The results of evaluating the breeding value of 12 winter wheat varieties based on grain mass per main spike during 2021–2023 are presented. The variability of the trait (minimum and maximum values) was examined and the breeding value (Sc) was calculated for each variety. It was established that higher mean grain mass values over the three-year period were formed by the varieties Madyarka (2.13 g) and Acratos (2.10 g). The highest breeding value (Sc = 1.9) was recorded in the variety Fidelius, indicating its stability and high genetic potential. The data obtained allow for the identification of promising source material for further breeding work aimed at improving productivity under variable hydrothermal conditions. Breeding value (Sc) was calculated according to V. V. Khangildyn and M. A. Lytvynenko (1981): Sc = X × (Xlim / Xopt), where: Sc – breeding value; X – the mean value of the studied trait; Xlim – the minimum value of the trait; Xopt – the maximum value of the trait.