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Phylogenetic origin of limes and lemons revealed by cytoplasmic and nuclear markers.
No full textBackground and Aims The origin of limes and lemons has been a source of conflicting taxonomic opinions. Biochemical studies, numerical taxonomy and recent molecular studies suggested that cultivated Citrus species result from interspecific hybridization between four basic taxa (C. reticulata, C. maxima, C. medica and C. micrantha). However, the origin of most lemons and limes remains controversial or unknown. The aim of this study was to perform extended analyses of the diversity, genetic structure and origin of limes and lemons.
Methods The study was based on 133 Citrus accessions. It combined maternal phylogeny studies based on mitochondrial and chloroplastic markers, and nuclear structure analysis based on the evaluation of ploidy level and the use of 123 markers, including 73 basic taxa diagnostic single nucleotide polymorphism (SNP) and indel markers.
Key Results The lime and lemon horticultural group appears to be highly polymorphic, with diploid, triploid and tetraploid varieties, and to result from many independent reticulation events which defined the sub-groups. Maternal phylogeny involves four cytoplasmic types out of the six encountered in the Citrus genus. All lime and lemon accessions were highly heterozygous, with interspecific admixture of two, three and even the four ancestral taxa genomes. Molecular polymorphism between varieties of the same sub-group was very low.
ConclusionsCitrus medica contributed to all limes and lemons and was the direct male parent for the main sub-groups in combination with C. micrantha or close papeda species (for C. aurata, C. excelsa, C. macrophylla and C. aurantifolia – ‘Mexican’ lime types of Tanaka’s taxa), C. reticulata (for C. limonia, C. karna and C. jambhiri varieties of Tanaka’s taxa, including popular citrus rootstocks such as ‘Rangpur’ lime, ‘Volkamer’ and ‘Rough’ lemons), C. aurantium (for C. limetta and C. limon – yellow lemon types – varieties of Tanaka’s taxa) or the C. maxima × C. reticulata hybrid (for C. limettioides – ‘Palestine sweet’ lime types – and C. meyeri). Among triploid limes, C. latifolia accessions (‘Tahiti’ and ‘Persian’ lime types) result from the fertilization of a haploid ovule of C. limon by a diploid gamete of C. aurantifolia, while C. aurantifolia triploid accessions (‘Tanepao’ lime types and ‘Madagascar’ lemon) probably result from an interspecific backcross (a diploid ovule of C. aurantifolia fertilized by C. medica). As limes and lemons were vegetatively propagated (apomixis, horticultural practices) the intra-sub-group phenotypic diversity results from asexual variations
Effects of grafting combinations on the nutritional composition of pepper fruit
Get PDFIntroduction. Interest in grafting onto rootstocks resistant to soil-borne pathogens has risen since the
phasing-out of methyl bromide, an efficient soil disinfectant. In this study, we have evaluated the putative effect of
rootstock–scion combinations on pepper fruit nutritional quality in relation to grafting, an effect that is sometimes overlooked. Materials and methods. As the scions, we used two representative sweet pepper cultivars, ‘Almuden’ and
‘Coyote’, and as rootstocks ‘Foc’ and ‘Charlot’, both resistant to Phytophthora capsici and Meloidogyne incognita.
Dry matter, soluble solids, proteins, phenolics, and vitamin C content, as well as eight minerals (P, K, Ca, Mg, Na,
Fe, Cu, and Zn) were measured in fruits from non-grafted, self-grafted, and grafted plants. Results and discussion.
Differences in the fruit composition were found, depending on the genotype, rootstock, or rootstock–scion combination. The main effects were as follows. Higher values of ◦Brix, phenolics, P, Mg, and Na were found in the fruit
of ‘Coyote’ whereas the vitamin C and Fe levels were higher in ‘Almuden’ fruit. The dry matter, protein, and K
concentrations were higher in the fruit from grafted plants with respect to the values from non-grafted plants, especially in the fruit from plants grafted onto ‘Charlot’ and ‘Foc’ rootstocks (increases of 11.8%, 17.6%, and 9.6%,
respectively; when average values of the four combinations of these rootstocks). Fruit from ‘Almuden’ and ‘Coyote’ plants grafted onto the rootstock ‘Foc’ had lower ◦Brix values (about one degree less than the control) and
lower values of phenolics were also obtained when used this rootstock (14.4% less than for the control). On the
other hand, the P concentration was higher in the fruit of ‘Coyote’ grafted onto ‘Charlot’ (17.2% higher than for
the control). This combination also exhibited the highest fruit K concentration (226.70 mg 100 g−1 fresh weight).
