Sorghum bicolor landraces: Selection criteria and diversity management in Ethiopias East-Central Highlands, 1992-2012

The dynamics of sorghum on-farm landrace diversity in five North-Eastern, Central Highlands communities in Ethiopia have been investigated through 300 farmer interviews and surveys of their fields in each of the 1992/1993, 2000/2001 and 2011/2012 cropping seasons. Over the 20-years, farmers’ selection criteria increased from 10 to 28 and the landraces from 60 to 77. That 50 of the landraces were recorded in all the surveys, suggests that they were chosen for their acceptable performances over the various and variable climatic seasons and/or for their cultural values. Landraces grown in only one or two communities increased from 37 to 53, while landraces cultivated in three or more increased by 1 (23 to 24). These increases have occurred despite increased land fragmentation related to government land redistribution policies and population growth having decreased the average field area planted to sorghum landraces by 42% (1.97 to 1.14 ha). Despite the reduced land area cultivated, 56% of the farmers increased their on-farm sorghum landrace richness and 72% increased their selection criteria over the period. The implications of cultivating huge landrace diversity, using multiple selection criteria and increasing the practice of interplanting quick-maturing standby crops in a situation of shrinking and increasingly fragmented land areas for the feeding of a growing population in an area of recognizable climate uncertainty and extremes are discussed.   Key words: Agricultural landscape, agroclimatic variations, farmers’ selection criteria, landrace richness, Spatio-temporal dynamics.