A Functional Analysis of Inflorescence Architecture in Musa (Musaceae)

Abstract

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.