Evaluation of Salinity and Drought Stress Effects on Germination and Early Growth of Maize Inbred Lines (Zea mays L.)

Present study was conducted to investigate the effects of different osmotic potentials (0.0 MPa, -0.4 MPa, -0.8 MPa and -1.2MPa) induced by NaCl and Polyethylene glycol-6000(PEG) as salinity and drought stress respectively on germination and early growth of two inbred lines of maize (Mo17 and B73). The objective was to compare the germination ability between tow maize inbred lines in salt and drought stresses and to determine factors (salt toxicity or osmotic stress due to PEG) inhibiting seed germination. The experimental design was completely randomized design with three replications in which factors were arranged as factorial. The experiment was carried out in a germinator (251 C, 40% relative humidity). Results of variance analysis showed that the effect of osmotic potential levels on germination index, germination percentage, length of root and shoot and seedling dry weight was significant. Germination and seedling growth appeared to decrease with increasing osmotic pressure. While this decrees was more considerable in seedling growth than in germination. It concluded that at each level of osmotic potentials the inhibitory effect of drought stress on germination was more drastic than that of salinity stress. The germination responses of inbred lines to the both stresses were nearly same. When seeds were transferred to unstressed condition, after 10 days of salinity treatment, there was some recovery. This showed that the main inhibitory influence of salinity on maize inbred lines seed germination was mostly due to osmotic effect.