Effect of Foliar Application of Gibberellic Acid on Growth and Yield of Mungbean (Vigna radiata L.)

Abstract

Gibberellic acid (GA3) can significantly improve growth, yield and yield components of mungbean when applied as a foliar spray or seed treatment. This study aimed to determine the optimal rate and time of foliar GA₃ application on the improvement of growth and yield of mungbean (Yezin 14) variety in the post-monsoon seasons of 2023-24 and 2024-25. The experiment was conducted at Yezin Agricultural University farm, Myanmar by using Randomized Complete Block Design with three replications. In both experiments, there were ten treatments:  control (no GA3 with water spray) (T1), 50 ppm GA3 at 20 days after sowing (DAS) (T2), 100 ppm GA3 at 20 DAS (T3), 150 ppm GA3 at 20 DAS (T4), 50 ppm GA3 at 40 DAS (T5), 100 ppm GA3 at 40 DAS (T6), 150 ppm GA3 at 40 DAS (T7), 50 ppm GA3 at 20 and 40 DAS (T8), 100 ppm GA3 at 20 and 40 DAS (T9) and 150 ppm GA3 at 20 and 40 DAS (T10). Key growth parameters yield and yield components, and some physiological traits were measured throughout the growing season. Results showed that foliar application of 100 ppm GA₃ at both 20 and 40 DAS (T9) significantly enhanced plant height, SPAD value, leaf area index (LAI), crop growth rate (CGR), and total dry matter compared to other treatments. This treatment also resulted the highest number of branches and pods per plant, pod length, seed yield (1927.9 kg ha⁻1 in 2023-24 and 1554.7 kg ha⁻1 in 2024-25), shelling percentage, and harvest index. These findings highlight that application of 100 ppm GA3 twice during the early growth stages markedly enhances mungbean productivity under the agro-climatic conditions of Yezin, Nay Pyi Taw.