Optimizing population density and harvest timing in cassava can improve agronomic efficiency, productivity and quality of industrialization. The objective of this study was to evaluate the influence of plant population density and harvest timing on yield of two cassava cultivars with different canopy architectures (IAC 13 and Branca de Santa Catarina), each planted at four population densities, from 7,000 to 31,000 plants ha-1 for IAC 13 and from 5,000 to 29,000 plants ha-1 for Banca de Santa Catarina. The aerial plant shoots were pruned 12 months after planting, and the whole plant was sampled at three different harvesting times at 4, 8 and 12 months after pruning. The maximum yield was 46.63 t ha-1 for IAC 13 at 7,000 plants ha-1, with no significant effect of harvest timing. The maximum yield was 76.85 t ha-1 for Banca de Santa Catarina at 29,000 plants ha-1 at 20 months after planting. Both cultivars responded differently to variations in population density and harvest timing.

Keywords: Manihot esculenta Crantz, Root, Harvest Timing, Plant density, Fresh Root Mass, Pruning