ReDivia - Repositorio Digital de l'Instit Valencià d'Investigacions Agràries
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Chlorophyll fluorescence imaging as a tool to evaluate calyx senescence during the ripening of persimmon fruit treated with gibberellic acid
Get PDFThe effect of gibberellic acid (GA) on retarding loss of persimmon firmness and fruit coloration has been previously reported. Nevertheless, information about the effect of this treatment on calyx senescence is lacking. In this study, chlorophyll fluorescence imaging (CFI) was used to evaluate calyx senescence in persimmon fruit treated with GA. At three harvest times, physico-chemical parameters measured on persimmon fruit and CFI parameters (Fo, Fm and Fv/Fm) on calyx sepals were evaluated on the fruit treated once or twice with GA, and also on untreated fruit (CTL). A decline in the chlorophyll fluorescence parameters correlated with calyx senescence and progressed during fruit ripening. Spatial images heterogeneity in the Fm/Fv measurements illustrates senescence and necrosis dynamics, which began in the apical area of sepals and progressed to the basal area. Besides retarding fruit ripening, GA treatments delayed the calyx senescence process, and hence improved external fruit quality maintenance. The CFI parameters measured on the calyx correlated with both external color evolution and firmness loss during fruit ripening. Consequently, these chlorophyll fluorescence parameters could act as a potential non-intrusive tool to determine persimmon harvesting time
Effect of rootstock on the fruit quality of mandarins ‘Clemenules’ and ‘Tango’, and blood oranges ‘Tarocco Rosso’ and ‘Moro’
Get PDFCitriculture constantly faces changing environmental scenarios that cause
different biotic and abiotic stress that can make production difficult or might
affect fruit quality. The rootstock onto which a specific variety is grafted is an
important tool to help to improve its agronomic adaptability to each crop area.
The present Thesis was carried out to study the effect of rootstock on physicochemical and nutritional fruit quality in some varieties of much commercial interest today: ‘Clemenules’ and ‘Tango’ mandarins, and ‘Tarocco Rosso’ and ‘Moro’ blood oranges. In ‘Clemenules’, the most representative mandarin variety in the Mediterranean Region, the fruit of the trees grafted into eight rootstocks at three harvest times was evaluated by performing studies during two seasons. Of the evaluated rootstocks, Forner-Alcaide 13 and C-35 Citrange stood out for their earlier color change, which is very interesting for this variety, in which early harvesting is a relevant aspect from the commercial point of view. Forner-Alcaide V17 also stood out for maintaining optimum acidity levels until the season ended, and also presented the highest contents in vitamin C, flavonoids, glucose and fructose. Carrizo Citrange brought about high concentrations of sucrose and vitamin C in fruit. ‘Tango’ is a mandarin variety that has been recently introduced into the
Mediterranean Region. Its harvest time is very interesting because it starts
when that of clementines ends. The present Thesis studies changes in the
physico-chemical, nutritional and sensorial quality of the ‘Tango’ mandarin
grafted onto two rootstocks (Carrizo Citrange and Forner-Alcaide 5) during the harvest period in the two main production areas in Andalusia (S Spain). The results revealed that fruit quality during harvest was influenced by the location of orchards, which was particularly related to soil texture composition. However, in both areas, Forner-Alcaide 5 was the rootstock that induced higher acidity content, and more total soluble solids, sucrose, vitamin C and citric acid in fruit. The physico-chemical determinations, along with the sensorial evaluation, allowed the optimum harvest time to be established
depending on the different studied conditions
Changes in plant responses induced by an arthropod influence the colonization behavior of a subsequent herbivore
Get PDFBackground: Plants in nature can be sequentially attacked by different arthropod herbivores. Feeding by one arthropod species may induce plant-defense responses that might affect the performance of a later-arriving herbivorous species. Understanding these interactions can help in developing pest-management strategies. In tomato, the sweet-potato whitefly Bemisia tabaci and the two-spotted spider mite Tetranychus urticae are key pests that frequently cohabit on the same plant. We studied whether colonization by one species can either facilitate or impede later colonization of tomato plants by conspecific or heterospecific individuals. Results: B. tabaci females showed a strong preference for and increased oviposition on plants previously colonized by conspecifics. In contrast, plants infested with T. urticae repelled B. tabaci females and reduced their oviposition rate by 86%. Although females of T. urticae showed no preference between conspecific-infested or uninfested plants, we observed a 50% reduction in