Conclusion. From a nutritional point of view it is important to evaluate and select the best rootstock–scion combinations: in our assay, this was ‘Charlot’–‘Coyote’ the fruit of which showed the highest ◦Brix and K, P, and protein
concentrations
Effects of Trunk-shaker Harvester and Ethephon on Plant Water Status, Leaf Gas Exchange, and Yield of Citrus Cultivated under Mediterranean Conditions
Get PDFThis work was aimed to study whether the application of ethephon as an abscission agent and mechanical harvest using a trunk shaker have any effect on plant water status, leaf gas exchange, and yield of mandarin and orange trees cultivated under Mediterranean conditions. The experiment was performed from 2008 to 2011 in five commercial orchards where parameters related to the plant water status and leaf gas exchange were measured before the application of ethephon, at harvest time and at different occasions after harvest. In addition, the effects of ethephon dose on yield in the current and subsequent seasons were also evaluated. Results showed that ethephon applications and mechanical harvest did not detrimentally affect plant water status in any of the cultivars studied. Furthermore, either had no effect or had a short temporal decrease effect on leaf gas exchange depending on the cultivar studied although with no consequences for the fruit yield obtained during the current season. Increasing ethephon doses led to fruit yield reductions in the mandarin ‘Orogrande’ trees in subsequent seasons. When trunk-shaker and ethephon applications were combined, however, yields from the late-maturing orange significantly decline in subsequent seasons. Overall, results show that using a trunk shaker is a viable technique to mechanically harvest citrus trees destined to both fresh and industry market and can be considered as an alternative to the traditional manual harvest usually performed under Mediterranean conditions. However, its use cannot be recommended for late-maturing oranges, such as the ‘Navel Lane Late’ in which mature fruit and fruitlets coexist in the tree at the time of harvest
Evaluation of sodium benzoate and other food additives for the control of citrus postharvest green and blue molds
Get PDFThe curative activity of the food additives dehydroacetic acid, dimethyl dicarbonate, ethylene diamine tetracetic acid, sodium acetate, and sodium benzoate (SB) was tested in in vivo preliminary screenings against green and blue molds on citrus fruit artificially inoculated 24 h before with Penicillium digitatum and Penicillium italicum, respectively. SB was the most effective compound and it was further tested in trials simulating postharvest industrial applications. Dip treatments for 60 s with 3% (w/v) SB heated above 50 °C resulted in about 90% reduction of green and blue mold incidence on ‘Valencia’ oranges inoculated, treated, and incubated at 20 °C and 90% RH for 7 days. This treatment was also effective on ‘Lanelate’ oranges, ‘Fino’ lemons and ‘Ortanique’ mandarins, but not on ‘Clemenules’ mandarins. Heated solutions combining SB with low doses (25 or 50 μL L−1) of the fungicide imazalil (IMZ) were synergistic and greatly improved the efficacy of stand-alone treatments. On ‘Valencia’ oranges stored for 8 weeks at 5 °C followed by 7 days of shelf-life at 20 °C, this combination reduced the incidence of green and blue molds almost by 100%. It was found in additional trials to test the preventive activity that 3% SB dips at 50 °C for 60 s did not reduce green mold on ‘Valencia’ oranges treated, inoculated with P. digitatum 24 h later, and incubated at 20 °C for 7 days. It can be concluded from this work that heated SB aqueous solutions might be in the future an interesting nonpolluting disease control alternative for the commercialization of citrus in markets with zero tolerance to fungicide residues
Maturity assessment of ‘Rojo Brillante’ persimmon by Hyperspectral Imaging
Get PDFPersimmon cv. ‘Rojo Brillante’ is an astringent cultivar highly appreciated by consumers due to its good aspect, high size, sweetness and absence of seeds. However, this cultivar is very astringent and the fruit cannot be consumed until a high degree of overripeness with takes long time and makes the fruit difficult to handle. A method based on exposing fruit to high CO2 concentrations was recently developed to eliminate quickly the astringency preserving the firmness; however, the adequate duration of this treatment depends mostly on the maturity at harvest. Therefore the aim of this work was to investigate a non-destructive and reliable method based on hyperspectral imaging to assess the maturity of persimmon cv ‘Rojo Brillante’ before deastringency treatments. For this purpose, 150 persimmon fruits were harvested at three different stages of commercial maturity and flesh firmness was determined