Development of an Efficient Micropropagation Protocol for Philodendron erubescens ‘Pink Princess’ Using a Temporary Immersion System and Assessment of Genetic Fidelity

Conventional propagation of the highly sought-after ornamental Philodendron erubescens ‘Pink Princess’ is constrained by slow multiplication rates, the risk of unstable variegation, and the limited availability of elite mother stock, making advanced in vitro techniques essential for large-scale production. This research aimed to establish an efficient micropropagation protocol by optimizing the shoot multiplication phase in a twin-flask Temporary Immersion Bioreactor (TIB) system (RITA-type) and subsequently assessing the genetic fidelity of the regenerated plants. Shoot induction was evaluated in a TIB system with an immersion frequency of 4 min every 8 h. Among the tested cytokinins, liquid Murashige and Skoog (MS) medium containing 1.0 mg/L 6-benzylaminopurine (BAP) provided the optimal conditions for shoot proliferation, accounting for approximately 21 shoots/explant. While the TIB system was highly effective for shoot multiplication, it proved suboptimal for root induction. Therefore, rooting was optimized on a semi-solid medium, where MS medium supplemented with 0.5 mg/L indole-3-acetic acid (IAA) was identified as the most effective treatment, yielding an average of 3.0 well-developed roots per explant (1.1 cm in length) within 30 days. For acclimatization, a substrate mix of peat moss, perlite, and vermiculite (2:1:1, v/v/v) ensured a 100% survival rate. Critically, genetic fidelity analysis using RAPD markers revealed monomorphic banding patterns between the micropropagated plantlets and the mother plant (100% similarity), confirming their genetic uniformity and true-to-type nature. The established protocol provides a robust and reliable method for the in vitro propagation of P. erubescens ‘Pink Princess’. This work offers a foundation for developing large-scale commercial production strategies and effectively overcomes many limitations of classical propagation techniques.