Osmotic stress tolerance at the juvenile developmental stage of wheat

Aim. To evaluate the level of tolerance of ten winter soft wheat varieties bred by the SGI-NCNS to osmotic stress simulated by a 12% PEG 6000 solution, to identify adaptive juvenile genotypes. Methods. Laboratory rapid screening method for breeding material for water deficit, morphometric analysis of vegetative organs, one-way analysis of variance (ANOVA), and calculation of the integrated tolerance index (ITₓ). Results. Under control conditions, differences among varieties were non-significant (p < 0.05). Osmotic stress caused significant differentiation of genotypes by morphometric parameters (p < 0.05). The highest adaptability was demonstrated by the line Erythrospermum 2437/16 (ITₓ = 0.81) and the cultivar Velychava (ITₓ = 0.78), maintaining the stability of organ growth processes under moisture deficit conditions. The cultivar Nasnaha proved to be the most sensitive to stress (ITₓ = 0.57) due to a significant slowdown in the development of underground and aboveground organs. Conclusions. Modeling stress with 12% PEG 6000 and evaluating integrated tolerance index effectively screens juvenile plant water deficit tolerance. Identified tolerant genotypes offer valuable source material for breeding. The results of the analysis of variance (p < 0.05) confirmed the reliability of the obtained data, while the clear differentiation of genotypes by the integrated tolerance index (ITx) demonstrated the effectiveness of approach.