MORPHOLOGICAL CHARACTERIZATION OF PORTUGUESE ITALIAN RYEGRASS LANDRACES

Italian ryegrass (Lolium multiflorum Lam.) is one of the most important forage grass species in Europe. In Portugal 34% of the cultivated area is dedicated to animal fodder. Italian ryegrass area in Entre Douro e Minho (EDM) region was mainly with landraces. Changes in traditional agricultural systems are contributing to a major loss of genetic diversity mainly to landraces. Portuguese Italian ryegrass landraces are threatened since nineteen years and collecting missions took place in EDM to ex situ conservation. The main Italian ryegrass landraces from EDM are “castelhano’s” and “verdeal’s” agro type. The aim of this study was to evaluate the existence of morphological variability between EDM Italian ryegrass landraces, to analyse the existence of duplicates in the germplasm collection and to evaluate the farmer’ classification. The landraces were characterised based on morphological traits of International Plant Genetic Resources Institute and International Union for the Protection of New Varieties of Plants descriptors list and the most discriminated traits were utilised in the multivariate analysis, using NTSYS v.2.0. Italian ryegrass accessions belong to two different agro types based on morphological characteristics and farmers identified. Each landrace showed inter-population variability mainly on “verdeal” landrace. It was possible to differentiate the most of ryegrass accessions using the morphological traits used were initial stage of plant maturity. The EDM germplasm preserves the Italian ryegrass genetic diversity, which is conserved in ex situ and is a good basis for research programs

Qualitative Approach to Semi-Classical Loop Quantum Cosmology

Recently the mechanism was found which allows avoidance of the cosmological singularity within the semi-classical formulation of Loop Quantum Gravity. Numerical studies show that the presence of self-interaction potential of the scalar field allows generation of initial conditions for successful slow-roll inflation. In this paper qualitative analysis of dynamical system, corresponding to cosmological equations of Loop Quantum Gravity is performed. The conclusion on singularity avoidance in positively curved cosmological models is confirmed. Two cases are considered, the massless (with flat potential) and massive scalar field. Explanation of initial conditions generation for inflation in models with massive scalar field is given. The bounce is discussed in models with zero spatial curvature and negative potentials.Comment: Online at http://www.iop.org/EJ/abstract/1475-7516/2004/07/01

Influência da umidade inicial na produção de holocelulases por espécies de Lentinula em biomassa de Eucalyptus benthamii.

Editores técnicos: Marcílio José Thomazini, Elenice Fritzsons, Patrícia Raquel Silva, Guilherme Schnell e Schuhli, Denise Jeton Cardoso, Luziane Franciscon. EVINCI. Resumos

Temperature effects on dislocation core energies in silicon and germanium

Temperature effects on the energetics of the 90-degree partial dislocation in silicon and germanium are investigated, using non-equilibrium methods to estimate free energies, coupled with Monte Carlo simulations. Atomic interactions are described by Tersoff and EDIP interatomic potentials. Our results indicate that the vibrational entropy has the effect of increasing the difference in free energy between the two possible reconstructions of the 90-degree partial, namely, the single-period and the double-period geometries. This effect further increases the energetic stability of the double-period reconstruction at high temperatures. The results also indicate that anharmonic effects may play an important role in determining the structural properties of these defects in the high-temperature regime.Comment: 8 pages in two-column physical-review format with six figure