Response of BRRI dhan34 to Different Levels of GA3 on Growth, Flag Leaf ChlorophyllContent, and Grain Yield

A field experiment was conducted to investigate the effect of foliar application of gibberellic acid (GA3) on chlorophyll content, growth, and yield of BRRI dhan34 rice. Five concentrations of GA3 (0, 50, 75, 100, and 125 ppm) were applied as foliar sprays at early vegetative, vegetative, and pre-flowering stages. Growth attributes, photosynthetic pigments, yield components, and yield were evaluated. Foliar application of GA3 significantly influenced most of the measured traits. The highest values of plant height, tiller number, node number, internode length, panicle length, effective tillers hill−1, filled grains panicle−1, and 1000-grain weight were recorded with 125 ppm GA3 application. Chlorophyll-a content increased significantly with increasing GA3 concentration, whereas chlorophyll-b and carotenoid contents were not significantly affected. The highest grain yield (3.41 t ha−1), straw yield (4.28 t ha−1), biological yield (7.69 t ha−1), and harvest index (44.37%) were obtained from the 125 ppm GA3 treatment. The findings suggested that foliar application of 125 ppm GA3 at early vegetative, vegetative, and pre-flowering stages can enhance chlorophyll-a content and improve the yield performance of aromatic rice cv. BRRI dhan34 under field conditions. However, further validation across different environments is recommended before large-scale adoption. Bangladesh Agron. J. 2026, 29(1): 80-94