In breeding poinsettias, there are two stages, making the process both laborious and time-consuming. That's because poinsettias are trees and only become shrubs (with a low habit and many branches, making them suitable for pots) as a result of a phytoplasma infection. But as a consequence of this infection, poinsettias won't produce seeds for the next generation.
聖誕紅育種需要 2 階段選種，費工費時，原因是聖誕紅本來是喬木，因微生物感染才「病變」為灌木（很多分枝，無法向上拔高，此特性適合做盆花），但也因此無法結種生育下一代。