the number of eggs laid on conspecific-infested plants. Both herbivorous arthropods up-regulated the expression of genes involving the jasmonic acid and abscisic acid pathways, increasing emissions of fatty-acid derivatives, but only B. tabaci increased the expression of genes related to the salicylic acid pathway and the total amount of phenylpropanoids released. Terpenoids were the most abundant compounds in the volatile blends; many terpenoids were emitted at different rates, which might have influenced the arthropods' host selection. Conclusion: Our results indicate that B. tabaci infestation facilitated subsequent infestations by conspecifics and mites, while T. urticae infestation promoted herbivore-induced resistance. Based on both the molecular and behavioral findings, a novel sustainable pest-management strategy is discussed
Phenotyping Local Eggplant Varieties: Commitment to Biodiversity and Nutritional Quality Preservation
Get PDFGiven the little variability among commercialised eggplants mainly in developed countries, exploring, and structuring of traditional varieties germplasm collections have become a key element for extending ecotypes and promoting biodiversity preservation and consumption. Thirty-one eggplant landraces from Spain were characterised with 22 quantitative and 14 qualitative conventional morphological descriptors. Landraces were grouped based on their fruit skin colour (black-purple, striped, white, and reddish). Landraces B7, B20, and B24 were left out for their distinctive fruit characteristics. Wide variation for plant, leaf, flower, and fruit phenology traits was observed across the local landraces, and fruit descriptors were considered the most important ones. In a second experiment, landraces, B14, B16, and B17 were selected to determine fruit quality. By contemplating the benefits provided by antioxidants and sugars for human health, pulp antioxidant capacity, total phenolic, ascorbic acid, carotenoid, flavonoid, and total sugar content were determined. Significant differences were observed across these three landraces, and B14 was highlighted for its antioxidant properties, while B17 stood out for its high sugar content. B16 did not stand out for any traits. The results indicate the wide variability in eggplants for their phenotypic and nutritional characteristics, which emphasises the importance of traditional varieties as the main source of agricultural biodiversity
Irrigation Recommendation for Water Saving and Salinity Control in Horticulture in the Semi-arid Lower Cheliff Plain (Algeria)
No full textSalinity and water deficit are two major issues for agricultural development in Algeria. The Lower Cheliff plain, northwestern Algeria, is, furthermore, characterised by semi-arid Mediterranean climate, and soils with high clay content. Our study area was a 4 ha farm located in Oued Rhiou and another 1 ha farm located in Ouarizane, both upstream in the Lower Cheliff plain, and irrigated with waters of different salinities: 1.8 and 5.5 dS m-1, respectively. The plots were equipped with drip irrigation and subsurface drainage systems. Farmer’s irrigation management of artichoke and melon were observed during the respective cropping seasons from September 2010 till June 2011, and from April till July 2011. The total irrigation amounts were, respectively, 364 mm and 240 mm, while the precipitations were 367 mm and 67 mm. The soil properties were determined in the entire rooting depths down to 80 cm for artichoke and 60 cm for melon. In addition to these, irrigation water composition, and crop development parameters were used to simulate soil salinity using the SALTIRSOIL_M model. Simulations and observations of soil pH, main ion concentrations and ECe showed reasonable agreements for June 2011. Next, the irrigation schedules that would have met the water needs of both crops, while simultaneously keeping soil salinity below harmful levels were estimated using the model. For the artichoke plot, a lower irrigation rate (290 mm yr-1) could have kept water deficit and soil salinity below their respective harmful thresholds. For the melon plot, on the contrary, a higher irrigation rate (480 mm yr-1) is able to neutralise the water deficit, though not completely the salinity stress would have been adequate. Farmers’ irrigation practices in the context of the climate, water quality and soil properties of the Lower Cheliff plain can be analysed and improved with the aid of soil salinity modelling
Cold Stress in Citrus: A Molecular, Physiological and Biochemical Perspective
Get PDFDue to climate change, we are forced to face new abiotic stress challenges like cold and heat waves that currently result from global warming. Losses due to frost and low temperatures force us to better understand the physiological, hormonal, and molecular mechanisms of response to such stress to face losses, especially in tropical and subtropical crops like citrus fruit, which are well adapted to certain weather conditions. Many of the responses to cold stress that are found are also conserved in citrus. Hence, this review also intends to show the latest work on citrus. In addition to basic research, there is a great need to employ and cultivate new citrus rootstocks to better adapt to environmental conditions
