Vol. 9, Special Issue 1, Part E (2025)

An investigative study was conducted to elucidate the physiological responses of soybean (Glycine max (L.) Merill) cv. Suvarn Soya (AMS-MB-5-18) to various foliar applications of PGRs and micronutrients. The experiment was carried out during the kharif season of 2023-24 at the Experimental and Research Field of the Department of Agricultural Botany, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola (M.S.), situated in a tropical region. The site's edaphic characteristics revealed a medium black clay soil with a relatively level and uniform topography, facilitating adequate drainage. The experiment was designed in a Randomized Block Design (RBD) with three replications and seven treatments, comprising 21 plots. The treatments included foliar applications of Ethrel (200 and 250 ppm), Cycocel (500 and 750 ppm), and Zinc Sulphate (0.5% and 0.10%), along with a control treatment. Sowing was done on July 5, 2023, using the dibbling method, with a spacing of 45 cm × 10 cm. Subsequent intercultural operations were performed as necessary. Foliar applications of Ethrel, Cycocel, and Zinc Sulphate were administered at two critical growth stages: 50% flowering (40 DAS) and pod initiation (55 DAS). Crop Growth Rate (CGR) and Relative Growth Rate (RGR) were calculated at 30-60, 60-90, and 90-115 DAS, while dry matter production was recorded at harvest. Yield components, such as pod number, seed number, test weight, grain yield, and Harvest Index (HI), were evaluated at harvest. Biochemical parameters, including chlorophyll content index, were measured at 30, 60, and 90 DAS. Seed protein content was estimated before sowing and after harvesting. The results revealed that foliar application of Cycocel (500 ppm) at 50% flowering and pod initiation stages significantly enhanced grain yield and yield components, as well as biochemical parameters, compared to the control. Furthermore, foliar application of Zinc Sulphate (0.10%) at 50% flowering and pod initiation stages showed a marked increase in seed germination percentage and vigour index. Overall, the study demonstrated that two foliar sprays of Cycocel (500 ppm) and Zinc Sulphate (0.10%) at critical growth stages can be an effective strategy for improving the biochemical, and yield parameters of soybean cv. Suvarn Soya (AMS-MB-5-18).