Impact of bioregulators on groundnut (Arachis hypogaea L.) growth under deficit irrigation conditions

A field experiment was conducted during Rabi 2024-25 at Professor Jayashankar Telangana State Agricultural University, Hyderabad, to evaluate the effects of irrigation schedules and bioregulator applications on groundnut growth under semi-arid conditions. The experiment was laid out in a split-plot design with three replications. Main plot treatments included four irrigation schedules: full irrigation (I1), irrigation skipped at pre-flowering (I2), irrigation skipped at pre-flowering and pegging (I3) and irrigation skipped at pre-flowering, pegging and pod formation (I4). Sub-plot treatments comprised foliar application of bioregulators: Triacontanol 2 ml l⁻¹ (B1), Salicylic acid 2 ml l⁻¹ (B2), PPFM 10 ml l⁻¹ (B3) and control (B4).

Results revealed that full irrigation (I1) significantly enhanced plant height, dry matter production and leaf area index (LAI) compared to the most stressed treatment (I4). However, growth parameters under I1 and I2 were statistically similar at 60, 80 DAS and harvest, demonstrating the ability of groundnut plants to recover from early-season water stress through compensatory growth. Among the bioregulators, Triacontanol (B1) consistently outperformed other treatments, significantly improving all growth traits compared to the control (B4), owing to its role in promoting photosynthesis, nutrient uptake, and cell elongation. Interaction effects between irrigation schedules and bioregulators were non-significant.

In conclusion, deficit irrigation at the pre-flowering stage (I2) combined with Triacontanol application (B1) provides a sustainable management strategy for enhancing groundnut growth while conserving water under semi-arid conditions.