Gabriel Dehon Sampaio Peçanha Rezende

Combining ability of elite clones of Eucalyptus grandis and Eucalyptus urophylla with Eucalyptus globulus

In Brazil, eucalyptus breeding programs for cellulose production has used two species, Eucalyptus grandis and Eucalyptus urophylla. Nevertheless, it would be useful to introgress alleles from other species to improve wood quality and volume. The objective of this research was to evaluate the hybrid potential of elite clones of E. grandis and E. urophylla from the Aracruz Celulose Company S. A. with Eucalyptus globulus clones. To do so, six elite clones were crossed with ten E. globulus clones in a half-diallel mating design. The resulting hybrid combinations as well as the four check clones were evaluated in randomized complete block experiments with single plant plots and 40 replicates from September to October 2001 at three Brazilian sites, Aracruz and Sao Mateus in the Espirito Santo state and Caravelas in Bahia State. Two years later the circumference at breast height (CBH) and the wood density (WD) were measured. The means were submitted to diallel analysis according to the Griffing method (1956), adapted by Geraldi and Miranda Filho (1988). Although the number of clones involved was small, the crossings of elite clones of E. grandis and E. urophylla with clones of E. globulus were promising, especially for wood quality gains.

Comparison Between Open Pollinated Progenies and Hybrids Performance in Eucalyptus grandis and Eucalyptus urophylla

Summary The cellulose industry in Brazil uses, mainly, hybrids between Eucalyptus grandis × E. urophylla. Not only the volume but also the wood density has great influence in the cellulose productivity, therefore a selection for both characteristics should be done as an alternative to increase the improvement program efficiency. The present work has been carried out with the objective of comparison between Open Pollinated progenies (OP) and hybrids performance in E. grandis and E. urophylla. To do so, 15 OP progenies of E. grandis, 15 OP progenies of E. urophylla, and 15 hybrids between E. grandis × E. urophylla, plus four controls were evaluated. The experiment was carried out from October to November 2001, in three sites, Aracruz and São Mateus, in the Espírito Santo State, and Caravelas, Bahia State, Brazil, in a 14 × 14 lattice design, involving the 49 treatments mentioned plus other progenies not considered in this article, with single tree plots and 40 replicates. Two years later the circumference at breast height (CBH) and the basic wood density (BWD) were evaluated. The hybrids performance for CBH was higher, an average, 38,7% than the OP progenies for both species. Part of the heterosis in relation to parental means could be attributed to the inbreeding depression due to selfing that occurred in the OP progenies and the dominance controlling this character. For the BWD the hybrids performance was the same of the OP progenies. Since there was divergence between the parents, it can be inferred that dominance has no importance for this trait. The negative correlation between the CBH and the BWD could impair the simultaneous selection for both traits, depending on the wood basic density range used by the industry.

Eucalyptus Breeding for Clonal Forestry

As global demand for wood increases, planted forests will also become increasingly important. Accepting and promoting them as the only way to address the wood scarcity problem and also to help suppress the demand for illegally logged timber from natural forests is a major issue globally. Eucalypt clonal forestry is proving to be an iconic alternative in this context, due to their fast growth, wood quality appropriate to many different uses, huge existing variability, and suitability to vegetative propagation. However, efficient breeding and deployment strategies are essential. The present chapter aims to present, based on the authors’ practical experience, an overview on the most successful approaches that may be used during the different phases of eucalypt breeding programs for clonal forestry. Relevant topics covered are: identifying breeding objectives and related traits for the main eucalypt businesses worldwide; the major planted species and their value for different objectives; breeding strategies (recurrent selection methods, breeding cycle, etc.); recombination issues, such as effective population size, mating designs and controlled pollination methods; evaluation and selection procedures as applied to progeny and clonal trials; and deployment aspects, such as number of commercial clones, large scale vegetative propagation methods, and risk management.

