Incidência dos principais fungos fitopatogênicos em sementes de sorgo (Sorghum bicolor (L.) Moench), em duas épocas de colheita.

O teste de sanidade das sementes foi realizado com o objetivo de avaliar a qualidade sanitaria das sementes de sorgo. O material genetico utilizado era formado por 11 linhagens e quatro hibridos de sorgo granifero. Observou-se que as linhagens/hibridos tiveram comportamento diferenciado quanto a incidencia de patogenos nas sementes. Os periodos de colheita e as condicoes ambientais devem ter sido suficientes para alterar, significativamente, as frequencias de patogenos associados as sementes das amostras analisadas

Adequacao de modelos no estudo do coefiente de trilha dos componentes primarios e secundarios de progenies F6 de soja (Glycine max (L.) Merrill).

Progenies F6 de soja, oriundas de selecoes entre familias F5 do cruzamento 'FT-Cometa' x 'IAC-8', foram avaliadas em Vicosa,MG. Os coeficientes de correlacoes entre nove caracteres quantitativos foram desdobrados em efeitos diretos e indiretos, considerando-se um diagrama em cadeia e os modelos aditivos e multiplicativos da producao de graos, alem de seus componentes primarios. As analises de trilha, com dados logaritmizados (aditivo) e nao-logaritmizado (multiplicativo), apresentaram os mesmos caracteres em ordem de importancia. Entretanto, o modelo aditivo foi mais eficiente ao traduzir a determinacao total dos componentes primarios sobre a producao de graos, devendo ser indicado para essas situacoes. O numero de vagens por planta, como componente primario, e dias para maturacao, altura da planta na maturacao e numero de nos na floracao, como componentes secundarios, aprarecem como os mais importantes no processo de selecao indireta pra aumento da producao de graos de soja

Efeito do tratamento de sementes sobre a germinação e necrose cotiledonar da soja, Glycine max (L.) Merrill.

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Balanco hídrico num latossolo vermelho escuro álico cultivado com milho com irrigação por aspersão.

The water balance components were determined for cerrado soil planted with corn (Zea mays L.) under sprinkler irrigation conditions. A neutron probe was used to determine the soil moisture profile, which was then used, in association with soil water potential, to estimate deep percolation and evapotranspiration fluxes. The method used to estimate deep percolation and evapotranspiration fluxes proved to be reliable for soil water stress condition and unreliable for rainy day condition, when water storage increased in the soil profile. The upward movement of soil water was the major source of water supply for corn growth, mainly after a shortage of water in the soil profile. Deep percolation represented up to 67% of total water loss (Through drainage and evapotranspiration). The averages for evapotranspiration fluxes, with no water stress condition, were: 1,94mm day -1, for 42 through 60 days after planting; increasing to 5,19mm day -1, during 60 through 84 days after planting, raching a maximum of 5,96 mm day -1, during 84 through 108 days after planting; and decreasing to 4,25mm day -1, during 108 through 115 days after planting

Qualidade de sementes de soja BRS Tracajá, colhidas em Roraima em função do tamanho no armazenamento.

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Carbon exchange in a Caatinga area during an unusually drought year.

The objective of this study was to analyze the daily and seasonal variation of the carbon balance components in a caatinga area during an unusually drought year. Data were collected from a turbulent vortices covariance system installed at an area in Caatinga, in the region of Petrolina Municipality, State of Pernambuco, Brazil. Carbon dioxide flux data were collected in the year 2012, and the partitioning between gross primary productivity (GPP) and ecosystem respiration (Re). The vegetation cover index, weather elements and the soil water content were monitored. It was observed that the daily emissions of CO2 flux was dependent upon photosynthetically active radiation in the first days after rainfall events, being influenced by the water vapor pressure deficit with the reduction in the soil water content. The occurrence of up to 2 mm rainfall promoted peaks of Re after long periods of drought. The measured NEP was equal to 468.18 gC m-2 year-1. So, it is concluded that in years with severe drought, Caatinga may act as a source of carbon to the atmosphere