RESUMO Um grave problema nas regiões de cultivo de milho verde é a baixa disponibilidade de fósforo (P), principalmente no bioma Cerrado. Objetivou-se avaliar o desempenho de híbridos duplos experimentais de milho para consumo in natura sob baixa e alta disponibilidade de P Utilizou-se delineamento experimental de blocos casualizados, em esquema fatorial (2 × 21), sendo duas disponibilidades de fósforo (37,5 e 75 mg dm−3 de P2O5) e 21 híbridos de milho, com nove repetições. As características avaliadas foram altura da inserção da espiga, altura de planta, florescimento masculino e feminino, comprimento e diâmetro de espigas, massa de grãos, peso de espigas empalhadas e despalhadas. Os híbridos duplo s experimentais DH94 e DH102, para baixa disponibilidade de P, e os híbridos DH71 e DH81, para alta, possuem a melhor qualidade e produtividade para o mercado de milho, visando ao consumo in natura. O híbrido DH81 possui desempenho mais adequado ao mercado consumidor, independentemente da disponibilidade de P, e, dessa forma, apresenta versatilidade e aptidão para esse mercado e para diferentes níveis tecnológicos.

ABSTRACT A serious problem in fresh corn growing regions is the low availability of phosphorus (P), especially in the Cerrado (Brazilian Savanna) biome. This study aimed to evaluate the performance of experimental double hybrids of fresh corn intended to in natura consumption grown under low and high P availability. A randomized blocks experimental design was used, in a 2 × 21 factorial arrangement, consisting of two P availabilities (37.5 and 75 mg dm−3 of P2O5) and 21 corn hybrids, with 9 replications. The following variables were evaluated: ear insertion height, plant height, male and female flowering, ear length and diameter, grain weight, husked and unhusked ear weight. The best quality and yield for the corn market focused on in natura consumption were observed for the experimental double hybrids DH94 and DH102 under low P availability and for DH71 and DH81 under high P availability. The DH81 hybrid performs better for the consumer market, regardless of the P availability, and, therefore, has versatility and aptitude for this market and for different technological levels.

ABSTRACT This study investigated the effect of different phosphites on the control of coffee leaf rust (CLR) caused by Hemileia vastatrix, considered the major disease affecting coffee yield worldwide. Three-month-old coffee plants were sprayed with two doses each of the phosphite solutions (standar., and double), as follows: K (40% P2O5; 1.., and 3 mL∙L-1), K (30% P2O5; ., and 6 mL∙L-1), Cu (2.., and 5 mL∙L-1), Mn+Zn (., and 6 mL∙L-1., and Na (., and 6 mL∙L-1) 24 h before being inoculated with H. vastatrix. Leaves were not washed or washed with deionized water after the foliar phosphites spray. Plants sprayed with water served as the control treatment. Inoculation was performed on the abaxial side of the first pair of expanded leaves using a camel hairbrush with a suspension of urediniospores (1 mg per leaf). All phosphites applied at the standard doses (from 1.5 to 3 mL∙L-1) reduced the total number of pustules (TNP) per leaf by 28-69% regardless of washing treatment. The biggest reductions were observed for Cu phosphite, which decreased the TNP per leaf by 6., and 69% withou., and with leaf washing, respectively. A similar trend was observed when the double doses of phosphites (from 3 to 6 mL∙L-1) were used, though Na phosphite without leaf washin., and Mn/Zn phosphite withou., and with leaf washing were not efficient to reduce the TNP per leaf. Without leaf washing, only C., and Na phosphites decreased CLR severity at the standard doses (53-61%), whereas all phosphites, except the Mn/Zn phosphite, reduced CLR severity at the double dose. The CLR severity was decreased using K 30%, K 40., and Cu phosphites when applied at the standard doses with leaf washing (41-59%). With double doses, only C., and Na phosphites decreased CLR severity by 55% for both treatments. In conclusion, the efficiency of the phosphites for CLR control varied according to the accompanying cation, dos., and washing conditions. The Cu phosphite resulted in the best CLR control regardless of the dose use., and the washing conditions.

