Abstract

The study was carried out to determine the effect of stem density on growth, yield and quality of potato (Solanum tuberosum L.) variety amethyst in Zimbabwe. Three stem density treatments were used and these were initially derived from the number of sprouts or eyes per tuber: 2 stems/hill, 4 stems/hill and +6 stems/hill. Emergence, haulm growth, yield and quality characteristics of tubers were the main parameters measured. There was a significant difference in emergence among the 3 treatments (P<0.05). A mean of 30 plants/plot were recorded from the treatment with 6 stems/hill compared to 27.50 plants/plot from the treatment with 2 stems/hill at 12 day after planting. No statistical differences in tuber yield (P>0.05) among the three stem density levels was achieved. A high marketable yield was obtained at 2 stems/hill compared to 6 stems/hill. An average of 21.08 small tubers per hill that is, those considered unsellable were obtained from treatments derived from 6 stems per hill compared to 3.75 small tubers /plant from plants with 2 stems per hill. Seed producers whose main objective is to increase the multiplication rate, high stem densities per planting station have the potential of increasing plant populations resulting in many smaller tubers.  For ware production, low stem densities promote greater proportion of medium to oversized tubers.

Key words: Potato, stem density, growth components, yield.