Physiological and vegetative changes in grapevines (cv. Alvarinho) promoted by biological control agents (BCAs) : preliminary results

The induction of a natural disease resistance in grape using several biological and/or chemical elicitors, known as Biological Control Agents (BCAs), has received increasing attention over the last years, and is now considered the elected strategy for disease management. Vegetative and physiological changes (number of leaves; roots and stem length; total photosynthetic pigments; leaf gas exchanges) promoted by four BCAs (Best Cure; Mycotric; FitoAlgas; BioClean) and four conventional chemical products (Maestro M; Flint; Aliette; Horizon) were evaluated in potted grapevines (cv. Alvarinho) comparatively to a control group (Ctl). Each compound was applied, independently, to a minimum of 12 plants (to Ctl plants just distillated water was added), every fifteen days, during July and August of 2007. The results, in the first year, do not reveal significant physiological differences between the treatments and the Ctl. In vegetative terms, some differences were observed in the roots and leaves. However, the results were erratic, eventually due to the short time of the experience. The trial will proceed for a 2nd and a 3rd year.Fundação para a Ciência e a Tecnologia (FCT

Long-term studies on ground management in rainfed olive orchards

Two decades of research on soil management in rainfed olive graves, encompassing four experimental ftelds, one of which took eighteen years of continuous assessment, allowed comparative evaluation of severa! treatments including conventional tillage, residual herbicides, post-emergence herbicides, covers of natural vegetation (fertilized and unfertilized), sown covers managed as green manures and incorporated into the soil, or shredded and kept in the ground as a mulch, and sown covers of self-reseeding pasture legumes. This series of studies allowed showing that a better contrai of the herbaceous vegetation improves olive growth and yield and a greater development of the herbaceous vegetation improves severa! indicators of the soil fertility, which creates a great ambiguity. However, a large set of advantages comes from the use of early-season self-reseeding annual legumes. These plants presenta very short growing cycle and develop asynchronously with the trees (in winter, during the resting period of olive), showing reduced competition for water, allowing high productivity even in rainfed conditions. Additionally, they protect the soil from erosion ali year round, with live vegetation during winter anda mulch of dead vegetation during the summer, improve soil fertility, including the increase of soil organic matter, and are able to ftx nitrogen improving the nitrogen nutritional state of the trees.info:eu-repo/semantics/publishedVersio

Effects of Esca disease on leaf gas exchange of cv. Alvarinho in a vineyard of the Portuguese Vinho Verde region

Esca is a very complex disease that is usually noticed when the grapevine show external symptoms. However, the grapevines can be infected for a long period of time and rarely manifest the typical leaf symptoms. Moreover, little is know about the consequences of Esca on vineyard productivity. In Portugal, in Vinho Verde region, Alvarinho sub-region, most vineyards are infected with Esca. In this work we evaluate the impact of Esca on some physiological parameters of grapevines cv. Alvarinho.This preliminary work reveal the importance that these kind of physiological measurements can have in the valuation of the infected Esca grapevine physiological conditions. These results may be used as a pattern to predict the damage magnitude of Esca disease in grapevines.Fundação para a Ciência e a Tecnologia (FCT)Fundação Luso-American

A Two-Step Segmentation Method for Breast Ultrasound Masses Based on Multi-resolution Analysis

Breast ultrasound images have several attractive properties that make them an interesting tool in breast cancer detection. However, their intrinsic high noise rate and low contrast turn mass detection and segmentation into a challenging task. In this article, a fully automated two-stage breast mass segmentation approach is proposed. In the initial stage, ultrasound images are segmented using support vector machine or discriminant analysis pixel classification with a multiresolution pixel descriptor. The features are extracted using non-linear diffusion, bandpass filtering and scale-variant mean curvature measures. A set of heuristic rules complement the initial segmentation stage, selecting the region of interest in a fully automated manner. In the second segmentation stage, refined segmentation of the area retrieved in the first stage is attempted, using two different techniques. The AdaBoost algorithm uses a descriptor based on scale-variant curvature measures and non-linear diffusion of the original image at lower scales, to improve the spatial accuracy of the ROI. Active contours use the segmentation results from the first stage as initial contours. Results for both proposed segmentation paths were promising, with normalized Dice similarity coefficients of 0.824 for AdaBoost and 0.813 for active contours. Recall rates were 79.6% for AdaBoost and 77.8% for active contours, whereas the precision rate was 89.3% for both methods.info:eu-repo/semantics/publishedVersio