ABSTRACT Asian soybean rust (ASR), triggered by Phakopsora pachyrhizi, can cause great yield losses on soybean and nickel (Ni) has potential to control this disease. This study evaluated the effect of using soybean seeds with different Ni contents on ASR control by performing two experiments. In experiment 1, seeds with different Ni contents were obtained by spraying plants three times with solutions containing either 60 or 100 gNi·ha-1. Plants sprayed with water served as the control treatment. In experiment 2, plants originated from seeds obtained in experiment 1 (T1 = 0.9 µgNi·seed-1, T2 = 1.2 µgNi·seed-1, and T3 = 1.6 µgNi·seed-1) were inoculated with P. pachyrhizi at the V4 growth stage. The ASR severity was evaluated 16 days after inoculation (DAI) and the chlorophyll (Chl) a fluorescence parameters at 8 and 16 DAI. The ASR severity decreased by 64 and 47% for treatments T2 and T3, respectively, in comparison to T1 treatment. The photosynthetic apparatus was negatively affected by ASR. The efficiency of the use of light by photosystem II decreased while the energy dissipated by nonregulated form increased in the infected leaflets. There was no significant difference for Chl a fluorescence parameters for T1, T2, and T3 treatments applied to inoculated plants probably due to the biotrophic lifestyle of P. pachyrhizi associated with lower ASR severity. In conclusion, the potential of using seeds with higher Ni content as a tool for ASR integrated management control is highlighted in this study.

ABSTRACT Nickel (Ni) was the latest element to have its nutritional essentiality recognized for plants (Brown et al. 1987). It is a component of various enzymes, including glyoxalases (family I), hydrogenases, superoxide dismutase and urease (Chen et al. 2009). Inadequate Ni supply promotes changes in the plant metabolism, including processes related to nitrogen metabolism, such as amino acids, urea and ureides metabolisms (Rodríguez-Jiménez et al. 2016; Bai et al. 2006). Legumes that are dependent on N2 fixation (e.g., soybean) have their process impaired by Ni deficiency, because this element is an essential catalytic cofactor of [NiFe]-hydrogenase, an enzyme found in some symbiotic bacteria that recycles the H2 produced by a side reaction of nitrogenase in root nodules formed by the plant-bacteria association (Cammack 1995; Bagyinka 2014). Moreover, Ni has shown the potential to control soybean diseases, such as powdery mildew (Barcelos et al. 2018) and Asian soybean rust (Einhardt et al. 2020a; 2020b).

ABSTRACT White mold, caused by Sclerotinia sclerotiorum, is one the most devastating disease on soybean worldwide. Considering the potential of phosphites to protect plants against different diseases, this study investigated the possibility of using potassium (K), calcium (Ca), and zinc (Zn) phosphites for white mold control in soybean. The contact effect of the phosphites on fungal mycelial growth was evaluated in vitro. In the greenhouse study, plants were inoculated with S. sclerotiorum at 48 h after being sprayed with water (control), K, Ca, and Zn phosphites by using an agar plug (0.8 cm2) containing fungal mycelia. Lesion area of white mold and chlorophyll (Chl) a fluorescence parameters were evaluated on the leaflets of plants at 96 h after inoculation. The Chl a parameters were also evaluated in noninoculated leaflets at the same time. Fungal mycelial growth was abundant in the absence of phosphites, but inhibited in the presence of the three phosphites indicating their direct effect. The lesion area in the leaflets of plants sprayed with K, Ca, and Zn phosphites were 90, 98, and 68% lower, respectively, compared to plants sprayed with water. The functionality of the photosynthetic apparatus was more preserved on the leaflets of plants sprayed with phosphites due to the lower lesions size, especially for the Ca phosphite. In conclusion, the K, Ca, and Zn phosphites were effective in reducing white mold symptoms mainly through a contact effect on the fungal mycelial growth.

