Optimization of Chabaud carnation cv. Chabaud Mix performance using plant growth regulators under different growing conditions

Chabaud carnation ( Dianthus caryophyllus L.) possesses considerable ornamental and commercial potential; however, its systematic cultivation and production technology remain largely understudied. Moreover, the performance of carnation is strongly influenced by environmental conditions and the application of plant growth regulators. Therefore, the present study was conducted to optimize the performance of Chabaud carnation using PGRs, namely GA 3 (100, 150, and 200 ppm) and cycocel (CCC: 500, 1000, and 1500 ppm), along with a control, under open-field (C 1 ) and naturally ventilated polyhouse (C 2 ) conditions during 2021–2022 and 2022–2023. The experiment was laid out in a two-factor factorial Randomized Complete Block Design with three replications. The results revealed that C 2 increased plant height (23.75%) and stem length (31.95%); however, it reduced other parameters, including stem diameter (74.72%), No. of branches/plant (29.41%), and No. of leaves/plant (57.58%). In addition, C 2 delayed flower bud initiation by 20.63 days and shortened the flowering duration by 8.24 days. Conversely, greatest flower diameter (26.17%), No. of flowers/plant (107.07%), flower yield/plant (g) (114.96%), total flower yield (q/ha) (439.21%), No. of flower stalks/plant (145.24%), and No. of flower stalks/hectare (138.26%) were observed under C 1 conditions. Similarly, GA 3 at 200 ppm showed the maximum increase in plant height (8.87%), stem length (10.04%), leaf length (22.73%), and leaf breadth (39.75%). GA 3 (200 ppm) also hastened flower bud initiation by 7.96 days and improved flower diameter (18.47%), No. of flowers/plant (29.81%), flower yield/plant (74.86%), total flower yield (72.23%), No. of flower stalks/plant (11.87%), and No. of flower stalks/hectare (16.87%). In contrast, although CCC at 1500 ppm showed the greatest increase in stem diameter (30.80%), No. of branches/plant (27.52%), flower bud width (21.52%), and No. of flowers/plant (26.26%), it generally reduced or inhibited overall vegetative growth, flowering, and yield attributes of Chabaud carnation . The treatment combination C 1 G 3 (open field × GA 3 at 200 ppm) was found to be the most effective.