The development of a new cultivar in tulip can take more than 20 years due to its long juvenile phase and low natural propagation rate. Full grown flowering bulbs produce yearly only two to four viable daughter bulbs. Consequently, about ten years are needed to propagate a new cultivar and to obtain sufficient plant material for commercial purposes. Several attempts to speed up the vegetative propagation process in tulip through in vitro techniques have been undertaken in the last decades, but unfortunately, without success. According to these studies bulb regeneration is slow, unpredictable, and low-yielding. In contrast, efficient in vitro propagation protocols exist for lily. Most of the propagation studies in lily and tulip have focused on the physiological conditions required for in vitro culture, whereas hardly any research has been done at the molecular level, neither on tulip vegetative propagation capacity in the field.
We aim to unravel the molecular processes underlying bulblet initiation and outgrowth in tulip and lily through genetic and genomical approaches. Lilium will be used as a model species for in vitro propagation, because this species can be efficiently propagated. Nevertheless, propagation efficiency strongly depends on the genetic background, making Lily an ideal model system to study and unravel this biological process and to identify involved genes and regulatory mechanisms. A combination of RNAseq, hormonal measurements, and detailed phenotyping will be used to identify potential key regulatory genes. Additionally, already available information from the model species Arabidopsis thaliana, Oryza sativa and Zea mays will be used to guide the identification of candidate genes. In parallel, propagation will be studied in a field-grown tulip population. Ultimately, the different knowledge resources will be combined and integrated to get insight in the vegetative propagation process in tulip and lily, both in vitro and in vivo.