Inoculação de bactérias diazotróficas e diferentes doses de nitrogênio em dois genótipos de trigo em condições de campo.

bitstream/item/159664/1/FD-0356.pdfTrabalho apresentado na IX Semana Científica Johanna Dobereiner, Seropédica, out. 2009. Ver também SP-15709

Beneficial plant-associated microorganisms from Semiarid regions and seasonally dry environments: a review.

Semiarid regions are apparently low biodiversity environments; however, these environments may host a phylogenetically diverse microbial community a asociated with plants. Their microbial inhabitants are often recruited to withstand stressful settings and improve plant growth under harsh conditions. Thus, plant-associated microorganisms isolated from semiarid and seasonally dry environments will be detailed in the present review, focusing on plant growth promotion potential and the microbial ability to alleviate plant abiotic stress. Initially, we explored the role of microbes from dry environments around the world, and then, we focused on seasonally dry Brazilian biomes, the Caatinga and the Cerrado. Cultivable bacteria from semiarid and seasonally dry environments have demonstrated great plant growth promotion traits such as plant hormone production, mobilization of insoluble nutrients, and mechanisms related to plant abiotic stress alleviation. Several of these isolates were able to improve plant growth under stressful conditions commonly present in typical semiarid regions, such as high salinity and drought. Additionally, we highlight the potential of plants highly adapted to seasonal climates from the Caatinga and Cerrado biomes as a suitable pool of microbial inoculants to maintain plant growth under abiotic stress conditions. In general, we point out the potential for the exploitation of new microbial inoculants from plants growing in dry environments to ensure a sustainable increase in agricultural productivity in a future climate change scenario.Article 55322

Verticillium diseases of vegetable crops in Brazil: Host range, microsclerotia production, molecular haplotype network, and pathogen species determination.

Recent outbreaks of Verticillium wilt diseases in various vegetable crops have been reported in Brazil. This fact was our initial stimulus to carry out a nationwide survey aiming to determine their causal agent(s). Thus far, Verticillium dahliae has been reported as the predominant species based solely on morphological traits. As other Verticillium species can be associated with wilt diseases, we characterized a collection of 80 isolates, collected across 10 agricultural Brazilian regions, by combining morphological, biological, and molecular traits. A multilocus approach was employed for identification of Verticillium species with information from three genomic regions (ribosomal internal transcribed spacer region, glyceraldehyde-3-phosphate dehydrogenase, and actin genes). Only 21 out of the 80 isolates were unable to produce microsclerotia in culture. The analyses of all genomic regions indicated V. dahliae as the sole species associated with vascular wilt of distinct hosts, including major solanaceous vegetables and other hosts such as trawberry, okra, and cacao. Pathogenicity tests confirmed the infection by the V. dahliae isolates and the development of typical disease symptoms on their original hosts. This is the first nationwide characterization of Verticillium isolates associated with major vegetable crops in Neotropical areas. This provides valuable information to design sound management strategies for these diseases, mainly for establishing efficient rotation systems and for the development of resistant cultivars.On-line first

Adaptabilidade e estabilidade de genótipos de trigo irrigado no Cerrado do Brasil Central.

O objetivo deste trabalho foi estimar a adaptabilidade e estabilidade de genótipos de trigo irrigado, nas condições do Cerrado do Brasil Central. O rendimento de grãos de cinco cultivares e nove linhagens de trigo irrigado foram aferidos no ensaio de valor de cultivo e uso. Os ensaios foram conduzidos nos anos de 2005 e 2006, em seis locais em Minas Gerais, três em Goiás e um no Distrito Federal. Os dados de rendimento de grãos foram submetidos à análise de variância individual e à análise de variância conjunta, para a estimativa dos parâmetros de adaptabilidade e estabilidade. Verificaram-se diferenças significativas, entre os genótipos, em 14 dos 16 ambientes avaliados. Nenhum dos genótipos avaliados apresentou o comportamento ideal preconizado pelo método de Cruz e colaboradores. Destacaram-se a cultivar BRS 264 e a linhagem CPAC 02167, pela superioridade em todas as condições do Cerrado do Brasil Central (adaptabilidade geral). Entre os demais genótipos avaliados, destacaram-se as cultivares BRS 207 e EMBRAPA 22, responsivas à melhoria das condições ambientais, e as cultivares BRS 254 e EMBRAPA 42, pela adaptabilidade específica a ambientes desfavoráveis ao cultivo de trigo irrigado

Saúde do solo em sistemas de integração lavoura pecuária.

Nos últimos 45 anos, com a incorporação de solos do Cerrado ao processo agrícola, foi desenvolvida no Brasil, uma agricultura tropical única no mundo. Diferentemente dos demais locais com extensas áreas agrícolas no planeta, a agricultura do Cerrado foi estabelecida em solos ácidos e pobres em nutrientes, em uma região em que a distribuição de chuvas é concentrada em um período, geralmente, de seis meses. Investimentos feitos pelo governo federal em infraestrutura básica, instrumentos de política agrícola e especialmente, ciência e tecnologia para agricultura tropical, resultaram no desenvolvimento e incorporação de tecnologias modernas para os sistemas de produção no Cerrado. De país importador de alimentos na década de 1970, o Brasil é atualmente um dos grandes exportadores de alimentos