EFFECT OF SALINITY STRESS ON ANTIOXIDANT ACTIVITY AND GRAIN YIELD OF DIFFERENT WHEAT GENOTYPES

In order to evaluate the antioxidant activity of wheat in salinity stress conditions, an experiment with 27 wheat genotypes grown on two types of soil was conducted: solonetz (increased salinity) and chernozem (control), during two vegetation seasons (2015/2016 and 2016/2017). Analysis of DPPH radical scavenging activity and phenolic content (PC) were performed in different phenophases of wheat (tillering, stem elongation and heading). Genotypes showed significantly higher DPPH radical scavenging activity (9.82 mg trolox equivalents (TE) per mg of dry matter (d.m.)) and PC (8.15 mg gallic acid equivalents (GAE) per mg d.m.) under salinity stress conditions compared to values obtained on control (8.52 mg TE mg-1 d.m. and 7.13 mg GAE mg-1 d.m., respectively). All analyzed factors (genotype, soil type and year) had the highly significant influence on phenotypic variation of grain yield. Salinity stress reduced grain yield by 30%, whereas drought stress in 2016/2017 vegetation season reduced grain yield by 20%. Highly significant and positive correlations are present between grain yield and parameters of antioxidant activity in all growth stages of wheat and both soil conditions. Therefore, it could be possible to select salinity tolerant genotypes in early growth stages. DPPH scavenging activity and total phenolic content are in highly significant and positive correlation in all growth stages, which indicates that antioxidant activity is highly derived by phenolics.