Performance of Eucalyptus Clones in Auto and Allocompetition

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 (c_i), ability to tolerate competition (t_j), the specific competitive ability (s_ij) and the performance per se of the clones (a_j) were estimated using a model similar to that of diallel crosses. The clones differed as to their c_i, t_j and a_j. No one clone exhibited high and positive c_i and t_j. 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.