Effect of different time periods of pinching on growth and flowering of an ornamental plant, Platycodon grandifloras Jacq. var. 2009B

Abstract

Platycodon (Platycodon grandifloras Jacq.) is an ornamental species that requires controlled growth to meet quality standards of potted flowers. The timely practice of pinching, involving the removal of the apical bud at the appropriate time, has been explored as a crucial cultural technique to enhance both plant growth and flowering quality. This study was aimed to investigate the effects of pinching at various time periods on the plant growth and flowering of the P. grandiflorus Jacq. 2009B variety under greenhouse conditions. The experiment was laid out in Completely Randomized Design (CRD) with six treatments and ten replications. Different time periods of pinching treatments including pinching after 6 (T1), 7 (T2), 8 (T3), 9 (T4), and 10 weeks (T5) of sowing and control treatment without pinching (T0) were studied to evaluate the impact of pinching time. Plant growth and flowering parameters were analysed using SAS statistical software at 5% significance level. The maximum number of leaves (56.2) and branches (6.4) were recorded in the T5 followed by T3 and T4, whereas the highest stem diameter (3.13mm) and plant height (17.2cm) were recorded in T0 control treatment. When pinching time was delayed (10 weeks after sowing) flower bud formation also was delayed (111.9 days in T5) compared to the treatment without pinching (90.3 days in T0). However, the highest number of flowers were observed in the T3 (16.8) while T4 recorded the lowest (11.8). Also flower diameter was significantly higher in T0 (11.6cm) and the lowest was recorded in T1 (8.8cm). Hence, based on the results obtained from the present study, it can be concluded that pinching after 8 weeks of sowing (T3) was found to be effective in promoting early-stage branching and enhancing flower yield of P. grandiflorus Jacq. 2009B.