The adoption of conservationist systems can improve the protection of soil organic matter (SOM) and mitigate greenhouse gas emissions. Thus, we aimed to quantify the soil carbon (C) and nitrogen (N) stocks, C content in the SOM fractions and microbial C (Cmic) in the topsoil of an Acrisol under traditional and agrisilvicultural systems in the Southeast of Brazil. The evaluated treatments were native vegetation of Cerrado (NV), pasture of Urochloa brizantha (PAST), monoculture of pigeon pea (MCP), and agrisilvicultural system (Eucalyptus+pigeon pea; AGS). Soil samples were collected at depths of 0–5, 5–10, and 10–20cm to determine the soil C and N contents and stocks, C associated with granulometric and humic fractions of SOM, and soil Cmic. The C contents in AGS and MCP systems were similar to NV at 5–10 and 10–20cm, and soil C stocks in AGS were similar to NV and higher than in PAST system at 0–20cm. We found a higher percentage of protected C in the silt+clay fraction, and the AGS system contributed to an increase in this organomineral fraction at 10–20cm soil depth. The C contents in the free light fraction (0–5cm) and humin (5–10 and 10–20cm) were also similar between AGS and NV, giving greater protection of SOM in both systems. For Cmic and microbial quotient values we found no differences among the evaluated systems. The results indicated that after conversion of NV to different land uses, the AGS system more effectively increased the C stocks in the topsoil and protected the SOM.

In recent decades, the expansion of soybean production in Brazil has been observed. This advance was motivated by the search of environments with better cultivation conditions, as well as the development of genotypes with wide adaptation. The diversity of "environments" hinders the process of selection and recommendation of cultivars, since the productive potential of a cultivar is given as a function of the sum of the genotype effect, the environment and the interaction between the latter two (G x E). In the case of this G x E interaction, regional studies are necessary in order to detail the differential behavior of the cultivars. Thus, the objective of this work was to evaluate the genotype interaction by environments, adaptability and phenotypic stability for grain yield, of fifteen soybean cultivars, in four sowing seasons, in order to identify cultivars that combine high productive potential, predictability of behavior and adaptation to the edaphoclimatic conditions of Uberlândia-MG. The trials were conducted at the Experimental Farm Capim Branco, in Uberlândia-MG. Fifteen soybean cultivars were evaluated in four sowing seasons (October 23, 2016, November 19, 2016, December 10, 2016 and January 14, 2017), in relation to grain yield. The experimental design was of randomized complete blocks, with three replications, in each season. Data were submitted to individual and joint analyzes. The G x E interaction was decomposed by the method proposed by Cruz and Castoldi (1991). The differential behavior of the genotypes was detailed by the adaptability and phenotypic stability by the methods of Eberhart and Russell (1966), Lin and Binns (1988) modified by Carneiro (1998), AMMI and Centroid. By the analysis of joint variance, it was observed the existence of the cultivar interaction by sowing times (C x E), for the grain yield trait, at the 5 % probability level by the F test. The C x E was predominantly complex in nature. The cultivar CD 2737 RR presented satisfactory results for the four sowing seasons in Uberlândia-MG, with high grain yield and predictability of behavior, by the evaluated methods. The cultivar NS 6909 IPRO was classified into favorable environments by the methods of Eberhart and Russell (1966) and Lin and Binns (1988) modified by Carneiro (1998). Considering Lin and Binns (1988) modified by Carneiro (1998) and Centroid the cultivar that is also classified for this cultivation condition is UFUS 8301. By AMMI, UFUS 7415, CD 2737 RR and UFUS Milionária are considered stable and adaptable.

Conservation, the use of sustainable management techniques and the development of management plans for the extraction of barbatimão are strategies to reduce their unbridled exploitation and threat of extinction. The aim of this study was to characterize and verify the biometric diversity of fruits and seeds from different localities for the collection of barbatimão [Stryphnodendron adstringens (Mart.) Coville] in the North of Minas Gerais. The fruits used were collected in nine locations in northern Minas Gerais in August 2014. The weight, length and width of the fruits were evaluated, and in the seeds, the weight, the number of seeds per fruit, the number of intact, malformed and predated seeds. Biometric data were submitted to multivariate analysis of clusters, discriminant and main components. The locations were grouped into four groups, and group 1, consisting of the locations MIR1 (Mirabela), BRM2 (Brasília de Minas) and MIR2 (Mirabela), presented the best biometric characteristics, being thus indicated for matrix selection. The morphological variations were greater within the locality than between the localities, and the most important variables for the study of seed biometrics were the number of seeds per fruit, the weight of the seeds and the numbers of intact and predated seeds.

BICALHO, THAÍS FERREIRA. Influence of sowing season on agronomic traits, adaptability and stability of soybean cultivars, 2018, 70 f. Dissertation (Master in Agronomy

O impacto provocado por afídeos e mosca-branca, tem crescido consideravelmente nas últimas décadas, devido ao aumento nos casos de surtos populacionais destas pragas que são transmissoras de vírus em diversas culturas de importância econômica. A aquisição e a transmissão da maioria dos vírus fitopatogênicos por um inseto vetor é o ponto central para o ciclo de uma infecção. Os vírus de plantas podem interagir com seus hospedeiros de insetos em uma variedade de formas, em alguns casos inclusive a replicação do vírus pode ocorrer em células do inseto. A interação do vírus com seus inseto hospedeiro/vetor requer interações moleculares específicas entre vírus e hospedeiro, comumente via proteínas, no entanto, quais componentes do vetor estão envolvidos e como eles funcionam para facilitar a transmissão ainda não está bem entendido. O objetivo do presente trabalho foi realizar uma revisão sistemática sobre as relações básicas de vírus/vetor em afídeos e mosca-branca; mostrar as práticas utilizadas atualmente no manejo integrado de pragas para afídeos e mosca-branca, além disso, relatar como as interações vetoriais de inseto estão abrindo novas portas para o controle de insetos vetores de vírus de plantas com o uso de novas tecnologias genéticas e computacionais. O presente estudo seguiu a metodologia de revisão sistemática, o trabalho foi conduzido em etapas que envolveram o desenvolvimento do protocolo de revisão com as questões da pesquisa, a estratégia de busca, a identificação dos critérios de inclusão e exclusão, a busca nas bases de dados previamente definidas, avaliação crítica, extração dos dados relevantes e síntese. A identificação dos artigos foi realizada na base de dados PUBMED www.ncbi.nlm.nih.gov/pubmed/. Foi concluído que é necessário aliar o uso de novas tecnologias como o RNAi com as ferramentas já utilizadas no manejo integrado de pragas para uma maior efetividade do controle de pulgão e mosca-branca, contudo, o contínuo estudo e aplicação de novas tecnologias moleculares na investigação de interações vírus-vetor fornecerá maior ajuda no controle das doenças virais de plantas disseminadas por pulgão e mosca-branca no futuro.