Effects of mbta [n,n-diethyl-2-(4-metylbenzyloxy) ethylamine hydrochloride] on yield and fruit quality of 'pêra' sweet orange (Citrus sinensis L. Osbeck)

O objetivo deste trabalho foi avaliar os efeitos do biorregulador MBTA [cloridrato de N,N-dietil-2-(4-metilbenziloxi) etilamina] aplicado em diferentes épocas e concentrações na produtividade e qualidade dos frutos da laranjeira 'Pêra'. Em duas safras consecutivas, o MBTA foi aplicado em três diferentes concentrações (8; 16 e 32 mg L-1) e em duas diferentes fases fenológicas (25% e 100% de flores abertas), em árvores cítricas adultas, utilizando um volume de 7 litros de solução por planta, acompanhado do adjuvante Silwett L-77 0,05%. Foram amostrados 20 frutos por planta, em quatro diferentes épocas estudadas, para determinar o teor de sólidos solúveis (SS); acidez titulável (AT); quantidade de sólidos solúveis por caixa de 40,8 kg; pH; rendimento de suco; ratio (relação SS/AT), e a massa média dos frutos. Os efeitos do MBTA variaram de acordo com a concentração aplicada e com a fase fenológica de aplicação. O MBTA, na concentração de 8 mg L-1, aplicado com 25% das flores abertas, incrementou o teor de sólidos solúveis, a acidez, a quantidade de sólidos solúveis por caixa de 40,8 kg e a produtividade. Esse mesmo tratamento também reduziu a massa média dos frutos e não alterou o rendimento de suco e o ratio do suco dos frutos. O incremento médio foi de 0,49 a 0,65% na concentração de sólidos solúveis, de 0,11 a 0,13 kg na quantidade de sólidos solúveis por caixa de 40,8 kg e de 20,4 kg/planta na produtividade.The purpose of this research was to evaluate the effects of MBTA [N,N-diethyl-2-(4-metylbenzyloxy) ethylamine hydrochloride] bioregulator applied on different times and concentrations on the yield and fruit quality of 'Pera' sweet orange. In two consecutive harvest seasons, the MBTA was sprayed in three different concentrations (8; 16 and 32 mg L-1) and in two different phenological phases (25% and 100% open flowers) in citrus mature trees, using 7 L of spray per tree added with Silwett L-77 adjuvant at 0.05%. For each cultivar, twenty fruits per tree were sampled in four different times to determine the soluble solids concentration (SS), titratable acidity (TA), quantity of soluble solids per 40.8 kg box, juice yield, ratio (SS/TA) and average fruit weight. The effects of MBTA varied according to the concentration and phenological phase of application. The MBTA at 8 mg L-1 concentration, sprayed on 25% of the open flowers, increased the soluble solids concentration, acidity, the quantity of soluble solids per 40.8 kg box and the yield. The same treatment also decreased the average fruit weight and did not affect the juice yield and the ratio. The average increase was from 0.49 to 0.65% on soluble solids concentration, from 0.11 to 0.13 kg on the quantity of soluble solids per 40.8 kg box and 20.4 kg/tree on yield

Crescimento radicular em sementes de trigo e arroz tratadas com Bioativador

This research aimed to evaluate the initial root growth of wheat and rice subjected to increasing doses of thiamethoxam, the doses were 0; 8.75; 17.5; 35 e 70 g a.i. per 100 kg of seeds for wheat and 0; 17.5; 35; 70 e 105 g a.i. per 100 kg of seeds for rice, applied in seeds and to growing in mini-rhizotrons placed at greenhouse. Daily evaluations began after the emergence of the root, for ten days. The bio-activator showed great variability in the response of daily root growth, when the effect was significant the increasing doses led to length reductions.Esse trabalho objetivou avaliar o crescimento inicial das raízes de trigo e arroz, submetidas a doses crescentes do tiametoxam. As doses do bioativador foram 0; 8,75; 17,5; 35 e 70 g i.a. por 100 kg de sementes para trigo e 0; 17,5; 35; 70 e 105 g i.a. por 100 kg de sementes para arroz, aplicadas via tratamento de sementes, com cultivo em mini-rizotrons alocados em casa-de-vegetação. Avaliações diárias iniciaram-se após a emergência da raiz, por um período de dez dias. O bioativador apresentou grande variabilidade na resposta do crescimento radicular diário, quando seu efeito foi significativo as doses crescentes levaram a reduções no comprimento. Root growth in wheat and rice seeds treated with bio-activatorThis research aimed to evaluate the initial root growth of wheat and rice subjected to increasingdoses of thiamethoxam, the doses were 0; 8.75; 17.5; 35 e 70 g a.i. per 100 kg of seeds for wheatand 0; 17.5; 35; 70 e 105 g a.i. per 100 kg of seeds for rice, applied in seeds and to growing in minirhizotronsplaced at greenhouse. Daily evaluations began after the emergence of the root, for tendays. The bio-activator showed great variability in the response of daily root growth, when the effectwas significant the increasing doses led to length reductions

