Genome-wide DNA-(de)methylation is associated with Noninfectious Bud-failure exhibition in Almond (Prunus dulcis [Mill.] D.A.Webb).

Noninfectious bud-failure (BF) remains a major threat to almond production in California, particularly with the recent rapid expansion of acreage and as more intensive cultural practices and modern cultivars are adopted. BF has been shown to be inherited in both vegetative and sexual progeny, with exhibition related to the age and propagation history of scion clonal sources. These characteristics suggest an epigenetic influence, such as the loss of juvenility mediated by DNA-(de)methylation. Various degrees of BF have been reported among cultivars as well as within sources of clonal propagation of the same cultivar. Genome-wide methylation profiles for different clones within almond genotypes were developed to examine their association with BF levels and association with the chronological time from initial propagation. The degree of BF exhibition was found to be associated with DNA-(de)methylation and clonal age, which suggests that epigenetic changes associated with ageing may be involved in the differential exhibition of BF within and among almond clones. Research is needed to investigate the potential of DNA-(de)methylation status as a predictor for BF as well as for effective strategies to improve clonal selection against age related deterioration. This is the first report of an epigenetic-related disorder threatening a major tree crop

Application of genomic and quantitative genetic tools to identify candidate resistance genes for brown rot resistance in peach.

The availability of a complete peach genome assembly and three different peach genome sequences created by our group provide new opportunities for application of genomic data and can improve the power of the classical Quantitative Trait Loci (QTL) approaches to identify candidate genes for peach disease resistance. Brown rot caused by Monilinia spp., is the most important fungal disease of stone fruits worldwide. Improved levels of peach fruit rot resistance have been identified in some cultivars and advanced selections developed in the UC Davis and USDA breeding programs. Whole genome sequencing of the Pop-DF parents lead to discovery of high-quality SNP markers for QTL genome scanning in this experimental population. Pop-DF created by crossing a brown rot moderately resistant cultivar 'Dr. Davis' and a brown rot resistant introgression line, 'F8,1-42', derived from an initial almond × peach interspecific hybrid, was evaluated for brown rot resistance in fruit of harvest maturity over three seasons. Using the SNP linkage map of Pop-DF and phenotypic data collected with inoculated fruit, a genome scan for QTL identified several SNP markers associated with brown rot resistance. Two of these QTLs were placed on linkage group 1, covering a large (physical) region on chromosome 1. The genome scan for QTL and SNP effects predicted several candidate genes associated with disease resistance responses in other host-pathogen systems. Two potential candidate genes, ppa011763m and ppa026453m, may be the genes primarily responsible for M. fructicola recognition in peach, activating both PAMP-triggered immunity (PTI) and effector-triggered immunity (ETI) responses. Our results provide a foundation for further genetic dissection, marker assisted breeding for brown rot resistance, and development of peach cultivars resistant to brown rot

Phenotypic diversity among local Spanish and foreign peach and nectarine [Prunus persica (L.) Batsch] accessions

17 Pags., 7 Tabls., 1 Fig. The definitive version is available at: http://link.springer.com/journal/10681Phenotypic data for tree and fruit characteristics was collected over three consecutive years from a germplasm collection of 94 peach and nectarine accessions representing both traditional Spanish as well as foreign cultivars with widespread global plantings. All accessions were grown at the Experimental Station of Aula Dei located in the Ebro Valley (Northern Spain, Zaragoza) under a Mediterranean climate. Tree traits evaluated included bloom and harvest date, vigor, yield, yield efficiency and flower and leaf characteristics. Fruit traits included fresh weight, firmness, soluble solids, titratable acidity, levels of individual soluble sugars (sucrose, glucose, fructose and sorbitol), vitamin C, total phenolics, flavonoids, anthocyanins, relative antioxidant capacity and ripening index. Extensive variability was observed for most qualitative and quantitative traits with significant correlations identified between many traits. While the traditional Spanish accessions demonstrated good adaptability to the northern Spain evaluation site, opportunities for continued improvement in tree and fruit quality traits were demonstrated by an extensive phenotypic variability within the germplasm collection.This study was funded by the Spanish Ministry of Science and Innovation (MICINN) grants AGL2005-05533, AGL2008-00283 and AGL2011-24576, and RFP 2009-00016 cofunded by FEDER and the Regional Government of Aragon (A44). C. Font was supported by a JAE fellowship from Consejo Superior de Investigaciones Científicas (CSIC).Peer reviewe

Phenotypic diversity among local Spanish and foreign peach and nectarine [Prunus persica (L.) Batsch] accessions

17 Pags., 7 Tabls., 1 Fig. The definitive version is available at: http://link.springer.com/journal/10681Phenotypic data for tree and fruit characteristics was collected over three consecutive years from a germplasm collection of 94 peach and nectarine accessions representing both traditional Spanish as well as foreign cultivars with widespread global plantings. All accessions were grown at the Experimental Station of Aula Dei located in the Ebro Valley (Northern Spain, Zaragoza) under a Mediterranean climate. Tree traits evaluated included bloom and harvest date, vigor, yield, yield efficiency and flower and leaf characteristics. Fruit traits included fresh weight, firmness, soluble solids, titratable acidity, levels of individual soluble sugars (sucrose, glucose, fructose and sorbitol), vitamin C, total phenolics, flavonoids, anthocyanins, relative antioxidant capacity and ripening index. Extensive variability was observed for most qualitative and quantitative traits with significant correlations identified between many traits. While the traditional Spanish accessions demonstrated good adaptability to the northern Spain evaluation site, opportunities for continued improvement in tree and fruit quality traits were demonstrated by an extensive phenotypic variability within the germplasm collection.This study was funded by the Spanish Ministry of Science and Innovation (MICINN) grants AGL2005-05533, AGL2008-00283 and AGL2011-24576, and RFP 2009-00016 cofunded by FEDER and the Regional Government of Aragon (A44). C. Font was supported by a JAE fellowship from Consejo Superior de Investigaciones Científicas (CSIC).Peer reviewe

