Ecological plasticity of soft winter wheat varieties and resistance to snow mould pathogen (Microdochium nivale (Fr.) Samuels & I.C. Hallett)

Identifying superior genotypes of soft winter wheat with high ecological plasticity to soil and climatic conditions, combined with tolerance to common diseases caused by fungal pathogens, including snow mould, is becoming increasingly important for both production and breeding. This is driven by the global demand for environmentally safe products. The preliminary selection of the most valuable initial material with high-stress resistance to periodic climate changes and deteriorating phytosanitary conditions is essential for the success of the breeding process in addressing current challenges. This study aimed to determine the level of ecological plasticity in soft winter wheat varieties, differentiated by their resistance to the snow mould pathogen, through the analysis of genotype effect ranks and yield regression coefficients. Additionally, high-yielding sources were identified for use in breeding for adaptability. The research was conducted according to commonly accepted methodologies for evaluating materials based on disease resistance and adaptive traits, ensuring a highly objective interpretation of the results obtained. It was determined that the highest ecological plasticity among the studied material was differentiated by resistance to Microdochium nivale (Fr.) Samuels & I.C. Hallett, was exhibited by five varieties (16.7%) that achieved yields ranging from 118% to 129% of the standard. These include the varieties Muza Bilotserkivska, Askaniiska Berehynia, Hetmanska, Malovanka (UKR), and Nordika (CZE), as evidenced by the lowest sum of ranks (sum of ranks 2) for the genotypic effect (εi ) and regression coefficient (Ri ). New sources of high and stable resistance in soft winter wheat to the snow mould pathogen were identified, specifically: Sanzhara, Malovanka, Svitiaz, Muza Bilotserkivska (UKR); Smuga (POL), and Nordika (CZE). It was found that, in soft winter wheat varieties, resistance to Microdochium nivale (Fr.) Samuels & I.C. Hallett significantly negatively correlates with the sum of ranks for genotypic effect and yield plasticity, with r =-0.69, P < 0.01. The systematisation of the results obtained and the identification of varieties with the highest ecological plasticity under variable weather conditions within the agroecological zone allows for the identification of the best gene pool for adaptive breeding