ABSTRACT The objective of the work was to evaluate the response of growth and production, the interception efficiency of photosynthetically active radiation, the extinction coefficient, and the productivity components of sunflower in with the use of cover nitrogen doses in subtropical environments. The experiment was conducted at Santa Maria-RS, Brazil, where they were evaluated the leaf area index (LAI), interception efficiency (εi), and extinction coefficient (k) of photosynthetically active radiation (PAR), plant height (PH), chapter diameter (CPD), stem diameter (SD), the mass of one thousand achenes (MTA), and grain productivity (PROD) were evaluated. Nitrogen doses influenced the LAI only at 52 and 65 DAE, while the canopy interception efficiency (CIE) was influenced at 36, 42, 52, and 86 DAE. Therefore , for growth and production doses of cover N positively influence stem diameter and grain productivity. The application of cover nitrogen fertilizer linearly and positively affects the sunflower crop, and 160 kg ha-1 N. Interception efficiency of photosynthetically active radiation by the canopy and the leaf area index are positively influenced by the doses of nitrogen in the canopy. The extinction coefficient of the photosynthetically active radiation in sunflower decreases with the increasing dose of cover N.

ABSTRACT The flaxseed is little explored under Brazilian cultivation conditions, generating a gap in information about the appropriate management of the crop, in the country. Hence, the objective was to find the appropriate dose of nitrogen for the development of the variables: technical length, yield length, main stem diameter, number of grains per pod, plant grain yield, and plant dry mass of two flaxseed varieties, brown and golden, in places with subtropical and tropical climate in Brazil. The treatments consisted of a two-factor 2 x 6 experiment, consisting of two flax varieties (brown and golden) and six nitrogen doses (0; 30; 60; 90; 120 and 150 kg ha-1), in randomized blocks with four repetitions and three different environments: Santa Maria and Frederico Westphalen, in the state of Rio Grande do Sul, and Viçosa, in the state of Minas Gerais. The brown variety obtained greater technical and yield length compared to the golden variety, on the other hand, the golden variety showed a higher number of grains per capsule and higher plant grain yield compared to the brown variety, in the three environments. The plant dry mass increased linearly and proportionally to the increase in nitrogen doses in Santa Maria and Frederico Westphalen environments. Therefore, flaxseed responds differently to nitrogen supplementation according to the cultivation environment, showing wide variability. The different doses of nitrogen influenced the variables analyzed and the varieties of flaxseed differently, depending on the environment.

Abstract UFSMFW 2202 is an early black oat cultivar with high dry matter and grain yield potential. When used in rotation systems, the early cycle has the immediate advantage of allowing anticipated sowing of subsequent crop. Initially, the cultivar is recommended for the North and Northwest of Rio Grande do Sul.

Abstract The black oat cultivar UFSMFW 2101, recommended for Northwest of the state of Rio Grande do Sul, is very early and can produce high dry matter and grain yields. In rotation systems, an immediate advantage is the very early cycle, with the possibility of anticipated sowing of the subsequent crop.

ABSTRACT The interception of photosynthetically active radiation (PAR) is a key factor for biological productivity, and its magnitude depends on the availability of solar radiation, the stage of the plant development cycle, and the arrangement of plant structures. Given the arrangement of the vegetative and reproductive structures in different portions in the canola canopy, the objetive of the study was to morphologically characterize canola cultivars and establish relationships with the stratification of the efficiency of PAR intercep tion. Eight canola cultivars were evaluated in regards to PAR and plant morphological traits. Following the analysis of variance, treatment means were grouped, and the phenotypic correlation matrix between the traits was determined. We observed a strong relationship between the PAR interception efficiency of vegetative and reproductive structures with morphological traits. Plants with a higher number of branches have more siliques and greater efficiency of PAR interception, mainly through the reproductive structures. The characterization of morphological differences between canola cultivars in the PAR interception efficiency should be performed by measures stratified by vegetative and reproductive structures.

