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Made available in DSpace on 2022-04-29T08:36:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Techniques to increase grain production such as nitrogen fertilization and plant growth regulators are essential to enable and enhance rice yield. Therefore, our goal was to evaluate the effect of nitrogen fertilization and application of trinexapac-ethyl on vegetative and reproductive traits of upland rice. Experiments were established in Registro, Brasil during the 2011 and 2014 growing seasons and treatments tested consisted of N rates (0; 50; 100; 150; and 200 kg N ha−1) and timings of TE application: V4, V7, R1 and control (without TE). Upland rice grain yield at N rates greater than 117 kg ha−1 applied as topdress combined with TE application at V7 will start to decrease grain yield. In addition, application of TE at V7 combined with N rates equal to or close to 117 kg ha−1 will lead to higher yields and shorter plants. The combination of N application at topdress combined with TE application at V4 led to a linear increase in the number of grains per panicle of rice plants. Nitrogen topdressing was found to increase plant height in the absence to TE or when TE is sprayed at V4 or R1. In addition, nitrogen topdressing had a positive increase in the number of tillers, stems, panicles, and SPAD index in rice plants. College of Agricultural and Technological Sciences São Paulo State University (Unesp), Dracena. Rod. Cmte João Ribeiro de Barros, km 651 - Bairro das Antas, Dracena São Paulo State University (Unesp) Campus of Registro, SP Tropical Root and Starches Center São Paulo State University (Unesp), SP College of Agriculture and Veterinary Sciences São Paulo State University (Unesp), SP Department of Soil Water and Climate Southwest Research and Outreach Center University of Minnesota, 23669, 130th, St. College of Agricultural and Technological Sciences São Paulo State University (Unesp), Dracena. Rod. Cmte João Ribeiro de Barros, km 651 - Bairro das Antas, Dracena São Paulo State University (Unesp) Campus of Registro, SP Tropical Root and Starches Center São Paulo State University (Unesp), SP College of Agriculture and Veterinary Sciences São Paulo State University (Unesp), SP

Water stress causes alterations in physiological and metabolic processes in plants and is considered the primary environmental factor affecting the management of sports turf grass species.This glasshouse experiment was conducted to investigate the effect of trinexapac-ethyl (TE) on canopy net photosynthesis (Pn), cell membrane stability (CMS), turf quality (TQ) and water soluble carbohydrate (WSC) accumulation responses of sports turf cultivars [Cv] (100% fescue, Rootzone and Arena sports) subjected to water stress. Commercially obtained sods of turf plants were treated with 2 L/ ha TE and then exposed 7 days after to water stress. The treatments were: (i) water untreated, (ii) water TE-treated, (iii) water stress untreated; and (iv) water stress TE-treated and the experiment was a randomized complete block design with four replicates. Results showed that specifically in Cv. Rootzone, Pn was 50% higher for well water TE treated plants compared to the other treatments during the second and third week of the study. Similarly, at 14 days after application, the effect TE resulted to 35% and 50% reduction in cell membrane leakages respectively in well water and water stressed TE-treated Cv. Rootzone plants and this was statistically significant (P=0.05) different from the untreated plants. On a scale of 1-9, all turf types recorded TQ rating of ≥8 at the start of the experiment. By the fourth week of the study, it was observed that all water stress untreated plants had mean TQ (5.75) ratings lower than the minimum acceptable TQ (6). WSC content of well-watered TE-untreated plants was maintained below 60 mg/g DW throughout the study regardless of turf type. After 28 day of water stress duration, the WSC contents obtained in water stress TE-treated plants were 41%, 43% and 50% higher for Cv. Rootzone, 100% fescue and Cv. Arena sports, respectively , than in well water untreated plants. Summer preconditioning of plants with TE can be a possible management tool in alleviating the detrimental impacts of water stress in sport turf species.

Field pea (Pisum sativum) is an important economic and rotational crop in Alberta, Canada; however, standability problems are a major barrier to increasing seeded area in highly productive growing environments. Field experiments were conducted from 2015 to 2017 at three sites in the central and Peace regions of Alberta to determine if (i) pea standability and production can be improved using inter-row seeding into untilled standing wheat stubble; (ii) pea standability and production can be improved using chlormequat chloride (CCC), trinexapac-ethyl (TXP), or ethephon (ETH) plant growth regulators (PGRs); and (iii) PGR responses are cultivar-specific. Depending on the site–year, there were 16–17 inter-row seeding, PGR, and cultivar treatment combinations arranged in a randomized complete block design. Relative to the no-stubble control, inter-row seeding into 20- or 30-cm-tall, untilled wheat stubble significantly improved standability between 6% and 23% under conditions when lodging occurred. It also reduced days to maturity and increased 1000-seed weight, but had no effect on yield. Individual PGR treatments (CCC, TXP, and ETH) generally had small and inconsistent impacts on agronomic traits, yield, and seed quality. In dry conditions, PGRs reduced yield. CDC Meadow was slightly more responsive to PGR treatments than AAC Lacombe, indicating responses may be cultivar-specific. Because of the small and inconsistent responses, PGRs have little value as an agronomic tool in field pea. Alternatively, inter-row seeding into standing wheat stubble is a low-cost, easy to implement practice for improving field pea standability.

Made available in DSpace on 2021-06-25T10:57:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Trinexapac-ethyl (TE) has recently been shown to have a stimulatory effect on the initial growth of Eucalyptus seedlings. However, the optimal dose and seedling age at which TE should be applied has not been assessed. The objective of our study was to evaluate the effects of sub-doses of TE on the initial growth of eight Eucalyptus clones. The experiment was conducted in an open area. The treatments were arranged in an 8 × 3 factorial scheme, meaning eight Eucalyptus clones and three doses of TE (0, 15 and 30 g a.i. ha-1) sprayed at 70 days after planting. Plant height, stem diameter, shoot and root dry mass, and leaf area were evaluated. Eucalyptus clones differed in their growth regardless TE application. TE did not negatively affect the growth of any clones but doses used in our study were not sufficient to give a significant positive effect on growth when applied at 70 days after planting. We suggest that older Eucalyptus seedlings need higher doses of TE to reveal potential stimulatory effects on growth of the plants. Sao Paulo State University UNESP FCAV Department of Biology Applied to Agriculture Sao Paulo State University UNESP FCAV Department of Biology Applied to Agriculture

High nitrogen rates favor maize vegetative growth and grain yield losses due to stem lodging. The use of growth regulators can mitigate such effect. This work was carried out aiming to evaluate the effect of trinexapac ethyl on maize hybrids response to side-dress nitrogen rates. The experiment was carried out in Lages, Santa Catarina State, South of Brazil, during two growing seasons with two hybrids (P1680 and P30F53), and four nitrogen rates (0, 150, 300 and 450 kg N ha-1) were tested, with and without the presence of trinexapac ethyl. The experimental design was in randomized blocks arranged in split-split plots, with three replications per treatment. The plants height and ear insertion height, plant lodging and breaking, grain yield and yield components were evaluated. Grain yield increased in a quadratic way with increased nitrogen rate. The highest grain yields were 15,784 and 15,257 kg ha-1, in 2014/15 and 2015/16, respectively. Application rates higher than 150 kg of N ha-1, regardless of the use of the plant growth regulator, promoted maximum grain yield increases, ranging from 14.7 to 18.1%. The application of trinexapac-ethyl reduced the upper stem internode length, 1000-grain dry weight and did not affect the percentage of lodged plants and grain yield of both hybrids. Therefore, the use of trinexapac-ethyl did not enhance the maize grain yield response to increased rates of side-dress nitrogen. RESUMO: Altas doses de nitrogênio favorecem o crescimento vegetativo do milho e a perda no rendimento de grãos devido ao acamamento de plantas. Este efeito pode ser mitigado pelos reguladores de crescimento. Objetivou-se com este estudo avaliar o efeito do regulador de crescimento trinexapac-ethyl na resposta de híbridos de milho as doses de nitrogênio em cobertura. O experimento foi conduzido em Lages, SC, em dois anos agrícolas, testando dois híbridos (P1630 e P30F53) e quatro doses de nitrogênio em cobertura (0, 150, 300 e 450 kg de N ha-1), com e sem o uso de trinexapac-ethyl. O delineamento experimental foi em blocos casualizados dispostos em parcelas sub-subdivididas, com três repetições por tratamento. Avaliaram-se a altura de plantas e inserção de espiga, o acamamento e quebra de plantas, o rendimento de grãos e os componentes do rendimento. O rendimento de grãos aumentou de forma quadrática com o incremento das doses de nitrogênio. Os máximos rendimentos de grãos foram de 15.784 e 15.257 kg ha-1, em 2014/2015 e 2015/2016, respectivamente. Doses maiores do que 150 kg ha-1 de N, independentemente da utilização do regulador de crescimento, promoveram, no máximo, incrementos no rendimento de grãos de 14,7% a 18,1%. A aplicação de trinexapac-ethyl reduziu o comprimento dos entrenós superiores do colmo e a massa de mil grãos, mas não interferiu na porcentagem de plantas acamadas e no rendimento de grãos. Portanto, o uso de trinexapac-ethyl não aumenta a resposta do rendimento de grãos do milho ao incremento na dose de nitrogênio em cobertura.