Olive response to potassium applications under different water regimes and cultivars

Although potassium (K) is a macronutrient few studies have evaluated the response of olive tree to K fertilization. In this work results of two field and two pot K fertilizer experiments are presented. One of the field trials was conducted in a commercial young olive grove. The second was conducted in a plantation purposely established for this study. In the two fieldand thefirst potexperiment,theK supply was the single variation factor. The second pot experiment was arranged as a factorial with two K rates, two water regimes and two cultivars (‘Arbequina’ and ‘Cobranc¸osa’). K supply did not increase olive tree growth or yield. Accumulated olive yield in the first field experiment, for instance, varied from 2.46 and 2.84 kg tree-1, respectively in K treated and untreated plants. K supply increased the shoot/root ratio (1.6–2.0 from the control to the most fertilized treatment) and the concentration of K in roots (2.9–11.2 g kg-1) to a greater extent than in leaves (7.0–11.9 g kg-1), suggesting that shoots are a priority sink for K and roots may store the nutrient as a reserve. Plant water status and chlorophyll a fluorescence were not significantly affected by K applications. Plants suffering from water stress yielded less phytomass (40.2–56.4 g pot-1, respectively in control and well-watered plants) and showed higher K concentrations in leaves (14.2–11.6 g kg-1) and lower in roots (4.9–6.8 g kg-1) which is probably due to the reduction of K uptake from the dry soil. ‘Cobranc¸osa’ appeared to be more tolerant to water stress than ‘Arbequina’. These experiments showed a poor response of olive tree to K fertilization. Considering that K is usually applied by farmers every year, it seems that further studies on K fertilizationin olive are needed in order to adjust K fertilizer rates to crop needs.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013). The work was also funded by the INTERACT Project—‘‘Integrative Research in Environment, Agro-Chains and Technology’’, No. NORTE- 01-0145-FEDER-000017, in its line of research entitled ISAC, co-financed by the European Regional Development Fund (ERDF) through NORTE 2020 (North Regional Operational Program 2014/2020). For authors integrated in the CITAB research centre, it was further financed by the FEDER/ COMPETE/POCI—Operational Competitiveness and Internationalization Programme, under Project POCI-01-0145- FEDER-006958, and by National Funds of FCT–Portuguese Foundation for Science and Technology, under the Project UID/ AGR/04033/2013.info:eu-repo/semantics/publishedVersio

Olive tree response to applied phosphorus in field and pot experiments

Phosphorus (P) application in olive orchards is very common in the Mediterranean basin although experimental evidence of crop response to applied P is practically non-existent. In this work soil P and tree P nutritional status of the olive groves of NE Portugal were assessed from a population of 1808 soil and 2252 leaf samples. Plant response to applied P was evaluated from two field and two pot experiments carried out with the cultivar ‘Cobrançosa’. The analyses of soil and leaf samples of the olive orchards of the region indicate that P fertilizer recommendations should be based on leaf rather than on soil analyzes, since the latter seems to overestimate the need for P. The field and pot experiments hardly showed any positive response to P applications, which is a sign that the use of P fertilizer in olive can be substantially reduced. Nonetheless, in one pot experiment, P application significantly increased total dry matter yield during three consecutive years, in a strict association with higher tissue P concentrations and enhanced photosynthetic activity, as revealed by gas exchange and chlorophyll fluorescence traits. The experimental results also showed that the roots can uptake and store P when available in the soil, which may buffer the levels of P in the shoots. The acid phosphate activity can provide useful information but deserves caution in the interpretation of results since it depends not only on the availability of inorganic P in the soil, but also on the available organic substrate and pH.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013). The work was also funded by the INTERACT project – “Integrative Research in Environment, Agro-Chains and Technology”, no. NORTE-01-0145- FEDER-000017, in its line of research entitled ISAC, co-financed by the European Regional Development Fund (ERDF) through NORTE 2020 (North Regional Operational Program 2014/2020). For authors integrated in the CITAB research centre, it was further financed by the FEDER/COMPETE/POCI – Operational Competitiveness and Internationalization Programme, under Project POCI-01-0145-FEDER- 006958, and by National Funds of FCT–Portuguese Foundation for Science and Technology, under the project UID/AGR/04033/2013.info:eu-repo/semantics/publishedVersio

