Diversity and symbiotic performance of peanut rhizobia from Southeast region of Brazil.

The use of peanut as a trap-plant for obtaining rhizobia may result in a high diversity of efficient isolates. This study aimed to evaluate the diversity and symbiotic efficiency of peanut rhizobia from the Southeastern region of Brazil. The bacteria were isolated from nodules of two genotypes in soils from the States of São Paulo and Rio de Janeiro, Brazil. The bacteria were authenticated and evaluated regarding to their symbiotic capacity. The rhizobial diversity was evaluated through their culture characteristics on yeast mannitol agar (YMA) culture media and by polymerase chain reaction Box- (PCR). Two selected isolates were characterized phenotypically regarding their capacity to solubilize phosphate, to grow on media with different concentrations of NaCI, pH's and incubation temperatures. For these the 16S rRNA gene sequencing and symbiotic efficiency using non-autoclaved soils were conducted. The majority of the obtained isolates showed rapid growth and acidified the culture medium. Analysis of the isolates through the Box-PCR revealed low similarity to the reference strain indicated for the culture and a large genetic variability of the obtained isolates. The isolates AM 01 and AM 07, which clustered with Bradyrhizobium and Rhizobium genus, respectively, showed a potential for evaluations and a means to recommend new rhizobia strains for peanut

Desempenho em confinamento de animais three-cross em sistema super precoce.

O objetivo deste experimento foi comparar o desempenho dos cruzamentos envolvendo raças sintéticas (Canchim), taurinas adaptadas (Caracu) e não adaptadas (Angus e Valdostana) em sistema super precoce. Foram utilizados 105 animais, filhos de touros Angus (RA), Canchim (CC) e Caracu (CR) com matrizes Angus/Nelore (AN), Caracu/Nelore (CN) e Valdostana/Nelore (VN). Os animais foram confinados do desmame ao acabamento (5 milímetros de gordura subcutânea na região dorso-lombar) e avaliados quanto ao ganho de peso diário (GPD) e total (GPT), peso final (PF) e dias em confinamento (DC). Os dados foram submetidos a análise de variância com os efeitos de raça paterna, materna e sexo, seguido de teste t para comparação das médias

Production and economic viability of Kent mango subjected to regulated deficit irrigation in the semi-arid.

Mango (Mangifera indica L.) production has great importance for Brazilian agriculture, being concentrated in the states of Bahia and Pernambuco. Although mango is a drought-tolerant crop, inadequate irrigation management reduces its yield. Thus, the objective was to evaluate production parameters and economic viability of ‘Kent’ mango subjected to controlled water deficit in the phenological stages of flowering, fruit growth and maturation. The experiment was conducted in the municipality of Petrolina/PE, semi-arid region of the São Francisco Valley, in a ultisol. The experimental design was randomized blocks, in a triple factorial scheme, with application of four irrigation depths (40, 60, 80 and 100% of crop evapotranspiration -ETc), three phenological stages (F1 -flowering, F2 -fruit growth, F3 -fruit maturation) and two production cycles (2018 and 2019 seasons), with four replicates, each of which consisting of four plants. The irrigation with 40% ETc in the flowering stage and 80% of the ETc in the growing and ripening of fruits phases promoted higher yield, water use efficiency and benefit/cost ratio in the cultivation of ‘Kent’ mango in the Brazilian semi-arid region

Efeito de fontes orgânicas de nutrientes no crescimento de fungos dark septate.

Os fungos dark septate atuam na promoção do crescimento vegetal, contudo as funções ecológicas destes fungos ainda permanecem obscuras. Este trabalho teve como objetivo avaliar o efeito de Fontes orgânicas de nutrientes no crescimento de fungos dark septate. Utilizando um delineamento de blocos casualizados, isolados de fungos dark septate, obtidos de Oryza glumaepatula, foram avaliados quanto à capacidade para utilizar Fontes orgânicas de nutrientes. Os Resultados mostraram que o isolado ERR 04 desenvolveu-se melhor na presença de Fontes orgânicas de nutrientes comparativamente aos demais isolados. O fungo ERR 04 é promissor para testes de avaliação da transferência de nutrientes a partir da matéria orgânica para seu hospedeiroEffect of organic sources of nutrients on the growth of dark septate fungi. Edição dos Anais do VI Congresso Latino-americano de Agroecologia; X Congresso Brasileiro de Agroecologia; V Seminário de Agroecologia do Distrito Federal e Entorno, Brasília, DF, set. 2017