Participatory breeding of superior, mosaic disease-resistant cassava. Final Technical Report.
Situation analyses of two farming communities in the Forest and Forest Savannah Transition Zones (Nkaakom and Aworowa respectively) identified the main customs and practices of cassava production. Cassava has changed over the last several decades from being not grown or a minor crop to becoming the main food crop and a major cash crop. Much of this increase was associated with lack of new land to open and impoverished soils on previously cropped land. The activities of non-farmer stakeholders in cassava breeding and how they might interact with the project have also been explored. The IFAD-funded RTIP project has funded increase research and development activities in the university and public research sector and large-scale distribution of released varieties. GTZ has also supported the agricultural sector generally; relatively few NGOs seem to support cassava-linked activities. There is increasing industrial interest in cassava as a source of food for humans and livestock and starch as a chemical feedstock. In ten diverse farming communities, no farmer interviewed understood the role of pollen; most were aware of cassava seeds and seedlings. Cassava seedlings seem generally to be avoided by farmers as a source of planting material and food, often being weeded out. However, a few farmers in most communities had tested a few seedlings and many farmers used them when other planting material was scarce. Farming communities seldom exchanged landraces, though occasionally did so purposefully. Migrant workers and settlers bringing new varieties from their place of work or previous home seem an important means by which communities obtain new landraces.
Seed stocks derived from diverse genetic backgrounds but including resistance to pests and diseases, particularly CMD, and high storage root yields were selected by IITA. These were provided to the Nkaakom and Aworowa farming communities for evaluation and selection of superior genotypes and were sown in communal plots. They were also sown at the CRI research farm. Seedlings were monitored monthly by the multidisciplinary project team for agronomic and pathological characters. They were also evaluated with farmers, firstly for aboveground characters, secondly for pests and diseases and finally at harvest for both above- and below-ground characters. Farmer recorded a wide range of mostly positive criteria. Using their own criteria, both farmers, the CRI cassava breeder and CRI pathologists selected seedlings to retain as clones in a further trial at each location. A further similar annual cycle of monitoring, evaluation and reselection of clones was conducted at each location, reducing their number tenfold over the two generations. Clones have now been distributed to individual farmers. The resultant clones are mostly preferred by farmers over their own landraces, being both higher yielding and less affected by CMD. Farmers were consistent in their selection and overlapped that of the CRI breeder by about 60%. Farmers generally rated the project as beneficial and participants at an end-of-project workshop also validated the approach. The project provided both experiential training and formal training in participatory research and plant breeding to CRI staff.