Desempenho da laranjeira 'Valência' enxertada sobre porta-enxertos híbridos de trifoliateiro

The objective of this work was to evaluate tree size, production, and fruit quality of 'Valência' sweet orange (Citrus sinensis) grafted on various trifoliate orange rootstocks, in order to select genotypes with a high performance. Twenty rootstock genotypes were evaluated, including trifoliate orange hybrids with mandarin (citrandarins) and with grapefruit (citrumelos), as well as 'Rangpur' lime. The experiment was implemented in the northwestern region of the state of Paraná, Brazil, in a 6.0×2.5 m spacing, in a sandy soil under subtropical and rainfed conditions. The statistical model used was the randomized complete block design with four replicates and four trees per plot. Tree size and fruit yield and quality were analyzed during three consecutive harvest seasons. Data were subjected to the analysis of variance, and means were grouped by the Scott-Knott test. Principal component analysis and agglomerative hierarchical clustering were also carried out. F.80-18, F.80-5, and F.80-3 citrumelos and IPEACS-239 citrandarin are adequate rootstock options for 'Valência' sweet orange, with dwarf trees and a high production efficiency. These rootstocks, except F.80-18, are also adequate options to obtain oranges with good industrial properties.O objetivo deste trabalho foi avaliar o tamanho da planta, a produção e a qualidade dos frutos da laranjeira-doce 'Valência' (Citrus sinensis) enxertada sobre diversos porta-enxertos híbridos de trifoliateiro, para selecionar genótipos de alto desempenho. Vinte genótipos de porta-enxertos foram avaliados, tendo incluído híbridos de trifoliateiro com tangerineiras (citrandarins) e com pomeleiros (citrumelos), além do limoeiro 'Cravo'. O experimento foi implantado na região noroeste do estado do Paraná, Brasil, em espaçamento 6.0×2.5 m, em solo arenoso, sob condições de clima subtropical e sem irrigação. O modelo estatístico utilizado foi o delineamento em blocos ao acaso, com quatro repetições e quatro plantas por parcela. O tamanho da planta e a produção e a qualidade dos frutos foram analisados durante três safras consecutivas. Os dados foram submetidos à análise de variância, e as médias foram agrupadas pelo teste de Scott-Knott. Também foram realizados a análise de componentes principais e o agrupamento dos porta-enxertos por meio da classificação hierárquica de clusters. Os citrumeleiros F.80-18, F.80-5 e F.80-3 e o citrandarineiro IPEACS-239 são opções adequadas de porta-enxertos para a laranjeira 'Valência', com plantas anãs e alta eficiência produtiva. Esses porta-enxertos, exceto F.80-18, também são opções adequadas para a obtenção de laranjas com boas propriedades industriais

Mapeamento da produtividade, fertilidade do solo e falhas de plantas em pomar de laranjeiras

The current high competition on Citrus industry demands from growers new management technologies for superior efficiency and sustainability. In this context, precision agriculture (PA) has developed techniques based on yield mapping and management systems that recognize field spatial variability, which contribute to increase profitability of commercial crops. Because spatial variability is often not perceived the orange orchards are still managed as uniform and adoption of PA technology on citrus farms is low. Thus, the objective of the present study was to characterize the spatial variability of three factors: fruit yield, soil fertility and occurrence of plant gaps caused by either citrus blight or huanglongbing (HLB) in a commercial Valencia orchard in Brotas, São Paulo State, Brazil. Data from volume, geographic coordinates and representative area of the bags used on harvest were recorded to generate yield points that were then interpolated to produce the yield map. Soil chemical characteristics were studied by analyzing samples collected along planting rows and inter-rows in 24 points distributed in the field. A map of density of tree gaps was produced by georeferencing individual gaps and later by counting the number of gaps within 500 m² cells. Data were submitted to statistical and geostatistical analyses. A t test was used to compare means of soil chemical characteristics between sampling regions. High variation on yield and density of tree gaps was observed from the maps. It was also demonstrated overlapping regions of high density of plant absence and low fruit yield. Soil fertility varied depending on the sampling region in the orchard. The spatial variability found on yield, soil fertility and on disease occurrence demonstrated the importance to adopt site specific nutrient management and disease control as tools to guarantee efficiency of fruit production

The ASTRI SST-2M prototype for the Cherenkov Telescope Array: status after the commissioning phase of the telescope

ASTRI SST-2M is an imaging atmospheric Cherenkov telescope developed by the Italian National Institute of Astrophysics (INAF) in the framework of the Cherenkov Telescope Array (CTA) project as an end-to-end prototype for the Small Size array. Large-, medium-, and small-sized telescopes will compose the CTA observatory that represents the next generation of imaging atmospheric Cherenkov telescopes and will explore the very high-energy domain from a few tens of GeV up to few hundreds of TeV. The ASTRI SST-2M telescope has been installed at the INAF-Catania observing station at Serra La Nave, on Mt. Etna (Sicily, Italy) in September 2014. In these 3 years of open-air operations the telescope has been commissioned and its opto-mechanical performance is now well understood. The apparatus was made ready to host its main scientific instrument, the camera with Silicon-Photomultiplier based detectors. This contribution is a status report on the complete ASTRI SST-2M telescope assembly including the electro-mechanical structure and the optical system

The ASTRI SST-2M prototype for the Cherenkov Telescope Array: opto-mechanical performance

