VARIATION IN RESPONSE OF ACCESSIONS OF MINOR MILLETS, PENNISETUM-AMERICANUM (L) LEEKE (PEARL-MILLET) AND ELEUSINE-CORACANA (L) GAERTN (FINGER-MILLET), AND ERAGROSTIS-TEF (ZUCC) TROTTER (TEF) TO SALINITY IN EARLY SEEDLING GROWTH

The response to increasing NaCl concentration of seedlings of 25 accessions of Ethiopian land races of each of Pennisetum americanum (L.) Leeke (pearl miller) and Eleusine coracana (L.) Gaertn (finger millet), and 15 accessions of Eragrostis tef (Zucc.) Trotter (tef), was examined after two week's growth in NaCl solution culture. Although increasing NaCl concentration significantly reduced seedling root lengths, there was considerable variation within, and between accessions within each species. Analysis based upon a non-linear least square inversion method, using root length data, revealed significant differences in accessions of P americanum and E. tef on the basis of the estimated salinity threshold, C-t, the NaCl concentrations at which root length begins to decrease. C-t did not differ significantly between E coracana accessions. Estimates of C-50 and C-0, minimum concentrations causing a 50% decrease in root length, and zero root growth respectively, revealed differences between and within accessions for all three species. Overall, finger miller was more tolerant than tef, which was more tolerant than pearl miller. There is clear evidence that differences in tolerance are genetically based from broad sense heritability estimates.