Improved in vitro rooting of Prunus avium microshoots using a dark treatment and an auxin pulse

- The positive effect of in vitro rooting on the survival of Prunus avium plantlets during acclimatization was verified.
- A 48 h IBA pulse led to a significant increase in the rooting percentage; however, disproportional growth of the roots was observed.
- A dark treatment of four days induced a higher number of rooted plants without a negative influence on the plant habitus.
- Data collected during commercial production verified the root-inducing effect, illustrating its applicability in commercial practice.

The influence of a four-day dark treatment and a 48 h IBA pulse on in vitro root formation of Prunus avium microshoots was examined. Both treatments led to significantly higher rooting percentages in the majority of the six genotypes. While the IBA pulse led to a disproportional growth of roots compared to shoots, the plantlets under the dark treatment during root induction were healthy and were not visually distinct from the control plants. Further data collected during the commercial production of 17 genotypes verified the improved root induction using the dark treatment and identified the gelling agent Gelcarin (a carrageenan) as an additional factor with positive effects on rooting. In addition, the importance of in vitro rooting for the successful transfer to greenhouse conditions was confirmed. Rooted plantlets (>3 roots) had a significantly higher survival percentage and showed improved growth during acclimatization compared to unrooted microshoots.