Inflorescence architecture underpins sexual reproduction in wild Musa species and productivity in edible banana cultivars. To establish the functional aspects of inflorescence architecture we identified its three main components and tested their response to environment and internal plant resources in two clone-sets. Five genotypes of edible plantains (Musa AAB) grew for four generations along an elevation gradient (1100 m to 2200 m, 16°C to 24°C) straddling the equator in the humid highlands of East Africa. Measurements of hands per bunch (Hb), fruit per hand (Fh) and peduncle length were made. Peduncle length is determined by the activity of the apical inflorescence meristem and fruit per hand from lateral cushion meristems. However, hands per bunch is determined by a change in flower type. This independence of mechanisms was reflected in their variable responses to site temperature, genet development and genotype. Cooler temperatures reduced the number of fruit-forming flowers in an inflorescence, but not as much as expected, and changed the balance away from female towards male flowers. The genet changed the allocation of resources between Hb and Fh, independently of the effect of site temperature. In banana breeding schemes, manipulating inflorescence components independently raises options for producing genotypes better suited to markets, environments and cultural practices.

Changes in land-use have been observed in banana-based systems in the African Great Lakes region affected by Xanthomonas wilt disease (XW) of banana. Through participatory focus group discussions (FGDs) and the 4-cell method, changes in land-use were retrospectively assessed in 13 XW-affected landscapes/villages along a 230 km transect from Masisi (XW arrived in 2001) to Bukavu (XW arrived around 2014) in eastern Democratic Republic of Congo during 2015. The four-cell chart ranked land-use by mapping the area under production and the number of households involved in production. Farmers’ perceptions on the sustainability of new land-uses were also documented. Soil nutrient content and erosion levels were measured for five major land-use options/ trajectories on 147 fields across 55 farms in three landscapes along the transect. From being ranked the most important crop (92% of landscapes i.e. produced on large areas of land and by many households) before XW outbreaks, its importance had declined with most households in 36% of the landscapes growing it on smaller farms while in 64% of cases by few households on smaller pots. Farmers uprooted entire banana mats or fields, expanding land under other crops, mainly beans, taro, sweet potato, cassava, maize, coffee and eucalyptus. Species richness did not change at landscape level, though 21 crops were introduced at farm level. Land-use for banana is however still perceived to be more sustainable due to its multi-functional roles. Soils under banana plots were found in general to be better in their chemical attributes while high erosion levels (Mg ha-1 year-1) were observed under cassava (1.7-148.9) compared with banana (0.3-10.7) and trees (0.3-5.9). The current shift away from banana could thus have profound effects on supply of key services and sustainability of the production systems. This study offers a good basis/entry point for interventions in the XW-affected landscapes.

Misuse and poor handling of chemical pesticides in agriculture is hazardous to the health of farmers, consumers and the environment. We studied the pest and disease management practices and the type of pesticides used in four root, tuber and banana (RTB) crops in Burundi and Rwanda through in-depth interviews with a total of 811 smallholder farmers. No chemical pesticides were used in banana in either Rwanda and Burundi, whereas the use of insecticides and fungicides in potato is quite frequent. Nearly all insecticides and about one third of the fungicides used are moderately hazardous. Personal protective equipment is used by less than a half of the interviewed farmers in both countries. Reported cases of death due to self- or accidental poisoning among humans and domestic animals in the previous 12 months were substantial in both countries. Training of farmers and agrochemical retailers in safe use of pesticide and handling, and use of integrated pest management approaches to reduce pest and disease damage is recommended.

This paper evaluates the determinants of decision making in relation to the production of four crops (banana, cassava, potato and sweet potato). Understanding the division of labour and decision-making in crop management may lead to designing better interventions targeted at improving efficiency in smallholder agriculture. A household quantitative survey with heads of households involving 261 women and 144 men in Burundi and 184 women and 222 men in Rwanda was conducted in 2014. Most of the decisions and labour provision during production of both cash crops (potato and banana) and food crops (sweet potato and cassava) were done jointly by men and women in male-headed households. Higher values for ‘credit access’, ‘land size’ and ‘farming as the main occupation of the household head’ increased the frequency of joint decision-making in male-headed households. A decline in the amount of farm income reduced the participation of men as decision makers. A reduction in total household income and proximity to the market was correlated with joint decision making. Gender norms also contributed to the lower participation of women in both decision-making and labour provision in banana and potato cultivation. Although a large proportion of decisions were made jointly, women perceived that men participate more in decision-making processes within the household during the production of cash crops. Increased participation by women in decision-making will require an active and practical strategy which can encourage adjustments to existing traditional gender norms that recognise men as the main decision-makers at both the household and community levels.