Protocol optimization for in vitro propagation of Ginger (zingiber officinale rosc.) From sprouted rhizome Bud explants

Abstract

Although ginger is an important crop in Ethiopia, its production is limited by different factors like inefficient propagation method and disease transmission. Therefore, this study was initiated to develop a protocol for in vitro propagation of ginger from sprouted rhizome buds. Sprouted rhizome buds were cultured as whole and divided into half longitudinally in MS medium supplemented with different concentration of TDZ (0,0.1,0.3,0.&0.7) and BAP (0,1,2, 3& 4) mg/l to evaluate their effect on shoot multiplication. This particular experiment was laid in 2 x 5x5 factorial arrangement for types of explants, concentrations of BAP and concentrations of TDZ, respectively. Micro shoots were then transferred into 1/2MS medium supplemented with different combination of NAA (0, 0.5, 1, 1.5 & 2.0) and IBA (0, 0.5, 1, 1.5& 2.0) mg/l for root induction. Both experiments were laid out in completely randomized design (CRD) with three replication and three explants per jar. The cultures were kept at a temperature of 25 ± 2º C and light intensity of 2,000-µmol/m 2 / s 2 produced from cool white fluorescent tubes for 16 h photoperiod. Finally well rooted shoots were transferred into greenhouse for acclimatization. Data on number of day for shoot initiation, shoot number, shoot length and leaf number (for shoot multiplication) and number of days for root initiation, root number and root length (for rooting) were collected. The data was analyzed using SAS software (version 9.2). Statistical analysis revealed that there was significant difference among all treatments in both shoot multiplication and rooting experiment. Maximum numbers of shoots per explant (5.33±0.58) and (7.00±0.00) were obtained from MS medium containing 1.0 mg/l BAP combined with 0.5mg/l TDZ for whole and section bud explants respectively. The lowest shoot (2.33±0.58) number was observed from higher combination of the two hormones followed by MS medium with no hormone added in both explants. The highest number of induced roots per shoot (10.00±0.00) was obtained at 1.5 mg/l IBA combined with 0.5mg/l NAA. Among the rooted plantlets used for acclimatization, 80% of them survived. According to the result obtained in this study, MS medium supplemented with 1.0 mg/l BAP combined with 0.5mg/l TDZ for shoot multiplication and sectioned rhizome bud explants and 1/2MS medium supplemented with 1.5mg/l IBA combined with 0.5mg/l NAA are recommended for in vitro propagation of ginger from sprouted rhizome bud explants. However, further optimization of this protocol may be required for mass propagation of ginger as this study is limited to single of cultivar.