Establishment of seedlings of economic crops is often reduced if there is not a steady supply of water. Essential oils (EO) from plants are increasingly used instead of synthetic chemicals to protect plant and animal products against biotic and abiotic stresses. We investigated priming radish seeds by soaking or by matriconditioning with synthetic or natural compounds as a means of inducing resistance to drought stress, thus maintaining crop yield. Priming radish seeds for two hours in solutions of essential oils (EO) thymol and carvacrol derived from Origanum syriacum, with “oregano natural product” (ONP; a solution of the residue remaining after EO extraction), or with the gibberellin synthesis inhibitor trinexapac ethyl (TE), was much more effective in inducing drought resistance than was matriconditioning with the same compounds in sawdust for two days. The latter treatment induced considerable fungal and bacterial infection in treated seeds if the substrate-matrix was not heat-treated beforehand. The increase in specific leaf area in plants from treated seeds was mostly consistent with an increase in leaf water content. Seed treatments with EO, ONP, and especially TE led to a three-fold increase in radish seedling survival compared with water-treated controls, when 21 day-old seedlings were irrigated after 6 days of drought. Under drought conditions, seedlings from treated seeds had a 2–3-fold increase in relative water content increased 2–3-fold, while membrane permeability decreased 20–50-fold as a result of the treatments. However, the physical benefits of the treatments often did not correlate with treatment-induced increases in physiological parameters such as pigments (chlorophyll, carotenoid, anthocyanin), pigment ratios (chlorophyll a/b, carotenoid/chlorophyll), or antioxidant activity. Seed treatments with biostimulants can be as effective as treatments with synthetic compounds in inducing drought resistance in seedlings.

Annual bluegrass seedhead suppression on golf greens by spring-applied plant growth regulators (PGR) has been erratic between years and locations. To effectively suppress annual bluegrass seedheads on greens, current information suggest ethephon must be applied before floral initiation. Rogue seedheads, however, can sometimes be found in late winter indicating that a variable proportion of annual bluegrass plants may induce floral initiation in winter. Studies were conducted in Blacksburg and Harrisonburg, VA at five separate sites between 2011 and 2012 to determine if winter applications of ethephon or mefluidide would improve annual bluegrass seedhead suppression when applied in advance of a spring, two-treatment program. A spring, two-treatment program of ethephon plus trinexapac-ethyl reduced annual bluegrass seedhead cover 22 to 55% depending on trial and less than similar mefluidide programs. Applying an early application of ethephon in January or February prior to the spring treatment program resulted in 5 to 7 times less seedhead cover at cover maxima than the spring treatment program alone. Ethephon did not injure creeping bentgrass and caused only slight and transient discoloration to annual bluegrass. Mefluidide injured both creeping bentgrass and annual bluegrass and reduced annual bluegrass population density in late spring. Programs that consisted of an early ethephon application, a spring treatment of triademifon, and two spring treatments of ethephon plus trinexapac ethyl improved seedhead suppression and turf quality but slightly increased annual bluegrass injury. Methiozolin suppressed annual bluegrass seedheads primarily through severe injury to annual bluegrass, which led to a decline in turfgrass quality and NDVI but a substantial increase in creeping bentgrass cover. Applying PGRs in winter is a novel concept and may substantially improve ethephon consistency and performance for annual bluegrass seedhead suppression on greens.Nomenclature: Ethephon; mefluidide; methiozolin, 5-(2, 6-difluorobenzyl)oxymethyl-5-methyl-3-(3-methylthiophen-2-yl)-1, 2-isoxazoline, code names: EK-5229, SJK-03, and MRC-01; triademifon; trinexapac-ethyl; annual bluegrass, Poa annua L. POAAN; creeping bentgrass, Agrostis stolonifera L.

O uso do regulador de crescimento em aveia pode reduzir o acamamento de plantas com reflexos na produtividade de biomassa e graos. Objetivou-se, no estudo, determinar a viabilidade e a eficiencia do uso do regulador de crescimento Trinexapac-Ethyl em aveia branca em diferentes condicoes de uso de N-fertilizante e de ano favoravel e desfavoravel ao cultivo. Neste estudo, dois experimentos foram conduzidos nos anos de 2011, 2012 e 2013, um para quantificar a taxa de producao de biomassa e outro para determinacao da produtividade de graos e o acamamento. O delineamento experimental foi de blocos ao acaso com quatro repeticoes em esquema fatorial 4 x 3 para doses de regulador de crescimento (0, 200, 400 e 600 mL ha-1) e doses de nitrogenio (30, 90 e 150 kg ha-1) respectivamente. Ha reducao linear da taxa de biomassa com o incremento da dose de regulador de crescimento em aveia independente da condicao de ano e uso de N-fertilizante. No uso reduzido alto e muito alto de N-fertilizante, a dose de 495 mL ha-1 de regulador reduz com eficiencia o acamamento sem prejuizos na produtividade de graos de aveia, seja ano favoravel, intermediario ou desfavoravel ao cultivo.

The objective of this study was to evaluate the quality of seeds and yield of winter wheat under different retardants application. The two years field trials on winter wheat were carried out in the Institute of Plant Protection - National Research Institute in Poznan (Poland). Treatments consisted of trinexapac-ethyl, chlormequat and prohexadione calcium applied in mixtures with paraffin oil adjuvant or organosilicone surfactant in BBCH 31 growth stage of winter wheat. No lodging occurred in any experimental year. The retardants had varying effect on the quality parameters of wheat grain. The highest fluctuations in the content of protein, gluten and the Zeleny value were observed after the application of chlormequat chloride. Starch content in wheat grain, regardless of the retardant application method, was negatively correlated with others grain quality parameters evaluated in the experiment. Depending on the year of study and weather conditions, increased or decreased wheat quality. RESUMO: O objetivo deste estudo foi avaliar o tamanho e a qualidade do grão de trigo de inverno em condições de aplicação de diferentes retardadores e a possibilidade de os combinar com adjuvantes e herbicidas. Durante dois anos, o Instituto de Proteção de Plantas - Instituto Nacional de Pesquisa em Poznań (Polônia) realizou ensaios no campo de trigo de inverno. Os tratamentos consistiram em: trinexapac-etil ou clormequat ou prohexadiona-cálcio, aplicados em misturas com óleo adjuvante ou surfactante organossilicone na fase BBCH 31. Não se observou acamamento de plantas em nenhum ano dos ensaios. Os retardadores apresentaram efeitos variados sobre os parâmetros de qualidade do grão de trigo. As maiores variações no teor de proteínas, glúten e no índice de Zeleny foram observadas após a aplicação de clormequat. O teor de amido no grão, independentemente do retardador utilizado e do modo da sua aplicação, foi negativamente correlacionado com outros parâmetros de qualidade avaliados nos ensaios. Dependendo do ano de estudos, aumentava ou reduzia a qualidade do grão.

This study aimed to evaluate the effect of sequential applications of plant regulators on growth and seedhead emergence of Bahiagrass (Paspalum notatum). The study was carried out on a 15-month-old lawn, in a randomized block design, with four replicates. The treatments consisted of the following plant-growth regulators and dose: trinexapac-ethyl in sequential application of 113 + 113, 226 + 113, 226 + 226, 452 + 113, 452 + 226, 452 + 452 g a.i. ha-1; trinexapac-ethyl in single application of 678 and 904 g a.i. ha-1; and prohexadione-calcium in sequential application of 100 + 100 and 200 + 200 g a.i. ha-1, besides a control, with no application. The effects of treatments were evaluated based on visual injury, plant height, height and number of flower rachises and total dry matter production of clippings. Sequential applications of prohexadione-calcium at 100 + 100 or 200 + 200 g a.i. ha-1 were efficient to reduce plant height, but did not show efficacy to reduce the number and height of seedheads or the total dry matter of clippings of Bahiagrass. However, Bahiagrass lawns can be managed by trinexapac-ethyl sequential applications of 452 + 452 g a.i. ha-1 or single application of 904 g a.i. ha-1, with reduction in the need for mowing for a period of up to 113 days after application, without causing any deleterious effect on the visual aspect of the lawn. RESUMO Este trabalho teve o propósito de avaliar o efeito da aplicação sequencial de reguladores vegetais sobre o crescimento e a emissão de hastes florais da grama-batatais (Paspalum notatum). O estudo foi instalado em um gramado com 15 meses, no delineamento de blocos casualizados, com quatro repetições; utilizaram-se os seguintes inibidores de desenvolvimento vegetativo: trinexapac-ethyl em aplicações sequenciais de 113 + 113, 226 + 113, 226 + 226, 452 + 113, 452 + 226 e 452 + 452 g ia ha-1, trinexapac-ethyl em aplicação única a 678 e 904 g ia ha-1 e prohexadione-calcium em aplicações sequenciais nas doses de 100 + 100 e 200 + 200 g ia ha-1, além de um controle sem aplicação dos produtos. O efeito dos tratamentos foi avaliado quanto à injúria visual, altura de plantas, altura e emissão de hastes florais e produção de matéria seca de aparas. As aplicações sequenciais de prohexadione-calcium, independente da dose testada, foram efetivas na redução da altura de plantas mas não apresentaram eficiência na redução do número e altura de inflorescências nem na quantidade total de matéria seca produzida pela grama-batatais; entretanto, gramados formados com a grama-batatais podem ser manejados com o trinexapac-ethyl em aplicação sequencial de 452 + 452 g ha-1 ou em aplicação única na dose de 904 g ha-1, com a redução da necessidade de cortes por um período de até 113 dias após a aplicação sem que ocorra efeito deletério no aspecto visual sobre o gramado.