Experimental Verification of Resonant Reflection Notch Method for Quasi-Optical MM-Wave Dielectric Parameters Measurements

We present experimental verification of resonant reflection notch method for quasi-optical mm-wave characterisation of dielectric materials, particularly, those with large dielectric losses. The method utilises an open dielectric Bragg resonator with a “defect-layer” insertion that contains the material under test. The structure is tuned to show narrow reflection notches at certain frequencies which are exceptionally sensitive to the measured dielectric quantities. The method is analogous to the “capillary-in-a-waveguide” technique, though implemented in a simpler (planar) one-dimensional system and in reflection rather than in transmission mode. Here we present experimental implementation and verification of the method as applied to the dielectric characterization of water solutions in the millimetre-wave frequency band of 75-110 GHz

A fruit quality gene map of Prunus

<p>Abstract</p> <p>Background</p> <p><it>Prunus </it>fruit development, growth, ripening, and senescence includes major biochemical and sensory changes in texture, color, and flavor. The genetic dissection of these complex processes has important applications in crop improvement, to facilitate maximizing and maintaining stone fruit quality from production and processing through to marketing and consumption. Here we present an integrated fruit quality gene map of <it>Prunus </it>containing 133 genes putatively involved in the determination of fruit texture, pigmentation, flavor, and chilling injury resistance.</p> <p>Results</p> <p>A genetic linkage map of 211 markers was constructed for an intraspecific peach (<it>Prunus persica</it>) progeny population, Pop-DG, derived from a canning peach cultivar 'Dr. Davis' and a fresh market cultivar 'Georgia Belle'. The Pop-DG map covered 818 cM of the peach genome and included three morphological markers, 11 ripening candidate genes, 13 cold-responsive genes, 21 novel EST-SSRs from the ChillPeach database, 58 previously reported SSRs, 40 RAFs, 23 SRAPs, 14 IMAs, and 28 accessory markers from candidate gene amplification. The Pop-DG map was co-linear with the <it>Prunus </it>reference T × E map, with 39 SSR markers in common to align the maps. A further 158 markers were bin-mapped to the reference map: 59 ripening candidate genes, 50 cold-responsive genes, and 50 novel EST-SSRs from ChillPeach, with deduced locations in Pop-DG via comparative mapping. Several candidate genes and EST-SSRs co-located with previously reported major trait loci and quantitative trait loci for chilling injury symptoms in Pop-DG.</p> <p>Conclusion</p> <p>The candidate gene approach combined with bin-mapping and availability of a community-recognized reference genetic map provides an efficient means of locating genes of interest in a target genome. We highlight the co-localization of fruit quality candidate genes with previously reported fruit quality QTLs. The fruit quality gene map developed here is a valuable tool for dissecting the genetic architecture of fruit quality traits in <it>Prunus </it>crops.</p

Double-sided split-step MM-wave Fresnel lenses: design, fabrication and focal field measurements

Design, fabrication and focal field measurements of W-band Fresnel lenses to produce well-shaped Gaussian beams in the focal domain are presented. Two lenses, one of Teflon and another of Polyamide, have been compared in their performance with a double-sided Fresnel lens of different design, with full height of Fresnel steps. Experiments show that a good focusing ability of all the lenses is achieved. They produce the target beam according to the design. Yet, the lenses of split-step design are thinner, have lower insertion losses, and a greater focal depth as compared to more conventional Fresnel lenses

Coated dielectric lens design, modelling and measurements for future CMB polarimetry missions

We present an ongoing programme of work to investigate the use of large dielectric lenses with coating layers for future satellite-based cosmic microwave background (CMB) polarimetry missions. The primary purpose of this study is to validate modelling and manufacturing techniques. We present details of the study, and preliminary results of material and lens testing

Variation of almond yield, biometry, α-tocopherol levels, and antioxidant properties with nitrogen fertilization

A two years’ experiment (2015–2016) was set in a factorial design in which the effect of two application forms of nitrogen (N) (soil and soil + foliar spray) in different doses (0, 25, 50, and 100 kg N ha-1) on almond (Prunus dulcis Mill. cv. “Masbovera”) was evaluated. Kernel yield, biometric properties, phytochemicals, and antioxidant activities were assessed. The results showed that almond kernel yield increases with an increment in N rate doses and was positively correlated with kernel weight and thickness, and negatively with fruit weight. The levels of α-tocopherol and total polyphenol content were higher with lower N doses (25 and 50 kg N ha–1). The antioxidant activities were positively correlated with polyphenol content. Based on our results, excessive N rates over 50 kg/ha depreciate the levels of α-tocopherol, total polyphenols, and antioxidant bioactivities of kernels. Practical applications Almond is an important nut (dry) fruit that contains high levels of α-tocopherol, moderate levels of polyphenols, and high antioxidant activities, all responsible for their claimed health-promoting properties. Almond trees are known by their alternate behavior in which kernel yield and levels of phytochemicals and other compounds are highly variable between years. This article studies the usage of a sustainable nitrogen fertilization program toward a reduction of their alternate behavior, preserving and promoting their antioxidant properties and their levels of phytochemicals, particularly α-tocopherol and polyphenols. Our findings may provide a useful guide for adequate nitrogen fertilization program toward a better almond kernel qualityinfo:eu-repo/semantics/publishedVersio