Environmental influence on grain quality stability of common wheat cultivars

The purpose of the study was to determine the stability of winter wheat (Triticum aestivum L.) cultivars according to the quality indices: deformation energy (W), alveograph P (dough tenacity) to L (dough extensibility) ratio (P:L), and dough extensibility (swelling) index (IE). The data were collected from four locations with different climatic conditions, in three consecutive years. The evaluation of the cultivar stability was made for each index using the statistical software PBSTAT specialised for this purpose. The information from its 16 different parameters is combined into a parameter stab16, by which the cultivars are compared for stability. The indices studied are influenced to varying degrees by the environmental (E) conditions. As a result of a reliable genotype and environment interaction (G x E), the stability ranking of cultivars according to the ranks of each of the parameters was very different. The level of stability of the cultivar in the studied different aspects of its grain quality is related to different levels of the indices. For the IE index, many of the studied cultivars are unstable in performance, which excludes its use for stability assessment. A limited number of cultivars combine a high and stable quality in different environmental conditions (c6 and c7). The W and P:L indices can be used independently to evaluate the stability of the cultivar as an additional characteristic of its quality. The estimation of cultivar stability by averaging the ranks of parameters (stab16) proved to be an effective approach due to its proven high and positive correlations with most of the 16 parameters. The applied analogical approach for the simultaneous assessment of quality stability does not provide correct information for the individual cultivar due to a significant discrepancy when comparing the information from each of the three indices.