“…These hybrid forms are seed sterile and require vegetative maintenance in plant collections. The explants for cryopreservation are usually taken from nodal cultures (Towill 1988;Volk 2000;Staats et al 2006;Senula et al 2007). In chamomile (Matricaria recutita L.), vegetative maintenance is needed to support breeding of varieties with high bisabolol contents (Diettrich et al 1990).…”