Organic management of Brachiaria brizantha cv. Marandu pasture mixed with Stylosanthes spp. in the Cerrado.

2016

Bioensaio para avaliação de recuperação de nitrogênio contido em compostos obtidos a partir da mistura de palhada de gramínea e de leguminosa.

A compostagem constitui-se importante alternativa para obtenção de fertilizantes orgânicos, que são utilizados como condicionadores de solo e fornecedores de nutrientes, principalmente do nitrogênio (N), em diversos sistemas de produção agrícola. O objetivo deste trabalho foi avaliar a capacidade de recuperação biológica do N contido em diferentes formulações de compostos obtidos a partir da mistura de palhada de capim Napier e de Crotalaria juncea. Avaliou-se também a capacidade de recuperação do N de outros adubos. O bioensaio foi realizado em casa de vegetação, utilizando-se vasos plásticos de 650 ml com coletores de água lixiviada. Como planta indicadora, foi utilizado o Milheto Pérola (Pennisetum glaucum). Compostos orgânicos com maiores teores de N e menores relações C:N proporcionaram maiores taxas de recuperação de N pelo Milheto Pérola.

Soil N²O emissions from long-term agroecosystems: interactive effects of rainfall seasonality and crop rotation in the Brazilian cerrado.

2016

Co-Infestation and Spatial Distribution of Bactrocera carambolae and Anastrepha spp. (Diptera: Tephritidae) in Common Guava in the Eastern Amazon.

Field infestation and spatial distribution of introduced Bactrocera carambolae Drew and Hancock and native species of Anastrepha in common guavas [Psidium guajava (L.)] were investigated in the eastern Amazon. Fruit sampling was carried out in the municipalities of Calc¸oene and Oiapoque in the state of Amapa, Brazil. The frequency distribution of larvae in fruit was fitted to the negative binomial distribution. Anastrepha striata was more abundant in both sampled areas in comparison to Anastrepha fraterculus (Wiedemann) and B. carambolae. The frequency distribution analysis of adults revealed an aggregated pattern for B. carambolae as well as for A. fraterculus and Anastrepha striata Schiner, described by the negative binomial distribution. Although the populations of Anastrepha spp. may have suffered some impact due to the presence of B. carambolae, the results are still not robust enough to indicate effective reduction in the abundance of Anastrepha spp. caused by B. carambolae in a general sense. The high degree of aggregation observed for both species suggests interspecific co-occurrence with the simultaneous presence of both species in the analysed fruit. Moreover, a significant fraction of uninfested guavas also indicated absence of competitive displacement.

Qualidade física do solo e produtividade da cana-de-açúcar com uso da escarificação entre linhas de plantio.

2016

Expression of rice genes homologous of Arabidopsis genes previously related to drought tolerance.

The identification and validation of candidate genes related to traits of interest is a time consuming and expensive process and the homology among genes from different species can facilitate the identification of genes of the target species from the genomic information of a model species. This study aimed to quantify the expression of homologous rice genes previously related to drought tolerance in Arabidopsis. Five genes (CPK6, PLDa, GluR2, CesA8, and EIN2) were identified in rice by the homology of the amino acid sequence between rice and Arabidopsis. The genotypes Douradão (drought tolerant) and Primavera (drought susceptible) were subjected to a water deficit experiment, and subsequently evaluated for gene expression by qPCR for the five homologous and Lsi1 genes. The qPCR analysis clearly showed that the five homologous genes were expressed in rice, which is an indication that these genes could preserve their function in rice as a response to drought. In Douradão, of the five homologous genes, all but OsGluR2 displayed an increase in the average expression in drought treatment when compared to the control, while in Primavera, the average expression of the five genes did not differ between the control and drought treatment. In Douradão, the OsPLDa1, which showed the higher expression level in drought in relation to the control (10.82), significantly increased the gene expression in the leaf and root tissues as a response to drought, in both vegetative and reproductive stages, whereas in Primavera, this gene was suppressed in both tissues and stages under drought. Therefore, the OsPLDa1 gene was the most important in relation to drought response and is an interesting candidate for further studies in developing rice cultivars that are more tolerant to this stress.

Diversidade genética entre acessos do banco ativo de germoplasma de batata-doce mantido na Embrapa Hortaliças.

2015