In Brazilian agriculture there are few reports on trinexapac-ethyl (TE) effects on maize plant lodging management. This study aimed to evaluate the effects of sequential application of TE sprayed on different plant growth stages of maize using the simple hybrid P30F53HR and the variety SCS 154 Fortuna. Experiments were carried out in a greenhouse in the 2013 and 2014 harvests. Plants were grown singly in 5L pots filled with 75% soil and 25% substrate. The experimental design was a randomized complete block with four replications. The following treatments were performed: (T1) control (no application of growth retardant); (T2) application at V2 (100 g a.i. ha-1); (T3) sequential application of 100 g a.i. ha-1 at V2 plus V3; (T4) sequential application of 100 g a.i. ha-1 at V2+V3+V4; (T5) single application of 300 g a.i. ha-1 at V4; (T6) sequential application of 100 g a.i. ha-1 at V2+V3+V4+V5; (T7) sequential application of 100 g a.i. ha-1 at V2+V3+V4+V5+V6 and (T8) sequential application of 100 g a.i. ha-1 at V2+V3+V4+V5+V6+V7. The some morphological characteristics of the two maize genotypes changed in response to TE treatment. From stage V4 onwards, maize plant height showed signs of sensitivity to the growth retardant. Plants in T8 (TE applied over V2 to V7) were more sensitive to TE with over 45% reduction in plant height compared with application T7 (applied from V2 to V6). This response was similar in both maize genotypes, thus indicating that plants are highly sensitive to TE after the V6 stage. RESUMO: Na cultura do milho há poucos relatos sobre o uso de trinexapac-ethyl (TE) visando o manejo do acamamento de plantas. Este estudo teve por objetivo avaliar diferentes doses sequenciais de TE aplicadas em diferentes estádios fenológicos da planta de milho, utilizando o híbrido simples P30F53HR e a variedade SCS 154 Fortuna. Os experimentos foram realizados em casa de vegetação em dois anos de cultivo: 2013 e 2014. Foram empregados vasos com capacidade para 5 L, preenchidos com 75% de solo e 25% de substrato comercial, com uma planta de milho por vaso. O delineamento experimental foi de blocos ao acaso com quatro repetições. Os tratamentos consistiram de: (T1) testemunha (sem aplicação de regulador); (T2) aplicação em V2 (100 g i.a. ha-1); (T3) aplicação de 100 g i.a. ha-1 em V2+V3; (T4) aplicação de 100 g i.a. ha-1 em V2+V3+V4; (T5) única aplicação de 300 g i.a. ha-1 em V4; (T6) aplicação de 100 g i.a. ha-1 em V2+V3+V4+V5; (T7) aplicação de 100 g i.a. ha-1 em V2+V3+V4+V5+V6; e (T8) aplicação de 100 g i.a. ha-1 em V2+V3+V4+V5+V6+V7. A partir do estádio V4 as plantas de milho apresentaram sinais de sensibilidade ao regulador de crescimento; a aplicação de V2 a V7 (T8), comparada à de V2 a V6 (T7), evidenciou que as plantas foram mais sensíveis ao TE, com redução superior a 45% na estatura de planta - resposta esta similar entre os dois genótipos de milho. Os resultados indicam que após o estádio V6 as plantas são altamente sensíveis ao trinexapac-ethyl.

BACKGROUND: Trinexapac-ethyl is a plant growth regulator (PGR) that inhibits the biosynthesis of plant growth hormone (gibberellin). It is used for the prevention of lodging, increasing yields of cereals, and reducing mowing of turf. The experiment was conducted to establish a determination method for trinexapac-ethyl and its metabolites trinexapac in agricultural products using LC-MS/MS.METHODS AND RESULTS: Trinexapac-ethyl and trinexapac were extracted from agricultural products with methanol/ distilled water and the extract was partitioned with dichloromethane and then detected by LC-MS/MS. Limit of detection(LOD) was 0.003 mg/kg and limit of quantification(LOQ) was 0.01 mg/kg, respectively. Matrix matched calibration curves were linear over the calibration ranges (0.01-1.0 mg/L) for all the analytes into blank extract withr2> 0.997. For validation purposes, recovery studies were carried out at three different concentration levels (LOQ, 10LOQ, 50LOQ,n

Summary Compact and well branched ornamental peppers are commercially preferred. Plant growth regulators (PGR) and pinching, removal of shoot apices, are used to create ornamentals with high aesthetic value. Trinexapac-ethyl (TE) is a foliarly absorbed plant growth regulator (PGR) and belongs to acylcyclohexadione chemical family that inhibits gibberellic acid biosynthesis. The objective of this study was to investigate possibility of using TE as a PGR in ornamental pepper (Capsicum annuum L.) production to suppress vertical growth and/or substitute for pinching to produce more compact and quality plants. The 0, 2, 4, 8, and 12 ppm TE was foliarly applied onto either pinched or non-pinched plants. Pinching and TE reduced the canopy height up to 25% and 38%, respectively. TE along with pinching reduced Height/ Diameter (H/D) ratio from 2.3 down to 1.5, a more commercially desired compactness. TE increased the chlorophyll content and total fruit number. TE may substitute costly pinching treatment for growth control. The absence of phytotoxicity and improved production may justify recommendation of TE for commercial ornamental pepper production.

The objective of this study was to evaluate the effect of growth reducer and nitrogen fertilization on morphological variables, SPAD index, radiation interception, and grain yield of three cultivars of wheat. The experimental design was a randomized block in factorial scheme 3x5x2, with three cultivars (Mestre, Iguaçú and Itaipú), five nitrogen doses (0, 40, 80, 120, 160 Kg ha-1), and application or no application of a growth reducer, with three replications. The following characteristics were evaluated: plant height, SPAD index, leaf area index (LAI), Global Radiation Interception (GRI) and grain yield. The Tukey test (p < 0.05) was used for the comparison between the means of cultivar and growth reducer factors, and for a regression analysis to evaluate N levels. Increasing the dose of nitrogen promotes an increase in LAI of plants of wheat crops differently among cultivars, which leads to a greater degree of global radiation interception. At doses higher or equal to 120 Kg ha-1 of nitrogen, there are significant differences in grain yield between treatments with and without the application of the growth reducer. The significant interaction between growth reducer and nitrogen dose, showed that applications of growth reducer increase the GRI at doses above and below 80 Kg ha-1 of nitrogen. Nitrogen rates of 138 and 109 Kg ha-1 are responsible for maximum grain yields of wheat, which is 4235 and 3787 Kg ha-1 with and without the use of growth reducer, respectively. RESUMO O objetivo deste trabalho foi avaliar o efeito de redutor de crescimento e de adubação nitrogenada sobre variáveis morfológicas, índice SPAD, interceptação de radiação global e produtividade, de três cultivares de trigo. O delineamento experimental utilizado foi o de blocos casualizados, em esquema fatorial 3x5x2, com três cultivares (Mestre, Iguaçú e Itaipú), cinco doses de nitrogênio (0, 40, 80, 120, 160 Kg ha-1) e aplicação, ou não, de redutor de crescimento, com três repetições. Avaliaram-se altura de planta, índice SPAD, índice de área foliar (IAF), interceptação de radiação global (IRG) e produtividade de grãos. Utilizou-se o teste de Tukey (p < 0,05), para a comparação entre as médias dos fatores cultivar e redutor de crescimento, e análise de regressão, para avaliação das doses de N. O aumento da dose de nitrogênio promove aumento no IAF de plantas na cultura o trigo, de forma diferenciada entre os cultivares, acarretando maior interceptação de radiação global. Em doses de nitrogênio maior ou igual a 120 Kg ha-1, há diferença significativa na produtividade do trigo entre os tratamentos com e sem a aplicação do redutor de crescimento. A interação significativa entre redutor de crescimento e dose de nitrogênio mostrou que a aplicação de redutor aumenta o IRG nas doses acima e abaixo de 80 Kg ha-1 de nitrogênio. As doses de nitrogênio de 138 e 109 Kg ha-1 são responsáveis pela produtividade máxima da cultura do trigo, sendo de 4235 a 3787 Kg ha-1, com e sem a utilização do redutor de crescimento, respectivamente.

