Altitude effect on plantain growth and yield during four production cycles in North Kivu, Eastern Democratic Republic of Congo

This study assessed the effect of altitude on growth and yield of five commonly grown plantain (Musa, AAB) cultivars at four sites, Mavivi (1,066 m a.s.l.), Maboya (1,412 m a.s.l.), Butembo (1,815 m a.s.l.) and Ndihira (2,172 m a.s.l.) in North Kivu, Democratic Republic of Congo. The cultivars included three ‘French’ plantains (‘Nguma’, ‘Vuhindi’ and ‘Vuhembe’) and two ‘False Horn’ types (‘Kotina’ and ‘Musilongo’). Fifteen vigorous sword suckers of each cultivar were planted in three replicates of five plants, at each site. Growth and yield parameters were assessed for the plant crop and three subsequent ratoon cycles. High altitude and corresponding lower temperatures significantly increased suckering and crop cycle duration, whereas it reduced the number of functional leaves and yield. For example, all cultivars produced more suckers at 2,172 m a.s.l. (9-11 suckers) and 1,815 m a.s.l. (5-7), compared with 3-4 at 1,412 m a.s.l. and only two suckers at 1,066 m a.s.l. In contrast, all cultivars had a low bunch yield (2-3 kg) at 2,172 m a.s.l. compared with 19-25 kg at 1,815 m a.s.l., 19-23 kg at 1,412 m a.s.l. and 23-33 kg at 1,066 m a.s.l. Most bunches across the cultivars at 2,172 m a.s.l. were only partially developed, and unfit for consumption or the market. Choke throat symptoms were also observed and were associated with the year round low minimum temperatures (10.4-12.3°C) at this altitude. Plantains adapted to high altitude need to be sought and evaluated at the high altitude sites in North Kivu (1,815 and 2,172 m a.s.l.). The high altitude sites (e.g., at 2,172 m a.s.l.) that are also free of banana pests could however be beneficial for establishment of mother gardens for clean planting material multiplication because sucker development is enhanced at these elevations.