Effects of Day Length on Flowering and Rhizome Swelling in Ginger (Zingiber officinale Roscoe)

Abstract

Photoperiodic treatments were carried out with three Japanese cultivars (`Kintoki', `Sanshu' and `Oshoga') of ginger (Zingiber officinale Roscoe) . As day length was increased from 10 h to 16 h, the vegetative growth of the plants was enhanced, whereas it was inhibited and rhizome swelling was promoted as the day length was decreased from 16 h to 10 h. Further increase in day length from 16 h to 19 h did not give any rhizome swelling, and resulted in the lowering of the growth increment. The cultivar `Sanshu' was most sensitive to photoperiod for rhizome swelling , but `Oshoga' was relatively insensitive.