A note on a modelling environmental indexes

Abstract

The paper deals with the structuring of the Genotype x Environmental Interaction in an analysis of series of experiments. Regression analysis is one of the most often applied statistical techniques for this purpose. In regression analysis we should have two sets of variables, one characterizing genotypes while the second characterizing environments. The so-called adjusted means (or some other genotype characteristics) for genotypes usually constitute observations of the dependent variable. The problem is how to model the environmental indexes, these being the observation of independent variable. In the paper we examine three approaches to modelling the environmental indexes; two are based on socalled adjusted means for environments, while the third method uses iterative (”zig-zag”) algorithm for estimation of the considered indexes.