Trinexapac-ethyl and sulfometuron-methyl are the most widely used ripeners in sugarcane. The application is performed by airborne spraying. Thus, if weather conditions are unfavorable, spray drift to neighboring areas may occur. The objective of this study was to assess the selectivity of the plant growth regulators trinexapac-ethyl and sulfometuron-methyl, used as sugarcane ripeners, to eucalyptus (Eucalyptus urograndis) young plants. The experiment was installed in an eucalyptus commercial yield area, in the municipality of Tambaú, state of São Paulo, Brazil, and arranged in a 2 x 8 factorial design in randomized blocks with four replications. The treatments studied were trinexapac-ethyl and sulfometuron-methyl, sprayed in eight doses, 0; 1.0; 2.5; 5.0; 10; 25; 50 and 100% of the dose used in sugarcane as ripeners (200 g ha-1 of trinexapac-ethyl and 15 g ha-1 of sulfometuron-methyl). Chemical ripeners were applied on eucalyptus plants with 48 cm in height on average; 10.1 branches; 4.5 mm of stem diameter and 44.3 cm of crown diameter, at 46 days after seeding. Trinexapac-ethyl was selective to eucalyptus and stimulated crown diameter growth. At higher doses, sulfometuron-methyl promoted severe noticeable injuries in eucalyptus plants, such as apical bud death. However, during the assessment period the plants recovered and the visual symptoms of phytotoxicity and growth alterations were not observed at 60 days after application. The plant growth regulators trinexapac-ethyl and sulfometuron-methyl were selective to eucalyptus young plants. Entre os maturadores, o trinexapac-ethyl e o sulfometuron-methyl são os mais usados nos canaviais. A pulverização é aérea, de modo que, se as condições meteorológicas não forem favoráveis, poderá ocorrer deriva para culturas vizinhas. Assim, objetivou-se neste trabalho avaliar a seletividade dos reguladores vegetais trinexapac-ethyl e sulfometuron-methyl, utilizados como maturadores em cana-de-açúcar, para plantas jovens de eucalipto (Eucalyptus urograndis). O experimento foi instalado em área de produção comercial de eucalipto, no município de Tambaú, SP, Brasil. O delineamento experimental foi o de blocos ao acaso, em esquema fatorial 2 x 8, com quatro repetições. Os tratamentos estudados foram trinexapac-ethyl e sulfometuron-methyl, pulverizados em oito dosagens: 0; 1,0; 2,5; 5,0; 10; 25; 50; e 100% da dose utilizada em cana-de-açúcar como maturador (200 g ha-1 de trinexapac-ethyl e 15 g ha-1 de sulfometuron-methyl). Os reguladores de crescimento foram aplicados sobre as plantas de eucalipto com 48 cm de altura, 10,1 ramos, 4,5 mm de diâmetro de caule e 44,3 cm de diâmetro de copa, aos 46 dias após o plantio. O trinexapac-ethyl foi seletivo para o eucalipto e estimulou o crescimento do diâmetro de copa. Já o sulfometuron-methyl, nas maiores doses testadas, ocasionou injúrias visuais severas às plantas de eucalipto, como a morte de gemas apicais. Contudo, no decorrer das avaliações, as plantas recuperaram-se, não sendo observados sintomas visuais de fitointoxicação ou alteração do crescimento aos 60 dias após a aplicação. Os reguladores vegetais trinexapac-ethyl e sulfometuron-methyl foram seletivos para plantas jovens de eucalipto.

This study aimed to measure the effects of rates of plant growth regulator trinexapac-ethyl on the development of the aerial, root parts and yield components of corn. The experiments were conducted in a greenhouse: one assay was aimed at evaluating the growth and development of the plant, in a 4 x 4 factorial arrangement, with four rates of trinexapac-ethyl (0, 125, 250 and 375 g of i.a. ha-1) and four assessment periods (14, 21, 28 and 35 days after application), and the other was aimed at assessing the yield productions for corn in response to the same four rates of the regulator. The present study demonstrates that grain yield per plant was reduced with the use of trinexapac-ethyl, due to decrease in spike length, number of kernels in each row and hundred grain mass. The use of trinexapac-ethyl does not change the cycle of corn, but increases stem diameter and chlorophyll index, and reduces the plant height and spike insertion height, leaf area, dry mass of aerial part, dry mass and volume root system. The trinexapac-ethyl changes the size of the corn plants, enabling new spatial arrangements. Key words: Leaf architecture, yield components, plant growth, plant growth regulator, Zea mays L.

Objetivou-se com este trabalho avaliar a eficiencia do bispyribac-sodium como maturador quimico na cultura de cana-de-acucar variedade RB86-7515. O ensaio foi realizado no delineamento em blocos casualizados, esquema com parcelas subdivididas e 4 repeticoes. Os tratamentos principais (maturadores) foram compostos por testemunha T1 (sem aplicacao), T2, T3, T4, T5, T6 (20; 22; 24; 26 e 28 g ha-1 de bispyribac-sodium, respectivamente), T7 (15 g ha-1 de sulfometuron-methyl) e T8 (200 g ha-1 de ethyl-trinexapac). Os tratamentos secundarios (subparcelas) corresponderam as epocas de amostragens aos 15; 30; 45; 60 e 75 dias apos a aplicacao (DAA) dos maturadores. Foram considerados os parâmetros fitointoxicacao, produtividade de colmos, brotacoes laterais, solidos soluveis (%Brix), pol da cana (%Pol) e acucares totais recuperaveis (ATR em kg t-1). Os maturadores foram seletivos, onde nao foi constatado fitointoxicacao, independente do tratamento. Para as variaveis produtividade de colmos, Brix e ATR, nao houve diferenca significativa entre os diferentes tratamentos quimicos. Elevados indices de brotacoes laterais foram obtidos nos tratamentos com o bispyribac-sodium aos 60 e 75 DAA. Todos os tratamentos com maturadores apresentaram incrementos significativos nos indices de Brix e Pol, sem que houvesse decrescimo na produtividade e induziram ao aumento no teor de ATR aos 45; 60 e 75 DAA, em relacao a testemunha. O bispyribac-sodium, assim como o sulfometuron-methyl e ethyl-trinexapac foram eficientes na melhoria da qualidade tecnologica e apresentam potenciais para serem utilizados como maturadores na cultura da cana-de-acucar.

Chemical ripeners are frequently used on sugarcane crops in order to increase profitability. However, the drift of these products to neighbouring fields can expose susceptible non-target plants, such as sunflower, to these agents causing indirect impacts on growth and development. Therefore, this study aimed to assess the toxicity characterize possible changes in the growth of sunflower plants exposed to simulated drift of the ripeners glyphosate and trinexapac-ethyl. For each ripener, the following doses were used: glyphosate (0 (control), 3.6, 7.2, 14.4, 28.8 and 86.4 g a.e ha-1) and trinexapac-ethyl (0, 3.12, 6.25, 12.50, 25 and 75 g a.i ha-1). The effects of these products on plant height, number of leaves, leaf area, stem diameter and dry matter (leaves, stem, flower, root, shoot and total) were evaluated. We also conducted a visual analysis of symptoms of phytotoxicity after exposure. The effects of the ripeners on sunflower plants varied depending on the type of agent used and the dose. Plants treated with glyphosate showed altered growth patterns, indicating high sensitivity of these plants to the herbicide. With increasing doses, glyphosate drift promoted lower growth and development of sunflower plants and negatively affected productivity. Nevertheless, trinexapac-ethyl drift, in the evaluated doses, did not affect sunflower plants. RESUMO Atualmente, na cultura da cana-de-açúcar, têm-se utilizado com frequência maturadores químicos, de forma a aumentar sua rentabilidade. No entanto, a deriva desses produtos pode expor plantas suscetíveis não alvo, como o girassol, impactando indiretamente o crescimento e o desenvolvimento da cultura. Portanto, objetivou-se neste estudo avaliar a intoxicação e caracterizar possíveis alterações no crescimento de plantas de girassol expostas à deriva simulada de glyphosate e trinexapac-ethyl. Para cada maturador, foram utilizadas as seguintes doses: glyphosate (0 - controle; 3,6; 7,2; 14,4; 28,8; e 86,4 g e.a ha-1); e trinexapac-ethyl: (0 - controle; 3,12; 6,25; 12,50; 25; e 75 g i.a ha-1). Foram avaliados os efeitos desses produtos sobre a altura das plantas, número de folhas, área foliar, diâmetro de caule, matéria seca (folhas, caule, flores, raiz, parte aérea e total), além de análises visuais de sintomas de fitotoxidade. Plantas de girassol apresentaram efeitos distintos em relação aos maturadores e doses; plantas tratadas com glyphosate apresentaram seu padrão de crescimento alterado, indicando sua alta sensibilidade ao herbicida. Com o aumento das doses, os resultados demonstraram que a deriva do glyphosate promoveu menor crescimento e desenvolvimento das plantas, podendo afetar negativamente sua produtividade. Contudo, a deriva do trinexapac-ethyl, nas doses avaliadas, não afetou as plantas de girassol.

