Enhancing Sorghum Productivity with Methyur, Kamethur, and Ivin Plant Growth Regulators ^†

Sorghum is one of the most important foods, fodder, and technical crops grown in the world. Global climate change and environmental pollution with toxic industrial and agricultural waste are the most unfavorable environmental factors affecting the growth and development of sorghum, which leads to a decrease in product quality. The development of new environmentally friendly plant growth regulators to improve growth and increase the productivity of sorghum is an urgent task of modern agriculture. Currently, considerable attention is paid to the development of new environmentally friendly plant growth regulators based on 6-methyl-2-mercapto-4-hydroxypyrimidine sodium and potassium salts (Methyur and Kamethur) and N-oxide-2,6-dimethylpyridine (Ivin). Thanks to the use of plant growth regulators Methyur, Kamethur, and Ivin, it is possible to increase the productivity of agricultural crops and their adaptive properties to stress factors of abiotic nature. This work examines the use of plant growth regulators Methyur, Kamethur, and Ivin to increase the productivity of sorghum. Field experiments were carried out on grain sorghum (Sorghum bicolor L.) cv. Yarona and sweet sorghum (Sorghum saccharatum L.) cv. Favorite. Seeds sterilized with 1% KMnO₄ solution were treated either with distilled water (control sample) or with solutions of any plant growth regulators Methyur, Kamethur, or Ivin, applied at a concentration of 10⁻⁷ M for 24 h (experimental sample). Each control and experimental sample contained 50 plant seeds; the experiments were carried out in triplicate. Then the soaked seeds were planted in the soil. Yield indicators such as panicle length (in cm) and fresh weight of grain (in grams), determined in experimental samples of sorghum plants, were calculated as % in relation to similar indicators determined in control samples of sorghum plants. It was shown that the yield indicators of sorghum plants grown for 4 months in the field, treated with Methyur, Kamethur, and Ivin at a concentration of 10⁻⁷ M exceeded those of control plants. Panicle length (in %) of experimental grain sorghum (Sorghum bicolor (L.) Moench) cv. Yarona increased by 7%—in plants treated with Kamethur, 20%—in plants treated with Methyur, and 17%—in plants treated with Ivin, compared to the control. Panicle length (in %) of experimental sweet sorghum (Sorghum saccharatum (L.) Moench) cv. Favorite increased by 36%—in plants treated with Kamethur, 37%—in plants treated with Methyur, and by 25%—in plants treated with Ivin, compared to the control. Grain fresh weight (in %) of experimental grain sorghum (Sorghum bicolor (L.) Moench) cv. Yarona increased by 22%—in plants treated with Kamethur, 26%—in plants treated with Methyur, and 13%—in plants treated with Ivin, compared to the control. Grain fresh weight (in %) of experimental sweet sorghum (Sorghum saccharatum (L.) Moench) cv. Favorite increased by 24%—in plants treated with Kamethur, 38%—in plants treated with Methyur, and 35%—in plants treated with Ivin, compared to the control. Based on the results obtained, a conclusion was made about the high growth-stimulating effect of plant growth regulators, similar to the phytohormones auxins and cytokinin, and the dependence of their effect on their composition. It is proposed to use new environmentally friendly plant growth regulators Methyur, Kamethur, and Ivin to improve growth and increase the productivity of sorghum while reducing the use of environmentally toxic agrochemicals for plant protection and improving the environmental condition of the entire agricultural system.