Beneficial nanoparticles (SiO2 and TiO2) can have various profound effects on the crop physiological, biochemical and morphological characteristics. Here, we evaluated the mitigation of drought stress in barley genotypes by foliar application of SiO2 and TiO2 nanoparticles under filed condition in North West of Iran. Nanoparticles were foliar applied in late vegetative phase and during reproductive stages. Drought was imposed at by irrigation withdrawals during the dry months in the end of the growing season. We measured parameters related morphological growth, yield, and yield component. The genetic diversity between the genotypes was quite evident and the highest seed yield and yield component were recorded for G1, G2, G4, G11, G12 and G13. Foliar application of nanoparticles considerably affected the plant height, thousand seed weight, biological and seed yield. The best performance was observed for plant treated with SiO2 nanoparticles. Spike length of G2, G6, G13 and G20 considerably responded to nano silicone foliar application. However, the best results for G8, G11 and G20 were obtained by foliar application TiO2 nanoparticles while this treatment decreased the seed yield components in G1, G5, G9, G10, G15 and G20. This could be due to genetic variation between the evaluated genotypes and high sensitivity of some genotypes to the applied concentration. The results of current study showed that application of SiO2 nanoparticles under water stress condition could have more beneficial effects on yield component of barley genotypes.