ASTRI SST-2M is an end-to-end telescope prototype developed by the Italian National Institute of Astrophysics (INAF) in the framework of the Cherenkov Telescope Array (CTA). The CTA observatory, with a combination of large-, medium-, and small-sized telescopes (LST, MST and SST, respectively), will represent the next generation of imaging atmospheric Cherenkov telescopes. It will explore the very high-energy domain from a few tens of GeV up to few hundreds of TeV. The ASTRI SST-2M telescope structure and mirrors have been installed at the INAF observing station at Serra La Nave, on Mt. Etna (Sicily, Italy) in September 2014. Its performance verification phase began in autumn 2015. Part of the scheduled activities foresees the study and characterization of the optical and opto-mechanical performance of the telescope prototype. In this contribution we report the results achieved in terms of kinematic model analysis, mirrors reflectivity evolution, telescopes positioning, flexures and pointing model and the thermal behavior

Optimization and Evaluation of Sensor Angles for Precise Assessment of Architectural Traits in Peach Trees

Fruit industries play a significant role in many aspects of global food security. They provide recognized vitamins, antioxidants, and other nutritional supplements packed in fresh fruits and other processed commodities such as juices, jams, pies, and other products. However, many fruit crops including peaches (Prunus persica (L.) Batsch) are perennial trees requiring dedicated orchard management. The architectural and morphological traits of peach trees, notably tree height, canopy area, and canopy crown volume, help to determine yield potential and precise orchard management. Thus, the use of unmanned aerial vehicles (UAVs) coupled with RGB sensors can play an important role in the high-throughput acquisition of data for evaluating architectural traits. One of the main factors that define data quality are sensor imaging angles, which are important for extracting architectural characteristics from the trees. In this study, the goal was to optimize the sensor imaging angles to extract the precise architectural trait information by evaluating the integration of nadir and oblique images. A UAV integrated with an RGB imaging sensor at three different angles (90°, 65°, and 45°) and a 3D light detection and ranging (LiDAR) system was used to acquire images of peach trees located at the Washington State University’s Tukey Horticultural Orchard, Pullman, WA, USA. A total of four approaches, comprising the use of 2D data (from UAV) and 3D point cloud (from UAV and LiDAR), were utilized to segment and measure the individual tree height and canopy crown volume. Overall, the features extracted from the images acquired at 45° and integrated nadir and oblique images showed a strong correlation with the ground reference tree height data, while the latter was highly correlated with canopy crown volume. Thus, selection of the sensor angle during UAV flight is critical for improving the accuracy of extracting architectural traits and may be useful for further precision orchard management

Fruit Ripening Development of ‘Valencia’ Orange Trees Grafted on Different ‘Trifoliata’ Hybrid Rootstocks

The development of fruit ripening of ‘Valencia’ orange trees [Citrus sinensis (L.) Osb.] grafted on the following ‘Trifoliata’ hybrid rootstocks: ‘US-852’, IPEACS-256 and IPEACS-264 citrandarins, and F.80-3, ‘W-2’ citrumelo, and ‘Swingle’ citrumelo (control), was assessed in three different subtropical locations: Rancho Alegre (RA); São Sebastião da Amoreira (SSA); and São Jerônimo da Serra (SJS), Parana state, Brazil. The climate of the RA and SSA locations was classified as Cfa with hot summers, whereas that of the SJS location was Cfb with temperate summers, which are located at 380, 650, and 835 m a.s.l., respectively. A completely randomized block design with four replications and four trees per plot was used as a statistical model for each location. The soluble solids (SS) content, titratable acidity (TA), and the maturation index (MI) or ratio (SS/TA) of the juice, as well as the citrus color index (CCI) of fruit skin, were assessed monthly, beginning 200 days after flowering until harvest, totaling seven sampling dates. The data sets of each location were analyzed independently through a two-way analysis of variance (ANOVA) involving rootstocks in a split plot array in time (days) to allow for the assessment of the significance of the main effects, complemented by regression analysis. In general, the ripening of ‘Valencia’ orange fruits was influenced by the different ‘Trifoliata’ hybrid rootstocks. At the RA location, trees on IPEACS-256 and’ US-852’ citrandarins had the highest SS, and on ‘US-852’ citrandarin had the highest MI, reaching the MIim earlier than the other rootstocks. The highest CCI was achieved when trees were on IPEACS-256 citrandarin. At the SSA location, trees on ‘US-852’, IPEACS-256, and IPEACS-264 citrandarins had the highest SS, but on ‘US–852’ had the highest MI, reaching the earliest MIim among the rootstocks. The highest CCI was achieved when trees were on ‘US-852’ and IPEACS-256 citrandarins. In the SSJ location, there was no significant effect of the rootstocks on and of the variables of ‘Valencia’ orange fruit. This assessment can be useful in the planning of new orchards producing high-quality fruit with desirable features for the orange juice industry

Frequency and distribution of microsatellites from ESTs of citrus

Nearly 65,000 citrus EST (Expressed Sequence Tags) have been investigated using the CitEST project database. Microsatellites were investigated in the unigene sequences from Citrus spp. and Poncirus trifoliata. From these sequences, approximately 35% of the non-redundant ESTs contained SSRs. The frequencies of different SSR motifs were similar between Citrus spp and trifoliate orange. In general, mononucleotide repeats appeared to be the most abundant SSRs in the CitEST database, but we also identify di-, tri-, tetra-, penta- and hexanucleotide repeats. The AG/CT and AAG/CTT were the most common dinucleotide and trinucleotide motifs, with frequencies of 54.4% and 25.2%, respectively. Primer sequences flanking SSR motifs were successfully designed and synthesized. After in silico polymorphism analysis, a subset of sixty-eight primers was validated in different Citrus spp. and Poncirus trifoliata. PCR-amplification revealed polymorphism in citrus with all tested primer pairs and showed the potential of these markers for linkage mapping. Our study showed that the CitEST database can be exploited for the development of SSR markers that can amplify Citrus spp. and related genus for comparative mapping and other genetic analyses

The LLAMA Brazilian-Argentinian radiotelescope project: progress in Brazil and BRICS collaboration

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