Prysiazhniuk O. Theoretical and agrobiological bases of identification of abiotic stress of agricultural crops and increase of their tolerance

The paper highlights the results of comprehensive research conducted during 2014 - 2020 on the theoretical justification and determination of agrobiological basis for identifying abiotic stress of sugar beets, peas and lentils, establishing patterns of growth and development of plants and methods to increase their tolerance. The works of domestic and foreign scientists on the mechanisms of formation of tolerance of cultivated plants to abiotic stresses that arise during their cultivation in modern conditions of climate change are analyzed. Peculiarities of plant stress identification by determining the efficiency of the photosynthetic apparatus are considered. The peculiarities of the application of additional agricultural measures aimed at stimulating the growth and development of plants and their interaction with the soil microbiota in order to minimize abiotic stresses are highlighted. It is proposed to measure the efficiency of the photosynthetic apparatus by the ratio of variable to maximum fluorescence (Fv/Fm) of chlorophyll in order to effectively determine the stress of plants. Measurements should be performed with the help of the device "Floratest" in sugar beets in macro stage 3 (30-39), in pea plants - from macro stage 5 (51-59) to the end of macro stage 7 (71-79), and in lentils - in macro stage 6 (61-69). When conducting a qualification examination for effective field testing to follow the laws of zonal adaptive study of varieties, while assessing them by the method of determining their stability and plasticity, which allows to determine their response rate to the influence of abiotic factors. In the conditions of Mongolia to grow hybrids of sugar beets Zluka, Olzhych, Romul and Bulava. And to increase the tolerance of plants to abiotic stresses to use moisture-retaining polymers AQUASORB (600 kg/ha). In Ukraine, before sowing sugar beets apply moisture-retaining polymers AQUASORB (300 kg/ha) with a concentrate of soil bacteria Mirazonite (20 l/ha), and during the growing season to carry out foliar treatment with growth regulator KELPAK RK, 2 l/ha (BBCH 14) + 4 l/ha (BBCH 18) and fertilization with microfertilizer Alpha-Grow-Extra Beets, 3 l/ha (BBCH 18) or Micro-Mineralis (Beets), 1.5 l/ha (BBCH 18). In Ukraine, when growing peas or lentils before sowing, apply moisture-retaining polymers AQUASORB (200 kg/ha) and mycorrhizal biopreparation MICOFREND, 1 l/ha, as well as pre-sowing seed treatment with growth regulator KELPAK RK, 3 l/t. For foliar feeding of pea plants use biofertilizers Biovit, 7 l/ha (BBCH 14) or Freya-Aqua Beans, 1.5 l/ha (BBCH 14). But for foliar feeding of lentil plants to apply foliar treatment of plants with microfertilizer Reakom-SR-Beans, 3 l / ha (BBCH 14) or Quantum-Beans, 1.0 l/ha (BBCH 14).