Effect of liming and fertilization on nutritional state and dry rubber production of rubber-tree

Foram avaliados os efeitos da calagem e da adubação NPK no estado nutricional e na produção de borracha seca do clone RRIM 600. Utilizou-se o delineamento de blocos casualizados, com quatro repetições, em parcelas subdivididas. Nas parcelas foram testados duas testemunhas (sem adubação e sem calagem; sem adubação e com calagem), e seis tratamentos com calagem e adubação (N1P1K0, N2P2K0, N1P1K1, N2P2K1, N1P1K2 e N2P2K2). Os níveis anuais de NPK utilizados corresponderam a 40 e 80 kg ha-1 de N, 17,5 e 35,0 kg ha-1 de P2O5 e 0, 33,2 e 66,4 kg ha-1 de K2O. Nas subparcelas foram utilizados os sistemas de explotação ½S d/4 6 d/7 ET 2,5% LaPa 1/1 10/y e ½S d/6 6 d/7 ET 5,0% LaPa 1/1 10/y. Houve efeito significativo dos tratamentos sobre os teores de N, P, S, Cu e Zn nas folhas. A aplicação de N, nas duas doses, não elevou o seu teor nas folhas. O aumento nas doses de K2O na presença de N2P2 promoveu decréscimo no teor de zinco. A maior produção de borracha seca (1.778,9 kg ha-1), na média dos três anos, foi obtida no tratamento N2P2K1 + calagem nos dois sistemas de explotação.The effects of lime and NPK application on nutritional state and dry rubber production of clone RRIM 600 were evaluated. The experimental design was a randomized split-plot with four replicates. In the plots were tested two controls (without fertilizer and without lime; without fertilizer and with lime) and six treatments with lime and NPK fertilization (N1P1K0, N2P2K0, N1P1K1, N2P2K1, N1P1K2 and N2P2K2). The two sub-treatments were the following tapping systems: ½S d/4 6 d/7 ET 2.5% LaPa 1/1 10/y (S1) and ½S d/6 6 d/7 ET 5.0% LaPa 1/1 10/y (S2). The NPK levels used, in kg ha-1 y-1, were represented by 40 and 80 of N; 17.5 and 35.0 of P2O5 and 0, 33.2 and 66.4 of K2O. There was a significant effect of treatments on the N, P, S, Cu and Zn content in leaves. The N applied to soil up to the second dosage was not enough to increase the N level in leaves. Increasing the application of K2O, in the presence of N2P2, promoted a linear decreasing effect on the Zn level. The highest rubber yield (1,778.9 kg ha-1), as an average of the three years, was obtained with the treatment N2P2K1 plus liming, under both tapping systems

