Banana and plantain are one of the most important staple food crops and a significant source of income to smallholder farmers in the East African Great Lakes Region. Banana Xanthomonas Wilt (BXW) is a devastating bacterial disease that threatens smallholder production and livelihoods. We use a systems approach to describe how gender shapes roles and practices in the household, on the farm and in innovation processes. We draw on a case study in Burundi, where single disease stem removal (SDSR) has been introduced as a labour-saving package to reduce BXW incidence. Banana is grown by an estimated 90% of farmers, and BXW poses a critical threat to food security. We use qualitative data that include focus group discussions, interviews and transcripts from farmer learning group (FLG) discussions to describe gender norms, roles and practices and implications for awareness and uptake of SDSR in households. We identify gender patterns in innovation process, namely that men gain higher levels of access to information in FLGs than women and men are also primarily responsible for implementing SDSR. These patterns reflect gender-differentiated norms, roles and practices that are common in the household and in banana-based farming systems, thus demonstrating the ways that innovation processes perpetuate and reinforce common gender roles and practices. Women's participation in FLGs, albeit lower than men, increases the potential of women to implement specific practices of the SDSR package. Systems approaches may be similarly used in different contexts where awareness and uptake of banana disease management packages, and other technical innovations, are not well understood. We found that gender norms, roles and practices significantly influence uptake of SDSR practices and warrant further investigation across the region, where smallholder uptake remains a pressing challenge to establish household food security.

Macropropagation is considered as a rapid means of producing, at a local level, numerous plantlets of preferred and/or improved Musa spp. cultivars at a putative low cost. The technology was evaluated in an on-station research-led experiment covering two contrasting agro-ecological sites in Burundi: Bujumbura (818 m above sea level - masl, mean temperature 25°C) and Gitega (1655 masl, mean temperature 19°C). Two types of humidity chambers (a 'standard' unit made of wooden planks and plastic sheeting placed under 50% natural shading, versus a 'prototype' unit made out of locally available Eucalyptus wood and papyrus [Cyperus] mats), three non-sterilized substrates (sawdust, rice hull and coffee husks) and four Musa cultivars ('FHIA-17', AAAA; 'Igisahira', AAA-EA, cooking; 'Kamaramasenge', AAB, dessert; and the plantain 'Mzuzu', AAB) were evaluated in two successive experiments at each site. A third experiment, comprising similar treatments, was subsequently carried out solely in Bujumbura using rice hull and sawdust as substrates. Corm viability, number of days to emergence of the first shoot (latency period) and number of shoots produced per viable corm after scarification (productivity) were recorded. Independent of Musa genotype, unit type and/or substrate, a cooler climate such as that of Gitega was found to be less suitable for macropropagation because corm viability and productivity were reduced and the latency period was doubled. Despite lower temperatures observed in the prototype unit, corm viability and latency period were not significantly altered. Sawdust and rice hull performed significantly better than coffee husks as initiation substrates. Differences linked to genotype were observed in viability of corms, latency period and productivity. Out of the four cultivars tested, 'Kamaramasenge' performed poorly with low productivity. In contrast, 'Igisahira' produced up to 22 shoots/corm, while 'FHIA-17' produced up to 25 and 'Mzuzu' produced up to 28. The study has identified a prototype humidity chamber made out of local materials using non-sterilized rice hull (initiation media) as an alternative low-cost option for skilled and motivated resource-poor farmers, farmer groups or associations looking to multiply banana and/or plantain locally at lower altitudes in Burundi. Moreover, clean planting material can be successfully produced under such conditions despite the high pressure from banana bunchy top disease in the Rusizi valley (Bujumbura).

Finding out how to scale innovations successfully is high on the agendas of researchers, practitioners and policy makers involved in agricultural development. New approaches and methodologies seek to better address related complexities, but none of them include a systematic perspective on the role of capacity in (partnerships for) scaling innovations. We posit that this has left an important topic insufficiently addressed in relation to partnerships for scaling innovations. The need to address this gap became apparent in the context of the CGIAR Roots, Tubers, and Bananas (RTB) Scaling Fund initiative. This paper presents how we explored ways forward in relation to this by combining three methodological approaches: The Five-Capabilities, Scaling Readiness, and the Multi-Level Perspective on socio-technical innovation. This combined approach—dubbed Capacity for Scaling Innovations (C4SI)—was applied in three projects related to scaling innovations for sweet potato, cassava and banana, involving five countries in Africa. It then discusses implications for a partners-in-scaling perspective, the contribution of scaling innovations to sustainable development, the importance of research organisations considering their own capabilities in partnerships for scaling, and the extent to which C4SI was helpful in the three cases—for example, in decision making. The paper concludes that a capacity perspective on the scaling of innovations should be an essential part of a ‘science of scaling’. Finally, it provides recommendations for using the approach or parts of it in research and intervention practice for scaling, pointing in particular to the need for context-specific adaptation.

Xanthomonas wilt (XW) of banana caused by Xanthomonas vasicola pv. musacearum (Xvm) is an important emerging and non-curable infectious disease which can cause up to 100% yield loss. At the start of the XW epidemic, complete uprooting of diseased mats (CMU) was recommended. There was little adoption of CMU, especially by women farmers, because it was labor-intensive and it sacrificed banana production for up to 2 years. CMU assumed that infection on a single plant would systemically spread to all plants in a mat. However, field experiments showed that Xvm did not spread systemically in a mat and that latent infections occurred. As a result, not all shoots on an infected plant show symptoms. This led to the idea of removing only the visibly infected banana plants, referred to as single diseased stem removal (SDSR). The SDSR package comprises three innovations: (1) regularly cutting symptomatic stems at ground level, (2) sterilizing cutting tools with fire, and (3) early male bud removal using a forked stick. The SDSR package was promoted jointly with a set of complementary practices: (i) avoiding infections by browsing animals, (ii) using clean planting materials, (iii) bending leaves at the petiole level when intercropping in infected fields, (iv) training on disease recognition and epidemiology, and (v) demand-specific extension and knowledge sharing. Several approaches that have been used for scaling out XW management technologies are documented in this chapter. This review looks at the process, practices, challenges, lessons learned, and future policy implications associated with scaling of XW management practices.