In vitro screening of two quality protein maize (QPM) varieties for drought tolerance using polyethylene glycerol-6000
Maize genotypes responded differently to water stress at early seedling growth. Genetic potentials of four maize varieties; two Quality Protein Maize (ILE-1-OB and Oba 98) and two drought tolerant maize varieties (TZLCom4C3 DTand Syn8 DT) were evaluated for drought tolerance through artificially created water stress. Polyethylene glycol of molecular weight 6000 (PEG-6000) at four concentrations (0, 5, 10, 15 and 20%) PEG with liquid Murashige and Skoog basal (MS) medium supplemented with 30g/l sucrose, 0.1g/l myo-inositol was used to induce water stress during seedling growth stage of plant development. Results revealed that genotype mean squares were significantly different for shoot length, fresh root weight, fresh shoot weight, number of roots, and number of leaves, dry shoot weight and dry root weight. Most of these traits were positively and significantly correlated with one another with high coefficient of correlation. Also, treatment effects were significant for all traits. Genotype by treatment interactions were also found highly significant for all traits under study. By taking all traits including relative tolerance into account in this study, it can be inferred that two QPM varieties evaluated responded appreciably to overcome effect of imposed stress by PEG, therefore, they can be regarded as tolerant maize varieties.