Effect of Dry-Heat Treatment at 76?C on germination and Vigor of radish seed

The effects of different dry-heat (76°C) treatment times (12h to 72h) and initial seed moisture contents (3.2% to 9.4%) on seed germination and seed vigour of radish (Raphanus sativus L. var, longipinnatus Bailey cv. Xin Li Mei) were studied. At 3.2% seed moisture content, germination and vigour were maintained well after 48h drying, but vigour was reduced after 60h and germination after 72h. At 9.4% seed moisture content germination fell significantly after 36h and vigour was reduced after 12h. The recommended 48h dry heat treatment at 76°C reduced seed quality (germination and/or vigour) for all seed moisture contents above 3.2%, these reductions increased as initial seed moisture content increased.