The main aim of this study was to investigate the phenotypic correlation of yield component traits using several environmental stratifications methods. We also aimed to propose cause and effect of relationships for grain yield components in soybean genotypes under several environmental conditions. The tests were conducted in the agricultural year of 2013/2014 in four growing sites in Rio Grande do Sul, Brazil. The experimental arrangement was randomized blocks in factorial scheme (11 x 4), consisting eleven soybean genotypes in four environments with four repetitions each. All the growing environments Tapera-RS, Derrubadas-RS and Frederico Westphalen-RS were classified as favorable for soybean cultivation. The traits such as total number of pods per plant, number of branches and number of pods with 2-3 grains showed significant linear correlations with grain yield in both methods of analysis. The path analysis was applied under favorable and unfavorable environments to accurately estimate the direct and indirect effect of traits on soybean grain yield. The mass of a thousand grains and plant height were highly associated with grain yield but mostly influenced by environmental effects. The total number of pods should be prioritized for selecting superior soybean genotypes due to its direct and indirect effects on grain yield. It has shown constant in all environmental conditions. The direct effects of number of branches and number of pods (with one grain) presented distinct effects on yield in favorable and unfavorable environments.

The aim of this study was to evaluate the phenotypic interrelation among agronomic characters associated with wheat grain yield of the main Brazilian cultivated genotypes through path analysis in two environments. The tests were conducted in Tenente Portela-RS and Braga-RS. The experimental design was randomized blocks arranged in factorial scheme, 2 locations × 17 genotypes and 3 repetitions. The evaluated characters were plant height, main stem spike mass, tiller spikes mass, main stem spike grains number, tiller spikes grains number, main stem spike grains mass, tiller spikes grains mass, mass of a thousand grains and grain yield. Path analysis was performed for characters associated with grain yield. The results show that main stem spike grains mass, main stem spike grains number, and tiller spikes grains mass have direct effects on grain yield. Larger main stem spike grains mass, main stem spike grains number, and tiller spikes grains mass should be considered for achieving genotypes of high grain yield potential.

The aim of this study was to determine associations of cause and effect agronomic traits with grain yield in contrasting growth habits of soybean genotypes, as well as to verify the magnitude of similar behaviors in different growing environments. The trials were conducted for one crop season using randomized blocks design arranged in factorial scheme, including two growing environments (Independência -RS and Tenente Portela -RS) x four genotypes (FPS Solimões RR e FPS Júpiter RR; BRS Tordilha RR and Fepagro 36 RR, 2 indeterminate and 2 determinate growing habits, respectively) in three replications. Ten important soybean yield components were evaluated. The data were subjected to individual analysis of variance for each environment and growing habits. For each environment within habits, the phenotypic path analysis was performed among the traits. The components number of pods on the main stem, number of ramifications, number of pods in the ramifications, and number of one and two-grain pods presented contrasting results in growing environments. The number of three-grain pods is among the components mostly related to grain yield for both determinate and indeterminate growing habit genotypes, regardless of the environment. The adoption of genotypes with higher weight of thousand grains may provide satisfactory results for grain yield, regardless of the growth habit and environment of cultivation.

Rice (Oryza sativa L.) presents a strategic role in social and economic levels. The aim of this study was to elucidate the presence of genetic variability for the genus Oryza, and the possibility of using genotypes with wild characteristics in rice breeding programs. The Oryza genus shows great genetic variability through wild genotypes available in the most varied environments around the world. The negative effects imposed by abiotic stresses such as flood, salinity, low temperatures, water deficiency and high temperatures may be minimized by the efficient identification of a genetic variability source from the Oryza genus. Among the main wild species presented by the Oryza genus, Oryza glumaepatula stands out being an active source of germplasm. The occurrence and preservation of genetic variability of Oryza genus is indispensable to obtain new rice genotypes, to guarantee food security for the human population, as well as to develop genotypes that adapt to climatic changes and natural adversities.

The objective of this work was to evaluate the chemical composition of the macronutrients: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and sulfur (S), and micronutrients: boron (Cu), iron (Fe), manganese (Mn), molybdenum (Mo) and zinc (Zn), and the elements aluminum (Al) and sodium (Na) measured in soybean seeds from different producing regions of Brazil. This work was carried out by sampling 2543 lots of soybean seeds produced in the 2009, 2010, 2011 and 2012 growing seasons. There is high variability of macro and micronutrients concentration in soybean seeds produced in several regions of Brazil. The nitrogen, potassium, phosphorus, and calcium are the most pronounced macronutrients in soybean seeds. Among the micronutrients, iron, manganese and zinc are those with more evidence. Understanding macro and micronutrients variability is critical for improving management and fertility treats in soybean seed production fields.