after the image acquisition. Hyperspectral images of each fruit were taken using a hyperspectral system based on two liquid crystal tuneable filters, sensitive in the spectral range 420-1080 nm. Partial Least Square-Discriminant Analysis (PLS-DA) was used on the hyperspectral images to select optimal wavelengths and classify persimmon fruits by maturity. The results achieved 90.1% of correct classification using six selected wavelengths. Additionally, flesh firmness was predicted by using partial least square regression (PLS-R) and the selected wavelengths. A R2 of 0.80 and a square error of prediction (SEP) of 4.34 N were obtained. All of these results were considered as good for a non-invasive maturity assessment technique of ‘Rojo Brillante’ persimmon
Temperature-specific competition in predatory mites: Implications for biological pest control in a changing climate
No full textClimate change is affecting the future of sustainable agriculture, because increasing temperatures may interfere with the functioning of natural enemies that are used in biological pest control. In this work, we examined the role of abiotic conditions in shaping the structure of a simple agricultural community that is dominated by two species of predatory mites (i.e., Eusieus stipulatus and Eusieus scutalis) competing for resources. Population and community dynamics experiments were carried out at two abiotic conditions mimicking local climates in a Mediterranean region, to estimate the population cariying capacity (k) and interspecific competition (a) for each predatory mite species. Subsequently, we used this data to parameterize a competition model, thereby predicting species dominance at each abiotic condition. To test our model predictions, we sampled several orchards located in areas influenced by each of the local climates, to determine the abundance of each species of natural enemy. Results showed that the outcome of the competitive interactions between predatory mites was strongly affected by abiotic conditions, leading to temperature-dependent changes in the community structure. Furthermore, the pattern of species dominance found in the field agreed with the model predictions built upon our laboratory experiments. We therefore emphasize that, in a changing climate, if we are to guarantee the successful use of biocontrol agents, we need to account for the effect of temperature upon biotic interactions. (C) 2015 Elsevier B.V. All rights reserved
Principal component analysis (PCA) of volatile terpene compounds dataset emitted by genetically modified sweet orange fruits and juices in which a D-limonene synthase was either up-or down-regulated vs.empty vector controls
Get PDFWe have categorized the dataset from content and emission of terpene volatiles of peel and juice in both Navelina and Pineapple sweet orange cultivars in which D-limonene was either up- (S), down-regulated (AS) or non-altered (EV; control) (“Impact of D-limonene synthase up- or down-regulation on sweet orange fruit and juice odor perception”(A. Rodríguez, J.E. Peris, A. Redondo, T. Shimada, E. Costell, I. Carbonell, C. Rojas, L. Peña, (2016)) [1]). Data from volatile identification and quantification by HS-SPME and GC–MS were classified by Principal Component Analysis (PCA) individually or as chemical groups. AS juice was characterized by the higher influence of the oxygen fraction, and S juice by the major influence of ethyl esters. S juices emitted less linalool compared to AS and EV juices
Application of 2D and 3D image technologies to characterise morphological attributes of grapevine clusters
Get PDFBackground:
Grapevine cluster morphology influences the quality and commercial value of wine and table grapes. It is routinely evaluated by subjective and inaccurate methods that do not meet the requirements set by the food industry. Novel two‐dimensional (2D) and three‐dimensional (3D) machine vision technologies emerge as promising tools for its automatic and fast evaluation.
Results:
The automatic evaluation of cluster length, width and elongation was successfully achieved by the analysis of 2D images, significant and strong correlations with the manual methods being found (r = 0.959, 0.861 and 0.852, respectively). The classification of clusters according to their shape can be achieved by evaluating their conicity in different sections of the cluster. The geometric reconstruction of the morphological volume of the cluster from 2D features worked better than the direct 3D laser scanning system, showing a high correlation (r = 0.956) with the manual approach (water displacement method). In addition, we constructed and validated a simple linear regression model for cluster compactness estimation. It showed a high predictive capacity for both the training and validation subsets of clusters (R2 = 84.5 and 71.1%, respectively).
