The traditional inexplicable replacement of seed and seed ware of landraces and cultivars: A review

A review is presented on the often inexplicable seed replacement by farmers. Such a seed replacement has been mentioned since Biblical times and earlier. It occurred and still occurs all over the world and for all cultivated plants. In order to find out whether or not this seed replacement has some meaningful background, farmers in those areas where this type of seed replacement still takes place should be interviewed. Maybe, this seed replacement is based on farmers' experience since times immemorial in which farmers obtained (or believed to obtain) lower yields if seed is not replaced. If so, the cause of this type of seed replacement can be explained. This revised version was published online in August 2006 with corrections to the Cover Date.