EFFICIENCY OF THE BIOSTIMULANT IN WINTER WHEAT (TRITICUM AESTIVUM L.)

Pre-sowing treatment with plant growth regulators is one of the most efficient ways to improve seed germination and seedling tolerance to diverse environmental conditions. The presented study sought to evaluate the effects of polyprenols (emulsion concentrate) of the Paulownia tomentosa tree on the growth, physiological, and yield-related traits in winter wheat ( Triticum aestivum L.). Biologically active substances (polyprenols) of the Paulownia tomentosa tree have stimulating and auxin-like activity, contributing to an increase in seed germination, plant height, spike length, grains per spike, grain weight per spike, 1000-grain weight, which increased the grain yield by 5.5-10.5 t/ha in winter wheat. According to the results, the Grom cultivars had the highest degree of drought resistance (94%). Local wheat cultivars Khisorak and Bunyodkor belonged to group IV (above average) and displayed 77.7% to 80.0% drought resistance. Polyprenols also positively affected the leaf chlorophyll a, b, and the total chlorophyll formation during the vegetation phase in winter wheat. Chlorophyll b increased by 0.23 mg/g for the cultivar Bunyodkor, 0.29 mg/g in Khisorak, and 0.07 mg/g in the Grom cultivar under the Republic's Southern Region conditions.