Plants density in soybean cultivation is an important management practice to achieve high grain yield. In this way, the objective was to evaluate the agronomic traits and grain yield in soybean in different plant densities, in two locations in the south of Minas Gerais. The experimental design was in randomized blocks, arranged in a split plot design, with three replications. Plots were composed of four population densities (300, 400, 500 and 600 thousand plants per hectare) and the subplots were composed of six cultivars (‘BMX Força RR’, ‘CD 250 RR’, ‘FMT 08 - 60.346/1’, ‘NA 5909 RR’, ‘TMG 7161 RR’ and ‘V - TOP RR’) grown in Lavras and Inconfidentes, both in Minas Gerais. At the time of harvest was determined the plant height, lodging, insertion of the first pod, harvest index, number of pods per plant, number of grains, number of grains per pod and yield. Regardless of the soybean cultivar, the plant density of up to 600,000 per ha does not affect grain yield, plant height, lodging, harvest index, and number of grains per pod. The cultivars ‘V-TOP RR’ and ‘BMX FORÇA RR’ showed high grain yield and good agronomic traits in Lavras and Incofidentes.

O objetivo desse trabalho foi avaliar por meio da análise de trilha, a influência de alguns caracteres agronômicos de cultivares de soja, em função de diferentes densidades de planta, e a contribuição dessas características no rendimento de grãos. O delineamento experimental utilizado foi o de blocos ao acaso completos, dispostos em esquema de parcelas subdivididas, com três repetições. As parcelas foram compostas por quatro densidades populacionais (300, 400, 500 e 600 mil plantas por hectare) e, as subparcelas foram compostas por seis cultivares (BMX Força RR, CD 250 RR, FMT 08 ? 60.346/1, NA 5909 RR, TMG 7161 RR e V ? TOP RR) cultivados em Lavras e Incofindentes, ambos em Minas Gerais. Por ocasião da colheita determinou-se a altura de plantas, a inserção do primeiro legume, o índice de colheita, o número de legumes por planta, o número de grãos, o número de grãos por vagem e a produtividade dos grãos. Com os dados obtidos foram elaboradas as matrizes de correlação fenotípica. As correlações foram desdobradas em efeitos diretos e indiretos das variáveis independentes (componentes de produtividade e caracteres agronômicos) sobre a variável dependente (produtividade de grãos). Os caracteres número de legumes por planta e o número de grãos por legumes são os componentes que apresentam maiores efeitos diretos sobre a produtividade de grãos de soja, sendo assim, estes podem ser utilizados na seleção indireta visando o incremento da produtividade de grãos.

Alternative methods of inoculation such as the application of the bacteria Azospirillum brasilense via spray in an advanced stage of the crop can increase the soybean performance. The aim of this study was to evaluate the agronomic traits and grain yield in soybean crops through Azospirillum brasilense doses applied by spray coverage. The experiment was conducted in randomized blocks in a 4 × 6 factorial, with four cultivars (Anta 82 RR ® , BRS Favorita RR ® , BRS 780 RR ® , BRS 820 RR ® ) and six doses of Azospirillum brasilense (0, 300, 400, 500, 600, 700 mL ha -1 ) with three replications in two crop years. The characters such as plant height, shoot dry mass, chlorophyll content, leaf nitrogen content at flowering were evaluated. At harvest, the evaluated characters were plant height, height of the first pod insertion, number of pods per plant, number of grains per pod, thousand grain mass, grain yield and grain harvest index. For the conditions that this study was carried out and according to the results, the spray with different Azospirillum brasilense doses did not affect the agronomic variables studied and the grain yield in RR ® soybean cultivars.

In the last decades, the Brazilian soy productive chain has passed through a transformation process in which the yield, efficiency, profitability, economic and environmental sustainability are very important issues. In this context, the introduction of microorganisms has provided an increase in grains yield. The objective of this study was to evaluate the inoculation of Azospirillum brasilense associated with Bradyrhizobium japonicum in agronomic traits and the soybean productivity. The experiment was conducted in randomized blocks in 4 × 2 factorial, with four cultivars (Anta 82 RR ® , BRS Favorita RR ® , BRS 780 RR ® , BRS 820 RR ® ) and two treatments with A. brasilense (inoculated and non-inoculated) with three replications in two growing seasons. The following traits were evaluated: plant height, shoot dry biomass, chlorophyll content, leaf nitrogen content at flowering; and at harvest, the plant height, the insertion of the first pod, number of pods per plant, number of grains per pod, thousand-grain weight , grain yield, and grain harvest index were evaluated. There was a significant effect of growing seasons and cultivars in an isolated way and their interaction in most traits. The conditions in which the study was conducted, with or without inoculation of A. brasilense associated with B. japonicum do not affect the agronomic traits and grain yield in RR ® soybean cultivars.