Planting density effect on growth and yield of taro (Colocasia esculenta) landraces.
Taro (Colocasia esculenta), or amadumbe (in isiZulu), currently occupies low levels of utilisation in South Africa. Information describing its agronomy is still scant. The aim of this study was to determine the effect of planting density on growth and yield of taro landraces. A secondary objective was to determine the effect of water stress on growth and yield of taro landraces. Three taro landraces, two eddo types [Dumbe dumbe (DD) and Dumbe omhlophe (DO)] and one dasheen type [Dumbe pondo (DP)] were collected from rural areas across KwaZulu-Natal. A field trial was conducted at two sites, Umbumbulu and Ukulinga Research Station. A controlled environment experiment was also conducted at the University of KwaZulu-Natal’s Controlled Environment Facility. For the field trials, the experimental design was a split-plot design arranged in randomised complete blocks replicated three times. The main factor was planting density [low (1 m x 1 m), medium (1 m x 0.5 m) and high (0.5 m x 0.5 m)] with the varieties allocated to the sub- plots. For the Controlled Environment Facility study, the experimental design was also a split-plot, with water [30% and 100% of crop water requirement (ETa)] as the main factor and two landraces as the sub-plots, replicated three times. Results of the field trial showed that emergence was affected by plant density, with plants emerging slower at high planting density. Growth and yield responded positively to increasing plant density with yield being highest at high plant density. Result for controlled environment study showed that emergence was slower at 30% ETa relative to 100% ETa. Growth was negatively affected by water stress. This translated into yield whereby yield was lower at 30% relative to 100% ETa. In terms of taro landraces, the DD landrace generally performed better than both DO and DP landraces. It was concluded that planting the DD landrace at a high plant density was recommended for upland cultivation of taro. Future studies should evaluate the yield quality of taro landraces.