Genotypic and spike positional difference in grain phytase activity, phytate, inorganic phosphorus, iron, and zinc contents in wheat (Triticum aestivum L.)

One hundred and eighty-six wheat genotypes from different areas of China were selected to evaluate the genotypic and positional differences in grain phytase activity, phytate, inorganic phosphorus, iron, and zinc contents. Results showed substantial differences in these chemical components among genotypes. Grain weight and phytate (r=-0.34**r=-0.34**), inorganic phosphorus (r=-0.23**)(r=-0.23**), and phytase activity (r=-0.43**)(r=-0.43**) were negatively correlated. In contrast, grain weight and iron (r=0.20**)(r=0.20**), phytate and zinc (r=0.37**)(r=0.37**), and iron and zinc (r=0.29**)(r=0.29**) were positively correlated. The effect of grain position on all these components was significant. Generally, grains on the third florets of the central spikelets had the lowest zinc and phytate contents within a spike. The significance of these results is discussed in relation to the improvement of wheat micronutrient quality.