Effects of plant growth regulators on peg and pod development in peanut (Arachis hypogaea L.) under drought stress

Peanut is a globally important legume crop consumed in various forms due to its high nutritional value. However, peanut production faces challenges, particularly under drought conditions, resulting in reduced flowering, peg and pod formation. This study aimed to investigate the changes in morphology, anatomy and activity of plant growth regulators during flowering, peg development and pod formation in peanuts, using the VD01-2 cultivar. The objective of the study was to explore the application of plant growth regulators to optimize flowering, peg development and increase pod yield in peanuts. The peanuts were cultivated at the Ho Chi Minh City High-Tech Agriculture Park under the following conditions: 150 ± 20 Klux light intensity, 45/26 ± 2 °C temperature and 35/80 ± 5 % humidity. The experimental soil composition was 63.4 % sand, 28.5 % silt and 8.1 % clay, with 24.91 g kg-1 organic matter, 0.165 % total nitrogen, 0.062 % phosphorus and 0.93 % potassium. Statistical analysis of the data revealed an increase in auxin and gibberellin activity during flowering, which contributed to peg elongation. However, as the peg entered the soil and formed the pod, the activity of these plant growth regulators decreased. Additionally, the combination of 50 mg L-1 IAA (indole-3-acetic acid) and 150 mg L-1 GA3 (gibberellic acid) effectively enhanced the development of flowers, pegs and pods in peanut plants under drought-stress conditions. Furthermore, this combined treatment resulted in an increase in the lipid content of the seeds from 545.2 mg to 570.0 mg/g of weight. These findings have the potential to improve peanut productivity under drought conditions, addressing the challenges faced in peanut production.