RESUMEN La interceptación de radiación fotosintéticamente activa (ARF) es importante para la productividad biológica y su magnitud depende de la disponibilidad de radiación solar, la etapa del ciclo de desarrollo de la planta y la disposición de las estructuras de la planta. Dada la disposición de las estructuras vegetativas y reproductivas de la canola en diferentes porciones del perfil del dosel de las plantas, el objetivo del trabajo fue buscar la caracterización morfológica de cultivares de canola y establecer relaciones con la estratificación de la eficiencia de interceptación de la radiación fotosintéticamente activa. Se evaluaron ocho cultivares de canola, se midió la ARF y se evaluaron los caracteres morfológicos de la planta. Se realizaron análisis de varianza, agrupamiento de medias y se determinó la matriz de correlación fenotípica entre los caracteres. Se observó una alta relación entre la eficiencia de interceptación de la RFA de estructuras vegetativas y reproductivas con caracteres morfológicos. Las plantas con mayor número de ramas tienen más sílice y mayor eficiencia en la interceptación de la radiación fotosintéticamente activa, principalmente debido a las estructuras reproductivas. La caracterización de las diferencias morfológicas entre cultivares de canola en la eficiencia de interceptación de la RFA debe realizarse mediante medidas estratificadas por estructuras vegetativas y reproductivas.

ABSTRACT The cultivation of second-harvest with soybean crop after first-harvest with maize crop has become an alternative to aggregate income to farmers in the South region of Brazil. However, there is little information about this cropping system in this region. The aims of this study were to: (i) evaluate the agronomic performance of soybean (Glycine max L.) cultivars growing in second-harvest during the summer; and (ii) evaluate the genetic divergence of the cultivars based on qualitative and quantitative traits. To do this, 18 soybean cultivars were evaluated in three field trials, sown during January in the northwestern region of Rio Grande do Sul state, Brazil. In each experiment, a randomized block design with four replicates was used. Five quantitative traits (representing the agronomic performance of the cultivars) and 12 qualitative traits (morphological descriptors) were assessed aiming at studying the genetic divergence. Variance components and genetic parameters were estimated using mixed models and BLUPs for genotypes were estimated for each quantitative trait. The cultivars FPS Iguaçu RR and BMX Turbo RR have good agronomic performance and are, based on quantitative and qualitative traits, genetically distant. These cultivars have shown agronomic features that allow their cultivation in the second-harvest in the northwestern of Rio Grande do Sul in addition to be potential genitors for future soybean breeding programs.

ABSTRACT This study aims to determine the most suitable model to estimate the leaf area of dwarf pigeon pea in function of the leaf central leaflet dimension. Six samplings of 200 leaves were performed in the first experiment, at 36, 42, 50, 56, 64, and 72 days after emergence (DAE). In the second experiment, seven samplings of 200 leaves were performed at 29, 36, 43, 49, 57, 65, and 70 DAE, totaling 2600 leaves. The length (L) and width (W) of the central leaflet were measured in all leaves composed by left, central, and right leaflets, the product of length times width (LW) was calculated, and the leaf area (Y – sum of left, central, and right leaflet areas) was determined by digital images. Linear, power, quadratic, and cubic models of Y as function of L, W, and LW were built using data from the second experiment. Leaves from the first experiment were used to validate the models. In dwarf pigeon pea, the linear (Ŷ = – 0.4088 + 1.6669x, R2 = 0.9790) is preferable, but power (Ŷ = 1.6097x1.0065, R2 = 0.9766), quadratic (Ŷ = – 0.3625 + 1.663x + 0.00007x2, R2 = 0.9790), and cubic (Ŷ = 0.7216 + 1.522x + 0.005x2 – 5E–05x3, R2 = 0.9791) models in function of LW are also suitable to estimate the leaf area obtained by digital images. The power model (Ŷ = 5.2508x1.7868, R2 = 0.95) based on the central leaflet width is less laborious because requires only one variable, but it presents accuracy reduction.

ABSTRACT The objectives of this work were to determine the optimum plot size and number of repetitions to evaluate the fresh matter weight of vetch (Vicia sativa L.) in sowing densities. Fortyeight uniformity trials of 6 m × 6 m were conducted. Sixteen trials were evaluated in each sowing density (40, 60, and 80 kg∙ha−1). Each trial was divided into 36 basic experimental units (BEU) of 1 m × 1 m, totaling 1,728 BEU. In each BEU, the fresh matter was weighed. The optimum plot size was determined by the method of maximum curvature of the coefficient of variation model. The means were compared among sowing densities by the Scott-Knott’s test. The number of repetitions — for experiments with completely randomized and randomized block designs, in scenarios of i treatments (i = 3, 4, …, 50) and d minimal differences between treatments means being detected as significant with 5% probability by Tukey’s test, expressed in percentage of the experiment average (d = 10%, 11%, …, 20%), was determined by iterative process until convergence. The optimum plot size to evaluate the fresh matter weight of vetch is 4.52 m2 at the 3 sowing densities. Four repetitions, to evaluate up to 50 treatments, in completely randomized and randomized block designs, are enough to identify as significant, at 5% probability by Tukey’s test, differences between treatment means of 29.15% of the experiment average.