ABSTRACT Considering the importance of silicon (Si) to increase rice resistance to blast, this study investigated the nutritional status of rice plants supplied with this element in response to Pyricularia oryzae infection. Plants were grown in nutrient solutions containing 0 and 2 mmol·L-1 of Si (referred to -Si and +Si plants, respectively). The area under blast progress curve decreased for +Si plants due to a significant increase of 714% on the foliar Si concentration in contrast to -Si plants. For +Si plants, the foliar N, P, K, Ca, Mg, Cu, and B concentrations were significantly lower in comparison to -Si plants. On infected plants, the foliar N, K, and Cu concentrations were significantly lower in comparison to noninfected ones. The foliar Zn, Fe, and Mn concentrations were significantly lower for -Si inoculated plants in comparison to -Si noninoculated ones. The foliar Mn and S concentrations were significantly lower for +Si inoculated plants in comparison to +Si noninoculated ones. The foliar Fe concentration was significantly lower for +Si inoculated plants in comparison to +Si noninoculated ones. Foliar Zn and Mn concentrations were significantly lower for +Si plants in comparison to -Si plants regardless of their inoculation with P. oryzae. Foliar Fe and S concentrations were significantly lower for +Si plants in comparison to -Si plants, respectively, for noninoculated and inoculated plants. Taken together, Si stood for itself in reducing blast symptoms without the need of high foliar concentrations of either macro or micronutrients that could affect plantgrowth.

ABSTRACT Considering the importance of blast, caused by Pyricularia oryzae, to impact wheat yield, this study investigated whether the foliar spray of potassium silicate (PS) could affect the photosynthesis of wheat plants and its potential to reduce disease symptoms. The Exp. 1 aimed to determine the effect of the foliar spray of PS on the photosynthetic performance of plants and was arranged in a completely randomized design with six treatments (plants sprayed with PS rates of 2.5, 5.0, 7.5, 10.0, and 12.5 g·L-1 at 35 days after emergence) and six replications. The leaf gas exchange (net CO2 assimilation rate (A), internal CO2 concentration (Ci), stomatal conductance to water vapor (gs), and transpiration rate (E)) as well as fluorescence of chlorophyll a (maximal photosystem II quantum yield (Fv/Fm), quantum yield of non-regulated energy dissipation [Y(NO)], photochemical yield [Y(II)], electron transport rate (ETR), and quenching non-photochemical [Y(NPQ)]) parameters were evaluated. The Exp. 2 was carried out to determine the effect of PS on blast control and also on the photosynthetic performance of plants. Plants at 35 days after emergence were sprayed with PS rate of 12.5 g·L-1, which did not affect photosynthesis on plants from Exp.1. This experiment was a 2 × 4 factorial and arranged in a completely randomized design with six replications. The factors studied were plants non-inoculated or inoculated plants and the spray of water, PS, fungicide (trifloxystrobin 10% + tebuconazole 20%; 0.75 L/ha), and fungicide + PS. There were no significant changes in the values of A, gs, E, Ci, Fv/Fm, Y(NO), Y(II), Y(NPQ), and ETR for plants sprayed three times (every 96 h interval) as the PS rates increased from 2.5 to 12.5 g·L-1. There was no significant relationship between the PS rates with either absorbance, reflectance or transmittance on the leaf blades. Linear regression model best described the foliar Si concentration-PS rates relationship. Foliar Si concentration significantly increased by 44 and 42%, respectively, for the PS and PS + fungicide treatments compared to water-sprayed plants. The area under disease progress curve was significantly lower by 64, 58, and 53%, respectively, for the fungicide, PS, and fungicide + PS treatments in comparison to water-sprayed plants. The photosynthetical process, primarily related to the Fv/Fm parameter, on wheat leaves was greatly impaired during the infection process of P. oryzae, but to a lesser extent on the leaves of PS-sprayed plants. In conclusion, the foliar spray of PS can be an environmentally friendly strategy to control wheat blast without causing perturbation to the photosynthetic machinery of wheat plants.

