Evaluation of highland maize (Zea mays L.) cultivars for polyethylene glycol (PEG) induced moisture stress tolerance at germination and seedling growth stages

摘要

A laboratory experiment was performed at Ambo University, Department of Plant Sciences in March 2014, to evaluate the effect of moisture stress on germination and seedling growths of highland maize cultivars. The experiment was arranged factorially in completely randomized design with three replications. Five highland maize cultivars (Hora, Wenchi, Jibat, Argene and Wabi) were exposed to six levels of water stress (0, 60, 120, 180, 240 and 300 g/L Polyethylene glycol 6000). The result revealed that no significant interactions exist between maize cultivars and moisture stress. However, cultivars varied significantly for germination percentage and rate, shoot and root lengths, root number, and shoot and root fresh weight. Increase in PEG 6000 concentrations decreased germination percentage and rate, where as shoot and root lengths decreased beyond 60 g/l. No significant differences were observed among 60, 120 and 180 g/L for shoot and root fresh and dry weights, and seedling fresh and dry weights. Maximum root number, root-to-shoot ratio and tolerance index was observed at 120 and 180, 240 and 60 g/L PEG, respectively. Hence, highland maize cultivars showed differential response in terms of germination and seedling growth with increased moisture stress, and increase in PEG 6000 reduced germination and seedling growth beyond 60 g/L.