SIMONE ALVES SILVA (2) ; FERNANDO IRAJÁ FÉLIX DE CARVALHO (3) ; JORGE LUÍS NEDEL (3) ; PEDRO JACINTO CRUZ (2) ; JOSÉ ANTÔNIO GONZÁLEZ DA SILVA (4) ; VANDERLEI DA ROSA CAETANO (5) ; IRINEU HARTWIG (5) ; CÁSSIA DA SILVA SOUSA (6) RESUMOO objetivo do trabalho foi avaliar o efeito dos caracteres número de espiga por planta, número de grãos por espiga, massa média de grãos, tamanho da espiga e número de espiguetas por espiga sobre o rendimento de grãos, em trigo (Triticum aestivum L.) diferenciado quanto à presença e ausência do caráter "Stay-green", através de seus coeficientes de correlação e sua decomposição por meio da análise de trilha. Foram utilizados sete genótipos, obtidos através de avanços de gerações de 1999 a 2001, utilizando duas épocas de semeadura por ano, na estação de verão e inverno, sob condições de campo e telado, na Universidade Federal de Pelotas, RS. O experimento foi desenvolvido em delineamento de blocos casualizados com cinco repetições. A análise de trilha permite identificar o componente primário MMG, como o de maior potencial para seleção de constituições genéticas superiores para rendimento de grãos.Palavras-chave: produtividade, enchimento de sementes, variabilidade. ABSTRACT PATH ANALYSIS FOR THE YIELD COMPONENTS OF SEEDS IN WHEATThe purpose of this work was to estimate the effect of the ear number per plant, number of seeds per ear, seed weight, size of the ear and spikiest number per ear in relation to the grain yield through its correlation coefficients and its decomposition by the path analysis. The genotypes were obtained through the advances generation in the years from 1999 to 2001, using two sowing dates per year, in the warm and cold season, in the field and in green-house conditions, at the Federal University of Pelotas, RS. The experiment was conducted as a randomized complete block design with five replications. The characters spikiest number for spike and hectoliter weight were identified by the path analysis, as being the one of high potentiality for selection of superior genetic constitutions for seed yield seeds.

High wheat yields, besides the genetic potential and edaphoclimatic conditions, are obtained by proper management and nitrogen use. The objective of the study was to define the most appropriate time for N-fertilizer application, considering the range of greatest wheat requirements, dependent on the succession system type and the predictability of favorable and unfavorable years. The study was carried out in the 2008 to 2012 years, in Augusto Pestana, Rio Grande do Sul, Brazil. The experimental design was randomized blocks with four replications, with N-fertilizer application at 0, 10, 30 and 60 days after emergence, considering the corn/wheat and soybean/wheat succession system. The study found that the best time for nitrogen fertilizer application on wheat is mostly influenced by the year of cultivation and is less influenced by the succession system type. The appropriate time for the Nfertilizer application in favorable years of cultivation was about 45 days after emergence. In unfavorable years, it must be anticipated. Regardless of the cultivation year and the succession system type, the Nfertilization at 30 days after emergence evidenced the highest means as the most stabile grain yield.

No abstract

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 sowing density adjustment in oatcan maximize the productivity expression.The aim of this study is to define the behavior of productivity expression of biomass, grains, straw andharvest indexthrough increasing sowing density in the main biotype cultivated in Southern Brazil. It proposesthe possibility of indicating higher sowing density to the productivity maximization of biomass and grains.With the densityadjusted to the grain productivity to simulate the reflexes on the biological and straw productivity and harvest index compared to recommendeddensity, considering high and reduced tillering cultivars in different succession systems.The study was carried out in 2013, 2014 and 2015 in randomized blockdesign with four replications in a 4 × 2 factorial scheme, for sowing density (100, 200, 300, 600 and 900 m -2 ) and oat cultivars (Brisasul and URS Taura), respectively, in the corn/oat and soybean/oat succession system.With the increase in sowing density, the biological and straw productivity evidence alinear behavior and the grain productivity and harvest index ofquadratic behavior, regardless of the cultivar,agricultural year and succession system. It is possible to indicate a higher sowing density to the biomass and grain productivity maximization with sowing density close to 500 seeds m -2 in the main succession systems.In high and reduced tillering cultivars, the adjusted density compared tothe recommended increasedthe biological and straw productivity, regardless of agricultural year and succession systems.

No abstract

Black oat crop occupies the largest area during winter. It is important for animal production, crop rotation and dry matter production of approximately 3.8 million hectares in Rio Grande do Sul State. To ensure sowing, seeds are produced which must have high quality standards and must be evaluated by seed testing laboratories. Given this, the present study evaluated the physical and physiological quality of oat seeds analyzed by the Seed Analysis Laboratory of UNIJUI from 2006 to 2014. 2,910 samples were evaluated; 2,229 were evaluated with seed production process; 357 were evaluated with seed analysis of own use and 324 were evaluated with tetrazolium analysis. The samples obtained through seed production process were analyzed in terms of their physical and physiological aspects, while the own seed and tetrazolium test used were evaluated only in terms of their physiological attributes, following the methodology described in the Seed Analysis Rules. The data were analyzed through descriptive statistics for each variable studied per year, and the averages, maximum and minimum standard deviation and coefficient of variation were identified. The data were also evaluated based on their dispersion, and compared to weather occurrences and national standards, in order to estimate the percentages of samples approved. Seeds produced according to the National Seed system had high levels of physical and physiological quality from 2006 to 2010. However, between 2011 and 2014, 14.0 and 14.5% of the samples were above the standard levels for seeds of other cultivated species and harmful prohibited species respectively. The own used seeds showed greater variability and dispersion, with 18.1 and 31.7% samples below the standards for germination in the years 2006 to 2010 and 2011 to 2014, respectively, while the samples analyzed through the tetrazolium test showed approved levels of 19.4 and 12.5%, respectively.

No abstract