Varietal difference and seasonal fluctuation of nitrate and oxalate contents in Spinach (Spinacia oleracea)

Abstract

Reduction of nitrate and oxalate content in spinach has become the major concern in the breeding program in terms of their toxicity to the human health. Although various experiments have already been performed to determine the nitrate and oxalate contents in spinach, no definitive factors that affect their contents have been elucidated. In the present study, we have determined genetic factors that affect nitrate and oxalate contents in spinach using 200 varieties by growing them in fall, winter and spring from 2002 to 2003 under the same cultural condition (N=10kg/10a) in vinyl houses. In both nitrate and oxalate, a wide range of variations was detected not only among the varieties but also the growing season. Interestingly, amount of nitrate negatively correlated with that of oxalate. Further results will be discussed.