No Planalto do Rio Grande do Sul, Brasil, local de clima subtropical, o cultivo da segunda safra de verão com a cultura da soja (safrinha), semeada após o cultivo de milho, vem agregando importância econômica, aumentando progressivamente sua área de cultivo e possibilitando maior produção de grãos durante o período de verão. Estudos dos caracteres dos genótipos semeados nessa condição específica, com efeito da redução da luminosidade, podem auxiliar nas futuras seleções em programas de melhoramento vegetal da cultura. O objetivo do trabalho foi avaliar as relações lineares entre caracteres de soja (Glycine max L.) e identificar caracteres para a seleção indireta, em segunda safra de cultivo de verão, em região subtropical. Dezoito cultivares de soja foram avaliadas em três locais do Rio Grande do Sul. As semeaduras foram realizadas em 09/01/2013, 10/01/2013 e 24/01/2013, para os experimentos conduzidos em Barra do Guarita, Vista Gaúcha e Tenente Portela, respectivamente. Foi utilizado o delineamento de bloco ao acaso, com quatro repetições. Foram mensurados os caracteres altura de inserção do primeiro legume, altura de planta, massa de cem grãos e produtividade de grãos. Realizou-se a análise de variância dos caracteres. Foi investigada a relação entre os caracteres por meio de análises de correlação e de trilha. No cultivo de soja em época de safrinha (segunda safra de verão), em clima subtropical, a altura de planta tem relação linear positiva com produtividade de grãos e pode ser usada para seleção indireta de cultivares mais produtivas.

In the highlands of Rio Grande do Sul, Brazil, with subtropical climate, the cultivation of the second summer crop with soybean (off-season), sowed after maize, has been adding economic importance, increasing progressively its cultivation area, and allowing greater grain yield during the summer period. Studies of traits of genotypes sown in this particular condition, with reducing luminosity effect, can assist in future selections in soybean plant breeding programs. The objective of this study was to evaluate the linear relations among soybean traits (Glycine max L.) and identify traits for indirect selection in the second crop of summer cultivation, in subtropical region. Eighteen soybean cultivars were evaluated in three locations of Rio Grande do Sul. Sowing was performed on Jan/09/2013, Jan/10/2013, and Jan/24/2013 for the experiments carried out in Barra do Guarita, Vista Gaúcha, and Tenente Portela, respectively. The randomized block design with four replications was utilized. The traits insertion of the first pod height, plant height, one hundred grains weight, and grain yield were measured. The traits analysis of variance was performed. Relation among traits was investigated through correlation and path analysis. In off-season soybean cultivation (second summer crop) in subtropical climate, plant height has positive linear relation with grain yield and it can be used for indirect selection of more productive cultivars.

O objetivo do trabalho foi avaliar os parâmetros morfológicos, produtivos e bromatológicos de híbridos de milho para silagem em condições de ambiente irrigado e sequeiro. Realizado na safra agrícola 2010/2011 em Campos Borges - RS. O delineamento experimental utilizado foi de blocos ao acaso em esquema fatorial, sendo dois ambientes x oito híbridos, dispostos em três repetições. A análise de variância revelou significância para interação ambiente x híbridos de milho paraaltura de planta, massa fresca e seca por hectare, percentagem de matéria seca, material mineral, proteína bruta, fibra em detergente neutro, lignina, carboidratos totais e não fibrosos. No ambiente irrigado os híbridos apresentam maior altura de planta, teor de clorofila, área foliar, massa fresca e seca por hectare, percentagem de matéria seca na silagem, pH, material mineral, fibra em detergente neutro, celulose e lignina. Os teores de carboidratos não fibrosos e carboidratos totais revelaram-sesuperiores para o ambientesequeiro. O teor de proteína bruta apresentou-se mais elevado em sequeiro. O híbrido HS1356 mostrou-se superior em ambiente irrigado para os caracteres altura de planta, massa fresca e seca por hectare, material mineral e fibra em detergente neutro. Em ambiente irrigado o híbrido HT4 originou um maior teor de proteína bruta na silagem.