The seed yield response of cocksfoot (Dactylis glomerata L.) to stem-shortening plant growth regulators (PGRs) chlormequat chloride (CCC) and trinexapac-ethyl (TE) applied during stem elongation were evaluated in eight field trials in Canterbury; five irrigated and three non-irrigated. Across all trials and treatments the average seed yield increase was 53% resulting in an extra 290 kg/ha. In irrigated trials, the average response to PGRs was 68%, resulting in an extra 380 kg/ha of seed, compared with an average 27% response in non-irrigated trials. A mixture of CCC + TE (either 750 + 100 or 1500 + 200 g active ingredient [ai]/ha), applied at Zadoks growth stage (GS) 32 or split between GS 32 and GS 37–39, provided the largest and most consistent seed yield response of 86%, an extra 450 kg/ha. Reduced lodging was a factor in one trial only. In all trials, reduced stem length was associated with increased seed yield even in the absence of lodging. Seed yields increased at 12.5 kg/ha for every cm reduction ...

To investigate the dissipation rate of trinexapac-ethyl and trinexapac in wheat ecosystem, field and microbial degradation experiments were designed and conducted. A simple and time-efficient analytical method for the determination of trinexapac-ethyl and trinexapac in wheat kernels, plants, straw and soil, using high-performance liquid chromatography–tandem mass spectroscopy (HPLC–MS/MS) was developed. The mean recoveries of trinexapac-ethyl and trinexapac in four matrices at three spiking levels ranged from 72.0% to 108.2%, and the relative standard deviation (RSD) ranged from 2.1% to 11.0%. In supervised field trials, the half-lives of trinexapac-ethyl in the plants were 0.93 and 2.36 d in Shandong and Tianjin, respectively; and those of trinexapac in soil and plants were 1.66 and 1.45 d in Shandong and 2.32 and 1.74 d in Tianjin. In microbial degradation experiment, the results show that the soil microbial communities have effects on their dissipation in the time scale employed.

As a result of the increasing popularity of fine-leafed zoysiagrasses on golf courses, a 2-year field study was conducted to assess ‘Diamond’ zoysiagrass [Zoysia matrella (L.) Merr.] putting green performance at The Cliff’s Communities Turfgrass Research Facility in Marietta, SC. Factors included four nitrogen (N) fertility rates and two trinexapac-ethyl (TE) regimes. Foliar applications of 0, 4.9, 9.8, and 14.7 kg·ha−1 N were made once weekly for 7 and 15 weeks in 2009 and 2010, respectively. Trinexapac-ethyl was tank-mixed and applied weekly for 7 weeks during July to August at 0 or 0.017 kg a.i./ha totaling 0.120 kg a.i./ha for both growing seasons. Putting green performance was measured by assessing turf quality (TQ), ball roll distance (BRD), surface firmness (SF), leaf tissue nutrient concentrations, and thatch accumulation. Turfgrasses receiving 4.9 kg N/ha weekly exhibited acceptable TQ and greater SF and BRD than plots receiving 14.7 kg N/ha weekly on all rating dates in 2010 before seasonal dormancy. Trinexapac-ethyl reduced clipping yield by 15% to 43% and influenced BRD, SF, and tissue nutrient concentration across the 2-year study. Surface firmness decreased as total N input increased during the 2010 growing season and is presumably the result of an increase in leaf tissue causing a cushioned putting surface. Linear regression of thatch accumulation and SF were analyzed and found to be significant at four rating dates in 2010 indicating that as thatch organic matter increased, SF decreased. Nitrogen input for ‘Diamond’ zoysiagrass putting greens grown in the transition zone should begin at 73.5 kg·ha−1/year with supplemental N applications applied as needed.

O acamamento das plantas de arroz aumenta sensivelmente as perdas dessa cultura, que A© ocasionado pelo fornecimento de Aigua e fertilizantes, principalmente os nitrogenados, manejados de forma inadequada. O uso de reguladores vegetais propicia reduA§A£o na altura de plantas e consequentemente no acamamento, podendo minimizar as perdas na colheita. O objetivo foi avaliar doses de nitrogAanio (N) com e sem a aplicaA§A£o de regulador vegetal em arroz de terras altas irrigado por aspersA£o. O delineamento experimental utilizado foi o de blocos casualizados, disposto em esquema fatorial 4 A— 2, com quatro repetiA§Aµes. Os tratamentos foram constituA­dos por quatro doses de N em cobertura (0, 40, 80 e 120 kg ha-1) combinadas com ou sem aplicaA§A£o de regulador vegetal. A aplicaA§A£o de 150 g ha-1 de etil-trinexapac, por ocasiA£o da diferenciaA§A£o floral, reduz a altura de plantas e o acamamento, e promove aumento da massa de 100 grA£os. O uso de doses de N em cobertura aumenta a altura de plantas e incrementa a produtividade de grA£os. O regulador vegetal interfere pouco no rendimento de engenho do arroz de terras altas. A adubaA§A£o nitrogenada em cobertura praticamente nA£o interfere no rendimento de engenho do arroz de terras altas irrigado por aspersA£o.

Trichogramma galloi Zucchi é um importante parasitoide de Diatraea saccharalis (Fabricius), principal praga da cana-de-açúcar. Como vários produtos químicos são utilizados no manejo dessa cultura, o presente trabalho objetivou avaliar a repelência de alguns produtos fitossanitários sobre adultos do parasitoide T. galloi e seu efeito na emergência dos descendentes. Os ensaios foram conduzidos em câmara climática a 23 ± 2 ºC, UR de 60 ± 10% e fotofase de 14h. Os produtos avaliados foram: inseticidas clorantraniliprole, etiprole, tiametoxam, triflumurom, lambda-cialotrina+tiametoxam, fipronil e Metarhizium anisopliae, herbicidas clomazone e diurom+hexazinona e os reguladores de crescimento de plantas sulfometurom-metílico e trinexapaque-etílico, nas maiores concentrações recomendadas à cana-de-açúcar. Para a avaliação de repelência de cada produto, realizou-se teste com livre chance de escolha, onde 30 ovos de D. saccharalis foram imersos em água destilada e outros 30 na calda do produto a ser testado. Cada uma das massas de ovos destes dois tratamentos foi transferida para um tubo de vidro, sendo os mesmos interligados por um conector de papel com um orifício central, por onde um tubo menor foi acoplado para liberação de três fêmeas de T. galloi, previamente alimentadas. O delineamento experimental foi inteiramente casualizado, com quinze repetições para cada produto avaliado. Avaliou-se a repelência, o número médio de ovos parasitados por fêmea e a emergência. Clorantraniliprole, triflumurom e sulfometurom-metílico não repeliram o parasitoide e nem afetaram o número de ovos parasitados. Para a emergência, verificou-se que os produtos M. anisopliae, tiametoxam, clomazone, diurom+hexazinona e sulfometurom-metílico não afetaram essa característica biológica.

Annual bluegrass (Poa annua L.) is a problematic weed on creeping bentgrass (Agrostis stolonifera L.) putting greens. Annual bluegrass produces extensive seedheads in spring, and plant growth regulators (PGRs) are frequently used to suppress seedhead formation. This study investigated the effects of single and sequential applications of mefluidide, maleic hydrazide, and ethephon alone or in combination with trinexapac-ethyl (TE), on annual bluegrass seedhead formation. A secondary objective evaluated whether addition of TE enhanced the efficacy of ethephon while improving the safety on creeping bentgrass. Three independent studies were established on golf course greens during a 2-yr period, with initial PGRs application before annual bluegrass seedhead formation. Regardless of PGR treatment, single or sequential applications in all studies showed no differences in annual bluegrass seedhead suppression. Ethephon-containing treatments provided the best seedhead suppression with up to 95% reduction. No PGR treatments caused visible phytotoxicity to creeping bentgrass following single applications. Sequential applications of both mefluidide and maleic hydrazide caused significant phytotoxicity to creeping bentgrass for up to 3 wk after initial treatment (WAIT). With the exception of one evaluation date in the third study, tank mixture of TE with ethephon had little effect on annual bluegrass seedhead suppression. Tank-mixing TE with ethephon marginally enhanced turf quality of creeping bentgrass up to 6% compared to ethephon alone.

