BACKGROUND The prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) has changed unevenly over time around the world. Although whole genome sequencing is the gold standard for virus characterisation, the discovery of alpha VOC causing spike gene target failure (SGTF) result, when tested using an reverse transcription real-time polymerase chain reaction (RT-qPCR) assay, has provided a simple tool for tracking the frequencies of variants. OBJECTIVES The aim of this study was to investigate if a multiplex RT-qPCR assay (BioM 4Plex VOC) could be used to detect SARS-CoV-2 and to perform a VOC screening test in a single reaction tube. Here, we present the multicentre study evaluating this assay. METHODS Twelve laboratories have participated in the multicentre study. The BioM 4Plex VOC was distributed to them with detailed instructions of how to perform the test. They were asked to test the BioM 4Plex VOC in parallel with their routine Commercial SARS-CoV-2 diagnostic assay. Additionally, they were requested to select SARS-CoV-2-positive samples with genome sequenced and lineage definition according to PANGO lineage classification. FINDINGS The BioM 4Plex VOC and commercial RT-PCR assay are equally effective in detecting SARS-CoV-2. Results revealed a specificity of 96.5-100% [95% confidence interval (CI)], a sensitivity of 99.8-100% (95% CI), and an accuracy of 99.8-100% (95% CI). A 99% concordance rate was found between results from the BioM 4Plex VOC and that from available genome sequencing data. MAIN CONCLUSIONS The BioM 4Plex VOC provides an effective solution to detect SARS-CoV-2 infections and screening for VOCs in a single reaction. It is a straightforward method to help us monitor the frequency and distribution of VOCs and develop strategies to better cope with the pandemics.

ABSTRACT There is little information on how different spatial arrangements affect modern maize hybrids under irrigation in the maize second growing season in Brazil. The objectives of this study were to evaluate the performance of maize genotypes with different canopy architecture as a function of different spatial arrangements in the Southeast Brazil. Two maize hybrids with semi-erect (DKB 390) and erect (DKB 230) leaves were cultivated during the second season and evaluated for different plant densities (4, 7 and 10 × 104 plants?ha?1) and row spacings (0.25, 0.50 and 1.00 m), under irrigation in a tropical environment. The increase in plant density increased plant height and ear insertion height, but reduced stalk diameter. The absorbed photosynthetically active radiation and the leaf area index also increased in higher plant densities, with a reduction of the SPAD index. The increase in plant density enhanced grain yield, however, there was no difference of yield between different row spacings. The hybrid DKB 230 (upright leaves) showed greater yield potential compared to DKB 390 (semi-upright leaves). The critical leaf area index was 5.2 and 4.3 for the hybrids DKB 230 and DKB 390, respectively. The estimated plant density that provides the maximum yield are 9.7 × 104 and 8.8 × 104 plants?ha?1 for the hybrids DKB 230 and DKB 390, respectively.

RESUMO O uso de pesticidas com alta toxicidade para controlar patógenos do solo, como Fusarium spp. e Sclerotinia sclerotiorum, tem gerado preocupação, devido aos impactos irreversíveis causados no meio ambiente, além de selecionar isolados resistentes. Dessa forma, os óleos essenciais surgem como uma alternativa eficiente no controle de doenças. Diante da problemática de controle de patógenos do solo e alto potencial antimicrobiano que os óleos essenciais possuem, este trabalho teve como objetivo avaliar o potencial fungicida de óleos essenciais no controle de Fusarium spp. e S. sclerotiorum, in vitro. Utilizou-se um delineamento inteiramente randomizado, esquema fatorial 2×4×8, com dois isolados (Fusarium spp. e S. sclerotiorum), quatro óleos essenciais (Aloysia citriodora, Cymbopogon winterianus, Lippia alba e Ocimum americanum) e oito concentrações de óleo essencial (0,0; 0,2; 0,4; 0,6; 0,8; 1,0; 1,2 e 1,4 ?L·mL-1), com dez repetições. Os óleos essenciais inibiram o crescimento micelial dos fungos em diferentes concentrações, sendo seu potencial justificado pela presença de compostos químicos antifúngicos. Os óleos essenciais de A. citriodora, C. winterianus, L. alba e O. americanum apresentam alto potencial fungicida, sendo alternativas viáveis para formulação de produtos comerciais, impulsionando a indústria de agrotóxicos.

