Estimation of genotypic features of effects of plant treatment with growth regulators on canopy parameters and yield of winter wheat

Aim. A study of the effects of growth regulators derived from natural raw materials on the photosynthetic apparatus surface and the yield of winter wheat. Methods. Morphometric, spectrophotometric, statistical. Results. An increase in the value of canopy chlorophyll index (ChlI) of Smuhlianka and Astarta varieties under the treatment of plants with Stimpo growth stimulator was established at anthesis, a positive effect of the regulator Regoplant – only for Smuhlianka variety at milk-wax ripeness. Chlorophyll photosynthetic potential (ChlP) during the period anthesis – milk-wax ripeness increased significantly under the use of growth regulators in both varieties, while the efficiency of treatments had varietal differences: growth was greater (11–18% compared to control) in the variety Smuhlianka than in the variety Astarta (6–7%). A positive correlation was established between the yield and ChlP during the period anthesis – milk-wax ripeness. Under the action of treatment of plants with growth regulators, the increase in grain yield was significant (0.29–0.45 t/ha) only in the variety Smuhlianka. Conclusions. The positive effect of treatments of plants with growth regulators, obtained from natural raw materials, on the value of canopy ChlI at anthesis and ChlP during period anthesis – milk-wax ripeness was established. A positive correlation between the winter wheat yield and ChlP during the period anthesis – milk-wax ripeness was found. Varietal differences in the effect of growth regulators treatment of plants on ChlP and yield were found. Keywords: Triticum aestivum L., grain productivity, chlorophyll index, chlorophyll photosynthetic potential, growth regulator.