In vitro development of sugarcane seedlings using ethephon or gibberellin

The use of plant growth regulators is directly related to the success of in vitro propagation, which is an advantageous alternative to obtain seedlings on a commercial scale. This study aimed to evaluate the in vitro development of ‘IAC 95-5000’ sugarcane seedlings after the addition of different doses of ethephon (0, 25, 50, 100 and 200 mg L-1) or gibberellic acid (0, 2.5, 5.0, 7.5 and 10.0 mg L-1) to the culture medium. Ethephon increased the number of tillers (up to 231.70%), reduced height of the main tiller (44.66 to 60.47%), and did not affect the shoot´s fresh and dry mass. On the other hand, gibberellin decreased the number of tillers and negatively changed biomass partitioning. It is concluded that the use of ethephon is a potential strategy to enhance in vitro production of ‘IAC 95-5000’ sugarcane seedlings, since it increased the number of usable shoots in subsequent subcultures, and its effects on height reduction can be reversible. However, the use of the tested doses of gibberellic acid is not recommended, because it impaired seedling development of this sugarcane variety.The use of plant growth regulators is directly related to the success of in vitro propagation, which is an advantageous alternative to obtain seedlings on a commercial scale. This study aimed to evaluate the in vitro development of ‘IAC 95-5000’ sugarcane seedlings after the addition of different doses of ethephon (0, 25, 50, 100 and 200 mg L-1) or gibberellic acid (0, 2.5, 5.0, 7.5 and 10.0 mg L-1) to the culture medium. Ethephon increased the number of tillers (up to 231.70%), reduced height of the main tiller (44.66 to 60.47%), and did not affect the shoot´s fresh and dry mass. On the other hand, gibberellin decreased the number of tillers and negatively changed biomass partitioning. It is concluded that the use of ethephon is a potential strategy to enhance in vitro production of ‘IAC 95-5000’ sugarcane seedlings, since it increased the number of usable shoots in subsequent subcultures, and its effects on height reduction can be reversible. However, the use of the tested doses of gibberellic acid is not recommended, because it impaired seedling development of this sugarcane variety

Are plant growth retardants a strategy to decrease lodging and increase yield of sunflower?

One of the major disadvantages of sunflower cultivation is the increased plant height, making it prone to the lodging. The use of plant growth retardants can be an alternative strategy to reduce plant height; however, these compounds may affect productivity. The aim of this study was to evaluate the effects of plant growth retardants on sunflower development and yield. Four treatments were studied: 1- control; 2- gibberellic acid (GA) 10 mg L−1; 3- trinexapac-ethyl (TE) 5 mL L−1, and 4- maleic hidrazide (MH) 8 mL L−1. TE and MH decreased plant height (16.9 and 35.9%, respectively); however, only TE positively influenced capitulim diameter and dry mass (46.7 and 311%, when compared to control) at 60 days after planting (DAP). At 81 DAP, dry mass of capitulum did not differ among control and TE-treated plants. On the other hand, MH impaired diameter and dry mass of capitulum (92.9 and 74.7%, respectively). It can be concluded that the application of TE is a potential strategy to decrease lodging probability without affecting sunflower yield. Furthermore, although MH negatively affected sunflower development, its use on the crop cannot be excluded since other doses, frequencies and moment of application can be studied.One of the major disadvantages of sunflower cultivation is the increased plant height, making it prone to the lodging. The use of plant growth retardants can be an alternative strategy to reduce plant height; however, these compounds may affect productivity. The aim of this study was to evaluate the effects of plant growth retardants on sunflower development and yield. Four treatments were studied: 1- control; 2- gibberellic acid (GA) 10 mg L−1; 3- trinexapac-ethyl (TE) 5 mL L−1, and 4- maleic hidrazide (MH) 8 mL L−1. TE and MH decreased plant height (16.9 and 35.9%, respectively); however, only TE positively influenced capitulim diameter and dry mass (46.7 and 311%, when compared to control) at 60 days after planting (DAP). At 81 DAP, dry mass of capitulum did not differ among control and TE-treated plants. On the other hand, MH impaired diameter and dry mass of capitulum (92.9 and 74.7%, respectively). It can be concluded that the application of TE is a potential strategy to decrease lodging probability without affecting sunflower yield. Furthermore, although MH negatively affected sunflower development, its use on the crop cannot be excluded since other doses, frequencies and moment of application can be studied

Mitigation of glyphosate side effects on non-target plants: use of different agrochemicals as protectants in common bean plants Mitigação dos efeitos colaterais do glifosato em plantas não alvo: uso de diferentes agroquímicos como protetores

