Effect of plant growth regulators on seed germination and growth performance of China aster (Callistephus chinensis (L.) Nees) var. Kamini

The present investigation was conducted to study the response of China aster var. Kamini to the varied concentrations of plant growth regulators; GA₃ (100 ppm, 200 ppm and 300 ppm), NAA (100 ppm, 200 ppm and 300 ppm), IBA (100 ppm, 200 ppm and 300 ppm), and IAA (100 ppm, 200 ppm and 300 ppm). Among the various concentrations used, GA₃ @ 200 ppm showed the best germination percentage (93.33±3.52%) under lab conditions and GA₃ @ 300 ppm showed the best germination percentage (94.00±0.57% under field conditions. GA3 @ 300 ppm resulted in best plant height (55.16±0.36 cm), plant spread (12.60±0.19 cm), number of primary branches (11.77±0.40), number of secondary branches (15.66±0.50) and number of leaves per plant (148.00±2.72). GA₃ @ 300 ppm resulted in the earliest bud initiation in the plants (162.00±0.19), bud showing colour (166.29±0.66), days of first flower opening (174.00±0.19), 50% flowering (176.33±0.50), days of complete flowering (185.22±0.29). The highest flower diameter (6.36±0.17), stalk length (33.03±0.93), number of flowers per plant (20.22±0.40), and weight of flower (3.41±0.12) was also recorded with GA₃ @ 300 ppm. The IAA @ 300 ppm showed the best result for vase life (10.77±0.72) of flowers and NAA @ 300 ppm showed the best result for shelf life (6.33±0.19) of flowers. Thus, it can be concluded that GA₃ @ 200 ppm was found effective for seed germination. While the for the best vegetative and flowering growth, the treatment containing GA₃ @ 300 ppm was found effective. NAA @ 300 ppm was found effective for enhancing shelf life of the flower. Similarly, IAA @ 300 ppm was found suitable for increased vase life of China aster.