ABSTRACT
Cheiranthus L. belongs to the family of Cruciferae and is a genus of ten species of biennial, perennial, or sub-shrubby herbs — natives of the Mediterranean and northern temperate regions. Cheiranthus cheiri L. is a perennial. However, in horticultural practice it is usually treated as a biennial. Cheiranthus allionii Hort, is a winter annual, however, in practice it is usually treated as a biennial. Both Cheiranthus cheiri L. and Cheiranthus allionii Hort, have an obligate cold requirement for flower induction. However, the two species differ with regard to factors affecting vernalization, i.e., age, temperature, and photoperiod. Cheiranthus allionii has been more thoroughly studied with regard to the relation between vernalization and age. Cheiranthus cheiri plants vernalized at 2 or 5°C under short, or long photoperiods for 7 or 8 weeks, followed by a transfer under these same photoperiods to either a relatively low, moderate, or high temperature. Cheiranthus allionii has been studied with regard to vernalization and temperature.
