Abstract:
(Solanum  tuberosum  L.)  is  one  of  the  most  economically  valuable  crops which consumed widely in the world. In developing countries, many cultivars have undesirable  traits  which  reduce  their  market  value.  Mutation  induction  in  potato produces mutants for diverse traits. Mutants can be produced in potato by mutagenic treatment  of  tuber  buds  of  potato.  Adventitious  buds  that  arise  from  adventitious roots of in vitro explants of tuber disc are used for mutation breeding of potato. In this  aspect,  this  study was  carried  out  to  determine  the  optimum  concentration  of IBA  for  induction  of  in  vitro  adventitious  root  formation  in  potato  tuber  disc.  A preliminary study was  done  to  determine  the  morphogenic  response  of  the  potato tuber discs which were in 0, 50 and 100 mg/l IBA concentrations. It was noted that higher  concentration  (100  mg/l)  of  IBA  did  not  induce  callus  formation  in  tuber discs  and  the  cultured  explants  at  the  concentration  of  100  mg/l  IBA  turned  into brown colour. In addition, it did not show any response to form adventitious roots. Therefore,  the  tuber  discs  were  cultured  in  MS  medium  supplemented  with  0-50 mg/l concentrations of IBA (5, 15, 25, 50 mg/l) to induce adventitious roots. Results revealed   that   IBA   concentration   significantly   (P<0.05)   affected   the   tested parameters such as days taken for root formation, root length, root diameter, number of  roots,  root  formation  percentage  as  well  as  amount  of  callus  formed  and  time taken   for   callus   initiation   in   granola   potato   variety.   IBA   at   25   mg/l   IBA concentration  gave  the  best  performance  for  root  initiation  and  amount  of  callus formed  in  potato  tuber  disc  explants  compared  to  all  other  treatments.  Hence,  it could   be   concluded   that   25   mg/l   IBA   concentration   is   the   most   favorable concentration for in vitro adventitious root formation in tuber disc explants of potato cv granola.