O objetivo deste trabalho foi avaliar o efeito de doses do regulador de crescimento trinexapac-ethyl e níveis de adubação nitrogenada sobre o desempenho agronômico e rendimento de grãos de três cultivares de trigo. O delineamento experimental foi de blocos ao acaso, em esquema fatorial, com três repetições, sendo: duas doses de adubação nitrogenada (60 e 120 kg ha-1), três cultivares de trigo (BRS 208, BRS 220 e BRS Guamirim), quatro doses de trinexapac-ethyl (0, 70, 140 e 210 g i.a. ha-1) e duas safras agrícolas (2008 e 2009). Na microrregião de Pato Branco, a dose de 60 kg ha-1 é suficiente para maximizar o potencial de rendimento de grãos dos cultivares avaliados. Independentemente da estatura dos cultivares, o regulador de crescimento não apresentou efeito positivo sobre o rendimento de grãos, com efeito negativo na presença de menor disponibilidade hídrica. The objective of this work was to evaluate the effect of trinexapac-ethyl and nitrogen doses on the agronomic performance and grain yield of three wheat cultivars. The experiment was arranged in a randomized block design in a factorial scheme, with three replications. The treatments were two nitrogen fertilization doses (60 and 20 kg ha-1), three wheat cultivars (BRS 208, BRS 220, and BRS Guamirim), four trinexapac-ethyl doses (0, 70, 140, and 210 g a.i. ha-1) and two harvest years (2008 and 2009). In the Pato Branco microregion, the nitrogen rate of 60 kg ha-1 was sufficient to maximize the yield potential of the evaluated cultivars. Regardless of the height of the cultivar plants, trinexapac-ethyl showed no positive effect on grain yield, with negative effect under water-deficit stress.

Decreased light quantity or quality affects the growth of turfgrass plants. Shade causes thinning of turfgrass stands and loss in surface quality. Plant changes include increased chlorophyll levels, lower soluble sugars, and loss of canopy cover. The objective of this research was to investigate if applications of foliar nitrogen and trinexapac-ethyl [4-(cyclopropyl-α-hydroxy-methylene)-3,5-dioxo-cyclohexane carboxylic acid ethyl ester] (TE) would result in beneficial biochemical changes in creeping bentgrass (Agrostis stolonifera L. cv. Penncross) grown in different shaded environments. Foliar applications of three nitrogen treatments, (NH2)2CO, Ca(NO3)2, or (NH4)2SO4, were made weekly at 0.43 g N/m2. Growth regulator treatments consisted of an untreated control or TE applied biweekly at an a.i. rate of 0.057 kg·ha−1. Plots were established in full sun (FS), neutral shade (NS), and deciduous shade (DS). Chlorophyll content, soluble carbohydrates, flavonoids, clipping yield, and color were measured. Nitrogen treatments caused some variation in levels of soluble carbohydrates in shaded conditions. Chlorophyll (Chl) levels varied between TE treatments, with increased levels of chlorophyll b (Chl b) found in TE-treated plots under FS. Application of TE resulted in higher flavonoid concentrations in leaf tissue in shaded conditions. Repeated applications of (NH2)2CO significantly improved color (P = 0.05). Turfgrass managers maintaining creeping bentgrass in shade may benefit from applications of TE and (NH2)2CO.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T19:01:18Z No. of bitstreams: 1 S0103-90162012000300004.pdf: 273621 bytes, checksum: e4280d510a293074a87baa8144ed359e (MD5) Made available in DSpace on 2013-08-22T19:01:18Z (GMT). No. of bitstreams: 1 S0103-90162012000300004.pdf: 273621 bytes, checksum: e4280d510a293074a87baa8144ed359e (MD5) Previous issue date: 2012-06-01 Made available in DSpace on 2013-09-30T20:01:10Z (GMT). No. of bitstreams: 2 S0103-90162012000300004.pdf: 273621 bytes, checksum: e4280d510a293074a87baa8144ed359e (MD5) S0103-90162012000300004.pdf.txt: 34909 bytes, checksum: a97c53cce9d7a995580ebe098d1a5fcb (MD5) Previous issue date: 2012-06-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:14:40Z No. of bitstreams: 2 S0103-90162012000300004.pdf: 273621 bytes, checksum: e4280d510a293074a87baa8144ed359e (MD5) S0103-90162012000300004.pdf.txt: 34909 bytes, checksum: a97c53cce9d7a995580ebe098d1a5fcb (MD5) Made available in DSpace on 2014-05-20T13:14:40Z (GMT). No. of bitstreams: 2 S0103-90162012000300004.pdf: 273621 bytes, checksum: e4280d510a293074a87baa8144ed359e (MD5) S0103-90162012000300004.pdf.txt: 34909 bytes, checksum: a97c53cce9d7a995580ebe098d1a5fcb (MD5) Previous issue date: 2012-06-01 The aerial spraying of plant ripeners on sugar cane (Saccharum officinarum L.) crops causes often the contamination of neighboring areas, which subsidizes formal complaints from the neighbors. These contaminations are due to spraying taking place during inadequate environmental conditions or from technical mistakes during the application. One of the most important causes of this contamination is the susceptibility of the species being cultivated surrounding sugar cane. In order to evaluate the effects of sugar cane plant ripeners trinexapac-ethyl and sulfometuron-methyl on peanuts, cotton, potato, coffee, citrus, beans, sunflower, cassava, rubber, soybean, and grapes, eleven experiments - one for each species - were carried out from May 2009 to Jan. 2010. The field experiment was set according to a completely random design with five treatments and four replications. Just before or during flowering, a single treatment of trinexapac-ethyl at 100 or 200 g ha-1 and sulfometuron-methyl at 7.5 or 15 g ha-1 was applied to plants. A control treatment (plants not treated) for each species was part of each experiment. Trinexapac, at the doses of 100 and 200 g ha-1, showed selectivity to peanuts, cotton, potato, coffee, citrus, sunflower, cassava, rubber, soybean, and grape. At the lowest dose (100 g ha-1), it was selective for bean. Sulfometuron, at the dose of 7.5 g ha-1, was selective for peanuts and, at the two studied doses (7.5 and 15 g ha-1), it was selective for coffee, citrus, cassava, and rubber. UNESP FCAV, Depto Fitossanidade, BR-14884900 Jaboticabal, SP, Brazil UNESP FCAV, Depto Fitossanidade, BR-14884900 Jaboticabal, SP, Brazil

The plant growth regulator trinexapac-ethyl (TE) [4-(cyclopropyl-a-hydroxymethylene)-3,5dioxo-cyclohexanecarboxylic acid ethylester] reduces turfgrass clipping yield and enhances turfgrass color and density. Typically, such responses are achieved through alteration of N application rate, yet few have comprehensively investigated the effect of TE on turfgrass N requirements. We hypothesized that TE reduces putting green N requirements without sacrifi cing turfgrass quality. A three year study was conducted on a creeping bentgrass (Agrostis stolonifera L.) putting green with treatments consisting of three N application rates (5, 10, and 20 kg N ha–1 14 d–1) with or without TE application. To sustain season-long growth suppression, TE was applied at 0.10 kg a.i. ha–1 every 200 growing degree days (GDD; base 0°C). Turfgrass yield and color were quantifi ed every other week, and clipping tissue N content was analyzed monthly. Clipping yield, tissue N content, N removal, and color index increased with N rate. All attributes responded linearly to N application rate. Trinexapac-ethyl enhanced color while suppressing clipping yield and nutrient removal from mowing. As a result, TE reduced creeping bentgrass putting green N requirements by 25% conservatively and on several occasions by greater than 50%. W.C. Kreuser, Department of Horticulture, Cornell University, Ithaca, NY 14853; D.J. Soldat, Department of Soil Science, University of Wisconsin-Madison, Madison, WI 53706. Received 18 July 2011. *Corresponding author (wck38@cornell.edu). Abbreviations: GDD, growing degree days; TE, trinexapac-ethyl. Published in Crop Sci. 52:1348–1357 (2012). doi: 10.2135/cropsci2011.07.0364 © Crop Science Society of America | 5585 Guilford Rd., Madison, WI 53711 USA All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permission for printing and for reprinting the material contained herein has been obtained by the publisher.

