BIOCHEMICAL PARAMETERS, DEVELOPMENT AND SPREAD OF DISEASES IN POTATO CROPS USING PLANT GROWTH REGULATORS

Objective.  To study the effect of growth regulators and planting dates on chlorophyll content, quality indicators, disease susceptibility and yield of potato tubers. Methods. Field, namely visual and measurement-weight; laboratory; statistical; calculation-comparative. Results. In 2020-2023, comprehensive studies were conducted on the influence of growth regulators Phytosubtyl, IntraCell, Kartoplex and planting dates on the content of pigments in potato leaves, biochemical parameters of potato tubers and the yield of the ultra-early Radomysl and mid-ripening Myroslava varieties. The use of plant growth regulators on potatoes contributed to an increase in the level of yield and biochemical parameters of the crop. In particular, the greatest increase in tubers in both varieties was provided by the Kartoplex, increasing the yield by 12.0–25.3 %. Plant regulators had a positive effect on the starch and dry matter content of potato tubers. Thus, in comparison with the control variant, the starch content of the Myroslava variety increased by 1.7–2.1%, dry matter by 1.4–2.97%, and the Radomysl variety by 0.7–2.0 and 1.5–2.88%, respectively. The maximum value of vitamin C content was recorded in 2023 in the Myroslava variety 23.4, in the Radomysl variety 20.3 mg/%, and the minimum in 2022 – Myroslava 21.3, Radomysl 18.1 mg/%. On average, over the years of studies, the use of growth regulators contributed to an increase in the content of vitamin C in potato tubers of Radomysl and Myroslava varieties as follows: for the Radomysl variety – Phytosubtyl by 9.1–10.9 mg/%, IntraCell: by 2.8–5.1 mg/%, Kartoplex: by 11.8–14.0 mg/%; for the Myroslava variety: Phytosubtyl – an increase of 5.2–11.0 mg/%, IntraCell 6.8–8.3 mg/%, Kartoplex 16.2–18.1 mg/%. The analysis of variance of the obtained data showed that the following factors had the greatest influence on the content of the sum of chlorophylls in potato leaves: varietal characteristics (factor A): this factor had the greatest influence on the content of chlorophylls, the share of which was 34.9 %; planting time (factor B): the influence of this factor was 25.3%, growth regulators (factor C): their influence was 10.4%, the interaction of factors of planting time and variety (AB): the share of influence of this factor was 14.8%, the interaction of factors AB, BC and ABC: their influence was as follows: AB interaction: 4.1%, BC interaction: 3.4%, ABC interaction: 4.7. The results of tuberous analysis showed that the prevalence (in total) of diseases a month after harvesting was the highest in the control varient (8.9% in the Radomysl variety and 9.8% in the Myroslava variety). When tubers were treated with Phytosubtyl, the prevalence of diseases decreased by 47.2% for the Myroslava variety and 55.1% for the Radomysl variety. Discussion. The results of studies positively correlate with the developments of domestic and foreign scientists to study the influence of plant growth regulators on various aspects of technological and biochemical indicators of potato productivity. Conclusions. The influence of growth regulators Phytosubtyl, IntraCell, and Kartoplex on the biochemical components of plants and tubers, the development and spread of diseases that determine potato yield and productivity was studied.