Minuartia laricina (L.) Mattf. is a Korean native plant with high potential as a commercial flowering potted plant due to its compactness and long flowering duration. However, because this plant is a groundcover, it is susceptible to lodging and leggy growth. Therefore, this study investigated the effects of plant growth retardants (PGRs) on the inhibition of stem elongation and flowering characteristics of M. laricina. Commercial products, Trimmit, Cycocel, and B-Nine, were used for the exogenous PGR application of paclobutrazol (PBZ), chlormequat chloride (CCC), and daminozide (DMZ), respectively. Application concentrations were 50 and 100 mg·L-1 for PBZ; 100, 500, and 1,000 mg･L-1 for CCC; and 500, 1,000, and 2,000 mg·L-1 for DMZ. Paclobutrazol was the only PGR that inhibited stem elongation. The stem lengths of the plants treated with 50 or 100 mg·L-1 PBZ were 2.2 cm (13%) or 9.8 cm (57%) shorter, respectively, than those of the control. 50 mg·L-1 PBZ retarded stem growth effectively without negatively affecting flowering or other growth parameters, whereas 100 mg·L-1 PBZ caused excessive dwarfing and significantly reduced flowering by 59%. CCC and DMZ applications were ineffective for growth control. Flowering time was accelerated with most PGRs, except for 2,000 mg·L-1 DMZ, reducing the time to flowering by 2–8 days. These results indicate that the stem growth of M. laricina was successfully inhibited with PBZ but not with CCC or DMZ. Thus, we concluded that a single application of 50 mg·L-1 PBZ or similar treatment is effective in miniaturizing M. laricina without causing harm to its growth or aesthetic value, such as the flower number. Additionally, because CCC and DMZ are not persistent in the growing medium, testing multiple application times for these PGRs is crucial.

Abstract
Introduction
Materials and Methods
    Plant materials and growth conditions
    Plant growth retardant (PGR) treatment
    Data collection
    Experimental design and statistical analysis
Results and Discussion
Acknowledgments
References

• Ji Woo Park(Department of Agriculture, Forestry and Bioresources, Seoul National University, Seoul 08826, Korea)
• Un Seop Shin(Seed Viability Research Team, Baekdudaegan National Arboretum, Bonghwa 36209, Korea)
• Hye Jin Oh(Division of Garden and Plant Resources, Korea National Arboretum, Pochen 11186, Korea)
• Sang In Lee(Division of Garden and Plant Resources, Korea National Arboretum, Pochen 11186, Korea)
• Yae Eun Kwon(Genolution, Seoul 07793, Korea)
• Seung Youn Lee(Division of Horticulture & Medicinal Plant, Andong National University, Andong 36729, Korea)
• Wonwoo Cho(Division of Garden and Plant Resources, Korea National Arboretum, Pochen 11186, Korea)
• Hyo Beom Lee(Department of Agriculture, Forestry and Bioresources, Seoul National University,Research Institute of Agricultural and Life Sciences, Seoul National University)
• Mi Jin Jeong(Division of Garden and Plant Resources, Korea National Arboretum, Pochen 11186, Korea) Corresponding author