EFFECTS OF NITROGEN LEVELS ON GROWTH AND YIELD OF BROAD-LEAFED AFRICAN NIGHTSHADE (SOLANUM SCABRUM)

African nightshade (Solanum scabrum) is an important indigenous vegetable in many African countries, yet factors affecting leaf yields have not been fully investigated. A market survey conducted in Kakamega Municipal market in Kenya revealed that broad-leafed African nightshade was among the preferred African vegetables in the region. Besides being rich in micronutrients, it has several medicinal properties and is less bitter than other vegetable nightshades. For the potential of this crop to be exploited, there is a need to look at factors that would contribute to optimal leaf yields. Nitrogen affects growth and development of many leafy vegetables through its effect on cell division and hence leaf expansion. Little work has been reported on nitrogen effects on this emerging crop. The objective of the study was therefore to investigate effects of nitrogen rates on growth and yield of Solanum scabrum. A pot and two field experiments were conducted at Maseno University, Western Kenya, between June 2003 and December 2005. The pot experiment was laid out in a completely randomized design with four treatments and four replications. The treatments included 0, 25, 50, and 75 mg of N per kg. The field experiments were set up in a randomized complete block design with six nitrogen rates and three replications. The treatments included 0, 10, 20, 40, 80 and 100 kg of N per hectare. Nitrogen levels significantly (p ≤ 0.05) affected plant growth and leaf yields in both pot and field experiments with optimal levels at 25 mg N/kg and 40 kg N/ha respectively.