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:26:22Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:42:07Z : No. of bitstreams: 1 2-s2.0-84859984005.pdf: 78095 bytes, checksum: e516cd8981478e4eae9c70474e49cebd (MD5) Made available in DSpace on 2014-05-27T11:26:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-01-01 The objective of this work was to study the morphological and physiological characteristics of the wheat flag leaf as affected by increasing sowing densities and plant growth regulators application. The experimental design was a split-plot with completely randomized blocks and four replications. Plots were consisted by four sowing densities (30, 50 70 and 90 plants m-1) and the split-plots by plant growth regulators: a product composed by auxin+gebberellin+cytokinin (Ax+GA+CK), Trinexapac-Ethyl e (Ax+GA+CK) + Trinexapac-Ethyl, and a control without application. Dry mass accumulation, plant height, morphological characteristics, SPAD index, nitrogen and photosynthetic pigments contents in the flag leaf were determined. The increase in the sowing density resulted in lower dry mass accumulation and SPAD index of the flag leaves. Trinexapac-Ethyl caused increase in the SPAD index, but the chlorophyll content of the flag leaf was reduced. The SPAD index values were more correlated with the nitrogen than the chlorophyll contents. Ax+GA+CK did not affect flag leaf characteristics in wheat plants. Universidade Estadual Paulista Júlio de Mesquita Filho Faculdade de Ciências Agronômicas de Botucatu Departamento de Produção Vegetal, Rua José Barbosa de Barros, 1780, CEP 18603-970, Botucatu-SP Universidade Estadual Paulista Júlio de Mesquita Filho Departamento de Botânica Instituto de Biociências, Distrito de Rubião Júnior, s/n, CEP 18618-970, Botucatu-SP Universidade Estadual Paulista Júlio de Mesquita Filho Faculdade de Ciências Agronômicas de Botucatu Departamento de Produção Vegetal, Rua José Barbosa de Barros, 1780, CEP 18603-970, Botucatu-SP Universidade Estadual Paulista Júlio de Mesquita Filho Departamento de Botânica Instituto de Biociências, Distrito de Rubião Júnior, s/n, CEP 18618-970, Botucatu-SP

Options for suppressing bermudagrass seedheads in managed turfgrass systems are limited. Experiments were conducted in 2009 and 2010 evaluating the use of fenoxaprop (25, 50, 75, and 100 g ha−1) for ‘Riviera’ bermudagrass seedhead suppression and growth regulation compared to imazapic (52 g ha−1), trinexapac-ethyl (91 g ha−1) and mefluidide (561 g ha−1). In field experiments, seedhead suppression ranged from 77 to 100% for fenoxaprop and imazapic at 35 d after treatment (DAT). Comparatively, seedhead suppression was < 25% for either trinexapac-ethyl or mefluidide at 35 DAT. Seedhead suppression was > 90% from 7 to 35 DAT for fenoxaprop applied at ≥ 50 g ha−1. Injury, determined visually, from fenoxaprop and imazapic in both the field and greenhouse measured < 25% on all rating dates, with no significant injury present after 21 DAT. In greenhouse experiments, fenoxaprop and trinexapac-ethyl showed similar reductions of bermudagrass growth; no differences in aboveground biomass were detected between these treatments at 42 DAT. Results of the current study illustrate that fenoxaprop and imazapic can be applied for bermudagrass seedhead suppression and growth regulation if moderate (< 25%) injury can be tolerated up to 21 DAT. Additional research is needed to evaluate the use of fenoxaprop and imazapic for seedhead suppression on other common and hybrid bermudagrasses.

Influence of growth regulators chlormequat chloride, ethephon, trinexapac-ethyl, and a combination of chlorme quat chloride and ethephon on decreasing sunflower height was examined in the years 2006–2009. Height was re duced by as much as 63 cm by double application of chlormequat chloride (915 g/ha) + ethephon (465 g/ha) at early and later growth stage (BBCH 32 and 50). Trinexapac-ethyl (375 g/ha) did not affect the height. One-time applica tion of chlormequat chloride (1440–2160 g/ha), chlormequat chloride (458 g/ha) + ethephon (233 g/ha) (BBCH 30 or 50), or ethephon (480 g/ha) (BBCH 30) was sufficient for a ca 30 cm reduction during flowering, but this effect did not last until harvest. With double application (BBCH 30 and 50), reduction lasted until harvest. For ethephon (480 g/ha), application at BBCH 50 reduced height by as much as 35 cm and lasted until harvest. Combining a lower rate of ethephon with ammonium sulfate was effectively equivalent to using a full rate. Flower head diameter at maturity showed no significant negative influence compared to the control. In 2008 and 2009, a delay in flowering onset was observed after applying growth regulators.

Lodging can be a limiting factor of hard red spring wheat (HRSW) production. The main objective of this study was to determine the optimum timing and rate of trinexapac-ethyl (TE) to improve straw strength, resistance to lodging, and related agronomic responses ofHRSW. Field experiments arranged in randomized complete blocks were conducted from 2004 to 2006 in Crookston, MN. Five TE rates (0, 62.5, 93.75, 125.0, and 250.0 g a.i. ha -1 ) and one ethephon rate (280.2 g a.i. ha -1 ) were applied at Zadoks growth stage (GS) 30, 32, or 37. Measurements included crop injury, plant height, lodging, straw strength, acid detergent lignin (ADL) content, plant maturity, plant density, and yield. Increasing TE rates linearly decreased plant height and increased lodging resistance, straw strength, and ADL content. Lodging resistance was negatively correlated with plant height and positively associated with straw strength and ADL content. The TE rate of 125 g a.i. ha -1 decreased plant height by approximately 6%, and increased plant erectness by 9% and straw strength by 13%, without causing crop injury, delaying maturity, or affecting yield. Applications of TE at GS 37 resulted in less crop injury, shorter stand, and more erect plants than those at GS 30 or 32. These data suggest that the optimum application rate and timing of TE may be 125.0 g a.i. ha -1 at GS 37 for HRSW.

Seashore paspalum is used on golf courses in warm temperate regions, but prolific growth and seedhead development may reduce turfgrass quality. Field experiments were conducted to investigate efficacy of flazasulfuron and trinexapac-ethyl on seashore paspalum seedhead suppression, clipping reduction, and canopy height. Flazasulfuron applied from 4.5 to 27 g ai ha−1 increased clipping reductions from the untreated by 22 to 75% and seedhead suppression from the untreated by 16 to 86% at 2 to 4 wk after treatment. Trinexapac-ethyl applied alone at 96 g ai ha−1 provided erratic levels of seedhead suppression from the untreated, but reduced clippings by approximately 50 to 75% from nontreated by 2 to 4 wk after treatment. On several dates, trinexapac-ethyl enhanced clipping reductions and seedhead suppression from flazasulfuron compared to flazasulfuron alone. Trinexapac-ethyl exacerbated seashore paspalum injury from high flazasulfuron rates (18 to 27 g ha−1) but injury never exceeded 23%. Trinexapac-ethyl reduced seashore paspalum height by 50% in unmowed areas at 16 wk. Flazasulfuron at 16 or 27 g ha−1 with trinexapac-ethyl provided consistent seedhead suppression and clipping reductions ranging from approximately 70 to 95% of nontreated. These tank-mixtures have promising implications for use in seashore paspalum golf course fairways.

Studies aimed at improving production and yield of bush snap beans are desirable; the results may provide growers with new techniques to improve profitability. In the literature, there are few reports on the productive performance of vegetables subjected to doses of glyphosate and plant regulators. Thus, this study aimed to evaluate the effect of glyphosate, trinexapac-ethyl, and mepiquat chloride doses on the production components and yield of bush snap beans. We tested various doses: a) glyphosate: 0.0; 18.0; 36.0; 72.0; and 144.0 g acid equivalent (ae) ha-1; b) trinexapac-ethyl: 0.0; 62.5; 125.0; 250.0; and 500.0 g ae ha-1; and c) mepiquat chloride: 0.0; 25.0; 50.0; 75.0; and 100.0 g ae ha-1. The experimental design was completely randomized, with four replications per treatment. We evaluated plant height, stem diameter, number and mass of pods per plant, mass, length, and diameter of pod, and yield. The analysis of variance was conducted by applying the F test, and the doses were submitted to regression analysis (p < 0.05). Each active ingredient was considered separately. Productive performance was favored by using doses up to 16.0 g ae ha-1 of glyphosate, showing increased pod mass per plant and yield. As trinexapac-ethyl doses increased, the number of pods per plant decreased but mean pod mass increased. Doses of mepiquat chloride up to 59.5 g ae ha-1 increased mean pod mass. Finally, pod yield was not influenced by trinexapac-ethyl and mepiquat chloride.

Prohexadione-calcium and trinexapac-ethyl, inhibitors of 2-oxoglutaric acid-dependent dioxygenases, were tested for their efficacy in controlling scab infection on apple (cv. Golden Delicious) scions under greenhouse and field conditions. Their effectiveness was compared with other types of growth inhibitors (chlormequat chloride and paclobutrazol). Furthermore, to determine the time required to build-up plant resistance against scab, the compounds were applied at different concentrations and timings prior the inoculation with Venturia inaequalis . Prohexadione-calcium and trinexapac-ethyl significantly reduced scab incidence starting approximately 10 and lasting for approximately 25 days after application. In field conditions, the practical application of these compounds may result valuable both to control the vegetative/reproductive balance of the trees and to effectively reduce the amount of fungicides used to control scab.

