Abstract
Spring wheat variety “Haruyokoi” was cultivated with different basal nitrogen applications at three locations in northern Hokkaido. Foliar spray of nitrogen as urea was conducted three times (0.92 g m-2/time per application) at the anthesis time, 7 days later, and 14 days later, and the grain protein content (GPC) and yield were investigated. These three applications resulted in a significant increase in GPC. Yield and 1000-grain weight were also increased. In lodged plants or younger plants with yellow leaves, the effect was not strong. The relationship between GPC with foliar application (y) and GPC without foliar application (x) was shown by the regression formula; y=0.790x+3.6 (9.6 < x < 13.9, n=25, r=0.973, p < 0.01). Because the nitrogen content varied with the amount of basal nitrogen applied, we suppose that the effect of foliar application is influenced by the nitrogen fertilization condition.
