Differential Energy Allocation Among 15 New Guineagrass (Panicum Maximum Jacq.) Hybrids

The main aim of this research work was to determine trends of energy allocation among newly developed guineagrass (Panicum maximum Jacq) hybrids, ranging from very-early to late-flowering genotypes. Besides the flowering cycle, eight phenological and two seed quality traits were scored in a greenhouse randomized complete block experiment including plant height (PH), reproductive tiller number/overall tiller number (RTN/OTN), panicle number/reproductive tiller (PN/RT), leaf length (LL), leaf width (LW), panicle length (PL), fresh weight (FW), dry weight (DW), number of seeds/gram (NS/G) and seed sample physical purity (SPP). Very-early and early-flowering hybrids consistently showed the highest correlations values between flowering cycle and RTN/OTN (r= - 0.59**), PN/RT (r= - 0.48**), NS/G (r= - 0.88**) and SPP (r= - 0.80**) (reproductive functions) while intermediate and lateflowering hybrids showed the highest values for LL (r= 0.53**), LW (r= 0.60**), PL (r= 0.77**), FW (r= 0.78**) and DW (r= 0.85**) (vegetative functions). The implications of these results for plant breeding and forage management purposes are discussed

Differential Behaviour of Guineagrass (\u3cem\u3ePanicum Maximum Jacq.\u3c/em\u3e) Hybrids, With Different Al\u3csup\u3e+3\u3c/sup\u3e Reactions, as to Major Nutrient Translocations to the Leaves

Most of the Brazilian cultivated pasture fields presents soils with high Al+3 levels and liming is economically unfeasible. So, there is an urgent need for grasses with good forage yielding potentials that can withstand Al+3 deleterious effects (abnormal root development: short, thick and poorly branched roots, which are unable to effectively translocate water and essential nutrients to the leaves) (Foy, 1984); as a consequence, susceptible genetic materials have their field persistences greatly affected, mainly during drought periods. Researches on Al+3 reaction are usually compare supposedly resistant/tolerant genotypes with a resistant control check; doing so, the genotypic effect is not isolated, making unreliable the comparisons made (Thomas & Lapointe, 1989). Guineagrass hybrids were tested as to nutrient translocations to the leaves, through comparisons of results obtained in treatments with and without N, P and K applications to the soil, for each genotype

Effect of Sowing Time on Phytomass Production during Early Growth of Two Varieties of \u3ci\u3eStylosanthes guianensis (Aubl.) Sw.\u3c/i\u3e

The objective of this research was to determine the effect of two sowing times on phytomass production of two varieties of Stylosanthes guianensis (var. pauciflora and var. vulgaris). Two experimental periods were studied (1: January - May/1998 and 2: November/1998 - March/1999) using a completely randomized factorial design 2 x 2 x 14 (two periods, two varieties and fourteen ages of evaluation), with four replications. The results showed a difference between the periods concerning the growth and development of Stylosanthes, and that period 2 was the most favourable to this forage plant. There was, also, different adaptability between the two varieties concerning the sowing times. The var. pauciflora was more adapted in period 1, and the var. vulgaris, in period 2. The data showed the possibility of selecting Stylosanthes cultivars adapted to different seasonal conditions

The use of Moringa oleifera seeds for treatment of surface water

This research had as its main purpose the evaluation of the use of natural coagulate, obtained from Moringa oleifera seeds and their efficiency in the slow direct filtration and sedimentation processes for the treatment of highly turbid water. In developing countries such as Brazil, technologies for water treatment must provide the possibility of water purification in an easy, self-maintainable and low cost process, for people who live in regions characterized by shortage of drinking water. Studies so far suggest that there is a potential application of Moringa oleifera in the water treatment with slow direct filtration. A flocker composed of a PET bottle and three filters composed of similar bottles with non-woven synthetic blanket were used in the slow filtration, with a discharge of affluent water to the filters of approximately 4 m³ m-2 d-1. In the water treatment process evaluation of the sedimentation efficiency, a flocker composed of PET bottles and a sedimentation tank was used. The water used for these experiments was the synthetic water obtained by bentonite, which presents adequate qualitative characteristics for the analysis.Visou-se, no presente trabalho, estudar o uso de sementes de Moringa oleifera para tratamento de água superficiais por filtração lenta direta em mantas sintéticas não tecidas e por sedimentação simples. Nos países em desenvolvimento, como o Brasil, as tecnologias para tratamento de água devem proporcionar às pessoas que habitam em regiões carentes de água potável, a possibilidade de sua clarificação, de maneira fácil, auto-sustentável e a baixo custo. Os estudos referidos no presente trabalho sugerem haver potencial de aplicação da Moringa oleifera. Utilizaram-se, no tratamento da água com Filtração Lenta Direta, um floculador constituído de garrafa Pet e três filtros, do mesmo material, com mantas sintéticas não tecidas, empregadas na filtração lenta, com vazão de água afluente aos filtros de aproximadamente 4 m³ m-2 d-1. No processo de tratamento de água em que se avaliou a eficiência da operação de sedimentação, o floculador era de garrafas pet e um tanque de sedimentação. A água bruta empregada na realização dos experimentos foi a água sintética obtida por Bentonita, a qual apresenta características qualitativas adequadas aos ensaios.76577

Seleção entre e dentro de famílias de meios-irmãos no milho dentado composto/NE M11 - HS II.

A substituição de variedades pouco produtivas, cultivadas há longos tempos pelos agricultores, tem sido uma das constantes preocupações por parte do pessoal envolvido com programas de milho no Nordeste

Agricultura e biodiversidade nas ciências sociais brasileiras: alimentando a comunicação entre ciência e políticas públicas.

O presente artigo decorre de uma reflexão sustentada em dois pressupostos: a) que as ciências e, em particular, as sociais, podem contribuir para informar as tomadas de decisão e a formulação de políticas públicas visando a melhoria da vida das pessoas no planeta e b) que o papel da agricultura na conservação da biodiversidade é uma questão atual de extrema relevância e que merece ser aprofundada. A relação entre a agricultura e a biodiversidade tem sido objeto de questionamentos recentes na sociedade e no campo das políticas públicas. Contudo, se os estudos relacionados à biodiversidade e à agricultura, separadamente, têm observado um considerável crescimento no Brasil, poucos são os investimentos de pesquisa sobre a relação entre esses dois grandes temas. A partir dessas considerações, seguimos dois objetivos principais: 1) investigar como o papel da agricultura familiar na preservação da biodiversidade tem sido abordado pelas Ciências Sociais no Brasil, particularmente nos artigos publicados em periódicos brasileiros nos últimos 20 anos; 2) testar uma metodologia de revisão bibliográfica, criteriosa, que possa ser útil aos tomadores de decisão em políticas públicas e demais interessados