Resumo O parasitismo intenso por tricodinídeos está frequentemente relacionado à doença grave em fazendas de peixes. Neste estudo, espécies de tricodinídeos das brânquias e da pele de tilápias do Nilo (Oreochromis niloticus) cultivadas na região centro-oeste do Brasil (estado de Goiás) foram caracterizadas morfologicamente. As lâminas secas foram preparadas a partir dos parasitas e impregnadas com nitrato de prata (2%). As características morfométricas foram determinadas e desenhos esquemáticos dos dentículos foram confeccionados com fotomicrografias produzidas a partir das lâminas. Sete espécies de ectoparasitos tricodinídeos (Protozoa: Ciliophora: Trichodinidae) foram encontradas parasitando as brânquias: quatro do gênero Trichodina Ehrenberg, 1838; um de Tripartiella Lom, 1959; um de Paratrichodina Lom, 1963; e um de Trichodinella Ṧrámek-Huṧek, 1953. Na superfície do corpo, três espécimes do gênero Trichodina foram identificados. Este estudo apresenta novos registros geográficos de tricodinídeos no Brasil, confirmando que Trichodina centrostrigeata, Trichodina compacta, Trichodina heterodentata, Paratrichodina africana e Tripartiella orthodens estão amplamente distribuídas mundialmente. Adicionalmente, é apresentado o primeiro registro do gênero Trichodinella no Brasil.

Abstract Massive occurrence of trichodinids is frequently accompanied by serious disease in fish farms. In this study, trichodinid species from the gills and skin of Nile tilapia (Oreochromis niloticus) farmed in the central-western region of Brazil (state of Goiás) were morphologically characterized. Dried slides were prepared from the parasites and were impregnated with silver nitrate (2%). Morphometric characteristics were determined and schematic drawings of the denticles were made using photomicrographs produced from the slides. Seven species of trichodinid ectoparasites (Protozoa: Ciliophora: Trichodinidae) were found parasitizing the gills: four of the genus Trichodina Ehrenberg, 1838; one of Tripartiella Lom, 1959; one of Paratrichodina Lom, 1963; and one of Trichodinella Ṧrámek-Huṧek, 1953. On the body surface, three specimens of the genus Trichodina were identified. This study presents new geographical records of trichodinids in Brazil, thus confirming that Trichodina centrostrigeata, Trichodina compacta, Trichodina heterodentata, Paratrichodina africana and Tripartiella orthodens are widely distributed worldwide. Additionally, the first record of the genus Trichodinella in Brazil is presented.

Resumo O ácido abscísico (ABA) é conhecido como o hormônio mais influente em desencadear mecanismos de tolerância a estresse em plantas, inclusive à deficiência hídrica. No entanto, o efeito da aplicação exógena como indutora de tolerância pré-estresse é pouco estudado em plantas de interesse agronômico. O objetivo deste trabalho foi avaliar o efeito do ABA sobre o desencadeamento de mecanismos de tolerância à deficiência hídrica em mudas de seringueira, cultivar RRIM 600. Foram usadas soluções nas concentrações 0, 50, 100 ou 200 µM, aplicadas semanalmente nas folhas durante 12 semanas, seguidas de suspensão da rega por 13 dias. As análises foram realizadas em folhas do segundo nó, da base para o ápice, em cinco plantas por tratamento (sendo o tratamento a concentração de ABA). As plantas tinham mais de seis folhas completamente expandidas e cultivadas em vaso com capacidade de 10 L contendo latossolo vermelho-escuro. Verificou-se sua influência sobre a eficiência quântica potencial do fotossistema II (Fv/Fm), medidas diariamente durante a suspensão da rega, e sobre trocas gasosas medidas nos dias 0, 3, 7 e 10 após a suspensão da rega. Após 120 dias do final do primeiro período de suspensão da rega e após ocorrer abscisão natural e recomposição foliar, as plantas foram novamente submetidas a um segundo período de 13 dias de suspensão da rega para verificar se haveria efeito residual da aplicação do ABA nas novas folhas não tratadas. Foi observado que a aplicação exógena de ABA induziu tolerância à deficiência hídrica, especialmente nas plantas tratadas com 100 e 200 µM e causou efeito residual de tolerância nas novas folhas não tratadas com ABA. Foi observado que a primeira suspensão da rega desencadeou mecanismos de tolerância, os quais foram observados durante o segundo período de suspensão da rega em plantas não tratadas com o hormônio. A aplicação foliar de ABA desencadeia, portanto, mecanismos que permitem maior tolerância à deficiência hídrica à qual a planta venha a ser submetida.

