Abstract
<jats:p>Barley (Hordeum vulgare L.) is a versatile crop utilized for food, feed, and industrial purposes; however, it remains highly sensitive to water stress. Chitosan-based biofertilizers reduce soil drought, thus improving the growth rate and yield of cereal crops. The article describes the effect of the chitosan biofertilizer Yunigel Plantum on barley resistance to soil drought. The study involved the Biom barley variety subjected to two triplicated series of experiments with Yunigel Plantum. The experiments featured the effect of Yunigel Plantum on seed germination energy under optimal conditions, as well on drought resistance. Yunigel Plantum improved the water status, reduced the oxidative damage, and stabilized the accumulation of such protective metabolites as anthocyanins and proline. The high levels of photosynthetic pigments reduced the negative impact of water stress on the photosynthetic system. Yunigel Plantum contained hydrogel structures that promoted water retention in the soil, making it more available to plants and reducing the stress. The synergy of these positive factors increased the drought resistance and reduced the damage caused by water deficiency. In this research, Yunigel Plantum showed good prospects for field trials in the sphere of barley farming.</jats:p>