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Jouy C.,British Petroleum | Gandelin M.H.,British Petroleum | Guitouni C.,British Petroleum | Pascal T.,French National Institute for Agricultural Research | And 17 more authors.
Acta Horticulturae | Year: 2012

Peach/nectarine is an important fruit tree crop in Europe and indeed worldwide. The registration of new cultivars, either for Plant Breeders' Rights or National Listing (PBR/NL) purposes in the European Union (EU), requires the completion of a distinctness, uniformity and stability (DUS) test in one of the EU Member States. The number of candidate cultivars and potentially required example cultivars entered for DUS testing is steadily increasing annually. Moreover, DUS testing of this type of tree crops requires the maintenance of large orchards, particularly with the aim of having a complete reference collection. In France, Hungary, Spain and Italy, peach tree breeding activity is characterized by an important number of cultivars available and a short turn-over of the cultivars. This situation will extend to new EU members states in the coming years, with the development of the European trade. However, although the diversification increases the number of segments, for each segment, new released cultivars are genetically closer and closer. The consequence is that it is now difficult in some cases to distinguish between cultivars. Clearly, developing means of "managing" reference collections is highly desirable in order to be able to compare candidate cultivars with the closest cultivars of common knowledge in the reference collections prior to planting them, and so reduce the number of cultivars that need to be grown, without eroding the strength of PBR and the relevance of DUS tests. Effective means of such a management include the definition of a standardised way to compare phenotypic data and to use molecular markers to eliminate the reference cultivars which do not need to be compared to the candidate cultivars. In peach tree, various molecular markers such as DNA microsatellites (SSR) have been developed and evaluated, but they have not yet been used for the characterization of large collections. Therefore, this project will generate a database compiling both phenotypic data, including standardised morphological descriptions and digital pictures, and a large data set of DNA profiles for 522 peach tree cultivars selected among the EU granted and listed cultivars. © ISHS 2012.

Teresani G.R.,Instituto Valenciano Of Investigaciones | Bertolini E.,Instituto Valenciano Of Investigaciones | Alfaro-Fernandez A.,Polytechnic University of Valencia | Martinez C.,Instituto Valenciano Of Investigaciones | And 8 more authors.
Phytopathology | Year: 2014

A new symptomatology was observed in celery (Apium graveolens) in Villena, Spain in 2008. Symptomatology included an abnormal amount of shoots per plant and curled stems. These vegetative disorders were associated with 'Candidatus Liberibacter solanacearum' and not with phytoplasmas. Samples from plant sap were immobilized on membranes based on the spot procedure and tested using a newly developed real-time polymerase chain reaction assay to detect 'Ca. L. solanacearum'. Then, a test kit was developed and validated by intralaboratory assays with an accuracy of 100%. Bacterial-like cells with typical morphology of 'Ca. Liberibacter' were observed using electron microscopy in celery plant tissues. A fifth haplotype of 'Ca. L. solanacearum', named E, was identified in celery and in carrot after analyzing partial sequences of 16S and 50S ribosomal RNA genes. From our results, celery (family Apiaceae) can be listed as a new natural host of this emerging bacterium. © 2014 The American Phytopathological Society.

Tena A.,Instituto Valenciano Of Investigaciones | Wackers F.L.,Biobest | Wackers F.L.,Lancaster University | Heimpel G.E.,University of Minnesota | And 3 more authors.
Current Opinion in Insect Science | Year: 2016

One focus of conservation biological control studies has been to improve the nutritional state and fitness of parasitoids by adding nectar and artificial sugars to agroecosystems. This approach has largely overlooked the presence of honeydew, which is likely the primary carbohydrate source available to parasitoids in many agroecosystems. Over the last decade, it has been demonstrated that parasitoids often utilize this sugar source and there is evidence that honeydew can indirectly impact the population dynamics of herbivores through its nutritional value for parasitoids. The consumption of honeydew by parasitoids can shape direct and indirect interactions with other arthropods. The strength of these effects will depend on: first, parasitoid biology, second, the presence of other sugar sources (mainly nectar), third, the quality and quantity of the honeydew, and fourth, the presence and competitive strength of other honeydew consumers such as ants. The combination of these four factors is expected to result in distinct scenarios that should be analyzed for each agroecosystem. This analysis can reveal opportunities to increase the biocontrol services provided by parasitoids. Moreover, honeydew can be a resource-rich habitat for insect pathogens; or contain plant secondary chemicals sequestered by hemipterans or systemic insecticides toxic for the parasitoid. Their presence and effect on parasitoid fitness will need to be addressed in future research. © 2016 Elsevier Inc. All rights reserved.

