**2.3 Variety development**

Rigorous adaptation test of ginger accessions has been conducted in different agro-ecologies, suitable propagation parts, and status to sprouting and subsequent field performance and rhizome yield. Pest reactions and quality were some of the traits used in the evaluation. According to the results obtained [5, 6], the varieties were proved promising and widely employed by users and distributed throughout the potential producing areas. Further evaluation continued to achieve better varieties. Ginger bacteria diseases have been devastating to the materials. This


#### **Table 1.** *Germplasms and varieties of ginger in Ethiopia.*

time, more than 45 accessions of ginger are being maintained for future disease management research [7].

### **2.4 Status of ginger breeding**

In Ethiopia, ginger breeding was started as a part of coffee diversification in JARC, since the inception of coffee research in 1969 [8]. Some preliminary research on local and introduced ginger germplasms indicated the existence of genetic variability in their morphological traits, rhizome yield, oil and oleoresin contents [9]. High variability was observed among ginger cultivars and/or accessions for plant height, rhizome yield, oil content, and oleoresin. According to Momina *et al*. [8] there was high genetic diversity in local ginger germplasms.

### **2.5 Diversity of ginger in Ethiopia**

The introduction of ginger to Ethiopia for a long time (thirteenth century), made the country to have diverse genetic resources. Variability (in morphology and quality) was reported by Momina *et al*. [8]. Such status of diverse genetic resources is crucial for breeding purpose. Southern Nation and Nationalities regional state are often understood to be major areas of ginger germplasms. Indicating that there is high diversity of ginger in Southern Nation and Nationalities regional state Wolaita zone farmers group local varieties into Masculine and Feminine [3]. Also, farmers in Kambata-Tambaro recognized one local genotype called Hargema (**Figure 1**). There is some similarity among these materials.

Production of local ginger materials in Wolaita and Hadiya zones has been since time immemorial and various local landraces were common in different areas (Bilbo and Volvo (**Figure 2**) introduced to the area recently (in 1998). According to Geta and Kifle [3] seed transfer and distribution as informal ways (farmer-to-farmer) remained very common.

The local grouping of the ginger materials discussed here (**Table 2**), and the selection and release of two ginger cultivars from Jimma Agricultural Research center/Tepi Agricultural Research Sub Center, confirmed that the country has a high diversity of the germplasm. This needs further research to exploit ginger genotypes with different quality parameters and special traits.

#### **2.6 In vitro propagation for maintenance of ginger**

Propagation of two ginger cultivars by tissue culture is one of the strategy to improve production and productivity by overcoming ginger bacterial wilt. The study was carried out with the objective of assessing the potential of axillary buds and shoot tips as explant sources and determination of suitable growth regulators for in vitro propagation. MS medium with four levels of benzyl adenine (BA) and kinetin was used for shoot multiplication in combination with two explant sources. Shoot tip explants on 2 mg l−1 BA and 1.2 mg l−1 kinetin was found to be better than other explant-media combinations. Consecutively, the plantlets developed an average of 8.75 roots within 4 weeks of the culture period and performed well in greenhouse acclimatization and field operations. In vitro propagation of the Yali and Boziab was proved possible with this explant and media combinations. Parameters such as number of leaves and dry weight of plantlets regardless of the varietal difference in comparison to axillary bud was higher. Similarly, shoots cultured on MS medium with 1 mg l−1 NAA alone developed vigorous roots. Plantlets produced by this propagation protocol were successfully acclimatized within 4 weeks of hardening. The acclimatization procedure has been supported with the application of

**Figure 1.** *Feminine Wolaita (left), Masculine Wolaita (right). Source: [3]*

**Figure 2.** *Subterranean parts of Bilbo with two taproots (left), Volvo with a single taproot (right). Source: [10].*

shade nets (at 30 and 70% shade level) and polythene under the greenhouse condition. Subsequently, the seedlings have survived well under field conditions [12].

### *2.6.1 Ginger tissue culture*

In Ethiopia, infection with *Ralstonia solanacearum* has resulted in significant losses of ginger rhizomes. To have successful ginger cultivation, disease-free planting material generation is required and practiced. Plant tissue culture technology has proven to be effective in the commercial production of pathogen-free plants as well as the preservation of rare and endangered species' genetics (**Table 3**). The initial surface sterilization experiment was effective when 0.7–1.5 cm shoot tips were treated with 70% ethanol for 5 min followed by double sterilization with 5% active chlorine concentration of local bleach (Clorox), for 15 min under aseptic condition. This treatment cleans bacterial contamination more than 95%. Also, antibiotics



**Table 2.** *Characteristics of different ginger vernaculars cultivated in SNNPRS.*