Abstract The abscisic acid (ABA) is known as the most influential hormone in triggering mechanisms of stress tolerance in plants, including water deficit. However, the effect of ABA exogenous application as a pre-stress inducing tolerance is poorly studied in plants of agronomic interest. The purpose of this research was to evaluate the effect of ABA triggering mechanisms of stress tolerance in rubber tree seedlings, cultivar RRIM 600. The concentrations used were 0, 50, 100 or 200 µM applied weekly on leaves for 12 weeks, followed by the suspension of watering for 13 days. Leaves of the second node, from the basis to the apex, were analysed, using five plants per treatment (ABA concentration), which had more than six leaves completely expanded and cultivated in vases of 10 L with dark-red latosol. It was evaluated its influence on the potential quantum efficiency of photosystem II (Fv / Fm), measured daily during the suspension of irrigation, and on gas exchanges measured on days 0, 3, 7 and 10 after the suspension of irrigation. After 120 days of the end of the first period of watering suspension and after occurring natural abscission and leaf recovery, the plants were again submitted to a second period of 13 days of water suspension to check the residual effects of the prior application of ABA on untreated leaves. It was observed that the exogenous application of ABA induced drought tolerance, particularly in plants treated with 100 and 200 µM and caused residual effect of tolerance on untreated new leaves. It was observed that the first watering suspension itself triggered tolerance mechanisms observed during the second period of water suspension on ABA untreated plants. The foliar application of ABA triggers mechanisms that improve the tolerance of the plants to the water deficit to which the plants can be submitted.

ABSTRACT This study analyzed the use of the water balance, precipitation, temperature and NDVI (Normalized Difference Vegetation Index) to determine the optimum moment for evaluating infestation by the nematode Meloidogyne exigua in a rubber tree plantation by remote sensing. Nineteen sampling points were defined, divided into three areas, with high and low defoliation degrees, on a property in the Triângulo Mineiro region, where soil and root samples were collected for nematological analysis. Monthly digital images (OLI - Landsat 8 sensor) were obtained from August 2015 to August 2016. Rainfall, temperature and water balance were analyzed. The latter had no correlation with the indices; in contrast, temperature and precipitation correlated directly with NDVI. The best months for nematode soil infestation analysis were December, January and February, while for root infection it was August.

O objetivo do trabalho foi avaliar o potencial de híbridos de milho destinados à produção de grão e a possibilidade de comercialização in natura. O delineamento experimental utilizado foi o de blocos casualizados, com três repetições, em duas safras. Foram utilizados dez híbridos indicados para a região Centro-Oeste de Goiás, sendo os híbridos AG1051 (controle), 2B512PW, 2B587PW, 2B707PW, 30F35HR, 30F53YH, BRS 1055, BM 3061, P3646H e P3862YH. As características avaliadas foram altura de espiga, produtividade de espigas empalhadas, produtividade de espigas despalhadas, palha, produtividade de espigas comerciais, refugo comprimento de espigas comerciais, diâmetro de espigas comerciais e massa de grãos. Verificou-se existir diferença significativa para a maioria das variáveis analisadas, com exceção de refugo, comprimento e diâmetro, na safra 2014/15, indicando que existe variabilidade entre os híbridos e entre as safras estudadas. O híbrido 2B587PW apresentou melhor desempenho para a comercialização de espigas empalhadas e os híbridos 30F35HR, 30F53YH e BRS3061 em bandejas, além de estarem acima dos padrões comerciais exigidos, principalmente para comprimento e diâmetro da espiga, superior ao do híbrido controle, sendo os mais indicados para o consumo in natura.

