Three new concepts of genotype wide adaptation levels I, II and III are presented and shown to the adequate describing quantitatively by measures such as superiority measure, Pi, Eskridge’s yield reliability measure, Ri and Eskridge’s yield reliability function, Ri(d). These indices have been called quantitative measures of genotype wide adaptation levels I, II and III, respectively. Relationships (consistency) between the three measures were studied using data for grain yield of winter wheat advanced lines from 15 preliminary multi-environment trials carried out across Polish test locations in the years 1993–2007. The quantitative measures are simple to interpret and useful quantitative characteristics of genotype wide adaptation levels I, II and III. High Spearman rank correlation coefficients were found between each of the pairs of the quantitative measures of genotype wide adaptation levels I, II and III within all sets of winter wheat genotypes. Then, for evaluating wheat genotype wide adaptation level in each aspect only one of the considered measures could be sufficient. The studies delivered new results on the usefulness of quantitative measures of genotype wide adaptation level for winter wheat. These findings indicate that those measures could be also useful for comparative evaluation of genotype wide adaptation level in other crops.
Authors:A. Derejko, M. Studnicki, W. Mądry and E. Gacek
The grouping of locations from local-scale multi-environmental trials (METs) into megaenvironments has been criticized. Some European countries, e.g. the Czech Republic, Poland and Germany, have been characterized as possessing homogeneous environmental conditions. For aligned environmental conditions, it has been assumed that cultivar rankings will be similar and consequently cannot be used to designate mega-environments. An example of METs at the local scale is the Polish Post Registration Variety Testing System. The objective of this study was to determine groups of test sites within 16 Polish regions which are characterized by similar yield ranking of 50 winter wheat cultivars over three growing seasons (2011–2013). The compatibility of these cultivar yield rankings across regions was evaluated using Pearson correlation coefficients. Thereby, the 16 regions were divided into six groups (mega-environments) of locations. Regions within each group have similar cultivar rankings, whereas between groups, we observed different cultivar rankings, indicating crossover interactions. Besides similar cultivar yield responses the regions within megaenvironments were characterized also by similar environmental (soil and/or climate) conditions.