Comparison of Sample Preparation Methods for NIR Analysis of Carbohydrate Content of Unbleached Eucalyptus Pulps

Abstract Near-infrared (NIR) spectroscopy provides a rapid method for estimating pulp carbohydrate content. Previous studies have used a variety of sample preparation methods; however, the influence of preparation method on calibration performance has not been examined. This study compares carbohydrate content calibrations for four sample preparation methods (coarse, fine, and milled pulp, and handsheets). Fifty-nine unbleached pulps (52 single-tree, 7 mill composite) with known carbohydrate composition (arabinose, fructose, galactose, glucose, rhamnose, and xylose) were prepared using the four methods. NIR spectra were collected from the samples, which were divided into calibration (40 samples) and prediction sets (19 samples). Calibrations were created for each combination of preparation method and carbohydrate, and tested on the prediction set. Calibration statistics were good for rhamnose and xylose but weaker for other carbohydrates. Coarse and fine pulp produced the best calibrations, but they were not significantly different from calibrations for handsheets; milled pulp provided the weakest calibrations.

Dialelo parcial entre clones de Eucalyptus camaldulensis e clones de E. urophylla, E. grandis e E. saligna

The objective of this research was to evaluate the hybrid potential between E. grandis, E. urophylla and E. saligna clones from Aracruz Celulose S. A. with E. camaldulensis clones. To do so, six elite clones were crossed with ten E. camaldulensis clones, in a half-diallel mating design. The resulting hybrid combinations as well as the four check clones were carried out from September to October 2001, in three sites, Aracruz and Sao Mateus, in the Espirito Santo State, and Caravelas, Bahia State, in a completely randomized block design with single plant plots and 40 replicates. Two years later, the circumference at breast height and the wood basic density were measured. The means were submitted to a diallel analysis, according to the Griffing (1956) method, adapted by Geraldi and Miranda Filho (1988). It was observed that the diallel crossings were promising for both the wood volume and wood quality gain. The general combining ability was responsible for most of the variations between the hybrids.

Development of near infrared calibrations for physical and mechanical properties of eucalypt pulps of mill-line origin

Near infrared (NIR) spectroscopy has been used in several studies to predict the physical and mechanical properties of pulp hand-sheets. In most of these studies, wood samples were pulped in a laboratory under different regimes and/or refined to introduce variability into the data set. This study investigates the potential of NIR spectroscopy to create calibrations for eucalyptus pulp properties of mill-line origin. Seven mechanical properties (air resistance, compressibility, drainability, hygro-expansivity, stretch, tensile index and tensile stiffness) and three physical properties (bulk density, specific volume, and surface area) were investigated. Coefficients of deter mination (R2) for all 10 properties were poor. The R2C value exceeded 0.70 for only one property (tensile index), while the R2CV values exceeded 0.40 for only two properties (drainability and surface area). Ratios of performance to deviation were equally poor, ranging from 0.87 for bulk density to 1.28 for drainability. These statistics indicate that none of the calibrations could be used to accurately predict the properties of unknown samples. The poor performance of the calibrations is likely due to the low variability of our dataset, which is generally inherent in samples of mill-line origin.

Estimation of whole-tree wood quality traits using near infrared spectra of increment cores

There is worldwide interest in the potential of eucalypts for fibre production. Selection of the most suitable stock for propagation is important and many wood quality traits related to pulp production are measured. Effective evaluation requires rapid, inexpensive and preferably non-destructive techniques. Near infrared (NIR) spectroscopy provides a rapid method for evaluating a range of wood quality traits but studies are generally limited to the evaluation of whole-tree properties requiring destructive sampling. In this study we compare calibrations for wood quality traits obtained using whole-tree data and NIR spectra obtained from milled wholetree composite chip samples, and 5mm diameter increment cores non-destructively sampled from 0.65m and 1.30 m. Increment core and whole-tree composite calibrations provided similar results indicating that calibrations based on increment cores can be used to estimate wood quality traits on a whole-tree basis. Of the two heights investigated 1.30m was identified as the most suitable height for nondestructive sampling.

Estimativas de parâmetros genéticos para a seleção precoce em clones de Eucalyptus spp.

Departamento de Engenharia Florestal UNICENTRO-Universidade Estadual Do Centro-Oeste., PR 153, Km 07-Riozinho