Yield size is the product of the genetic properties of the cultivar, environmental conditions, and the applied agrotechnics, including herbicide application. In agricultural practice, cultivars with high adaptation to changeable environmental conditions and tolerant in relation to many active substances of herbicides are preferred, as this ensures the obtainment of stable yield. The aim of the work was the evaluation of the effect of different herbicides on the yield changeability of winter wheat cultivars grown in diversified environmental conditions in Lower Silesia. In the years 2010-2013, field experiment was carried out on the yield changeability of four winter wheat cultivars (Boomer, Cubus, Nadobna, and Rapsodia) depending on the herbicide and environmental conditions. Studied environments were located in two towns in the vicinity of Wrocław, with diversified soil conditions (podsolic soil and chernozem). Three herbicides with different action mechanisms were applied: Panida 330 EC (pendimethalin), Snajper 600 SC (diflufenican + isoproturon), and Axial 100 EC (pinoxaden) with adjuvant Adigor 440 EC. Multivariate analysis of variance and discriminant analysis were used for the evaluation of the yield changeability of wheat cultivars in the particular environments. In order to group herbicides of similar effect, Ward’s method of cluster analysis was applied. Cultivar Rapsodia was characterized by significantly higher yield, whereas Nadobna gave lower yield, in particular on chernozem. The studied variants of plant protection against weeds did not diversify the yield size of winter wheat cultivars. Cultivar Cubus was characterized by higher yield stability in comparison with the other cultivars. Herbicide Panida 330 EC contributed to the higher yield changeability of the studied cultivars. The chemical may contribute to the reduction in grain yield of some winter wheat cultivars in unfavourable environmental conditions.

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