Impact of Foliar Application of Plant Growth Regulators in Soybean [Glycine max (L.) Merill)] on Seed Quality and Seedling Establishment

Abstract

In recent years, climatic adversities such as drought and flooding have severely impacted soybean production, productivity, and seed quality, especially during the Kharif season. Identifying the most favorable off-season sowing window is important for optimizing the efficient capture of radiation and partitioning of assimilates targeted for optimum seed yield and seed quality. Experiments were conducted during the Rabi to Rabi-summer seasons at the Experimental Research Farm, Seed Technology Research Unit, JNKVV, Jabalpur (M.P.) during 2021/2022 and 2022/2023, in a split-split plot design. The 28 treatments combinations comparing two dates of sowing with two spray schedules of seven PGRs treatments (T1Control (no spray), T2 (SA) @ 250 ppm, T3 (SA) @ 500 ppm, T4 (TU) @ 500 ppm, T5 (TU) @ 1000 ppm, T6 (CCC) @ 100 ppm, T7 (IBA) @ 200 ppm) were tested in soybean (JS 20-98) in a spilt-split plot design with three replications. The results revealed significant differences in germination percentage, seedling length, vigor index I, and vigor index II across different sowing dates. The Rabi-summer (D2) exhibited a superior germination percentage of 9.60%, seedling length of 2.81%, vigor index I of 12.64%, and vigor index II of 11.31% over the Rabi season (D1). The application of SA at 500 ppm (T3) increased the germination percentage by 1.48%, seedling length by 6.49%, and vigor index I by 9.70% compared to the control (no spray). The results showed that delaying the sowing date doesn’t affect the seed quality of soybean, and the foliar application of salicylic acid at 500 ppm enhanced the germination percentage, seedling length, and seed vigor index I and IBA at 200 ppm enhanced the seed vigour index II by 4.66% as compared to the control (no spray). These findings provide promising strategies for improving soybean production under various environmental stress conditions.