Performance of Eucalyptus Clones in Auto and Allocompetition

Abstract

This study was performed to estimate the abilities of eucalyptus clones to exercise as well as to tolerate competition and to compare their behaviors under auto- or allocompetition. Six commercial clones, belonging to PLANTAR S/A enterprise were evaluated for breast height circumference (BHC), total height (TH) and volume (VOL). At three locations of Minas Gerais, Brazil (two in Curvelo and one in Felixlândia) the clones were planted in two spaces. At 36 months of age each clone was evaluated for exercising and toleration competition amongst each other. The design for each experiment was similar to that of the nine-hole system; the center clone being under competition and the eight surrounding the center clone exercising competition. Each clone under competition was repeated eight times; therefore, for each spacing and location, six contiguous experiments were conducted. From the mean values; the parameters of ability to exercise competition (ci), ability to tolerate competition (tj), the specific competitive ability (sij) and the performance per se of the clones (aj) were estimated using a model similar to that of diallel crosses. The clones differed as to their ci, tj and aj. No one clone exhibited high and positive ci and tj. Regardless of location, spacing, or clone, the performance of autocompetition is similar to that of allocompetition. This indicates that a mixture of clones, if advantageous from the management or industrial point of view, may be performed without harm to the volume of wood produced.

Intra-and intergenotypic competition among commercial eucalyptus clones

“…Therefore, competition has a greater influence on DBH performance of the clones with canopy closure. Wood volume was more affected by intra-than intergenotypic competition, as this trait is calculated based on almost all other measurements (Martins et al 2014). Thus, for wood volume and MAI, there was an interaction of clones with the level of competition.…”

“…Alternatively, plantations with genetically heterogeneous individuals may result in improved sharing of resources as they are better able to exploit the resources available (Chesson 2000, Silvertown 2004, Boyden et al 2008. Furthermore, differences in growth habit and leaf, branch, and root architecture among clones can promote higher productivity depending on the different needs of the plants (Martins et al 2014).…”

“…For VOL and MAI, at 3 years, almost all clones obtained better or equal performance in intergenotypic competition than in intragenotypic competition. Therefore, clonal mixtures can be incorporated into planting systems without threatening production; they are also advantageous from an industrial perspective (Martins et al 2014), not requiring mixtures of different wood densities in the digester. Nevertheless, clone 5 had significantly lower production in intergenotypic competition, while other clones, such as clones 3 and 4, simply had inferior results.…”

“…To disrupt genetic uniformity, the use of mixtures of clones may increase productivity and benefit individuals in the face of biotic and abiotic stresses, due to unknown interactions that occur between genotypes (Martins et al 2014). These interactions can result in different forms of competition, which have a variable effect on genotype performance, as each genotype has specific competitive capacities (Pavan et al 2011, Pavan et al 2014.…”

The survival, development, and reproduction of Gonipterus platensis (Coleoptera: Curculionidae) on the main Eucalyptus (Myrtaceae) genotypes planted in Brazil

“…The unsuitability of E. camaldulensis and E. grandis to G. platensis , compared to the longer pre-oviposition period, lower number of egg capsules/female, and egg viability with the hybrid ‘H13’ indicate the potential of those species for planting as a management strategy for this pest. These plant materials can be used in separate stands on most of the available area or in mixed ones in mosaic or using E. grandis as a barrier in a mosaic landscape ( Forrester, Bauhus & Khanna, 2004 ; Martins et al, 2014 ).…”