Okello OP, Gweyi JPO, Nawiri Mp, Musila W. 2017. Effects of water stress on phenolic contents and antioxidant activity of African nightshades. Biofarmasi J Nat Prod Biochem 15: 79-95. This study aimed at mapping out the distribution of different African Nightshade species in Siaya and Kisii Counties of Kenya and to determine water stress effect on total antioxidant capacity and total phenolic content of two selected African nightshade namely, giant nightshade (Solanum scabrum) and black nightshade (Solanum villosum). Before selection of the two varieties, the study involved farmer field visits, mapping of nightshades present and administration of semi-structured questionnaires to farmers to determine the indigenous vegetables being grown, the nightshade species grown and factors affecting their production. The experiments were conducted both in the field and greenhouse conditions. Watering intervals were at 15 cbars, 50 cbars, and 85 cbars. Data on the number of secondary buds, leaf area, shoot height, shoot and root dry weights were gathered. The total antioxidant capacity and the total phenolic content were recorded using DPPH radical scavenging method and Folin-Ciolcalteu method, respectively. The data collected were subjected to ANOVA. In both counties where production was 100% under small scale, Solanum scabrum was the main variety grown is Siaya County (36%) while in Kisii the main variety was Solanum villosum (32%). There were significant differences (P≤0.05) among treatments in leaf area, plant height, shoot biomass, number of secondary buds, leaf and root total phenolic content and leaf and root antioxidant activity. At all stress levels, Solanum scabrum exhibited the tallest plants with a maximum height of 45.17cm at 15cbars, while Solanum villosum had the shortest plants at all stress levels, with the shortest one being recorded at 16.65 cm at 85 cbars. S. scabrum also had the highest root dry weight (7.78g), shoot dry weight (50.78g) and highest leaf area of (304.45cm2). However, Solanum villosum had the highest number of secondary buds at all stress levels with the highest being 24 at 15 cbars. Concerning phytochemicals, Solanum villosum had a higher concentration of both the total phenolics and antioxidant activity in the shoots (46.41g GAE/Kg DM total phenolic content and 52.68% total antioxidant activity). Meanwhile, Solanum scabrum had a higher concentration in the roots (25.06gGAE/Kg DM total phenolic content and 27.18% total antioxidant activity). Water stress cause a decline in all growth parameters but increased phytochemical accumulation in nightshade accessions grown. It is therefore suggested that for better yields, irrigation should be performed at every 15 cbars, however for adequate phytochemical accumulation, the irrigation should be carried out at 50 cbars. Further research to explore and quantify other phytochemical components as affected by different watering regimes need to be undertaken.

Finger millet (Elusine coracana) accounts for 8% of the total area and 11% of the millet production worldwide.  It is grown on over 4 million ha globally, mainly for food purposes. Millions of people in the dry lands of Central and East Africa, and South of India depend on finger millet as an important source of food to them (CGIAR, 2001). Finger millet is one of the most neglected and underutilized crops. Additionally, the crop has received limited research attention compared to wheat, rice, and maize (FAO, 2011). Therefore, production challenges such as those caused by weeds like goose grass Elusine indica remain at large. Manual weeding is the commonly employed weed control method in finger millet production, but is expensive and labour intensive. The current study was set to evaluate the influence of weed management practices on finger millet growth and yield components. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replicates. The plots measured 2 by 2m with a border width of 1m. The treatments included Pendimethalin, Dimethyl amine, Metolachlor, Metribuzin, Atrazine (at three rates each 1.0, 1.5 and 2.0 l/ha), No weeding and Hand weeding. Data was collected on the number of weed species, weed biomass, number of basal tillers, herbicide phytotoxicity, weed and crop heights, number of panicles, weight of panicles, weight of un-threshed and threshed grains and 1000 grain weight. Data was analyzed using one-way ANOVA using GenStat version 15.1. Application of Pendimethalin at 1.5 and 2.0 L/ha Active Ingredient (AI), resulted in weed optimal control and least phytotoxicity. Results also indicated that the height of finger millet was significantly (p<0.001) higher where the herbicides were applied. Lower weed biomass was also positively correlated with higher crop height, more panicles, high unthreshed and threshed weights and a 1000 grain weight. Application of 2,4D at rates of 1.5L and 2.0L resulted in significantly taller plants 33.00 cm, than the other weed management methods. Finger millet under Pendimethalin 1.5 L gave the highest number of 86 panicles while Atrazine 2.0L and Pendimethalin1.5L methods of weed control, had significantly higher weight compared to all the other treatments. The 1000 seed mass across the treatments averaged 2.31 g while the on the untreated treatments had an average of 1.54 g. Weed control using pre emergence herbicides significantly (p<0.001) increased the yields of finger millet.