Response of leaf yield and nutritive value of african nightshade (solanum villosum) genotypes to nitrogen application

The wild-type Solanumu villosum is an important leafy vegetable in Kenya, which however is low-yielding mainly due to the early flowering and prolific fruiting. Two new genotypes of S. villosum, T-5 and octoploid with different flowering and fruiting characteristics from the wild-type have been developed. Field experiments were conducted to evaluate leaf yield, plant height and iron content of the genotypes under varying nitrogen levels. The experiments were laid out as split plots in a randomized complete block design with three replications. Nitrogen rates 0, 2.7 and 5.4 g/plant formed main plots while the wild-type, T-5 and octoploid genotypes formed sub-plots. Plants were cut at 5-10 days interval to quantify plant height, leaf area, fresh weight and iron content. The leaf fresh weight in octoploid plants was 1.3-1.6 times higher than in T-5 and wild-type plants. Applying nitrogen at 2.7-5.4 g N/plant increased leaf fresh weights by 1.5-2.3 times over the control plants. The octoploid plants tended to have fewer but larger leaves than the wild-type and T-5 plants. All the genotypes formed 6-7 leaves per unit increase in plant height irrespective of the nitrogen rate. The three genotypes had similar iron content, ranging from 5.5-16.5 mg/100 g dry weight across the nitrogen rates. Thus the octoploid is an improved variety over the wild-type parent. T-5 productivity potential lies in its capacity to give leaf yields for longer periods than the wild-type. The genotypes octoploid and T-5 are recommended for African nightshade production using 2.7 g N/plant for leaf yield and subject to further field trials and plant chemical analyses.