The value of the variety in increasing the yield of soft winter wheat is undeniable. Therefore, the use of genetic patterns in breeding can improve the adaptability of modern varieties. In breeding and genetic studies, the formation of yield is considered as a complex characteristic due to many components. Studying the variability and stability of the main structural elements of productivity is an important task in the selection of soft winter wheat. The aim of the study was to investigate the peculiarities of the formation in soft winter wheat spike length and the number of spikelets in it depending on the genotype and the conditions of the year, and to select genotypes with a consistently high expression for involvement in the selection process. The research was carried out in the conditions of the experimental feld of the Educational and Production Center of the Bila Tserkva National Agrarian University in 2018–2020. The source material for the research was varieties of different ecological and geographical origin recommended for growing in Ukrainian forest-steppe. Arithmetic mean ( ), minimum and maximum value of features (min–max), standard deviation (s), coefcient of variation (V, %), homeostatic index (Hom) were determined. To characterize moisture availability, the hydrothermal coefcient was calculated. According to the research results, such varieties as Tobak, Bohemia, Kvitka poliov, Legenda bilotserkivska, Svitilo, Platin, Kolonia, Akratos formed the largest spike length, exceeding the standard variety Lisova pisnia by 1.6– 2.3 cm. A high homeostatic index was determined by this feature in varieties Kvitka poliov (758), Kolonia (343), Svitilo (334), Perlyna Lisostepu (204). The varieties Akratos, Favorite, Kolonia, Svitilo, Platin, Legenda Bilotserkivska, Tobak were selected according to the number of in the ear, which had indicators from 19.0 to 20.4 pcs., which is 2.1–3.5 pcs. more than the standard sort (16.9 pcs.). The highest homeostaticity, in terms of the number spikelets in the spike, was received in Skagen (930), Kolonia (826), Flower of the Fields (780), Akratos (682), and Forest Song (461).
Key words: soft winter wheat, variety, spike length, number of spikelets in the spike, homeostatics, selection.