GRAS Salts as Alternative Low-Toxicity Chemicals for Postharvest Preservation of Fresh Horticultural Products
No full textAmong means alternative to chemical fungicides to control postharvest decay of fresh horticultural products, low-toxicity chemicals, classified as food additives or Generally Recognized As Safe (GRAS) compounds, are of interest because of their low toxicological effects on mammals and minimal impact on the environment. These chemicals include some essential oils, plant extracts, and other natural compounds, but also synthetic inorganic or organic salts such as carbonates, sorbates, benzoates, acetates, paraben salts, silicates, etc. Major advantages of these salts are their inherent antimicrobial activity and high solubility in water. In general, research with GRAS salts initiates with the in vitro evaluation of the antimicrobial activity of aqueous solutions against target postharvest pathogens. Selected salt solutions and concentrations are then assayed in in vivo trials, first at the laboratory scale with fresh produce artificially inoculated with the pathogen and afterwards at semi-commercial or commercial scale with naturally infected produce. GRAS salts can also be used as antimicrobial ingredients of synthetic composite edible coatings, which can have an impact on both physiological and pathological factors limiting the postharvest life of fresh horticultural products. Coating formulation and selection is based on in vivo decay control ability and overall produce quality maintenance during cold storage
Patogenicidad de aislados de Xylella fastidiosa subsp. multiplex del foco de Alicante en diferentes hospedadores
Get PDFXylella fastidiosa es una de las principales bacterias de cuarentena en la Unión Europea, que habita en el xilema de la planta hospedadora y el tracto digestivo de insectos que actúan como vectores. Se multiplica en los vasos conductores de numerosas especies vegetales, pudiendo llegar a obstruir el flujo de savia, lo que provoca síntomas de estrés hídrico que pueden causar la muerte de la planta. En España, las zonas con focos activos son las Islas Baleares y la Comunidad Valenciana, con diferencias en cuanto a las características genéticas de los aislados bacterianos y las especies vegetales afectadas
Citizens’ Food Habit Behavior and Food Waste Consequences during the First COVID-19 Lockdown in Spain
Get PDFDuring the first COVID-19 wave in Spain, confining the population at home was seen as an effective way to prevent the disease from spreading. This limited mobility affected citizens’ routines at homes because it influenced their life habits, including food management. The main objective of this paper was to understand citizens’ food waste (FW) behavior during the first COVID-19 lockdown in Spain by understanding related food practices that could have influenced FW generation. An online survey was conducted from 14 May to 11 June, 2020; 6293 valid responses were collected and analyzed, and 95% of the participants declared not wasting more food than usual. On average, they reported wasting 234 g per household per week, which equals 88 g per capita. We found significant differences in the reported FW generation between participants regarding their age, gender, household composition, and employment status due to COVID-19. In addition, food-related behaviors such as buying more food than usual due to fear or anxiety, storing more food than before the lockdown, and improvising when buying groceries seemed to affect the FW reported by the participants. The paper ends by comparing the conclusions drawn by different works conducted in other countries for a similar purpose
Differences in milk production and lactation-related behaviours in breeding does housed in individual enriched cages and part-time systems
Get PDFThe effect of collective rearing of breeding does was assessed in terms of milk yield and behavioural patterns. A total of 40 breeding does were used, 20 of them housed in individual cages (50x90x50 cm) and 20 in a collective system in groups of 4 rabbits (200x90x50 cm) since 14 days post-partum until 28 days, in which weaning took place. Milk production was assessed during the 1st and 2nd parturition, finding differences between groups only in the second one, when does from the part-time system produced less milk. Straw was offered to animals as environmental enrichment ant its consumption was assessed, finding that does reduced straw consumption in the part-time system compared to individual cages. This effect might be related to the presence of social stimuli. In addition, the number of kits stolen by does from alien nests was higher during the first days after grouping, achieving 60% of the kits