Effect of Bio-Inoculant and Gibberellic Acid on Flowering Parameters of African Marigold

The study was carried out during the year 2024-2025 at the Main Experiment Station, Department of Horticulture, Faculty of Agriculture Sciences, Shree Khushal Das University, Hanumangarh, Rajasthan. In order to assess the individual and combined impacts of bio-inoculants (Azotobacter) and Gibberellic acid (GA3) on flowering characteristics of African marigold, the experiment was set up in a Factorial Randomized Block Design with 12 treatment combinations and three replications. The use of Azotobacter through soil treatment greatly improved early blossoming and overall flower quality. The earliest bud initiation, first flowering, 50% blooming, maximum flowering duration, flower stalk length, flower quantity, and fresh and dried flower weight were all noted in this treatment. By encouraging early bud formation, boosting cell division and elongation and increasing dry matter accumulation, foliar treatment of GA3 at 200 ppm (G4) at 30 DAT observed to be the most beneficial among the GA3 levels in improving flowering metrics. The combination A3G4 (Azotobacter soil treatment + GA3 200 ppm) consistently produced the most favorable trends for all flowering attributes, including flower diameter and overall floral yield, even though both bio-inoculants and GA3 individually showed significant improvements and their interaction effect was statistically non-significant. While GA3 administration successfully shortened the juvenile phase and accelerated the transition to reproductive development. In order to achieve superior blooming, greater quality, and higher output in African marigold, a combination of soil-applied Azotobacter (4 L/ha) and foliar GA3 spray (200 ppm at 30 DAT) were found to be the most effective treatment.