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.

Figurando como um dos principais produtores e exportadores de soja o Brasil destaca-se pela potencialidade de plantio de duas safras, uma em seguida da outra, também conhecidas como safra principal e safrinha. Para realização da safrinha com o milho, por exemplo, é necessário à utilização de cultivares precoces de soja que antecipem o período de plantio na segunda safra. Sendo assim, objetivou-se com este trabalho estudar a adaptabilidade de cultivares precoce de soja para o cultivo de verão na Região Sul de Minas Gerais. Os caracteres avaliados foram produtividade de grãos, altura de plantas, inserção do primeiro legume e ciclo de cultivo das cultivares introduzidas. O experimento foi conduzido na safra 2012/2013 e 2013/2014, adotando o delineamento experimental de blocos casualizados, com 25 cultivares e três repetições. Os resultados obtidos foram submetidos à análise de variância conjunta e as médias comparadas pelo teste de Scott-Knott (1974) a 5 % de probabilidade, com o auxílio do pacote estatístico SISVAR. Adotou-se a estimativa da acurácia para precisão experimental. Em função dos resultados obtidos pode-se inferir que das cultivares avaliadas destaca-se a cultivar BMX Força RR, por apresentar características favoráveis ao cultivo de verão, possibilitando a realização de segunda safra na região sul de Minas Gerais, associado a boas características agronômicas e precocidade.

Caracterização biométrica de frutos e sementes de mirindiba (Buchenavia tomentosaEichler R E S U M OAs espécies arbóreas tem potencial para aproveitamento em diversos setores e cadeias produtivas. Neste contexto, a biometria constitui-se em uma importante ferramenta para identificar as principais características intrínsecas ao fruto e a semente. Portanto, objetivou-se com este estudo caracterizar biometricamente os frutos e sementes de mirindiba e inajá e, correlacionar com os parâmetros dos frutos e sementes de cada espécie, a fim de obter informações sobre a variação das características biométricas. Analisaram-se 100 frutos frescos e 100 sementes, provenientes de 10 árvores de cada espécie, da região do sul do Piauí, quanto ao diâmetro equatorial, comprimento longitudinal, massa fresca, massa fresca da polpa do fruto e da semente, volume do fruto, índice de volume das sementes, umidade da polpa e umidade da semente. As características biométricas foram analisadas mediante distribuição de frequência, calculando-se o coeficiente de correlação de Spearman (rS) e o nível de significância através do teste t. Os frutos e sementes de mirindiba e inajá apresentam variabilidade para a maioria das características biométricas avaliadas, bem como correlação positiva predominante entre elas. Os frutos apresentam grande potencial econômico pelo alto rendimento de polpa observado, sendo possível a seleção de frutos com maior teor de polpa por características como o peso e tamanho do fruto.Palavras-chave: biometria, Cerrado, correlação Spearman, espécies arbóreas. A B S T R A C TTree species have potential for use in various industries and supply chains. In this context, biometrics constitutes an important tool to identify key features intrinsic to the fruit and seed. Therefore, the aim of this study was to characterize biometrically the fruits and seeds of mirindiba and inajá and to correlate the fruit and seed parameters of each species in order to obtain information on biometric variation. Equatorial diameter, longitudinal length, fresh pulp, fresh weight of the fruit pulp and seed, fruit volume, volume index of seeds, humidity of the pulp and seed moisture collected in south of Piaui, were analyzed, considering 100 fresh fruits and 100 seeds from ten trees of each species. Biometric features were analyzed by frequency distribution, calculating the Spearman correlation coefficient (rs) and the level of significance using the t test. The fruits and seeds of mirindiba and inajá exhibit variability for most biometric characteristics evaluated, as well as predominantly positive correlation between them. The fruits have great economic potential for the high yield of pulp observed, with the possible selection of fruits with higher pulp content by characteristics such as weight and fruit size.

Delayed harvesting may affect the physiological quality of soybean seeds, due to adverse conditions in the field. This study aimed to evaluate the physiological and sanitary quality of soybean seeds (BRS 820 RR® cultivar) harvested at eight periods (0; 5; 10; 15; 20; 25; 30; and 35 days after the R8 phenological stage - full maturity) and stored for two periods (0 and 8 months). The following evaluations were carried out: moisture content, germination and emergence rate, emergence speed index, total plant dry mass, accelerated aging, electrical conductivity, mechanical damage, vigor and viability (tetrazolium) and sanitary quality of the seeds. The delayed harvesting of soybean seeds from 10 days after R8 impairs seed vigor and germination, in addition to increase the incidence of pathogens. Regardless of the harvesting period, the soybean seeds stored for eight months showed a reduction in their physiological quality, with an increase in the incidence of Phomopsis spp.

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.

Nitrogen fertilization may interfere in the quality of soybean seeds. This study aimed to determine the physiological and sanitary quality of soybean seeds, in response to levels and times of nitrogen (N) application associated with Bradyrhizobium japonicum inoculation. Treatments were arranged in a randomized block design, in a 2 × 3 × 4 factorial arrangement [two soybean cultivars (BRS 1074 IPRO and ST 797 IPRO), three application times (sowing, 30 and 50 days after emergence) and four N levels (0 kg ha-1, 20 kg ha-1, 40 kg ha-1 and 60 kg ha-1), with four replicates. The 1,000-seed mass, moisture content, germination rate, seedling height, shoot length, primary root length, total seedling dry matter, electrical conductivity, mechanical damage, vigor and viability (tetrazolium test) and sanitary quality of the seeds were measured. The use of mineral N, associated with the inoculation of B. japonicum bacteria, does not prove to be consistent, in terms of its effects on the physiological quality of soybean seeds, although the incidence of pathogens may be reduced.