R E S U M OA expressão dos caracteres de produção do trigo depende de estímulos genéticos e ambientais. Portanto, objetivou-se avaliar, neste estudo, a expressão de caracteres de produção em trigos a partir de sua aptidão tecnológica para elucidar se cultivares com maior valor de alveografia também exigem maior fornecimento de N na elaboração dos componentes de produtividade de grãos em distintos sistemas de cultivo. O delineamento experimental foi o de blocos ao acaso com quatro repetições no esquema fatorial 2 x 4, para as cultivar [BRS Guamirim (classe básico) e Fundacep Cristalino (classe melhorador)] e doses de nitrogênio [0, 60, 120, 180 kg ha -1 (sistema milho/trigo) e 0, 40, 80, 120 kg ha -1 (sistema soja/trigo)]. O maior fornecimento de N-fertilizante na elaboração dos componentes de produção de trigo não tem apoio na classe tecnológica da cultivar, independentemente do sistema de cultivo; assim, cultivares de trigo de elevada qualidade tecnológica podem expressar valores médios nos componentes de produção superiores àqueles de menor qualidade.The expression of the components of wheat yield by technological class and nitrogen use A B S T R A C TThe expression of the characteristics of wheat production depends on the genetic and environmental stimuli. Therefore, the objective of the study was to evaluate the expression of production traits in wheat from its technological ability to elucidate whether cultivars with the highest alveography also require greater supply of N in the preparation of the components of grain yield in distinct cropping systems. The experimental design adopted was a randomized block with four replications in a factorial 2 x 4, consisting of two cultivars [BRS Guamirim (basic class) and Fundacep Cristalino (improver class)] and four levels of nitrogen [0, 60, 120, 180 kg ha -1 (corn/wheat system) and 0, 40, 80, 120 kg ha -1 (soybean/ wheat system)]. The highest supply of N-fertilizer in the preparation of components of wheat production has no support in the technological class of the cultivar regardless of the cropping system. Therefore, cultivars of high quality wheat technology can express the components of mean values higher than those from lower quality produce. Palavras-chave:Triticum aestivum L. classe tecnológica nitrogênio relação C/N

RESUMO A produção de biomassa de aveia voltada à elaboração de silagem de qualidade é dependente de elementos climáticos e nitrogênio sem ocorrência de acamamento. O objetivo do presente estudo é a definição da dose ideal do regulador de crescimento que possibilite, no máximo, 5% de acamamento de plantas de aveia, bem como a identificação das variáveis potenciais para composição do modelo de regressão linear múltipla com simulação da produtividade de biomassa à elaboração de silagem nas condições de uso do regulador, em reduzida, alta e muito alta fertilização com nitrogênio. O estudo foi conduzido em 2013, 2014 e 2015, em delineamento de blocos ao acaso, com quatro repetições em esquema fatorial 4x3, para doses de regulador (0, 200, 400 e 600mL ha-1) e doses de nitrogênio (30, 90 e 150kg ha-1), respectivamente. A dose de 495mL ha-1 de regulador se mostra eficiente na redução do acamamento de plantas de aveia em condição de reduzida, alta e muito alta fertilização com nitrogênio. A soma térmica, a precipitação, a radiação, a dose de regulador e o nitrogênio qualificam a composição do modelo de regressão linear múltipla, tornando eficiente a simulação da produtividade de biomassa da aveia para silagem ao longo do ciclo.

The retainers of water in the soil can favor nitrogen (N) use efficiency in oat yield. The aim of the study was to determine if the conditions of use of the biopolymer hydrogel increase the fertilizer-N use efficiency in oat yield in succession systems of high and low residual-N release. In each succession system (soybean/oat, corn/oat), two experiments were conducted in 2014 and 2015, one to quantify biomass yield and the other to estimate grain yield and lodging. The design was randomized blocks with four replicates in a 4 x 4 factorial scheme for hydrogel doses (0, 30, 60 and 120 kg ha-1), added in the furrow with the seed, and N fertilizer doses (0, 30, 60 and 120 kg ha-1) applied in the fourth-expanded-leaf stage. The use of hydrogel increases N use efficiency in oat yield, especially under the conditions of 30 to 60 kg ha-1 of biopolymer; however, this effect is dependent on the succession system and on weather conditions.

Studies on efficient use of the plant growth regulator can make this technology possible for leveraging oat yield in Brazil. This study aims to define the optimal dose growth regulator in oat, which allows plant lodging at most 5%. Establishing equations describe the yield indicators behavior and by using the optimal growth regulator dose for lodging, simulate the expression of these indicators regardless of reduced, high and very high conditions of nitrogen fertilization and favorable and unfavorable cultivation year. The study was conducted in 2013, 2014 and 2015, in carrying out two experiments, one to quantify the biomass yield and another aiming at estimating grain yield and lodging. The experimental design was a randomized block with four replications, following factorial scheme 4 x 3 to growth regulator doses (0, 200, 400 and 600 mL ha ), respectively. The use of 495 mL ha -1 growth regulator trinexapac-ethyl active principle is shown efficient at the reduction of oat plant lodging, regardless of the agricultural year condition and N-fertilizer rate. In the expression of grain yield and harvest index, quadratic behavior is obtained, however with decreasing linearity on the biomass yield and straw by increasing the growth regulator dose. The optimal dose of growth regulator in reducing oat lodging does not affect grain yield, but it reduces biological yield via biomass straw with elevation on the harvest index.