The aim of this study was to assess silage corn hybrids morphological, productive and bromatological parameters in irrigated and non-irrigated environmental conditions. The research was held in the 2010/2011 season, Campos Borges - RS. The experimental design was randomized blocks in factorial design, with two environments x eight corn hybrids, arranged in three replications. Analysis of variance showed environment x corn hybrids interaction significance for plant height, fresh and dry matter per hectare, dry matter percentage, mineral matter, crude protein, neutral detergent fiber, lignin, total and non-fibrous carbohydrates. In the irrigated environment, hybrids showed higher plant height, chlorophyll content, leaf area, fresh and dry matter per hectare, silage dry matter percentage, pH, mineral material, neutral detergent fiber, cellulose and lignin. Non-fibrous and total carbohydrate levels were higher for the non-irrigated environment. Crude protein content was higher in the non-irrigated environment. In the irrigated environment HS1356 hybrid showed higher plant height, fresh and dry matter per hectare, mineral material and neutral detergent fiber. HT4 hybrid led to higher silage crude protein content in the irrigated environment.

RESUMO: O objetivo deste trabalho foi identificar associações fenotípicas, genotípicas e relações de causa e efeito de componentes secundários sobre componentes primários para se estabelecer critérios nos processos de seleção indireta para milho. Os cruzamentos do dialelo parcial foram conduzidos em Clevelândia. Os F1's foram avaliados em cinco ambientes. Para fins de aumento do rendimento de grãos de milho, os melhoristas devem buscar a redução dos caracteres distância do último nó até primeira ramificação do pendão, comprimento do pendão e número de ramificações. A seleção indireta para menor distância do último nó até a primeira ramificação do pendão seria eficiente para o aumento do rendimento de grãos. A seleção para menor ângulo de folha, maior diâmetro de colmo e massa de mil grãos mostram-se favoráveis para o aumento do rendimento de grãos em milho.

ABSTRACT: The objective was to identify phenotypic and genotypic associations, and cause-and-effect relations of secondary components on primary components to establish criteria in the indirect selection process for maize. Partial diallel crosses were conducted in Clevelândia. F1's were evaluated in five environments. For the purpose of increasing the yield of corn grain, breeders should seek to reduce the characters distance from the last node to the first branch of the tassel, tassel length and number of branches. The indirect selection for distance from the last node to the first branch of the tassel would be effective to increase the grain yield. The selection for smaller leaf angle, larger stem diameter and thousand grain weight are favorable for increasing grain yield in maize.

Resumo:O objetivo deste trabalho foi identificar correlações canônicas entre caracteres morfológicos e componentes da produção de genótipos de trigo de duplo propósito, sob diferentes manejos de corte. Os experimentos foram realizados em 2013 e 2014, no delineamento de blocos ao acaso, em arranjo fatorial com cinco genótipos (BRS Tarumã, BRS Umbu, BRS Figueira, BRS Guatambu e BRS 277), quatro manejos de corte (sem corte, um corte, dois cortes e três cortes) e três repetições. Os grupos canônicos foram estabelecidos entre os caracteres morfológicos (grupo 1) e os componentes de produção (grupo 2). No grupo 1, foram avaliados número de perfilhos, diâmetro do colmo principal e dos perfilhos, e número de perfilhos férteis; no grupo 2, foram avaliados número de grãos por espiga e de espigas por metro quadrado, massa de grãos por espiga e de mil grãos, produtividade de grãos e peso hectolítrico. A correlação entre os grupos 1 e 2 depende do manejo de corte adotado. O diâmetro do colmo principal (nos manejos sem e com um corte), o diâmetro dos perfilhos (dois cortes), e o número total de perfilhos e de perfilhos férteis por planta (três cortes) devem ser priorizados para seleção de genótipos superiores quanto à produtividade de grãos e ao peso hectolítrico.

Abstract:The objective of this work was to identify canonical correlations between morphological traits and yield components in dual-purpose wheat, under different cutting managements. The experiments were carried out in 2013 and 2014, under a complete block design, in a factorial arrangement with five genotypes (BRS Tarumã, BRS Umbu, BRS Figueira, BRS Guatambu, and BRS 277), four cutting managements (no cuts, one cut, two cuts, and three cuts), and three replicates. The canonical groups were established between morphological traits (group 1) and yield components (group 2). In group 1, number of tillers, diameter of the main stem and of the tillers, and number of fertile tillers were evaluated; in group 2, the number of grains per spike and of spikes per square meter, the mass of grains per spike and of a thousand grains, grain yield, and hectoliter weight were evaluated. The correlation between groups 1 and 2 depends on the adopted cutting management. The diameter of the main stem (in the managements without and with one cut), tiller diameter (two cuts), and the total number of tillers and of fertile tillers per plant (three cuts) should be prioritized for selection of superior genotypes as to grain yield and hectoliter weight.