The effect of nitrogen applications on the growth of young olive trees and nitrogen efficiency

Two field trials (FieldExp1 and FieldExp2) and a pot experiment (PotExp) were c0onducted over a period of 3 years to assess olive tree response to nitrogen (N) applications and to estimate apparent N recovery. FieldExp1 was installed in a 3-year-old olive grove. FieldExp2 consisted of a plantation of young rooted plants. Two treatments were applied in both experiments: N application and a nonfertilized control. In PotExp, 4 N rates were used. In FieldExp1, olive yield significantly increased with applied N in only 1 of the 3 growing seasons. In FieldExp2, aboveground dry matter yield significantly increased with N application. In PotExp, total dry matter yield displayed a typical saturation curve in response to N rates. The poor response of olive yield to N application might be due to the reduced amount of N removed in the crop, and also to the negative interaction found between N application and water deficit. Apparent N recovery reached values varying from 13.1% in FieldExp2 to ~100% in PotExp. The results indicate that the olive response to N and N use efficiency seem to be influenced more by the agroecological conditions defining target yield and N loss, rather than by plant species.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Program PT2020 for financial support to CIMO (UID/AGR/00690/2013). The work was also funded by the INTERACT project “Integrative Research in Environment, Agro-Chains and Technology”, no. NORTE-01-0145- FEDER-000017, in its line of research entitled ISAC, cofinanced by the European Regional Development Fund (ERDF) through NORTE 2020 (North Regional Operational Program 2014/2020).info:eu-repo/semantics/publishedVersio

Liming and application of nitrogen, phosphorus, potassium, and boron on a young plantation of chestnut

European chestnut is the most important cash crop in the highlands of NE Portugal. However, limited data on cropping technique are available to help farmers make decisions. This work is motivated by the lack of data related to chestnut response to fertilizer application. It reports results from a field fertilization trial consisting of the application of a combination of lime (L), nitrogen (N), phosphorus (P), potassium (K), and boron (B), namely LNPKB, NPKB, –NPKB, N–PKB, NP–KB, and NPK–B. Seedlings of chestnut were planted in June 2013 and grown for four growing seasons. Plant height, trunk diameter, and pruning wood were assessed every year and used as indicators of tree crop growth. Elemental leaf analysis and other tools [SPAD-502 chlorophyll meter; Field Scout CM 1000 NDVI (normalized difference vegetation index) meter, and the OS-30p+ fluorometer] were used to assess plant nutritional stresses. In January 2017 soil samples were collected at three depths (0–5, 5–10, and 10–20 cm) to determine several soil fertility parameters. The nonapplication of K and B reduced the tree crop growth and pruning residues. Leaf analysis revealed leaf K and B concentrations respectively in the NP–KB and NPK–B treatments to be in the deficient range previously established for chestnut. SPAD readings and NDVI detected the reduced availability of N associated with the –NPKB treatment but not the reduced plant growth associated with NP–KB or NPK–B treatments. The dark adaptation protocols of FV/FM, FV/F0, and OJIP measurements performed with the OS-30p+ fluorometer failed to diagnose the nutrient stresses detected by leaf analysis or the reduction in plant growth.info:eu-repo/semantics/publishedVersio