The use of growth regulator in oats can reduce plant lodging with reflections in biomass and grain yield. The objective of the study was to determine the feasibility and efficiency of using Trinexapac-Ethyl regulator in the growth of white oat under different conditions of N-fertilizer and years favorable and unfavorable for cultivation. In this study, two experiments were conducted in the years 2011, 2012 and 2013, one for quantifying biomass production rate and the other for the determination of grain yield and lodging. The experimental design was randomized blocks with four replicates, in a 4 x 3 factorial scheme, for growth regulator doses (0, 200, 400 and 600 mL ha-1) and nitrogen doses (30, 90 and 150 kg ha-1), respectively. There is a linear reduction of biomass rate with the increase in the growth regulator dose in oat, regardless of the condition of year and use of N-fertilizer. The growth regulator dose of 495 mL ha-1 efficiently reduces lodging with reduced, high and very high use of N-fertilizer, without reducing the yield of oat grains, in favorable, intermediate or unfavorable year for cultivation.

A B S T R A C TThe simulation of oat development cycle can be used in the planning of agricultural practices. The aim of the study was to simulate and validate the duration of oat development cycle by photoperiod, temperature and coefficients of development of wheat for use in the WEStreck model, considering different doses of N-fertilizer and systems of succession of high and low C/N ratio. The study was conducted in 2015 in a randomized block design with four replicates in a 4 x 2 factorial scheme, corresponding to N rates (0, 30, 60 and 120 kg ha -1 ) and oat cultivars (Barbarasul and Brisasul), respectively, in the soybean/oat and maize/ oat systems. The duration of the stages from emergence to anthesis and from anthesis to maturation of oats was simulated in the WE-Streck model. The minimum, optimum and maximum temperatures that effectively simulate the oat development cycle were 4, 22 and 30 °C from emergence to anthesis and 15, 25 and 35 °C from anthesis to maturation, respectively. The intermediate-cycle oat development was efficiently simulated by the WEStreck model using coefficients developed for wheat, with vegetative and reproductive cycles estimated at 89 and 43 days, respectively. Simulação do ciclo de desenvolvimento da aveia por fotoperíodo e temperatura R E S U M OA simulação do ciclo de desenvolvimento da aveia pode ser utilizada no planejamento de práticas agrícolas. Objetivou-se simular e validar a duração do ciclo de desenvolvimento da aveia por intermédio de fotoperíodo, temperatura e coeficientes de desenvolvimento do trigo para uso no modelo WE-Streck, considerando diferentes doses de N-fertilizante e sistemas de sucessão de alta e reduzida relação C/N. O estudo foi conduzido em 2015, em delineamento de blocos casualizados com 4 repetições em esquema fatorial 4 x 2 para doses de nitrogênio (0, 30, 60 e 120 kg ha -1 ) e cultivares de aveia (Barbarasul e Brisasul), respectivamente, no sistema soja/aveia e milho/aveia. No modelo WE-Streck foi simulada a duração das fases emergência à antese e antese à maturação da aveia. As temperaturas mínima, ótima e máxima que simulam com eficiência o ciclo de desenvolvimento da aveia da emergência à antese, foram 4, 22 e 30 °C, respectivamente e da antese à maturação 15, 25 e 35 °C, respectivamente. A simulação do desenvolvimento da aveia de ciclo médio pelo modelo WE-Streck foi eficiente usando coeficientes desenvolvidos para o trigo, com ciclo vegetativo e reprodutivo estimado em 89 e 43 dias, respectivamente.

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The biomass productivity and wheat grains efficiency is determined by nitrogen dose adjustment (full or fractioned), environmental conditions, and cropping system. The aim of this study was to improve the efficiency of N-fertilizer usage on wheat to maximize the biomass productivity and grain yield by adjusting the full or fractioned nitrogen dose in favorable and unfavorable year conditions, in succession systems with high and reduced N-residual release. In this study, two experiments were conducted between 2012 and 2014. One was to quantify the biomass productivity rate and another to determine grain yield. The experimental design was a complete randomized block, with four replications, in a 4 × 3 factorial scheme to N fertilizer rates (0, 30, 60 and 120 kg ha-1) and supply forms of the nutrient [full dose (100%) in the V 3 phenological stage (third expanded leaf); fractioned (70 and 30%) at the V 3 and V 6 phenological stages (third and sixth expanded leaf, respectively) and; fractionated (70 and 30%) at the V 3 and E phenological stages (third expanded leaf and early grain filling), ] respectively, in soybean/wheat and maize/wheat cultivation systems. The nitrogen supply in wheat through single dose or fraction indicates linear tendency over the productivity biomass daily rate-1 with the increase of N-fertilizer, regardless of a favorable and unfavorable year and system of a succession of the high and reduced N-residual release. However, in favorable years, the use of full dose on V 3 stage is indicated. In the maize/wheat system, the full dose at V 3 stage is more efficient, especially with higher doses of the nutrient. For grain yield, the N-fertilizer fractioning was adjusted in intermediate cropping years, while the full dose became suitable at the V 3 stage in favorable years. However, in unfavorable years, nitrogen investments should be minimized, regardless of the supply form and succession system.