme activity and male age were found. We also observed significant positive correlations between male age and sperm concentration (r=0.26), progressive motility (r=0.17) and amplitude of lateral head displacement (r=0.21), and negative ones between male age and average path velocity (r=-0.56), velocity of the sperm head along its actual curvilinear path (r=-0.61), straight line velocity (r=-0.50), linearity index (r=-0.13), and cytoplasmic droplet (r=-0.33). Furthermore, a significant negative correlation between APN activity and the status of the acrosome (r=-0.20) and significant positive correlations between APN activity and the sperm abnormalities (r=0.21), GOT activity and sperm concentration (r=0.34) and the status of the acrosome (r=0.31), and ALKP activity and sperm concentration were observed (r=0.41). In our study, APN and GGT seem to be the most predictive enzymes for rabbit semen quality
Acta Horticulturae
No full textMandarin genotypes can be split in two main groups: the acidic and the sweet mandarins. Commonly, acidic are used as rootstocks when sweet mandarins are the varieties that are consumed as fruits. The acidic 'Cleopatra' mandarin (Citrus reshni Hort. ex Tan.) is considered to be the most salt stress tolerant rootstock since it is able to limit the absorption of chloride and sodium at root level. As a consequence, limited amount of toxic ions are translocated from root to leaves. If salt stress tolerance of 'Cleopatra' mandarin and its hybrids has been well documented, little data exist for sweet mandarins. We investigated 16 genotypes representing a large diversity in mandarins subjected to salt stress. Physiological parameters such as stomatal conductance and leaf chloride contents were analyzed. If most of the acidic varieties were tolerant, also some sweet varieties presented traits of tolerance. Taking into account the results of leaf ion contents, we observed that large leaf chloride contents were not always associated with sensitivity
First record of Pachycrepoideus vindemmiae (Rondani) (Hymenoptera: Pteromalidae) parasitizing pupae of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) in Tunisia
No full textActa Horticulturae
No full textAutocidal control of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), has become the cornerstone of area-wide integrated pest management programs in many countries. In this technique a critical point is the mating success of released sterile males which should contribute to reduce wild populations. Till this moment the evaluation of mating success is not performed regularly in area-wide programs, being used an indirect measure as the recapture ratio of sterile versus fertile males, to evaluate the success of the sterile insect technique. We present here a review of the state of the art in mating success evaluation including the application of a molecular tool, which allows the quantification of mating success of released sterile males, linked to the progeny reduction at different sterile males release ratios using different medfly hosts. Implications of these results on the efficacy measurement of an area-wide SIT program are discussed