Effect of nutrient solution concentrations on the growth and yield of potato (Solanum tuberosum L.) varieties grown from apical rooted cutting in a hydroponic system

This study evaluated the effects of nutrient stock solution concentrations on the growth and yield of potato varieties grown from apical rooted cuttings (ARCs). A greenhouse experiment was conducted at the Climate and Water Smart Agriculture Center at Egerton University, Kenya. The experiment was laid out in a split-plot arrangement in randomized complete block design, where the main plot comprised three nutrient concentrations, i.e., 75% (N75), 100% (N100) and 125% (N125) of the ADC-Molo’ nutrient formulation. The subplots were allocated to four potato varieties (Shangi, Wanjiku, Nyota and Unica). The results showed that there were no significant (p<0.05) interaction effects of the nutrient stock solution concentrations application rates on the growth attributes of ARCs. The main effects of N125 gave the tallest plants (32.29cm) at 60 days after planting (DAP), highest normalised difference vegetation index (NDVI) (0.60) at 75 DAP, plant survival rate (82.15%) at 75 DAP, and fresh weight (79.04g) and dry matter (31.26%) of aboveground biomass (AGB). Nyota variety produced taller plants (26.90cm) at 60 DAP, gave higher NDVI values (0.53) at 75 DAP, and higher fresh weight (64.87g) and dry matter (27.60%) of the AGB. Significant (p<0.05) interactions were observed in the yield parameters. The interaction between N125 and Nyota (11.33) and Wanjiku (10.67) gave the highest number of minitubers, the highest yields were obtained between the interaction of N125 and Unica (16.38t/ha). Therefore, to achieve high growth and yields of ARCs under hydroponic system, seed potato producers should use 125% of the ADC Molo nutrient formulation

African indigenous vegetables, gender, and the political economy of commercialization in Kenya

This study investigates the increased commercialization of African indigenous vegetables (AIV)—former subsistence crops such as African nightshade, cowpea leaves and amaranth species grown mainly by women—from a feminist economics perspective. The study aims to answer the following research question: How does AIV commercialization affect the gendered division of labor, women’s participation in agricultural labor, their decision-making power, and their access to resources? We analyze commercialization’s effects on gender relations in labor and decision-making power and also highlight women’s agency. Based on a mixed method design and analyzing household-level panel data and qualitative focus groups from Kenya, we observe an economic empowerment of women that we relate to women’s individual and collective strategies as well as their retention of control over AIV selling and profits. Yet, while we see economic empowerment of women through commercialization—how they broaden their scope of action and are empowered by generating revenue—that does not contribute to a redistribution of labor or land rights, which are key for gender equality, instead it increases women’s labor burden.Peer Reviewe

Impact of postharvest osmodehydration treatments and drying processes on the nutritional quality, bioactive compounds and preservation of leaf amaranth (Amaranthus cruentus)

Amaranth leaves are rich in micronutrients and health-promoting secondary metabolites, but highly perishable. The effect of osmodehydration and drying on nutritional quality, health-promoting compounds and their postharvest preservation in Amaranthuscruentus leaves was investigated. The experimental set up consisted of four treatment variants with different levels of osmotic solution (NaCl) concentration, temperature and immersion time, i.e.; variant 1 (2.5%, 20 °C, 60 min), variant 2 (10%, 20°C, 60 min), variant 3 (10%, 40°C, 60 min), and variant 4 (10%, 40°C, 180 min). Osmodehydrated leaves were oven-dried at 30°C or 60°C, freeze-dried or stored at ambient temperature for 3 days, with non-osmodehydrated leaves as control. Results showed that proteins,minerals (Ca, Mg, Fe, Zn), carotenoids, flavonoids, and phenolic acids were preserved in osmodehydrated leaves with no significant changes, except proteins in freeze-dried and a significantly decreased chlorophyll content in both freeze- and oven-dried leaves of variant 4, corresponding to higher osmotic solution concentration, temperature and longer immersion time. During shelf-life, most nutrients and secondary metabolites were maintained with no significant changes, except protein that significantly increased while ascorbic acid and chlorophylls in both osmodehydrated and control leaves significantly decreased. Lower-temperature and shorter-time immersion resulted in better quality preservation

Improving nutrition-sensitive value chains of African indigenous vegetables: current trends in postharvest management and processing

The value chains of African indigenous vegetables (AIVs) are highly constrained by high postharvest losses (up to 50%) along the chain, largely occasioned by poor postharvest management and a lack of optimized processing technologies. The technologies and practices are key technical aspects that can transform the capacity of the chain by enhancing the overall value generated from the system. AIVs have recently experienced an increase in demand due to their high nutritional value and the opportunity they present to enhance rural incomes, since they are predominantly produced by smallholder farmers in rural and peri-urban areas. This implies that they can positively contribute to increased availability and hence supply of nutritious food within local food systems. Furthermore, the fact that half of the economic value of AIVs is potentially lost due to inappropriate postharvest management and inadequate processing demonstrates the potential that related interventions and transformations could have in enhancing and preserving value along AIV value chains. Currently, the approaches applied to reduce food waste, preserve nutritional quality, and add value to AIVs are largely traditional in nature. They require upgrading and need to be aligned toward achieving a nutrition-sensitive value chain. By looking at these as value creation processes, this mini-review examines the current postharvest management practices, highlights relevant new and innovative technologies and related challenges, and suggests potential options to improve the benefits for AIV value chain actors and thus contribute to a sustainable transformation of nutrition-sensitive food systems.Peer Reviewe

