AMMI analysis of potato cultivar yield trials

Potatoes, Solanum tuberosum (L), are cultivated in South Africa under a variety of different climates and seasons. The wide environmental variation encountered and the confirmed occurrence of genotype-environmental interaction necessitates the use of criteria, other than averages, in the evaluation and selection of new potato cultivars. Yield data from cultivar trials countrywide, were used to evaluate the use of the AMMI model against the existing Finlay-Wilkinson regression technique. The AMMI model was found to be suitable for determining the reaction of cultivars/lines in an environment. The usefulness of the technique improves with a graphical presentation of the results to display the stability of a genotype in different environments.