Experimental Designs for the Evaluation of Candidate Varieties

Selection for a trait with quantitative variation is often based on a comparison of the candidates with regard to the trait. The probability of correct selection is higher as the environmental conditions under which the candidates are compared are more similar. For this reason breeders always seek trial fields providing growing conditions as uniform as possible. When knowing the plantto- plant or the plot-to-plot trend in the quality of the growing conditions, the breeder may adjust the phenotypic values observed for the candidates according to a procedure dedicated to the elimination of the contribution of the trend to these values (Chapter 14).