PLANT CELL BIOTECHNOLOGY AND MOLECULAR BIOLOGY

Maize is a third most important cereal crop after wheat and rice that produce mostly in the China, Brazil and Argentina. Maize kernels are a source of carbohydrates, proteins, water and fats. They provide us calories and a rich source of vitamin B. Maize also contain some important minerals such as magnesium and phosphorus. But some abiotic stresses affect growth of maize seedling. Salinity, drought conditions and metal toxicity can interference the nutrient up take that affect plant growth and biomass production. This study was carried out to investigate the affect of different abiotic stresses on maize growth and tolerance them against these abiotic stresses. Maize genotype pak afghoi was selected for research. Five treatments were tested under three abiotic stresses conditions; salinity, drought and metal stress. Five treatments (control, 20% irrigation water, 40% irrigation water, 60% irrigation water, 80% irrigation water) were tested for drought stress. Five treatments (control, 0.2mM NaCl, 0.4mM NaCl, 0.6mM NaCl, 0.8mM NaCl) were used for salt stress. Five treatments (control, 0.25mM MnCl₂, 0.5mM MnCl_2, 0.25mM CrCl₃, 0.5mM CrCl₃ ) were selected for metal stress. All pots were placed under natural environment.  During five weeks, the seedlings growth was evaluated by measuring their total plant height, no. of leaves per plant, leaf area, fresh stem weight, fresh root weight, dry stem weight, dry root weight, fresh plant weight and dry plant weight. Tukey’s test indicated that maize growth highly affected under metal stress while less affected under salt stress. Analalysis of variance indicated that all growth perameters were significant except plant height and leaves per plant. Step wise linear regression and person’s correlation were applied as statistical tool. Correlation indicated that positive, higher and significant correlation was found for dry plant weight with stem dry weight, fresh plant weight with leaf area, leaf area with root dry weight, leaf per plant with root dry weight, plant height with stem fresh weight, root dry weight with stem dry weight, root fresh weight with stem dry weight, stem dry weight with stem fresh weight. The accumulative medium coefficient of determination (54.72%) or R² was recorded for plant height but high coefficient of determination was recorded for stem dry weight (80.86%). High coefficient of determination indicated that maize genotype pak afghoi can be used for tolerance against abiotic stresses.