Rhizome dormancy and shoot growth in myoga (Zingiber mioga Roscoe

After the senescence of above ground plant parts the rhizomes of myoga undergo a period of dormancy. The length of this dormancy period and the requirement for chilling to break dormancy are examined in this paper. Myoga rhizome segments were capable of initiating shoot growth 6 weeks after excision from a recently senesced dormant mother plant. A period of chilling was not required for shoot growth, but chilling at 4°C for 3 weeks immediately after excision resulted in shoot development in newly divided myoga rhizome segments which would otherwise not have sprouted until after a 6-week dormancy phase. Longer storage periods before planting and increased duration of chilling treatments decreased the variability in the sprouting response of rhizome segments. Chilling at 4°C for 2-4 weeks was the most effective treatment for promoting uniform sprout emergence and subsequent flower production. Shoot growth rate and the number of vegetative shoots produced by the rhizome was not affected by chilling treatments. Increasing the length of chilling, promoted earlier sprouting and flowering, but may have decreased the weight of the flower buds produced. (C) 2000 Elsevier Science B.V.