The characterization of performance of sugar beets by variety × environment interaction

Summary

When planning variety tests over several locations and years, not only the main factors but also the possible interactions should be considered. In this paper we understand the term ‘variety x environment interaction’ for each variety as a linear function of the environmental effects. This type of interaction may be estimated by ß_i, the coefficient of regression. ß_i serves as an additional parameter to the mean for the performance of varieties under different environmental conditions. In contrast to the exclusive use of the mean in the characterization of varieties, the additional introduction of ß_i completes the variety description. This paper demonstrates that the environmental interaction of sugar beet varieties reaches sizable levels and that significant differences exist between the variety-specific interactions. If two varieties do not differ significantly in their means the proposed procedure supplies parameters to decide which variety is worth to be cultivated on the basis of its performance level at the location.