The dynamics of on-farm management of sorghum in Ethiopia: Implication for the conservation and improvement of plant genetic resources

On-farm conservation of plant genetic resources for food and agriculture has received strong support worldwide in recent years. It has been justified on appealing assumptions: it complements ex situ conservation, allows co-evolutionary interaction of host-pathogens and crop-weed complexes, and involves local knowledge systems. This article illustrates how on-farm conservation being set for its sake is extremely difficult under farmers' dynamic management of plant genetic resources based on sorghum. The dynamics of their management could be explained by continued introduction, displacement, loss and maintenance of aboriginal landraces that have distinct functional attributes, patch-occupancy and relative abundance profiles. Such management and hence the dynamic landrace demography has largely been triggered by co-evolving biophysical stresses, spatial and seasonal variations. The best viable alternative to support farmers' management of genetic resources is to link conservation to crop improvement both to enhance on-farm genetic diversity and make the biophysical environment a comfortable home for the plant genotypes.