Jatropha curcas L. is among important tree crops in the world with a potential for biofuel production. In Ethiopia, there is a soaring investors' interest to produce Jatropha in the country for biodiesel production. However, insufficient good quality propagation material is a major production constraint. A study was undertaken to establish a protocol for in vitro mass propagation of three Ethiopian Jatropha accessions viz. Metema, Adami Tulu and Shewa Robit through direct organogenesis from nodal explant. The result revealed that the highest percentage of shoot induction (86-90%) was achieved on MS medium with BAP (1 mg/L) and IBA (0.5 mg/L) for all the three accessions. The maximum number of shoots (6) was obtained for Metema when BAP (0.5 mg/L) with Kn (0.5 mg/L) was used. Whereas, the maximum (3.2 cm) shoot length was recorded for Shewa Robit on media with 0.5 mg/L Kn. The highest rooting percentage (84.8-88%) and maximum root number (5.43) were recorded on media supplemented with 0.25 mg/L IBA. Shewa Robit and Metema had longer roots on media with 0.25 mg/L IBA. Finally, the plantlets were successfully established in greenhouse with survival rate of 86.67% for Shewa Robit followed by 73.33 and 66.67% for Metema and Adami Tulu, respectively. This study provided optimal protocol for micro-propagation of Jatropha accessions through direct organogenesis to boost its production.

The present study was undertaken to establish a protocol for in vitro callusing of three Jatropha accessions, namely Metema, Adami Tulu and Shewa Robit from leaf explants. The medium supplemented with combination of 4.44 μM BAP and 4.52 μM 2,4-D resulted in maximum percentage of callus (100%) formed for all accessions. The maximum shoot regeneration (66.67%) from callus with 10.13 number of shoot was obtained from Shewa Robit in MS medum fortified with TDZ (2.27 μM ) and IBA (0.49 μM ). The presence of TDZ in the shoot regeneration medium has greater influence on the induction of adventitious shoot buds, whereas MS supplemented with BAP alone and combination with IBA did not induce shoot regeneration from callus culture. The results obtained in the present study would facilitate the high callus induction and regeneration responses in Jatropha for its improvement using biotechnological tools. Plant Tissue Cult. & Biotech. 30(1): 131-141, 2020 (June)