Objectives: This study assessed the on-farm Musa germplasm diversity across different agro-ecologies of Rwanda and the socio-economic utilization options and selection practices that create/maintain this diversity on-farm. Methodology and results: A Musa germplasm diagnostic survey was carried out in 2007 in five Rwandan districts on a transect from Lake Kivu (West) to Kirehe district (East) bordering Tanzania. Across all sites, 118 farms, each having at least 50 mats were sampled for determining Musa diversity. Forty three Musa cultivars were recorded across the five districts. Higher diversity was observed in the east declining westwards to the Lake Kivu region as reflected by the number of cultivars and their relative abundance. Nearly half of the recorded cultivars had a low diversity index (Gini-Simpson 1-D < 0.2) and therefore prone to genetic erosion. Cooking cultivars only dominate in the district of Kirehe, while beer cultivars dominate the banana production landscape in the other districts. Taste/flavor, bunch size and market demand were the most important criteria for banana cultivar selection and thus greatly influenced cultivar conservation and distribution on-farm. Diseases such as Fusarium wilt and Xanthomonas wilt greatly contributed to genetic erosion. Conclusion and application of results: Musa cultivar diversity in Rwanda is under threat. Ex-situ conservation of the menaced cultivars is of crucial importance. Beer cultivars dominated the landscape. Cultivar diversity on-farm was influenced by the prevailing altitude; taste/flavor, bunch size, and market demand of the cultivars; and their susceptibility to diseases especially Fusarium and Xanthomonas wilt. Banana breeding or adaptation strategies therefore should take into account the farmer preferred traits. In addition, strategies for managing these diseases are critical for preventing the genetic erosion of the affected cultivars.

The Great Lakes countries of East and Central Africa, including Rwanda, Burundi and the Democratic Republic of Congo (DR Congo) are a secondary centre of Musa diversity, especially for East African highland bananas (Musa AAA-EA group) and plantains (ABB). Musa cultivation in this region is characterized by low annual productions (5-30 t/ha). This is caused by biotic (pests and diseases) and abiotic (soil fertility and drought) factors. The impacts of these factors are, however, influenced by the different agronomic practices that are applied on farm. This study assessed the use of some key agronomic practices by Musa farmers across districts of Rwanda and Burundi, and the South and North Kivu provinces of eastern DR Congo. Farms in North Kivu were less intensively managed than those in Burundi, Rwanda and South Kivu. For example, farms in North Kivu were the least de-trashed (removal of dead leaves from the pseudostem, 66%) and de-suckered (63%) compared with 88% and 100% in Burundi, 93% and 99% in Rwanda and 89% and 100% in South Kivu, respectively. Agronomic practices such as seed selection and source, pseudostem splitting for mulch and weeding (mainly using the hand hoe) were similarly practised across the study sites. Suckers obtained from neighbourhood (76-100%) and own fields (0-39%) were the only source of planting material used by farmers at the time of this study. This has negative implications for the management of key plant pests and diseases. The use of hand hoes for weeding, though helpful for intercropping, could perpetuate the spread of Xanthomonas wilt disease, which is currently prevalent on farms. De-budding was practised more in Burundi (98%) and South Kivu (96%) than in Rwanda (52%) and North Kivu (62%), although more farmers in South Kivu (68%, compared with <20% in other sites) de-budded on time (3 weeks after flowering, after appearance of the last hand). Agroforestry and fallowing, which are helpful for revitalizing soil fertility, were not popular in Burundi or Rwanda, possibly due to the high population density in these sites. Fallowing could also be obsolete because most farms in this region are over 50 years old. The study revealed the need to strengthen the extension of knowledge to farmers, especially in North Kivu where the farms are not intensively managed. Some of the recommended agronomic practices, such as de-trashing, de-suckering, de-budding and weeding need to be revised in the light of new emerging challenges, especially diseases such as Xanthomonas wilt, and high population density.

Banana is an important crop for food and income in Burundi. However, average annual yields are low (5 t/ha) because of low and declining soil fertility, and pest and disease pressure. To help overcome the challenges to banana production in the Great Lakes region of Central Africa, the Consortium for the Improvement of Agriculture-based Livelihoods in Central Africa (CIALCA) has been promoting and facilitating access to new high-yielding, pest- and disease-resistant improved hybrid banana cultivars with good consumer acceptability. The agronomic performance of the improved hybrid 'FHIA-17' and six commonly grown dessert banana cultivars was evaluated at six sites with contrasting altitudes across Burundi from 2008 to 2012. The data were analysed using linear mixed-effects modelling. 'FHIA-17' significantly outperformed the other cultivars as it had the heaviest bunch weight, was in the group of cultivars with the most hands and fruits, and the fruits were long and thick. The cultivars 'ITC0680', 'Gros Michel', 'Prata' and 'Yangambi Km5' had the next best agronomic performance, while the cultivars 'Ikigurube' and 'Kamaramasenge' had the poorest performance. The high agronomic performance of 'FHIA-17' shown in this research demonstrates how its increased cultivation may help to ensure the continued production of dessert types of bananas in Burundi and the food and income security of the population.