Would it be possible to reduce the number of repetitions in the evaluation of clones in a single tree plot?

Abstract

In clonal progenies tests, using experiments with one single tree plot, the number of repetitions (cloned plants of each individual of the progenies under evaluation) must be smaller than the traditionally employed. This is because obtaining clones of each individual from the progenies must be carried out in the shortest possible time and, thus, contribute to the greatest advantage of clonal progenies test, which is to identify new clones earlier than other selection alternatives. With the objective of obtaining the minimum number of repetitions necessary in one single tree plot for use in clonal progenies tests, without significantly affecting the selection accuracy, this work was carried out. To estimate the minimum number of repetitions (number of plants of each clone), data obtained from the evaluation of 60 eucalyptus clones, with 30 repetitions in one single tree plot, conducted in six sites, were used. In these experiments, the mean annual increment (cubic meter per hectare per year) was evaluated. Through 1000 resamplings, without replacement, experimental data were obtained with the number of repetitions ranging from 2 to 29. The estimates of the general mean, genetic variance between clones and the selection accuracy obtained showed that, the estimates of general mean, genetic variance between clones and selection accuracy in means were very similar. It was inferred that for clonal progenies tests, in which the experiments will certainly be carried out in more sites, it is feasible to use five repetitions per experiment.