PERFORMANCE OF SOME SALT-TOLERANT AND SALT-SENSITIVE ACCESSIONS OF PEARL-MILLET AT THE ADULT STAGE

Salt tolerance of four salt-tolerant accessions, WIR-6-Ostistoe, KAT/PM-2, Kitui Local and Selection II and two salt-sensitive accessions, Y-84 and Togu Bold Grain, selected at the germination and seedling stages was assessed at the adult stage in sand culture salinized with 125 or 250 mol m(-3) NaCl in fun strength Hoagland nutrient solution. Salt tolerance of all six accessions which were tolerant or sensitive at the early growth stages was conferred at the adult stage, because the four tolerant accessions produced significantly greater fresh and dry biomass than the two sensitive accessions. The four salt-tolerant accessions clearly excluded Na+ from their shoots and roots under saline conditions. The salt-sensitive accessions had significantly greater shoot K+ than the tolerant accessions, so as to maintain tissue K/Na ratios similar to those of salt-tolerant accessions. The salt-tolerant and salt-sensitive accessions had almost uniform leaf osmotic potential. This may have been due to relatively higher soluble proteins, free amino acids, proline and soluble sugars in the tolerant accessions than in the salt-sensitive ones. From the present study it is very clear that the salt tolerance of pearl millet is a consistent phenomenon which is maintained throughout the different stages of plant life cycle.