Abstract
Isothiocyanate levels were determined for the hypocotyl‐root region of Raphanus sativus, grown under two daylengths and in three different soil types. Under a short photoperiod (8.5 h) radishes grown in loam soil had the highest isothiocyanate concentration but under a longer photoperiod (15 h) radishes grown in organic soil had the highest isothiocyanate concentration.