The aim of this study was to evaluate the potential of corn hybrids for grain productivity and the possibility of commercialization in natura. The experiment design was a randomized block with three replications, in two crops. Ten hybrids indicated for the Midwest region of Goiás state were used, namely AG1051 (control), 2B512PW, 2B587PW, 2B707PW, 30F35HR, 30F53YH, BRS1055, BM3061, P3646H and P3862YH. The characteristics evaluated were ear-setting height, unhusked ear productivity, husked ear productivity, straw, marketable ear productivity, reject, marketable ear length, marketable ear diameter and grain mass. There is a significant difference for most of the analyzed variables, except for reject, ear length and ear diameter, in the 2014/15 harvest, indicating that there is variability between the hybrids and among the harvests studied. The hybrid 2B587PW presents better performance for the commercialization of husked ear and the hybrids 30F35HR, 30F53YH and BRS3061 for sale in trays, besides being above commercial standards required, principally for length and ear diameter, higher than the control hybrid, being the most suitable for consumption in natura.

ABSTRACT Mango wilt, caused by the fungus Ceratocystis fimbriata, is an important disease affecting mango production. In view of the beneficial effects of potassium (K) in other profitable crops and the lack of information about the effect of macronutrients on mango wilt development, the present study aimed to evaluate how mango plants supplied with K respond physiologically when infected by C. fimbriata. Mango plants (» 3 years old) from cultivar Ubá were grown in plastic pots containing 58 mg of K·dm−3 (original K level based on the chemical analysis of the substrate) or in plastic pots with substrate amended with a solution of 0.5 M potassium chloride (KCl) to achieve the rate of 240 mg K·dm−3. Disease symptoms were more pronounced in inoculated plants grown at the lower K level. Substantial declines in stomatal conductance, in line with decreases in the internal-to-ambient CO2 concentration ratio and the absence of detectable changes in the chlorophyll a fluorescence parameters, suggest that the decrease in the net carbon assimilation rate is due, at least initially, to stomatal limitations. High concentrations of K and manganese were found in the stem tissues of inoculated plants and supplied with the highest K rate, most likely due to the involvement of these tissues in the local development of defense mechanisms. The results of this study suggest that the supply of K favored the physiological performance of mango plants and their resistance against C. fimbriata infection.

RESUMO. Os cotonicultores do mundo inteiro sofrem com as perdas causadas pela presença de fitonematoides nas lavouras. Assim o objetivo deste trabalho foi estudar a herança da resistência do acesso TX 25 de Gossypium hirsutum raça punctatum a Meloidogyne incognita raça 3. Foram utilizados acessos de Gossypium sp. pertencentes ao Banco de Germoplasma da Embrapa Algodão. Foram realizados dois experimentos em dois anos consecutivos. No primeiro ano foram testados FiberMax 966 e TX 25 como parentais suscetível e resistente, respectivamente, e as gerações F1, F2 e retrocruzamento. No segundo experimento foram testados os parentais FiberMax 966 e TX 25, a geração F2 além dos genótipos M315 (resistente) LA887 e DeltaOpal (moderadamente resistentes). Em ambos experimentos as plantas foram inoculadas com 2000 ovos e J2 de M. incognita raça 3. As avaliações ocorreram aos 120 dias após a inoculação, e avaliou-se índice de galhas, índice de massa de ovos e fator de reprodução. No primeiro experimento as plantas da geração F1 e do retrocruzamento se mostraram suscetíveis, As plantas da geração F2 nos dois experimentos apresentaram uma proporção de três plantas resistentes para uma suscetível indicando resistência de caráter oligogênico.

