ANALYZING GENOTYPE BY ENVIRONMENT INTERACTION IN DUTCH POTATO VARIETYTRIALS USING FACTORIAL REGRESSION

Genotype by environment interaction was investigated for yield data fr om the official Dutch Variety List trials for potato. The data set inc luded 64 genotypes by 26 environments, where environments consisted of year by soil type combinations. Factorial regression models incorpora ting genotypic and environmental covariates in the interaction were us ed to analyse the data. The merits of factorial regression models were compared with those of biadditive models. Factorial regression models and biadditive models described comparable amounts of interaction, bu t factorial regression models provided a better basis for biological i nterpretation of the interaction.