Variation of winter wheat plant height depending on ecotype and meteorological conditions

During 2021-2023, the formation of plant height in soft winter wheat varieties of Forest Steppe, Steppe, and Western European ecotypes was studied at the training and production center of Bila Tserkva National Agrarian University. A significant 11 < Cv ≤ 21% and a large 21 < Cv ≤ 51% variation of plant height in varieties of Forest-Steppe and Western European ecotypes and a significant one in Steppe ecotype was found. Lower indicators of plant height variability during the years of research were found in the following varieties: «Lisova pisnya» (23.6 cm) – forest-steppe ecotype; «Harmoniya Odesska» (24.8 cm), «Lastivka Odesska» (25.0 cm) – steppe ecotype. At the same time, the most variable plant heights has «Zorepad bilotserkivskyi» (45.0 cm), «Kalуnova» (39.9 cm), «Kvitka рoliv» (37.8 cm) – Forest-Steppe ecotype, «Mulan» (39.5 cm) and «Akter» (35.9 cm) – Western European ecotype. The influence of adverse meteorological conditions causes a decrease in the height of soft winter wheat plants, and stressful conditions form the indicators of the lower group according to the classification, which significantly increases the variability of the studied trait. According to the high indices of homeostasis (Hom) and breeding value (Sc) of wheat plant height formation, the following varieties stood out: «Madіarka» (Hom = 465; Sc = 68.6), «Kvitka poliv» (Hom = 459; Sc = 55.2) – Forest-Steppe ecotype, «Harmoniya Odesska» (Hom = 492; Sc = 53.5), «Lastivka Odesska» (Hom = 468; Sc = 52.8) – Steppe ecotype and «Akter» (Hom = 446; Sc = 53.7) – Western European ecotype. The variability of plant height of the studied varieties is largely (87.22 %) due to the year conditions. In the context of the studied ecotypes the greatest influence of the year conditions was found in varieties of Western European (98.42%) and Steppe (96.31%) ecotypes, and the «variety» factors of the Forest-Steppe ecotype was 8.08%. The smallest share of «variety–year conditions» interaction 0.70 % was found in the group of varieties of the Western European ecotype, with the influence of the «variety» factor at 0.87%. Key words: soft winter wheat, plant height, ecotype, variety, variability index, variability.