Plant regeneration and selection for salt and drought tolerance on the Africa finger millet (Eleusine coracana (L) Gaertn)
Hormonal concentrations for callus initiation and plant regeneration was investigated in KAT/FM-1,P244 and EKR finger millet varieties (Eleusine coracana L.) Compact nodular morphogenic callus was initiated from shoot tips of cultured germinating seedling on Ms medium supplemented with 0-4 mgl-1 2,4- D. alone or in combination with 0.5 mg-1 KIN. Shoots were induced on a medium supplemented with 0.5-1mg1-1 BAP alone or in combination 0.1 mgl-1 2, 4-D. Rooting occurred on one half-strength MS medium devoid of growth regulators. Plantlets were transferred onto soil and grown to maturity. Sodium chloride tolerant EKR callus lines were selected on MS medium containing 128m M sodium chloride after five passages of three weeks each. Sodium chloride tolerant callus lines showed better growth in comparison with the non-selected lines at all concentrations of salt tested. Tolerance was retained after three passages each lasting three weeks in absence of sodium chloride. EKR and P224 regenerants derived from tissue culture were studied for variability in characteristics related to salt and drought tolerance. The regenerants were not significantly different from the non-regenerants (seed derived) on shoot and root fresh and dry weights, number of nodes and leaves when subjected to regenerants in all the characteristics tested for salt tolerance. EKR regenerants showed improved tolerance to salinity as compared to the non-regenerants showed improved tolerance to salinity as compared to the non-regenerants in shoot and root dry weights and on the number of leaves. A protocol for finger millet regeneration was developed. Sodium chloride tolerant EKR callus and plants were obtained. These findings demonstrate that variations expressed in plants were obtained. These findings demonstrate that variations expressed in plants regenerated through tissue culture include basic physiological characteristics that influence saline tolerance. The results from the present study has the potential for considerable application for plant improvements by plants breeders.