Tulips: taxonomy, morphology, cytology, phytogeography and physiology (1982)
By Z. P. Botschantzeva

Juvenile Period in Tulips

The prolonged juvenile period of sown populations occurs under Tashkent conditions not only in the wild species but also in cultivars. Without proper selection for many years it is therefore difficult to obtain a decorative effect from seedling populations. This can be explained by the adaptation of the plants to the adverse conditions of growth and development which may occur in certain years. The long germination period and the varying periods required to reach the adult phase have evolved in the past as an adaptive response of the genus.

In the juvenile, as well as in the adult phase, all species and varieties initiate in the axils of the fleshy scales buds which can develop into daughter bulbs. As organs of vegetative reproduction these daughter bulbs are to some extent rejuvenated as compared with the apical bud of a juvenile plant and the main daughter bulb of an adult one. The degree of rejuvenation varies in different species and cultivars. After separation from the mother bulb the daughter bulbs of T. fosteriana continue to multiply vegetatively for several years by forming sinkers from apical buds and axillary buds and, although frequently having formed several large fleshy scales, do not flower. Daughter bulbs of T. kaufmanniana or T. greigii, of at least 1.5 cm diameter, start to flower under Tashkent conditions in the next season. From seedling populations of wild species forms can be selected with a high capacity for vegetative reproduction and through cultivation and subsequent selection it is possible to obtain forms similar to garden varieties.

Bulb bibliography