ABSTRACT The use of highly toxic pesticides to control soil pathogens, such as Fusarium spp. and Sclerotinia sclerotiorum has generated concern, due to the irreversible impacts caused on the environment, in addition to selecting resistant isolates. In this way, essential oils appear as an efficient alternative in control of diseases. Facing the problem of soil pathogens control and high antimicrobial fungicide that essential oils present, this work aimed to evaluate the in vitro fungicidal potential of essential oils in control of Fusarium spp. and S. sclerotiorum. A completely randomized design, factorial scheme 2×4×8 was used, with two isolates (Fusarium spp. and S. sclerotiorum), four essential oils (Aloysia citriodora, Cymbopogon winterianus, Lippia alba and Ocimum americanum), eight essential oil concentrations (0.0; 0.2; 0.4; 0.6; 0.8; 1.0; 1.2 and 1.4 ?L·mL-1), and ten replicates. The essential oils inhibited mycelial growth of the fungi in different concentrations, being their potential justified by the presence of antifungal chemical compounds. Essential oils of A. citriodora, C. winterianus, L. alba and O. americanum present high fungicidal potential, being viable alternatives for formulation of commercial products, boosting the pesticides industry.

RESUMEN El cultivo de tomate presenta un alto potencial productivo pero puede afectarse debido al estrés biótico y abiótico. Se ha informado un aumento de la resistencia de la planta a las condiciones de estrés con la aplicación foliar de compuestos minerales del suelo, sin embargo, aún es necesario comprender mejor cómo reacciona la planta al uso de este compuesto. Por lo tanto, este estudio evaluó el efecto de la aplicación foliar del compuesto mineral del suelo sobre los atributos fisiológicos y de crecimiento de las plantas de tomate. Este experimento se llevó a cabo en Lagoa Formosa / MG durante 2016. Se usaron diferentes tasas del compuesto mineral del suelo durante el ciclo del cultivo, lo que constituye cuatro manejos distintos. El manejo consistió en diferentes dosis del compuesto mineral en cuatro etapas después del trasplante de las plántulas de tomate. El diseño experimental utilizado fue de bloques al azar. Se realizaron las siguientes evaluaciones fisiológicas: proteína soluble total, peróxido de hidrógeno, actividad de la enzima nitrato reductasa, ureasa, superóxido dismutasa (SOD), peroxidasa, fenilalanina amoniaco liasa y peroxidación lipídica (LP). Las evaluaciones de crecimiento fueron biomasa vegetal y rendimiento. La aplicación foliar del compuesto mineral del suelo aumentó la actividad de la enzima SOD en 4,17 y 6,25%. El uso del compuesto mineral del suelo también aumentó la actividad de LP y redujo la actividad de las enzimas antioxidantes. La aplicación foliar de compost mineral del suelo a dosis de 0,5; 0,750; 1,0 y 1.0 kg ha-1 a los 15, 25, 40 y 60 días después del trasplante, respectivamente, aumentó el rendimiento de tomates de mesa al 20%.

ABSTRACT The tomato crop has a high productive potential that can be depleted by biotic and abiotic stresses. Increased plant resilience to stress conditions has been reported with foliar applications of soil-mineral compounds; however, it is necessary to better understand how plants react to the use of this compound. Thus, this study evaluated the effect of foliar applications of a soil-mineral compound on the physiological and growth attributes of tomato plants. This experiment was carried out in Lagoa Formosa/MG during 2016. Different rates of the soil-mineral compound were used during the crop cycle, forming four distinct managements. The management consisted of different doses of the mineral compound in four stages after transplanting the tomato seedlings. The experiment design used randomized blocks. The following physiological evaluations were performed: total soluble protein, hydrogen peroxide, nitrate reductase enzyme activity, urease, superoxide dismutase (SOD), peroxidase, phenylalanine ammonia lyase, and lipid peroxidation (LP). The growth assessments were plant biomass and yield. Foliar applications of the soil-mineral compound increased the activity of the SOD enzyme by 4.17 and 6.25%. The use of the soil-mineral compound also increased the LP activity and reduced the antioxidant enzyme activity. The foliar application of the soil-mineral compost at doses of 0.5, 0.750, 1.0 and 1.0 kg ha-1 at 15, 25, 40 and 60 days after transplanting, respectively, increased the yield of the table tomatoes by 20%.

