970 resultados para Caracteres tipográficos


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Eucalyptus camaldulensis has great importance in Brazil because of their phenotypic plasticity for different environmental conditions, as soils, altitudes and rainfall. This study is an investigation of a base population of E. camaldulensis from Australia through a progeny test implanted in Selvíria, MS. The trial was established in a randomized block design, with 25 families and 60 replications of single tree plots. Genetic parameters for anatomic traits and volume shrinkage were estimated, as well as their correlations with wood basic density. No significant differences among progenies were observed for the traits studied. The additive genetic variation coefficient at individual and among progeny levels ranged from low (0.26%) to high (16.98%). The narrow sense heritability at individual and family means levels also ranged from low (0.01) to high (0.87). This indicates that some traits are under strong genetic control and can be improved by selection. In the present situation, in order to attain the highest genetic gains, the sequential selection among and within progeny would be recommended.

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The aims of this study were to evaluate the variation and to estimate genetic parameters for silvicultural anatomic wood traits for genetic breeding of a Myracrodruon urundeuva (Engler) Fr. Allem, population from Selvíria-MS. For this, from samples of a progeny test established in the Fazenda de Ensino, Pesquisa e Extensão da Faculdade de Engenharia de Ilha Solteira/UNESP, macroscopic anatomic wood traits of M. urundeuva (tangential diameter and vases frequency per mm2) and growth traits were measured (height, DBH and stem form). Genetic parameters were estimated in 28 open-pollinated progenies, in three replications and 10 plants per plot, using a REML/BLUP approach. Between the analysed traits, the DBH is the most indicated for selection for timber production, because it presented the highest values of coefficient of genetic variation, heritabilities and selective accuracy. Between the anatomic traits, the vessels frequency in the pith showed the highest values for genetic parameters. For pulp yield, based on the multi-effect index, the strategy of selecting the best trees for vessels frequency in the pith, independent of the progeny, permitted to obtain substantial gains by mass selection, without progeny test.

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Eucalyptus urophylla S. T. Blake is outstanding for valuable wood production potential, adaptation plasticity for different environmental conditions, and for tolerance to canker. However, genetic improvement of this specie in Brazil depends on the existence of genetic variability in the introduced populations. The objective of this study was to investigate the genetic variation and gains in quantitative traits in a population established in 1992 in Selvíria - MS. The progeny trial was established in a partially balanced, 8 x 8 lattice design, with 64 families, collected at Anhembi Experimental Station (IPEF/ESALQ/USP). Each plot was made up of eight trees planted in a 3 × 3 m spacing. Significant among families genetic variations were observed in diameter at breast height (DBH), bark type, stem form, and survival. Estimates of average family heritability were high for all traits, ranging from 0.50 to 0.85. The simulated selection by using multi-effect index showed that under a varying number of plants per family. This method is the most indicated to maximize genetic gains (7.24%) and the effective population size (69.3). These results are a useful support for the transformation of this test into a seedling seed orchard and to become a source of vegetative material to build a clonal seed orchard.

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The objective of this work was to study the morphological and physiological characteristics of the wheat flag leaf as affected by increasing sowing densities and plant growth regulators application. The experimental design was a split-plot with completely randomized blocks and four replications. Plots were consisted by four sowing densities (30, 50 70 and 90 plants m-1) and the split-plots by plant growth regulators: a product composed by auxin+gebberellin+cytokinin (Ax+GA+CK), Trinexapac-Ethyl e (Ax+GA+CK) + Trinexapac-Ethyl, and a control without application. Dry mass accumulation, plant height, morphological characteristics, SPAD index, nitrogen and photosynthetic pigments contents in the flag leaf were determined. The increase in the sowing density resulted in lower dry mass accumulation and SPAD index of the flag leaves. Trinexapac-Ethyl caused increase in the SPAD index, but the chlorophyll content of the flag leaf was reduced. The SPAD index values were more correlated with the nitrogen than the chlorophyll contents. Ax+GA+CK did not affect flag leaf characteristics in wheat plants.

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Two experiments were conducted in southern Brazil in no-tillage system, in order to estimate genetic parameters and the direct and indirect effects of components for achene yield as a selection criterion in sunflower. We analyzed eight sunflower hybrids at two locations, in a randomized complete block design with four replicates, determined through quantitative descriptors: insertion height of the head, and head stem diameter, weight of 1000 achenes, number of achenes per head, mass by achene head and yield achene. Estimates of genetic parameters were based on combined analysis, decomposing interactions in genetic and environmental components. Considering the coefficient of genetic variation, indirect effects of components and heritability, there are higher possibilities for responses to selection in sunflower achenes by descriptors mass and mass of achenes per head, with its indirect association interrelated pathways for the increase in the achenes of yield.

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Pós-graduação em Ciências Biológicas (Biologia Celular e Molecular) - IBRC

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)