Objetivou-se avaliar o efeito de diferentes agroquímicos na reversão da fitotoxidez do glyphosate (Roundup WG 0,06 kg ha-1) em feijoeiro (Phaseolus vulgaris cv. Carioca), a aplicação do herbicida foi realizada em todas as plantas exceto na testemunha absoluta, aos 31 dias após o plantio (DAP), no estádio de 3° trifólio. Aos 36 DAP, as plantas foram tratadas com: ácido fúlvico 25% (1000 ml ha-1 e 2000 ml ha-1), aminoácido (500 ml ha-1 e 1000 ml ha-1), fosfito (2000 ml ha-1 e 4000 ml ha-1), além de bioestimulante (250 ml ha-1 e 500 ml ha-1). Aos 36, 40, 46 e 54 DAP foram conferidas notas às plantas e aos 54 DAP as plantas foram coletadas e determinou-se a área foliar e a massa seca de três plantas. Pelas notas conferidas verificou-se que somente a testemunha absoluta e o aminoácido 500 ml ha-1 apresentaram menores danos do que o tratamento com glyphosate. A área foliar somente mostrou-se maior na testemunha absoluta, sendo que a massa seca revelou-se superior na testemunha absoluta e nos tratamentos com aminoácido 500 e 1000 ml ha-1.AbstractGlyphosate is an herbicide widely used in agriculture. However, it may causes phytotoxic effects on non-target plants (crops), generating productivity losses. Currently there are evidences about agrochemicals as potential mitigators of glyphosate side effects. Therefore, the objective of this study was to evaluate the effects of distinct doses of fulvic acid 25% (k tionic® 1000 and 2000 mL ha-1), amino acids (Codamin BR®500 and 1000 mL ha-1), phosphite (Nutex0-30-20®, 2000 and 4000 mL ha-1) and biostimulant (Byozime TF® 250 and 500 mL ha -1) in reversion of fitotoxicity caused by glyphosate on ‘Carioca’ common bean plants. For comparison, plants treated only with glyphosate, and untreated plants (control) were also evaluated. Glyphosate spray (Roundup WG 0.06 kg ha -1) was performed at 31 days after planting (DAP), and agrochemicals were applied at 36 DAP. Phytotoxicity symptoms, as well as leaf area, dry mass of leaves andstems, and physiological indexes were evaluated at 54 DAP. Application of amino acid-based product (500 mL ha-1) significantly reduced (29.90%) phytotoxicity symptoms. Both doses of amino acid-based product increased dry mass of leaves; therefore, they were able to maintain the leaf weight ratio similar to the control plants. However, there was a decrease in leaf area, which was not reverted by any of the agrochemicals. It is concluded that application of amino acid-based product  Codamin BR 500 mL ha-1) reduces, even partially, glyphosate phytotoxicity in ‘Carioca’ common bean plants

Aplicação de KCN e linamarina e a incompatibilidade de enxertia por translocação no clone de seringueira IPA 1

