The reason why T. recurvata has a low production of seeds may be due to the lack of genetic variability (Soltis et al., 1987); in fact, field experiments(Orozco-Ibarrola et al., 2015) have suggested that this species may present inbreeding depression but this remains to be tested.
For horticurtural purposes seed number could limit the production of plants, especially if seed viability and seed longevity are of short duration. T. recurvata is the most restricted, while the rest of the species could be produced more succesfully because they present higher numbers of seeds per fruit, particularly in the case of T. hubertiana.