The impact of varying levels of Gibberellic Acid (GA3) on plant growth, flowering, flower quality, seed yield, and quality of Petunia(Petunia × hybrida Vilm.)

Abstract

Petunia, a popular ornamental plant, is known for its vivid flowers and wide color range. Petunia has long been valued for its aesthetic appeal, but recent research has begun to shed light on its possible medicinal properties. Petunia × hybrida is widely recognized for its medicinal characteristics, phytochemical content, and potential health benefits. A research study was undertaken between the years 2021 and 2022. The field experiment was laid out in a randomized complete block design (RCBD), with 11 treatments replicated three times. The treatments included 10 GA3 concentrations from 25 to 250 ppm applied 45 days post-transplantation, along with control—Petunia cv. 'White' seedlings were transplanted in main plots with 30 × 30 cm spacing. Based on the results, it was noted that foliar feeding the leaves with 200 ppm GA3 produced notable outcomes in various characteristics. This treatment recorded a higher plant height (53.45 cm), spread (50.32 cm), and branches per plant (26.77 cm). It also minimized time to first flowering (78.81 days), 50 % flowering (96.67 days), and peak flowering (107.33 days). Furthermore, 200 ppm GA3 optimized flowering duration (123.47 days), flower diameter (6.76 cm), flowers per plant (405.60), seeded capsules per plant (367.13), and seeds per capsule (535.67). Seed yield was maximized at all levels: per plant (12.51 g), per plot (54.33 g), and per hectare (380.33 kg). Seed quality parameters also peaked, including 1000-seed weight (93.65 mg), germination (93.75 %), germination speed (10.59), seedling length (3.63 cm), and dry weight (0.331 mg). Vigor indices I (340.54) and II (30.99) were significantly higher, while seed electrical conductivity was significantly low (77.13 μSm-1) with this treatment.