Conclusion:
The methodologies proposed in this work provide continuous and accurate data for the fast and objective characterisation of cluster morphology. © 2016 Society of Chemical Industr
Medición no destructiva del índice de madurez en mango ‘Kent’ usando tecnología de imagen hiperespectral
Get PDFEl mango es una fruta tropical de alto valor añadido que ha despertado el interés de la industria
agroalimentaria en los últimos años, que está incrementando sus esfuerzos para determinar la
calidad interna del mismo mediante técnicas no destructivas. En este trabajo se utilizaron 131
mangos de la variedad ‘Kent’ distribuidos en tres lotes (verdes, maduros y sobremaduros) y
almacenados en condiciones de humedad y temperatura controladas. Se tomaron imágenes de
dos caras de los mangos con un sistema hiperespectral basado en dos filtros sintonizables de
cristal líquido (LCTF), sensibles entre los dos en el rango espectral 420-1080 nm. Tras la captura
de las imágenes, se analizaron la firmeza, la acidez titulable y el contenido en sólidos solubles
mediante técnicas destructivas de referencia, estableciéndose un índice de madurez (RPI)
basado en una combinación de estas propiedades. Las imágenes hiperespectrales se analizaron
extrayendo la reflectancia de la superficie de ambas caras de los mangos. El análisis de los datos
se realizó mediante la creación de dos modelos de regresión por mínimos cuadrados parciales
(PLS) para establecer la relación entre los espectros medios de reflectancia de la superficie de
los mangos y el RPI obtenido. Se utilizó el 70% de las muestras para construir el modelo,
obteniéndose un R2=0,852 con todas las bandas para el conjunto de calibración. Posteriormente,
se redujo a un total de seis longitudes de onda (520, 560, 730, 760, 870 y 1050 nm) con un
R2=0,849. El modelo con las seis longitudes de onda se validó con el 30% de las muestras
restante, obteniéndose un R2=0,739, que indica que es posible predecir la madurez de esta
variedad de mango empleando un conjunto muy reducido de longitudes de onda en el visible e
infrarrojo cercano
Application of near Infrared Spectroscopy to the Quality Control of Citrus Fruits and Mango
Get PDFNIR spectroscopy is a proved tool to measure the optical properties of the samples, which are
related to their chemical and textural properties. This technology can be used for determining
the internal and external quality of fruits. Accordingly, many studies have been reported for
long time to assess the quality of different fresh fruits by using reflectance measurements
acquired with visible-NIR spectroscopy. We have been working on the estimation of the quality
of fruits using computer vision for more than twenty years, always focused on problems that
affect the local industry. As the region of Valencia (Spain) is one of the main producers and
exporters of citrus fruits worldwide, most of our research has been focused on this fruit,
especially developing fast and reliable methods to detect defective fruit in quality control lines1.
Nevertheless, our group have been carried out also other studies to determine the internal
quality in other fruits with commercial interest for our region, such as, mangoes cv. ‘Osteen’,
nectarines cv. 'Big Top' and cv. 'Magique', and persimmon cv. ‘Rojo Brillante’.
Nowadays, the fruit producers demand automated systems to detect fruits with decay lesions
that are not visible at early stages but that can spread the infection to other fruits during storage
or shipping. In the case of citrus fruits, this is the most economically important postharvest
disease of citrus worldwide. Detection of these diseases may considerably help to correctly
discriminate and classify different fruit lots and take important decisions, based on fruit quality,
about postharvest handling and final produce destination. However, the detection of rotten fruit
in citrus packing-lines is performed manually, using the naked eye under ultraviolet (UV) light
that induces visible fluorescence, what it is harmful for the workers. New automatic devices
using UV or hyperspectral imaging2 are being investigated as possible alternatives to manual
inspections. However, industry’s demands for innovative tools for rapid and cost-effective early
detection have spurred considerable interest among researchers on the application of nearinfrared
spectroscopy (NIRS) on citrus fruit quality monitoring as stated in the review carried
out by Magwaza et al.3.
Moreover, Spain is the main European producer of subtropical fruits and in particular the southwest
region has a large potential for the production of Mango fruit. In the past, external quality,
related to the skin colour, fruit size and shape, free from defects and the absence of decay were
the most common quality determinants, but nowadays other organoleptic characteristics related
to the internal quality play an important role in the consumer’s decision. Hence, another aim
was to investigate the potential of visible and NIR to determine the internal quality of mango cv.
‘Osteen’, the main variety of mango grown in Spain