ABSTRACT. Soybean is one of the main sources of foreign exchange credits for Brazil in the agricultural sector. There is increasing interest in growing this leguminous crop, especially in the southern region of Minas Gerais, due to its importance as an alternative for crop rotation with maize. In this respect, the study of the adaptability of new cultivars to the region is indispensable so as to obtain high yields. Thus, the aim of this study was to evaluate the performance of 38 soybean cultivars for growing in the summer season in the municipality of Lavras, MG, Brazil, in the 2010/2011 and 2011/2012 crop years. The experiments were conducted in a randomized block design with 3 replications and the treatments consisted of 38 cultivars. At the time of harvest, the following assessments were made: grain yield (kg/ha), height of the lowest pod (cm), plant height (cm), and lodging. The data were subjected to individual and combined analysis of variance. The phenotypic mean values were clustered, adopting the Scott and Knott test. For simultaneous selection of multiple traits, the sum of rank index of Mulamba and Mock was adopted. The cultivar TMG 801 RR had the best yield performance; the cultivars Monsoy 8001, MGBR-46 8996 I.O. Soares et al. ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 14 (3): 8995-9003 (2015) (Conquista), and BRSMG 68 (Vencedora) also stood out. Considering simultaneous selection for grain yield, plant height, height of the lowest pod, and lodging, the cultivar TMG 801 RR is recommended for growing in the summer season in the southern region of Minas Gerais.

Plant, environmental conditions and management type will determine final crop yield. Enhanced yield can be reached by using well-adapted and potentially productive genotypes; all of them ally to crop cultural practices and management. Among these, seed density stands out, once it interferes with plant morphology and competition for water and nutrients. Thus, this study aimed to evaluate the effect of varied seed densities on agronomic traits in soybean, besides identifying cultivars with wide adaptability to different environments and seed densities. Six soybean cultivars were assessed under four seed densities (100, 200, 300 and 400 thousand plants•ha −1 ), in nine different environments from Minas Gerais State, Brazil. The experimental design was a completely randomized block design with three replications. The BRSMG 760SRR and BRSMG 820RR cultivars had the best average performance independent of the environments and seed densities. The seed density of 300 thousand plants per hectare showed to be as the most adequate for soybean cultivation on the evaluated environments. Furthermore, seed density interacted with the agronomic traits in soybean.

No abstract

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.

The goal of this study was to verify the influence of the population effect in the estimates of genetic and phenotypic components and to identify the best soybean progeny or lines in a commercial soybean breeding programme. We evaluated 292 populations for grain yield and absolute maturity during three agricultural years. To quantify the efficiency of the inclusion of the population's effect in the model, we estimated genetic gain with the selection, the Spearman's correlation, the coincidence index, the realized gain and correlated response of selected genotypes with and without the effect of the population. It was found that the variance components, heritability and coefficient of experimental variation were better estimated when the effect of the population was included, providing greater gain with selection for grain yield and absolute maturity. Coincidence and ranking among the selected progeny with and without the effect of the population are of greater magnitude in more advanced inbreeding generations and at higher percentage of selected progeny. The use of the population effect has greater importance in earlier generations of inbreeding.

Soybean [Glycine max (L.) Merr.] has been studied and enhanced for most of its economically important traits. Previous research has studied the association among them and the effect of the genotype × environment interaction; however, less is known about their correlation considering absolute maturity, as well as the use of multiple selection indices to study the genotype × environment interaction and select superior cultivars. Regarding this, the aim of the present study was to identify lines that associate precocity, good yield performance, and high oil and protein contents in the grains, as well as to estimate the correlation among these traits and study the effect of genotype × environment interaction using a standardized multiple selection index. Trials were conducted in two crop seasons in the state of Minas Gerais, Brazil, with 39 lines in 13 evaluation environments. The experiments were conducted in a randomized complete block design with four replications, and the grain yield, absolute maturity, and oil and protein contents in the grains were evaluated. The results indicated high experimental precision and accuracy, with significant differences among lines for all traits. High‐magnitude correlations between evaluated traits were found, highlighting the negative correlation between absolute maturity and protein content in the grains. The genotype × environment interaction was also significant, and the use of the multiple selection index was efficient to identify superior and stable inbred lines by the genotype + genotype × environment (GGE) biplot method, which explained 82.23% of the genotype × environment interaction effect. Lines 27 and 31 stood out from the others because they associated stability and good performance for all evaluated traits.

R E S U M OO herbicida glifosato tem afetado os bioindicadores de qualidade do solo, aspectos morfofisiológicos e nutricionais das plantas de soja RR ® . Contudo, não se sabe o impacto desses efeitos fisiológicos na qualidade das sementes de soja RR ® . A expressão de enzimas está relacionada a qualidade das sementes de soja por ocasião dos genótipos e ambientes de produção. Foi objectivo neste trabalho, avaliar a qualidade fisiológica e a atividade enzimática de sementes de soja RR ® em dois ambientes de produção em função de doses do herbicida glifosato. As sementes foram produzidas na safra 2014/15 nos municípios de Lavras e Patos de Minas em esquema fatorial 3 x 6, sendo três cultivares comercias de soja RR ® (CD 250, TMG 1174, V-MAX) e seis doses do herbicida glifosato (0, 960, 1920, 2880, 3840, 4800 g e.a. ha -1 ). As sementes colhidas foram analisadas em laboratório quanto a expressão enzimática, bem como o teor de água, germinação em areia, germinação em papel, emergência de plântulas, índice de velocidade de emergência, condutividade elétrica, envelhecimento acelerado e o vigor e viabilidade de sementes, adotando-se delineamento inteiramente casualizado. A aplicação de doses crescentes de glifosato até 4800 g e.a. ha -1 não influencia a qualidade fisiológica de sementes de soja. Não houve efeito do aumento das doses de glifosato sobre a expressão enzimática para esterase, álcool desidrogenase, malato desidrogenase e catalase. A cultivar V-MAX RR apresentou percentagem de germinação em areia 80%, estando nos padrões de comercialização de sementes no Brasil.Palavras-chave: álcool desidrogenase, catalase, esterase, malato desidrogenase, Roudup Ready ® , vigor de sementes. A B S T R A C TThe herbicide glyphosate affects soil quality bio indicators and morph physiological and nutritional aspects of RR ® soybean plants. However, to the best of our knowledge, the impact of these physiological effects on the quality of RR ® soybean seeds is not known. The expression of enzymes is related to quality of soybean seeds according to the genotype and production environment. The aim of this study was to evaluate the physiological quality and the enzymatic activity of RR ® soybean in two production environments as a function of glyphosate doses. The seeds were produced in the 2014/15 crop in Lavras and Patos de Minas in a factorial 3 x 6, three soybean RR ® cultivars a function (CD 250, TMG 1174, V-MAX) and six doses of the herbicide glyphosate (0, 960, 1920, 2880, 3840, 4.800 g e.a. ha -1 ). The harvested seeds were analyzed in the laboratory and enzyme expression as well as water content, germination (in sand and in paper), seedling emergence, emergence speed index, electrical conductivity, accelerated aging and vigor and seed viability. A completely randomized design was adopted. The application of increasing doses of glyphosate up to 4.800 g a.e. ha -1 do not affect the physiological quality of soybean seeds. There was no effect of increasing rates doses of glyphosate on the enzymatic expression of esterase, alco...

No abstract