Abstract:
Ginger is one of the important cash crops in Ethiopia. However, unavailability of disease free
planting material (rhizomes), poor flowering and seed sets are the major problems in ginger
propagation. Tissue culture is the best option to overcome these problems, since it is
propagated under aseptic area to reduce disease transmission. Therefore, this study was
initiated to optimize protocol for micropropagation of ginger accession 52/86 under in vitro
conditions. Murashige and Skoog (MS) basal medium was used in this study. For culture
initiation, sterilized sprouted rhizome bud was used and data were collected on number of
initiated shoots. In vitro shoot multiplication, five different concentrations of 6-benzylaminopurin (BAP) and four concentrations of kinetin (KN) in a 5 x 4 factorial combination treated
with three replications and five explants per jar were used in completely randomized design
(CRD). Data were collected on number of shoot per ex-plant, shoot length and number of
leaves per shoot. In rooting experiment, five different concentrations of α-Naphthalene acetic
acid (NAA) and four concentrations of Indole-3-butyric acid in a 5 x 4 factorial combination
treated with three replications and five explants per jar were used in CRD. Data were
collected on root number per shoot and root length. Acclimatization was done on six
different soil media combined as treatments with 10 plantlets per pot with three replications
in greenhouse using CRD. Data were collected on numbers of survived plantlets in
greenhouse from each soil media. The results showed that from well sterilized sprouted
rhizome buds up to 91.3 % initiated shoots were achieved. On shoot multiplication,
maximum shoots per ex-plant (9.34±0.55) were obtained on a medium containing 2.5 mg/L
BAP + 1.0 mg/L KN. The largest shoot length (5.10 ± 0.17 cm) was obtained on MS medium
containing 2.5 mg/L BAP + 0.5 mg/L KN growth regulators. The highest mean number of
leaves per shoot (5.67± 0.06) was obtained on a medium containing 3.0 mg/L BAP+0.5 mg/L
KN. The highest mean number of root per shoot (12.60±0.17) was achieved on a medium
supplemented with 2.5 mg/L NAA + 1.0 mg/L IBA and largest root length (6.30±0.10 cm) was
achieved on a medium containing 1.0 mg/L NAA + 1.0 mg/L IBA hormones. Among soil
combined for the plantlets acclimatization, the highest survival percentage (98 %) was
recorded on top soil (TS): sandy soil (SS): coffee husk (CH) (1:1:1). Thus, MS + 2.5 mg/L
BAP + 1.0 mg/L KN and half MS+ 2.5 mg/L NAA + 1.0 mg/L IBA were the best hormone
combination for shoot multiplication and in vitro rooting, respectively. At greenhouse, media
combination of TS: SS: CH (1:1:1) ratio was found to be optimal for plantlets
acclimatization. Therefore, the optimized protocol can be used for rapid multiplication of the
clean planting materials for ginger accession 52/86.