To further evaluate previous indirect evidences of a role for the rubber tree cyanogenic glycosides, of which the main component is linamarin, this study evaluated the translocation incompatibility of the clone IPA 1 (Hevea brasiliensis) with budded crowns of clones of other species. Solutions of KCN were first applied, which caused rapid coagulation of the latex in the laticiphers of IPA 1, at very low concentrations, the same effect being observed in Fx 4098 at higher concentrations. The clone Fx 3864 presented no effect, only a slight reduction of the latex flow at the highest concentration. With linamarin solutions the necrosis, again preceded by latex coagulation, spread longer along the stem, indicating a higher mobility of linamarin than KCN. The clone IPA 1 behaved again sensitive to the lower concentrations of linamarin, with the higher concentrations causing the same effects on Fx 4098 and no effect on Fx 3864. With linamarin a build up of free HCN was detected in the bark of IPA 1. The incompatibility with IPA 1 is caused by the translocation of cianogenic glycosides from the budded crowns to the stem which is deprived of sufficient capacity to remove the HCN liberated by the hydrolisis of cyanogenic glicosides, while the Fx 3864 presented a very efficient detoxifying capacity.Para caracterizar evidências indiretas do envolvimento dos glicosídeos cianogênicos da seringueira, cujo principal componente é a linamarina, no desenvolvimento dos sintomas de incompatibilidade de enxertia por translocação apresentados pelo clone de painel IPA 1 (Hevea brasiliensis) em enxertos de copa com vários clones de outras espécies de Hevea, tentou-se sua reprodução através da aplicação de soluções com concentrações de cianeto de potássio (KCN) e linamarina no caule do clone IPA 1 e dos clones Fx 4098 e Fx 3864, que não apresentam reação de incompatibilidade com os mesmos clones incompatíveis com o IPA 1. A aplicação de soluções de KCN no caule provocaram rápida coagulação do látex nos laticíferos do IPA 1 com concentrações muito baixas de KCN e mais altas no Fx 4098. No Fx 3864, não houve efeito, exceto leve redução de escoamento com a dose mais alta. Os tratamentos com KCN causaram necrose apenas próximo ao local das aplicações. Com soluções de linamarina, a necrose, também precedida pela coagulação do látex, ocorreu em maior extensão do caule, o que indica maior mobilidade de linamarina, que do KCN. O IPA 1 mostrou-se, novamente, mais sensível às concentrações mais baixas de linamarina, com doses mais altas provocando os mesmos efeitos no Fx 4098 e sem ocorrência de efeitos no Fx 3864. Nos tratamentos com linamarina observou-se o acúmulo de HCN livre na casca do caule do clone IPA 1, responsável pelos sintomas observados. A incompatibilidade com o IPA 1 é provocada pela translocação de glicosídios cianogênicos das copas enxertadas no IPA 1, que não é dotado de suficiente capacidade de remoção do HCN liberado na hidrólise desses glicosídios, tendo o Fx 3864 apresentado desintoxicação mais eficiente

Ripening and senescence of papaya with 1-methilcyclopropene

Papaya (Carica papaya L.) fruits are highly perishable due the fast ripening after harvest. The search for techniques that extend the shelf life and reduce the post-harvest losses is desirable. In this study, papaya 'Sunrise Solo' fruits were harvested in two ripening stages (green and ripe) and treated with the competitive ethylene antagonist 1-methycyclopropene (1-MCP) at concentrations of 0, 30, 90 or 270 nL L-1 for 12 h at 20ºC followed by storage at room temperature (20ºC) during eight days. Application of 1-MCP (90 or 270 nL L-1) delayed degreening decay. Green fruits treated with 1-MCP (270 nL L-1) presented higher firmness in relation to control fruits. 1-MCP did not affect the soluble solids of fruits. The respiration rate and ethylene production were lower in fruits treated with 1-MCP (90 or 270 nL L-1) in both ripening stages. 1-MCP extended the shelf life of green fruits from four to six days and the shelf life of ripe fruits from two to four days. The 1-MCP was efficient to delay the ripening of papayas extending their shelf lifeO mamão (Carica papaya L.) é uma fruta altamente perecível devido ao rápido amadurecimento após a colheita. A busca de técnicas que ampliem o período de conservação e reduzam as perdas pós-colheita é desejável. Mamões 'Sunrise Solo' foram colhidos em dois estádios de maturação (verde e maduro) e tratados com o antagonista competitivo do etileno 1-metilciclopropeno (1-MCP) nas concentrações de 0, 30, 90 e 270 nL L-1, durante 12 horas a 20ºC. Após o tratamentos os frutos foram armazenados em condições ambientais (20ºC) durante oito dias. A aplicação do 1-MCP (90 e 270 nL L-1) retardou a perda de coloração verde dos frutos e a incidência de podridões. Frutos verdes tratados com 1-MCP (270 nL L-1) apresentaram maior firmeza do que os frutos controle. O 1-MCP não afetou o conteúdo de sólidos solúveis dos frutos. A taxa respiratória e a produção de etileno foram reduzidas nos frutos tratados com 1-MCP (90 nL L-1 e 270 nL L-1) em ambos estádios de maturação. O 1-MCP (90 nL L-1 e 270 nL L-1) aumentou a vida de prateleira dos frutos do estádio verde de quatro para seis dias e dos frutos maduros de dois para quatro dias. Este bloqueador da ação do etileno mostrou-se eficiente para retardar o amadurecimento de mamões e aumentar sua vida de prateleir