Abstract:
Potato is ranked fourth among food crops that have the potential o f meeting food
requirement o f the world. Ethiopia is mentioned to have appropriate climatic condition
for potato production. However, (he national average yield is lower (8 t ha'1) than the
world average. This work presents the method o f in vitro potato virus elimination, in
vitro conservation and in vitro production ofpotato miniatures. Foliar samples o f three
released potato varieties were tested against Potato virus Y (PVY), Potato virus X
(PVX) and Potato leaf roll virus (PLRV) using DAS-ELISA a month after planting.
Plants showing positive reaction were propagated in the laboratory. Nodes o f these
plantlets were subcultured on culture medium supplemented separately with ribavirin
(10, 15. 20, 25 and 30mg') and 8-Azaguanin (5, 10, 15, 20mg I'1) and were exposed to
thermotherapy (37 °C) for 30dctys. Virus assays indicated that PVX and PVY were all
eliminated from treated cultures. However, PLRV was not affected by ribavirin even
though it reduced in cultures treated with 10-20mg'! o f 8-Azaguanin. In vitro
conservation o f four varieties was undertaken by supplying sorbitol (3%, 4% and 5%)
in culture media and culture incubation at 13-15 "C. Culture media with 4% and 5%
sorbitol levels were found to reduce the growth rate o f plantlets. Three selected potato
varieties were tested for microtuberization from nodal explants cultured on MS
medium supplemented with benzy amino pure (BAP) (I, 2 and 3mg\') and sucrose at
4%, 6% and 8 % , incubated at 15 "C temperatures and 8-hr photoperiod in growth
chamber. Results showed that treatments consisting o f 6% sucrose and I m g1 BAP
were found to be effective in inducing miniature tubers.