A Temporary Immersion System as a Tool for Lowering Planting Material Production Costs Using the Example of Pennisetum × advena ‘Rubrum’

The aim of the study was to compare the variable costs of planting material production using the example of vitro cultures of Pennisetum × advena ‘Rubrum’. In the study, temporary immersion system (TIS)- and agar-based methods were used in innovative workday organisation. The workday structure involved a six-hour passaging period followed by a two-hour break for medium preparation, autoclaving, and maintenance tasks. The TIS was found to be more cost-effective than the agar cultures, with lower labour costs and comparable growing expenses. The most expensive element of agar production was labour which was 43% of the costs. The second biggest cost was materials and reagents which represented 25%. In a TIS, production materials and reagents are the most expensive part of production (44%), while labour represents 24% of costs. A TIS offers a much faster multiplication of plants than agar cultures. Plants obtained in the multiplication phase are two times cheaper using a TIS. Rooting accounted for a significant portion of production costs in both methods. Overall, the TIS demonstrated superior efficiency and cost-effectiveness compared to agar cultures in producing Pennisetum × advena ‘Rubrum’ plants.