New approaches for evaluation the grain yield of winter wheat in contrasting environments

Purpose is to verify the new approach for correct separating of wheat varieties in groups matching particular standards of their level of grain yield during the years and towards the different environmental conditions. Materials and Methods: 76 breeding lines were researched for two consecutive years. The first one was with favorable conditions for growing (2006) and the second one in 2007 was characterized by well-defined prolonged drought and unusually high temperatures during the active growing season of crop. Real values of grain yield of each variety were used for the calculation of breeding indexes, which establishes the level of tolerance to abiotic stress. It was made classification based on indices and parameters derived from combinations between them. The separation into groups according to their level of grain yield was founded on direct comparison using the correlations established these indices and combinations. Main Results: By applying the score assessment of the values of the studied indices and parameters is quite possible grain yield genotype be evaluated during contrasting environmental conditions. It was very clear the importance of derivatives indices by newly formed parameters because they were used to value the other cultivars in the certain group. Conclusions: The suitability of the new integrated approach to practical grouping of varieties, according to grain yield in contrast growing conditions was confirmed. An efficient method is proposed for grain yield assessment through all season which dissimilar weather conditions influences on wheat.