Phenotypic diagnostics of Linum ussitatissimum L. germ plasma sample resistance to osmotic stress

Due to the negative effect of climate change, the selection of stress-resistant genotypes becomes increasingly important for plant breeding and genetic research. This paper discusses the findings of laboratory testing of fiber flax accessions (G1-G20) from the collection fund of the Tyumen State University under osmotic stress. The research goal was to study the flax responses to three levels (E1-E3) of simulated stress factor on seed germination and the formation of morphometric parameters of sprouts. Using the combined analysis method according to the AMMI-biplot model, reliable (p < 0.05*, p < 0.01**) differences between the accessions (G1-G20) and environmental conditions (E1-E3) were revealed. Using principal component analysis, the structural nature of the complex genotype-environment interaction (GxE) was determined according to which the greatest contribution to its structure was made by the first IPCA1 (51.3-42.8%) and the second IPCA2 (34.6-22.8%) accounting for 85.9-65.6% of the total variability of the test criteria. The ambiguous nature of the phenotype-response reactions in the flax germplasm samples was expressed in decrease of the germination index (GP) by 5.7-2.8%, root length (RW) - 3.8-1.9%, shoot length (SW) - 8.3-4.7%, root wet weight (FRW) - 4.1-2.4%, shoot wet weight (FSW) - 6.1-2.9% with increased stress factor compared to the normal background (E0) without revealing the stimulating effect of the environment. According to the component analysis (IPCA), valuable genotypes were selected in the E1 medium (n = 10), E2 medium (n = 6), and E3 medium (n = 4). Based on the index method (SI, TOL), promising accessions of fiber flax G2, G7, G8, G13 were selected being of interest for further selective breeding work.