Scaling up In Vitro Crocus sativus Propagation Using SETIS Bioreactors: The Combined Effect of Cross-Cutting and Culture System

This study aimed at developing in vitro propagation methods for Crocus sativus L., focusing on the effectiveness of temporary immersion systems (TIS) or bioreactors as an alternative, cost-efficient technique for the large-scale production of saffron corms. The effects of the culture system and cross-cutting on saffron propagation were evaluated. Saffron shoots were cultured in TIS and compared with shoots produced using a conventional semi-solid tissue culture system (SS). The recipient material for automated temporary immersion used in this study was the SETIS™ bioreactor. The growth parameters measured for in vitro culture were the number of neo-formed shoots, shoot height, and the number and size of corms. Based on the present detailed study, the highest shoot multiplication rate (9.1 shoots/explant with 7.2 cm of shoot height) was achieved in the TIS system after shoot cross-cutting, while the lowest multiplication rates were obtained in the semi-solid system (1 shoot/explant with 14.8 cm long shoots). Furthermore, the highest corm formation was obtained in the TIS system, with an average of four corms per explant, with a larger corm weight (10.90 g) and diameter (21.78 mm). These findings highlighted for the first time the efficiency of the bioreactor system combined with cross-cutting of the shoot for efficient and scalable saffron corm propagation, thus making a valuable contribution to sustainable cultivation and conservation strategies while meeting the growing demand for this spice.