Although the lowest vitamin C was observed in control at green and
red fruit stages, however it increased by different levels of N compared with
control (Table 6). As the data shows, although N fertilizer affected fruit
vitamin C content, the highest level of N reduced this variable at green and
red stages compared with the lower levels (Table 6). This is in disagreement
with Anita et al. (2009), who reported that increasing the rate of N increased
vitamin C of pumpkin. Moreover, Mozafar (1993) reported the positive and
negative effects of N on vitamin C contents by fruits.