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

Gabriel Dehon Sampaio Peçanha Rezende,Odair Bison,Magno Antonio Patto Ramalho,Aurélio Mendes Aguiar,Marcos Deon Vilela De Resende

doi:10.1590/s1415-47572007000300019

Abstract

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.

Highlights

The success with improvement of eucalyptus in Brazil focusing on wood volume is undoubted but while the companies involved in the large-scale production of eucalyptus want the selection program for wood volume should continue they want other factors to be included that could reduce specific wood consumption or the costs of the industrial process
Selection studies targeting the cellulose industry have concentrated on the species Eucalyptus grandis and Eucalyptus urophylla as well as their respective hybrids, it would be very important to introgress alleles of other Eucalyptus species aimed at enhanced wood quality
Considering the circumference at breast height, the difference between the highest mean obtained in São Mateus and the lowest in Aracruz was only 2.6 cm (8.5% of the general mean) while for wood density (WD), the amplitude of variation between the sites was 21.7 kg.m-3, or about 5% of the general mean (Table 2)

Summary

Introduction

The success with improvement of eucalyptus in Brazil focusing on wood volume is undoubted but while the companies involved in the large-scale production of eucalyptus want the selection program for wood volume should continue they want other factors to be included that could reduce specific wood consumption or the costs of the industrial process. One option is the species Eucalyptus globulus from temperate climates which it probably has worse adaptation properties to tropical climates presents higher wood density and a lower lignin content than E. grandis and E. urophylla, allowing an increase in cellulose yield and reduced costs in regard to fiber extraction. F1 hybrids with E. globulus, a species that has as much large flowers than E. grandis and E. urophylla (Potts and Dungey, 2004). In this case F1 hybrid seeds can only be produced using E. globulus as the pollen parent (Gore et al, 1990). One strategy is to use diallel crosses to evaluate the combining ability clones. By means of diallel crossings it is possible to obtain information on the combining ability as well as draw conclusions on the type of genetic effect that prevails in the control of the traits

Objectives

Methods

Results