Effect of Top Dressing at Booting Stage on Crude Protein Content of Wheat in Kyushu District

To increase the crude protein content of wheat in the Kyushu district, the amounts of basal fertilizer and top dressing were decreased to 72% of standard and the remaining 28% fertilizer was applied at the booting stage. The relation between two dressing methods, conventional and with one more topdressing being added at booting stage, was examined in 16 cultivars, varying widely in crude protein content, over a perid of two years. The mature stage with top dressing at booting stage was delayed about 0.5 day. It increased 1, 000-grain weight and liter weight. Positive correlations were found between the 1, 000-grain weight and the brightness (R554), and between liter weight and flour yield. The influence on grain weight was different for each cultiver throughout the two years. In the second year (1994), the glassiness was more increased in the plot with top dressing at booting stage than in the control plot, but no relation to the decrease in grain and flour qualities was found. The crude protein content of grain and flour increased significantly, and crude protein weight (grain weight × crude protein content) increased in many cultivars in the second year. On the other hand, the ash content of flour decreased significantly. The influence on the whiteness (R445) and brightness of flour was different in cultivars. But brightness was negatively correlated with protein content in the second year. No difference was observed between high and low protein content cultivars as a result of the change of crude protein and ash contents by two dressing methods. Therefore the top dressing at booting stage was effective for an increase of crude protein content in wheat in the Kyushu district.