Optimizing the Evaluation of Candidates by means of Plots

At the end of Section 8.1 it was indicated why selection tends to be an inef- ficient process. Section 12.1 presented additional causes for this phenomenon. Breeders should therefore make efforts to promote the efficiency of selection in a situation where opportunities to be successful are apparently unfavourable. In the two preceding chapters the topic of disclosure of the genotypic values of candidates in situations where their phenotypic values strongly depend on the quality of the growing conditions, including the strength of the competition exerted by nearby fellow candidates, has been thoroughly considered. However, the evaluation of the genotypic values of candidates needs also to be optimized with regard to other points of view. A few of these are considered in this chapter. The optimum number of plots per candidate, i.e. the optimum number of replications, is considered in Section 16.1. Section 16.2 gives attention to the size, the shape and the positioning of the test plots. The optimum plot size from an economic point of view is also considered (Section 16.2.3).