Resumo Devido a sua relevante importância econômica, tanto para o setor alimentício quanto farmacêutico, a oliveira vem sendo cada vez mais cultivada em todo o mundo. Para isso, a obtenção de mudas de qualidade com uniformidade e idoneidade varietal surge como fator altamente relevante na implantação dos pomares de oliveiras. Dessa forma, o objetivo deste trabalho foi desenvolver protocolo de estabelecimento in vitro a partir de segmentos nodais de duas cultivares de oliveira sob diferentes concentrações de hipoclorito de sódio e concentrações de BAP. O experimento foi conduzido no delineamento inteiramente casualizado, em esquema fatorial triplo (2x3x3), sendo duas cultivares de oliveira (Arbequina e Koroneiki), três concentrações de BAP (0,00; 2,22 e 4,44 µM) e três concentrações de hipoclorito de sódio (0,6; 0,8 e 1,0% de cloro ativo) para a descontaminação dos explantes. Cada tratamento contou com três repetições e a unidade experimental constituída por cinco tubos de ensaio com um explante cada. Após 28 dias, foi possível observar que os tratamentos testados não promoveram o estabelecimento in vitro de Olea europaea cv. Arbequina. A concentração de 2,22 µM de BAP adicionada ao meio WPM e a concentração de 1,0% de hipoclorito de sódio, utilizada na desinfestação dos explantes, apresentaram resultados promissores no estabelecimento in vitro de Olea europaea cv. Koroneiki.

Abstract Due to its relevant economic importance, both for the food and pharmaceutical sectors, the olive tree is being increasingly cultivated around the world. For this, obtaining quality seedlings with uniformity and varietal suitability emerges as a highly relevant factor at the implantation of olive orchards. Thus, the objective of this work was to develop in vitro establishment protocol from nodal segments of two olive cultivars under different concentrations of sodium hypochlorite and different concentrations of BAP. The experiment was conducted on completely randomized design, in a triple factorial scheme (2x3x3), two olive cultivars (Arbequina and Koroneiki), three BAP concentrations (0,00; 2,22 e 4,44 µM) and three concentrations of sodium hypochlorite (0,6; 0,8 and 1,0% active chlorine) for the decontamination of the explants. Each treatment had three replicates and the experimental unit consisted of five test tubes with one explant each. After 28 days, it was possible to observe that the treatments tested did not promote in vitro establishment of Olea europaea cv. Arbequina. The concentration of 2,22 µM of BAP added to the WPM and the 1,0% concentration of sodium hypochlorite used in disinfestation of the explants, presented promising results in the in vitro establishment of Olea europaea cv. Koroneiki.

RESUMEN El objetivo de este estudio fue evaluar el efecto de tratamientos de boro edáfico y frecuencia del calcio foliar en floración, sobre la producción y ocurrencia de la pudrición apical de híbridos de tomate italiano, cultivados en el sistema convencional en dos temporadas de cultivo. Se realizaron dos experimentos en el área experimental perteneciente a la Universidade Federal de Santa Maria, campus de Frederico Westphalen (Brasil), en los años 2012 y 2013. El diseño experimental fue de bloques al azar con un arreglo factorial 2x2x3x3 cuyo factores fueron dos híbridos (San Vito y Neptuno), en dos épocas de cultivo (primavera-verano y verano-otoño), tres dosis de boro (0; 2,0 y 4,0 g/planta) y tres frecuencias de aplicación de calcio (ausencia de aplicación, aplicación semanal y quincenal) y cuatro repeticiones. El trasplante de plántulas se realizó el día 04 de septiembre de 2012 para la primavera-verano y el 26 de enero para el verano-otoño. El híbrido Neptuno es más productivo en comparación con el híbrido San Vito, pero más susceptible a la pudrición apical. Las dos épocas de cultivo pueden ser recomendadas para el cultivo del tomate italiano en Rio Grande do Sul, aunque el cultivo de primavera-verano presenta mayor productividad cuando se compara al verano-otoño. La frecuencia de aplicación quincenal de CaCl2 al 0,6% se constituye en la mejor opción de manejo de fertilización, en el sentido de obtener mayor productividad y menor número de frutos con incidencia de pudrición apical. El incremento de la dosis de boro condiciona mayor número de frutos por planta y aumento de la productividad.

ABSTRACT The objective of this study was to evaluate the effect of boron soil treatments and the frequency of calcium applications on the flowering, agronomic performance, and incidence of blossom end rot in Italian tomato hybrids grown in conventional systems during two growing seasons. Two experiments were carried out in the experimental area of the Federal University of Santa Maria, Frederico Westphalen campus (Brazil) during 2012 and 2013. A randomized block experiment design was used in a 2x2x3x3 factorial scheme with two hybrids (San Vito and Netuno) in two growing seasons (Spring-Summer and Summer-Fall), three boron doses (0.0, 2.0, or 4.0 g/hole), and three frequencies of calcium application (absence of application, weekly, or biweekly application) with four replicates. The seedlings were transplanted on September 4, 2012 for the Spring-Summer growing season and on January 26, 2013 for the Summer-Fall growing season. The Netuno hybrid was more productive in comparison to the San Vito hybrid, but more susceptible to blossom end rot. Both growing seasons can be recommended for Italian tomato production in Rio Grande do Sul although the Spring-Summer growing season was more productive than the Summer-Fall growing season. The biweekly application frequency of 0.6% CaCl2 was the best option for fertilizer management, resulting in higher yields and a lower number of fruits with an incidence of blossom end rot. The increment of the boron dose defined the higher number of fruits per plant and yield increase.

