Abstract: Juvenility and limited inductive photoperiod (LIP) of Petunia hybrida ‘Fantasy’were exam
ined by transferring plants between short days ( SD) and long days (LD). It is concluded that the end of the
juvenile phase of petunia is about 62leaf stage, and the LIP of petunia is 3 weeks. LIP inhibited stem elonga
tion of petunia compared to plants grown in continuous LD, while it did not affect crown diameter and branch
number at first flower. Suggestionswere p resented that petunia Fantasy should be p lanted under long days up
on 8-leaf stage for fast flowering, and planted under short days after 3 weeks for saving energy, and the plant
height can be shortened at the same time.

Key words: Petunia hybrida, Juvenility, Limited inductive photoperiod