Evaluation of new winter wheat varieties in diverse environments

Yield stability is largely determined by the ability of varieties and hybrids to withstand unfavorable environmental factors. Multi-environment variety testing is one of the most important approaches for assessing the adaptability, ecological plasticity, and stability of genotypes under contrasting growing conditions. In the present study, the grain yield of 15 winter wheat varieties was analyzed across 17 environments representing the three main natural and climatic zones of Ukraine: the Steppe, Forest-Steppe and Polissia . The aim of the study was to determine the extent to which yield is influenced by genotype, environment, and their interaction, and to identify the most stable and productive forms. Analysis of variance of the yield data showed that 29.0% of the total variability of the trait was attributable to environmental conditions, 44. 6 % to genotypic differences and 15.2 % to genotype × environment interaction. These proportions confirm the determining role of hereditary characteristics of the varietal material, while at the same time demonstrating the substantial contribution of environmental factors and the unequal response of individual genotypes under different growing conditions. The AMMI analysis showed that in the overall structure of yield variability, the leading role belonged to the genotypic component, whose share exceeded both the environmental effect and the contribution of genotype × environment interaction. This distribution of sources of variation indicates a pronounced change in varietal response depending on growing conditions and confirms that, when preparing recommendations for production, it is necessary to consider not only mean yield level but also adaptability parameters. In terms of mean yield, the best-performing varieties among those studied were Pamiati Horlacha , ZU Willem, BHV20GV0009, ZU Shamal and Slava Unavy . Particular attention should also be paid to the variety STK21G, which occupied leading positions in many environments and showed a broad adaptive potential. The highest stability of response was demonstrated by the variety HIATSYNT, which was characterized by minimal sensitivity to changes in environmental conditions, indicating its considerable ecological plasticity. The group of genotypes with relatively high stability also included Zoloto Stepu , Epos, Pamiati Horlacha and Slava Unavy . When both productivity and stability of trait e x pression are considered simultaneously, the most promising varieties for broad agricultural use are Pamiati Horlacha , Zoloto Stepu , Slava Unavy , HIATSYNT and BHV20GV0009. The zonal analysis made it possible to reveal certain features of varietal adaptation. Under Steppe conditions, represented by Dnipropetrovsk , Kirovohrad and Odesa regions, the best productivity was most often demonstrated by HIMALAYA, Slava Unavy and ZU Shamal . In addition, the variety DARYNA showed pronounced specific adaptation to the drier conditions of this zone. In the Forest-Steppe environments, the most frequent leaders were STK21G, Zoloto Stepu , Atrybut , and ZU Willem, which makes it possible to regard them as valuable genotypes for conditions of moderate moisture availability. In the Polissia zone, a high repeatability among the best-performing varieties was characteristic of Pamiati Horlacha , STK21G, Atrybut , Dnistrianka Odeska and ZU Willem. Kvitoslava and Dnistrianka Odeska should also be considered promising for this zone. In further studies, it would be advisable to focus not only on yield, but also on grain quality and yield structure components in order to more deeply assess the influence of environments and varietal material on the fo r mation of economically valuable traits.