Traditional maintenance breeding of landraces: 1. Data by crop

Examples of the methods of traditional maintenance breeding of several crops, cited in literature, are presented. It is concluded that, although crops are grown all over the world, only few examples are sufficiently described. Only for maize some reliable data are available. Three explanations for this small number are 1. the farmers are not aware of their knowledge of growing crops (including traditional maintenance breeding), 2. the interviewers and other scientists are not acquainted with this farmer's knowledge, or 3. most farmers do not actually perform traditional maintenance breeding, as they and their ancestors probably have experienced that traditional maintenance breeding does not result in a better crop. They must have thought that seed replacement was a better method to maintain the yielding capacity of their crops.