Homeostasis in terms of the number of spikelets in the main ear of soft winter wheat varieties in 2021-2023.

The results of three-year research (2021–2023) are presented on the evaluation of homeostatic stability in winter wheat varieties of different ecotypes based on the number of spikelets per main spike. The variability of the trait was analyzed, and variance (S²) and the homeostatic index (Hom) were determined for the forest-steppe, steppe, and Western European ecotypes. It was established that the highest homeostatic index values were recorded in the varieties Zoреpad Bilotserkivskyi (Hom = 858) and Moulan (Hom = 817). It was found that Western European ecotype varieties, particularly Acratos, exhibit a greater potential in terms of spikelet number per spike; however, they are characterized by considerable variability depending on annual growing conditions. The findings of the study allow for the identification of the most adaptive genotypes for further breeding work. Homeostatic ability (Hom) was calculated according to V. V. Khangildyn and M. A. Lytvynenko (1981): Hom = x² / S, where: Hom – homeostatic ability; x² – the mean value of the studied trait squared; S – standard deviation.