Yield plasticity of new varieties of soft winter wheat (Triticum aestivum L.) in different soil and climatic conditions of Ukraine

Purpose. To determine the level of productivity of new varieties of soft winter wheat, their stability and plasticity when grown in different soil and climatic conditions of Ukraine. Methods. The field trial was carried out in 2022–2023 under the conditions of the research stations of the Ukrainian Institute for Plant Variety Examination (UIPVE) in the Steppe, Forest Steppe and Polissia soilclimatic zones. The peculiarities of plant growth and development, the yield formation of 34 new varieties of soft winter wheat were studied. Plasticity and stability of yield formation were calculated and analyzed according to the Ebergard – Russell method, general homeostaticity and selection value according to Khangildin V.V. and Lytvynenko N.A. In the course of the research, computational and statistical methods were used. Analysis and synthesis were used to draw conclusions. Results. The yield varied from 5.4 to 8.4 t/ha, depending on the soil and climate zone and the location of the trial. The variety ‘LG Optimist’ had the highest average yield (8.1 t/ha) and ‘YUSON’ the lo west (6.0 t/ha). The most favorable conditions for the study of growth and development of genotypes in 2022 were in the Forest-Steppe (Ij = 0.9) and Polissia (Ij = 0.6) zones, in 2023 – Polissia (Ij = 0.2); the worst in 2022 – in the Steppe (Ij = –0.7), in 2023 – in the Steppe (Ij = –0.7) and ForestSteppe (Ij = –0.5) zones. In 2023, the best climatic conditions were in the Polissia zone (Ij = 0.2), the worst were in the points located in the Steppe (Ij = –0.7) and Forest Steppe (Ij = –0.5) zones. The theoretical yield values of the varieties at the research points did not differ from the actual values and averaged 7.1 t/ha, ranging from 6.0 to 8.1 t/ha. High homeostaticity and low level of variation (V ≤ 10.0%) were found in the varieties ‘Yevraziia’ (Hom = 15.6), ‘Dekaster’ (Hom = 15.2), ‘FORSAIT’ (Hom = 13.9) and ‘LG Optimist’ (Hom = 12.1). In addition, ‘LG Optimist’ (Sc = 6.9) and ‘Dekaster’ (Sc = 6.6) had the highest breeding value. The variety ‘FORSAIT’ (bi = 0.2; S2 di = 0.24), with an average yield of 7.4 t/ha, has a high plasticity, so it is recommended to grow it on extensive backgrounds and in unfavorable conditions. Varieties ‘Yevraziia’, ‘Nosivochka’, ‘SOLIFLOR CS’, ‘Mizynka’, ‘Troiana’, ‘LG Optimist’, ‘Biskvit’, ‘MIP Dovira’, ‘Etual’, ‘Tvorchist Odeska’, ‘Attribut’, ‘Epihraf’, ‘Dekaster’, ‘Epitet’, ‘Jannis’, ‘Pamiati Horlacha’, ‘Trembita Bilotserkivska’ and ‘Slava Unavy’ with a combined manifestation of high ecological plasticity bi = 1 and stability S2 di = 0 in average grain yield 7.2 t/ha, according to the genotype respond well to the improvement of growing conditions and are stable, are considered the most practically valuable. Conclusions. New varieties of soft winter wheat, when grown in different soil and climatic conditions, fully develop their genetic potential under significant changes in environmental conditions and produce the highest yield that can be obtained under ideal conditions.