Framing food security and food loss statistics for incisive supply chain improvement and knowledge transfer between Kenyan, Indian and United Kingdom food manufacturers

The application of global indices of nutrition and food sustainability in public health and the improvement of product profiles has facilitated effective actions that increase food security. In the research reported here we develop index measurements further so that they can be applied to food categories and be used by food processors and manufacturers for specific food supply chains. This research considers how they can be used to assess the sustainability of supply chain operations by stimulating more incisive food loss and waste reduction planning. The research demonstrates how an index driven approach focussed on improving both nutritional delivery and reducing food waste will result in improved food security and sustainability. Nutritional improvements are focussed on protein supply and reduction of food waste on supply chain losses and the methods are tested using the food systems of Kenya and India where the current research is being deployed. Innovative practices will emerge when nutritional improvement and waste reduction actions demonstrate market success, and this will result in the co-development of food manufacturing infrastructure and innovation programmes. The use of established indices of sustainability and security enable comparisons that encourage knowledge transfer and the establishment of cross-functional indices that quantify national food nutrition, security and sustainability. The research presented in this initial study is focussed on applying these indices to specific food supply chains for food processors and manufacturers

Impact of direct-electric-current on growth and bioactive compounds of African nightshade (<i>Solanum scabrum</i> Mill.) plants

Production of indigenous African leafy vegetables such as African nightshade (Solanum scabrum Mill.), whose high nutritional and medicinal value is well documented is still limited due to insufficient preharvest techniques. Electric current is known to improve quality in food crops. Therefore, in the present study, the effects of direct-electric-current (DC) on growth and characteristic bioactive and health promoting compounds were evaluated in different morphological sections, i.e., leaves and stems of African nightshade cv. Olevolosi. Six weeks old plants were exposed to different DC applied with a voltage of 8 and 16 V, 10 h/day for 12 days. Non-treated plants served as control. Plant growth, primary and secondary plant compounds were evaluated. Applying DC increased leaf fresh (11.5-14.4%) and dry (12.1-24.2%) weight as well as marketable leaves (29.1-55.3%). Biosynthesis of chlorophylls and carotenoids was enhanced by increased DC. Furthermore, dietary fibre fractions such as hemicellulose was promoted (23.3-45.3%) by DC applications, while cellulose and lignin remained unaffected. Minerals accumulated with increasing DC. Alteration of cell membrane permeability due to DC may enhance physiological processes leading to the improved growth and acceleration of bioactive compounds in African nightshade leaves

Different Agronet Covers Influence Physiological Traits, Growth and Yield of African Nightshade (Solanum scabrum Mill.) and Spiderplant (Cleome gynandra L.)

African indigenous leafy vegetables (AILVs) contribute significantly to improved nutrition, food security and income. However, the potential to meet the growing demand for AILVs in Kenya has not been satisfied. This study was conducted between August, 2015 and April, 2016 to evaluate the effect of different agronet colours on growth and yield of African nightshade and spiderplants The experiment was a 2x5 factorial laid on a randomized complete block design (RCBD), with three replications. Factors under study were vegetable types (African nightshade and spiderplant) and net covers (white, grey, blue, yellow net and open field). Spiderplant seeds were direct seeded and later thinned to a spacing of 30 cm by 30 cm. African nightshade seeds were started in the nursery and later transplanted five weeks after sowing. From the 7th weeks after planting (WAP) and at two weeks interval, plant height, primary branches, stomatal conductance, chlorophyll and leaf fresh yield were determined. Use of blue net significantly yielded taller plants of African nightshade (29.6%) compared to those in the open field by 13 WAP. Spiderplant were taller under white net (20.7%) and shorter under blue net (20.95%) compared to open field by 13 WAP. Yellow and white net enhanced primary branching of African nightshade and spiderplant, respectively while blue net exhibited the least for both vegetables. Days to first and 50% flowering was delayed under blue net by 13 and 6 days compared to control for spiderplant and African nightshade, respectively. Yellow and white net improved stomatal conductance for African nightshade and spiderplant, respectively. Regarding chlorophyll content, yellow and blue net had the highest concentration of chlorophyll a and b for both vegetables. Use of yellow net improved total fresh leaf yield by 15.82% and 12.42% compared to open field for African nightshade and spiderplant, respectively. Blue net significantly reduced total yield compared to open field for both vegetables. This study shows blue net cover has the potential to prolong the vegetative phase of these crops hence longer harvesting time of these crops and that yellow net has a greater potential to be used for production of African nightshade and spiderplant. However, a cost benefit analysis study should be done to assess the beneficial effect of yellow net over open field