ABSTRACT. Cotton producers worldwide suffer with the losses caused by the presence of phytonematodes. The aim of the present study was to investigate the inheritance of resistance to Meloidogyne incognita race 3 in Gossypium hirsutum variety punctatum accession TX 25. Accessions of Gossypium sp. were obtained from the germplasm bank of Embrapa Cotton. Two experiments were performed in two consecutive years. In the first experiment, a susceptible parental line, FiberMax 966, a resistant parental line, TX 25, and their F1, F2 and backcross generations were tested. In the second experiment, parental lines FiberMax 966 and TX 25, their F2 generation, and genotypes M315 (resistant), LA887 and DeltaOpal (moderately resistant) were tested. In both experiments, plants were inoculated with 2000 eggs and J2 of M. incognita race 3. The gall index, egg mass index and reproduction factor were evaluated 120 days following inoculation. In the first experiment, plants from the F1 and backcross generations were susceptible. Plants from the F2 generation presented a 3:1 resistant-to-susceptible ratio in the two experiments, indicating oligogenic resistance.

ABSTRACT Mango wilt, caused by Ceratocystis fimbriata, is one of the most important diseases affecting mango yield worldwide. Salt stress can affect host defense responses against pathogens infection. The aim of this study was to evaluate the development of mango wilt in 2 mango cultivars submitted to salt stress. Mango plants from cultivars Tommy Atkins and Ubá, considered to be moderately resistant and resistant to mango wilt, respectively, were grown in plastic pots which contained 20 kg of washed sand and daily irrigated with 3 L of a modified Hoagland solution during 40 days before being submitted to salinization. For this process of salinization, the plants received nutrient solution containing 0, 30, 60, and 90 mmol∙L–1 of sodium chloride (NaCl) during 50 days. At the 50th day, the plants were inoculated with C. fimbriata, and disease development was evaluated at 42 days after inoculation. During this period, the plants were also submitted to salinization. After disease evaluation, the stems of plants from each treatment were collected to determine the concentrations of chlorine (Cl) and sodium (Na). Plants from the 2 cultivars showed reduced mango wilt symptoms as the NaCl doses increased from 0 to 90 mmol∙L–1. Plants submitted to the highest NaCl doses showed greater Cl and Na concentrations on the stem. In conclusion, the resistance of plants against C. fimbriata infection can be potentiated when submitted to salt stress regardless of their basal level of resistance to mango wilt.

ABSTRACT The use of fuels for agricultural Diesel engines cycle, both of mineral origin (Diesel) or vegetable and animal origin (biodiesel) can significantly alter its performance. Therefore, the aim of this study was to quantify the change in torque, power and consumption of agricultural Diesel engine fuel using minerals and vegetables fuels. It was used a tractor power take-off coupled to a magnetic brake dynamometer (for measuring speed and torque for subsequent calculation of power), and a flow meter (for measuring the hourly fuel consumption and specific fuel consumption calculation). Eleven different fuels (S10 mineral diesel with 5%, 10%, 15%, 20% and 50% biodiesel and mineral diesel S500 with 5%, 10%, 15%, 20% and 50% biodiesel, have been used pure biodiesel B100). The results indicate that the increase of biodiesel in mineral diesel reduces torque and power, increases the specific fuel consumption and practically does not change the hourly consumption. This reduction in torque and power occurs with greater intensity in Diesel S10. Additions of 10% biodiesel in mineral diesel reduces the maximum torque 1.65 Nm (0.6%), the maximum power at 0.33 kW (0.6%) and increases the specific fuel consumption of 3.6 g kWh -1 (1.3%).