Caruso M.,University of Catania | Distefano G.,University of Catania | La Malfa S.,University of Catania | Gentile A.,University of Catania | And 3 more authors.
Acta Horticulturae | Year: 2012

Compared to what is known in model species, reproductive biology in citrus is still poorly understood. Although in recent years several efforts have been made to study pollen-pistil interaction and self-incompatibility, little information is available about the molecular mechanisms regulating these processes. Here we report the identification of candidate genes involved in pollen-pistil interaction and selfincompatibility in clementine (Citrus clementina Hort. ex Tan.). These genes have been identified comparing the transcriptomes of laser-microdissected stylar canal cells isolated from two clementine genotypes differing in their self-incompatibility response ('Comune', self-incompatible; and 'Monreal', a self-compatible mutation of 'Comune'). Transcriptome profiling was performed using the Affymetrix Citrus GeneChip representing up to 33,000 citrus transcripts. Among them, only 10 genes resulted over represented in 'Comune' stylar canals and 7 genes in 'Monreal' ones. The results of microarray hybridizations were validated using real time quantitative RT-PCR. Many of the differentially expressed genes are not functionally annotated in citrus or other plant species. The results suggest that the differential regulation of few specific transcripts is probably related to the breakdown of self-incompatibility in 'Monreal'.

Perez-Gago M.B.,Instituto Valenciano Of Investigaciones | Navarro M.L.,Instituto Valenciano Of Investigaciones | Del Rio M.A.,Instituto Valenciano Of Investigaciones
Acta Horticulturae | Year: 2010

'Ortanique' mandarins were coated with hydroxypropyl methylcellulose (HPMC)-beeswax (BW) composite coatings. Glycerol and fatty acid were added as plasticizer and emulsifier, respectively. The emulsion coatings had 4% total solid content and 40%BW content (dry basis). Stearic, palmitic or oleic acid were studied at two different BW: fatty acid ratios (2:1 and 5:1). After coating, the fruits were stored for 3 and 6 weeks at 5°C, followed by one additional week at 20°C. Another set of samples was also stored for 2 weeks at 20°C, simulating retail handling conditions. The coatings were effective reducing weight loss and maintaining texture of mandarins compared to the control. Coatings with oleic acid were more effective reducing weight loss than coatings with palmitic acid, and these ones more effective than those with stearic acid. However, oleic acid increased the gas barrier, ethanol level and off-flavor of coated mandarins in a greater extend that palmitic and stearic. Levels of internal CO2 were lower in coatings with a BW:fatty acid ratio 2:1 than in coatings with 5:1 ratio, which translated in lower ethanol level in juice. This could be due to the lower amount of HPMC in the 2:1 ratio-coatings, since hydrophilic materials, such as HPMC, are known to present low oxygen permeability. The results suggest the importance of controlling coating composition in order to extend shelf-life of citrus fruits with good quality.

Forner-Giner M.A.,Instituto Valenciano Of Investigaciones | Legaz F.,Instituto Valenciano Of Investigaciones | Primo-Millo E.,Instituto Valenciano Of Investigaciones | Forner J.,Instituto Valenciano Of Investigaciones
Journal of Plant Nutrition | Year: 2011

This study assesses the nutritional behavior of the new citrus rootstocks Forner-Alcaide no.5 (FA-5) and Forner-Alcaide no.13 (FA-13) under saline conditions compared to that of their parents, Cleopatra mandarin (CM) and Poncirus trifoliata (PT). Eighteen month-old plants grafted with Valencia orange scions were used in the experiment. The plants were grown in a greenhouse and irrigated over an eight-week period with nutrient solutions to which different amounts of sodium chloride (NaCl) had been added, namely 0, 20, 40 and 60 mM. Relative growth and the uptake of major mineral elements [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg)] were then determined. It was noted that the reduction in relative growth caused by salt treatment was greater in plants grafted on PT than those on FA-13, FA-5 and CM. Increasing the salt level in the growth medium reduced the absorption of the above mineral elements in all scion-rootstock combinations. However, this decrease was generally more marked in plants grafted on PT than in those on CM and FA-5. Plants on FA-13 showed an intermediate behavior. Positive correlations were found between growth and mineral element uptake by salt treated plants. Nutrient uptake was also plotted against chloride (Cl) and sodium (Na) concentrations in leaves and roots at increasing salt levels. This showed that N absorption was closely correlated (inversely) with Cl content in leaves, whereas K, Ca and Mg uptakes were correlated (inversely) with Na concentration in roots. This suggests that the accumulation of saline ions impacts growth and nutrient uptake by citrus plants. © Taylor & Francis Group, LLC.

Vera-Ruiz E.M.,Instituto Valenciano Of Investigaciones | Romero C.,Instituto Valenciano Of Investigaciones | Llacer G.,Instituto Valenciano Of Investigaciones | Badenes M.L.,Instituto Valenciano Of Investigaciones | And 2 more authors.
Acta Horticulturae | Year: 2010

Sharka disease, caused by Plum Pox Virus (PPV), produces important economic losses in Apricot (P. armeniaca L.). PPV natural resistance has been only found in some North American apricot cultivars and efforts are being made to introduce this character on Mediterranean germplasm. Recent studies on segregation of different intraspecific apricot crosses suggest that PPV resistance is controlled by at least one major dominant locus on the upper part of linkage group 1 (LG1). Using microsatellites already mapped in different Prunus spp. we have built a high density genetic map for an interval of 13 cM comprising this region in apricot. In addition, overgo probes designed from SSR clone sequences have been used to screen an apricot Bacterial Artificial Chromosome (BAC) library. Positive clones identified are being used to construct a BAC contig spanning the apricot genomic region containing the PPV resistance locus using the peach physical map developed by Zhebentyayeva et al. (2008) as reference.

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