RESUMO El ácido salicílico (AS) es conocido por estar involucrado en una serie de procesos fisiológicos que mejoran las características de germinación y vigor. El objetivo de este trabajo fue evaluar el efecto de concentraciones de AS sobre la calidad fisiológica de semillas de escarola (Cichorium endivia L.) cv. Escarola Lisa. Las semillas de escarola fueron embebidas durante 24 horas en concentraciones 0; 0,05; 0,1; 0,15 y 0,2 mM de Bion® (análogo al ácido salicílico) y después sometidas a pruebas de germinación y vigor (laboratorio e invernadero). Los lotes de semillas evaluadas diferían en cuanto a su calidad fisiológica. El uso de ácido salicílico no presenta beneficios a la calidad fisiológica de semillas de escarola. Sin embargo, se sugiere que nuevos trabajos sean realizados probando este producto en condiciones de estrés o aplicado en estadios posteriores a la germinación de las semillas.

ABSTRACT Salicylic acid (SA) is known to be involved in a series of physiological processes in the improvement of seed germination and vigor. The aim of this study was to evaluate the effect of SA concentrations on the physiological quality of escarole (Cichorium endivia L.) seeds, Escarola Lisa® cultivar. Escarole seeds were soaked for 24 h at concentrations 0, 0.05, 0.1, 0.15, and 0.2 mM of a similar to salicylic acid (Bion®) and afterwards submitted to germination and vigor tests (laboratory and greenhouse). The tested seed lots differed in their physiological quality. The use of salicylic acid does not present profits for the physiological quality of escarole seeds. However, it is suggested that new studies be carried out by testing this product under stress conditions or applied in stages after seed germination.

RESUMO: O objetivo deste trabalho foi determinar o filocrono, em cultivares de morangueiro, de duas procedências e em dois anos agrícolas, conduzidas em túnel baixo. Os experimentos foram conduzidos em área da Universidade Federal de Santa Maria, campus Frederico Westphalen (CESNORS/UFSM), constando da avaliação das cultivares 'Camarosa', 'Camino Real' e 'Albion'. Para o ano de 2012, avaliaram-se mudas procedentes do Chile e da região de Pelotas/RS e, para o ano de 2013, apenas mudas chilenas. Na determinação do filocrono, foi realizada contagem, duas vezes por semana, do número de folhas (NF) da coroa principal e, posteriormente, realizou-se regressão linear entre o NF e a soma térmica acumulada (STa). O delineamento experimental foi o de blocos casualizados, com três repetições, sendo cada unidade experimental composta por 12 plantas de avaliação, em esquema fatorial. Para os anos de 2012 e 2013, os resultados obtidos mostram que as cultivares 'Camarosa' e 'Camino Real' necessitam de maior acúmulo de graus dia para emissão de cada folha sucessiva do que a cv. 'Albion', que, por sua vez, apresenta maiores taxas de emissão de folhas, podendo ser considerada como mais precoce. Com relação à procedência, verifica-se que as mudas da cv. 'Albion' provenientes do Chile apresentam menores valores de filocrono total. Para a procedência Pelotas, não foi observada diferença entre as cultivares.

ABSTRACT: The aim of this study was to determine phyllochron in strawberry cultivars, from two origins during two crop years, conducted in low tunnel. Experiments were conducted at the Universidade Federal de Santa Maria, campus Frederico Westphalen (CESNORS/UFSM), Brazil, evaluating 'Camarosa', 'Camino Real' and 'Albion' strawberry cultivars. During the 2012 crop year, seedlings from Chile and Pelotas/RS, Brazil were evaluated, for the 2013 crop year, only seedlings from Chile were submitted to evaluations. In order to determine the phyllochron, twice a week the numbers of leaves (NL) of the main crown were counted and a regression between NL and accumulated thermal time (ATT) was held. The experimental design was a complete randomized block, with three repetitions with the evaluation of 12 plants per experimental unity, consisting of a factorial. For 2012 and 2013 crop years, it is possible to conclude that 'Camarosa' and 'Camino Real' cultivars required higher accumulation of degree-days (ºC day-1) to issue each successive leaf than cv. 'Albion', which, in turn, presented higher rates of leaf emergence, being considered earlier. Regarding to origin, seedlings from cv. 'Albion' from Chile presented lower total phyllochron values and for samples from Pelotas, no difference among cultivars was observed.