O acamamento de plantas na cultura do trigo tem sido controlado com o uso de redutores de crescimento. No entanto, há carência de informações sobre o efeito desses produtos na qualidade fisiológica de sementes. O objetivo deste estudo foi avaliar a qualidade fisiológica das sementes de trigo obtidas sob efeito de doses e épocas de aplicação de três redutores de crescimento. O experimento, conduzido em Viçosa, Minas Gerais, entre maio e setembro de 2005, foi instalado com tratamentos em esquema fatorial e hierárquico com uma testemunha, no delineamento em blocos casualizados, com quatro repetições. Os tratamentos foram 500, 1000 e 1500g ha -1 de clormequat; 40, 80 e 120g ha -1 de paclobutrazol e 62,5, 125 e 187,5g ha -1 de trinexapac-etil aplicados no estádio 6 ou 8 da escala Feeks e Large, mais uma testemunha sem aplicação de redutor. A aplicação foliar dos redutores de crescimento clormequat, paclobutrazol e trinexapac-etil não afeta a germinação e o vigor das sementes de trigo. Plant lodging in wheat has been controlled through growth retardants. However, there is lack of information on the effect of these products on the physiological quality of seeds. The objective of this study was to evaluate the physiological quality of wheat seeds obtained under different rates and application times of three growth retardants. The trial was carried out in Viçosa-MG, from May to September 2005, in a factorial and hierarchical scheme, in randomized block design with four replications and a control treatment. The treatments consisted of 500, 1000 and 1500g ha-1 of chlormequat; 40, 80 and 120g ha-1 of paclobutrazol and 62.5, 125 and 187.5g ha-1 of trinexapac-ethyl applied at the 6 or 8 growth stage based on the scale of Feeks and Large, and a control treatment without growth retardant application. Leaf application of growth retardants as chlormequat, paclobutrazol and trinexapac-ethyl did not affect the germination and vigor of wheat seeds.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T19:00:10Z No. of bitstreams: 1 S0103-84782010000200004.pdf: 158518 bytes, checksum: fcf2fb7cd77e5f11e98527be0304be47 (MD5) Made available in DSpace on 2013-08-22T19:00:10Z (GMT). No. of bitstreams: 1 S0103-84782010000200004.pdf: 158518 bytes, checksum: fcf2fb7cd77e5f11e98527be0304be47 (MD5) Previous issue date: 2010-02-01 Made available in DSpace on 2013-09-30T19:58:11Z (GMT). No. of bitstreams: 2 S0103-84782010000200004.pdf: 158518 bytes, checksum: fcf2fb7cd77e5f11e98527be0304be47 (MD5) S0103-84782010000200004.pdf.txt: 25251 bytes, checksum: 092f08c20a3e45fb4cd0c99ae6bbaef7 (MD5) Previous issue date: 2010-02-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T15:15:02Z No. of bitstreams: 2 S0103-84782010000200004.pdf: 158518 bytes, checksum: fcf2fb7cd77e5f11e98527be0304be47 (MD5) S0103-84782010000200004.pdf.txt: 25251 bytes, checksum: 092f08c20a3e45fb4cd0c99ae6bbaef7 (MD5) Made available in DSpace on 2014-05-20T15:15:02Z (GMT). No. of bitstreams: 2 S0103-84782010000200004.pdf: 158518 bytes, checksum: fcf2fb7cd77e5f11e98527be0304be47 (MD5) S0103-84782010000200004.pdf.txt: 25251 bytes, checksum: 092f08c20a3e45fb4cd0c99ae6bbaef7 (MD5) Previous issue date: 2010-02-01 A mangicultura no semiárido brasileiro destaca-se pelos altos rendimentos, pela qualidade do fruto produzido e pela possibilidade de produção durante todo o ano, devido a condições climáticas e tecnologias para o manejo do crescimento vegetativo e da floração, com uso da irrigação, podas e retardantes vegetais. O paclobutrazol aplicado ao solo é utilizado no manejo da produção da mangueira na maioria dos pomares. Entretanto, há a necessidade de identificar retardantes vegetais que possam ser aplicados via foliar, de forma a minimizar os resíduos no solo e evitar o uso de quantidades inadequadas ao longo dos anos. Assim, este trabalho teve como objetivo avaliar retardantes vegetais aplicados via foliar na inibição do crescimento vegetativo de mudas de mangueira 'Tommy Atkins'. Prohexadione-Ca, etil-trinexapac e cloreto de chlormequat, aplicados via foliar, na dose de 1g i.a. planta-1, regulam o crescimento de ramos vegetativos, mas apresentam tempo diferenciado de atividade nas mudas, sendo 20 dias para prohexadione-Ca, 30 dias para cloreto de chlormequat e 45 dias para etil-trinexapac, nas condições em que o experimento foi conduzido. The mango in the Brazilian semi-arid region stands out in the national scenario due to high yields and fruit quality, as well as to the possibility of all-year production due to climatic conditions and technologies which allow the management of plant growth and flowering through irrigation, pruning and use of plant growth regulators. Paclobutrazol applied to the soil is used for the production management of mangoes in most of the orchards. However, it is necessary to identify plant growth regulators which might be applied to the leaves, so as to minimize the risk of residues in the soil and to avoid inadequate application levels over several years. The present paper aimed at evaluating the effect of plant growth regulators applied to the leaves, regarding their efficiency for flowering management of mango 'Tommy Atkins'. Prohexadione-Ca, trinexapac-ethyl and chlormequat chloride at the dosage of 1.0 g a.i. plant-1 acts on the regulation of vegetative growth; the period of efficiency of the products applied to the leaves lasted 20 days for prohexadione-Ca, 30 days for chlormequat cloride, and 45 days for trinexapac-ethyl. Empresa Brasileira de Pesquisa Agropecuária Semiárido Universidade Estadual Paulista Instituto de Biociências Departamento de Botânica Universidade Estadual Paulista Instituto de Biociências Departamento de Botânica

Trinexapac-ethyl (TE) [4-(cyclopropyl-α-hydroxy-methylene)-3,5-dioxocyclohexanecarboxylic acid ethyl ester] and paclobutrazol (PAC) [(2RS,3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-tri-azol-1-yl)pentan-3-ol] are routinely used to suppress clipping production. Single-leaf turfgrass C exchange rates (CERs) in response to plant growth regulator (PGR) treatment have not been characterized. Individual Kentucky bluegrass (KBG, Poa pratensis L.) plants received label rates of TE or PAC and were placed in growth chambers at 23/18 or 30/25°C. Photosynthetic efficiency and CER measurements were recorded every 4 d for 44 d. Total root length (TRL), root surface area (SA), and average root diameter were measured at the end of the study. Reductions in CERs of TE- or PAC-treated plants were short lived with CERs suppressed 17 to 29% of control (POC) at 4 and 12 days after treatment (DAT), respectively. Plants treated at 23/18°C with PGRs typically had short-lived increases in CERs following CER suppression. A similar pattern of CER response to PGR treatment was observed at the 30/25°C temperature regime. Quantum efficiency was unaffected, but plants treated with PGRs had reduced root growth. PAC caused the greatest reduction in TRL and SA while increasing root diameter. A decline in TRL and SA in conjunction with increased tillering indicates that PGR reduced TRL and SA on a tiller basis. Changes in single-leaf CERs do not fully explain PGR-induced changes in plant growth.

Dwarf-type bermudagrasses [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davey] tolerate long-term golf green mowing heights but require heavy nitrogen (N) fertilizations. Inhibiting leaf growth with trinexapac-ethyl (TE) could reduce shoot growth competition for root reserves and improve nutrient use efficiency. Two greenhouse experiments evaluated four N levels, 6 (N6), 12 (N12), 18 (N18), and 24 (N24) kg N/ha/week, with TE at 0 and 0.05 kg·ha–1 a.i. every 3 weeks to assess rooting, nutrient allocation, clipping yield, and chlorophyll concentration of `TifEagle' bermudagrass grown in PVC containers built to U.S. Golf Association specification. Trinexapac-ethyl enhanced turf quality on every date after initial application. After 8 weeks, high N rates caused turf quality decline; however, TE treated turf averaged about 25% higher visual quality from nontreated turf, masking quality decline of high N fertility. `TifEagle' bermudagrass treated with TE had clippings reduced 52% to 61% from non-TE treated. After 16 weeks, bermudagrass treated with TE over all N levels had 43% greater root mass and 23% enhanced root length. Compared to non-TE treated turf, leaf N, P, and K concentrations were consistently lower in TE treated turf while Ca and Mg concentrations were increased. Root N concentrations in TE treated turf were 8% to 11% higher for N12, N18, and N24 fertilized turf than respective N rates without TE. Compared to non-TE treated turf, clipping nutrient recoveries were reduced 69% to 79% by TE with 25% to 105% greater nutrients recovered in roots. Bermudagrass treated with TE had higher total chlorophyll concentrations after 8 and 12 weeks. Overall, inhibiting `TifEagle' bermudagrass leaf growth appears to reallocate nutrients to belowground tissues, thus improving nutrient use efficiency and root growth. Chemical name used: trinexapac-ethyl, [4-(cyclopropyl-[α]-hydroxymethylene)-3,5-dioxo-cyclohexane carboxylic acid ethylester].