Spider plants (Gynandropsis gynandra, L. Briq.) are a semi-wild vegetable reported to have high nutritional, medicinal, insecticidal, and cultural values, yet continue to be neglected in research. The study was undertaken to investigate indigenous knowledge and utilization of the species in five regions of northern Namibia. Three tools were used; (i) focus group discussion, (ii) semi-structured interviews involving a random selection of 100 farming households and 24 consumers, and (iii) key informant interviews involving four agricultural staff and two open-market supervisors. Data were subjected to descriptive statistics, inferential, and cluster analyses. The study found that farming households and consumers placed higher nutritional, sociocultural, and medicinal values in spider plants than any other vegetable. Ranking of utilization traits, such as nutritional, sociocultural, and medicinal use, revealed three clusters of sociolinguistic groups associated with geographical region. The vegetable was sold and used in most cultural, traditional, and religious functions as a relish, as a source of honor, to bring luck, and for protection. The diverse uses and value placed on spider plants could offer an opportunity for the development of technologies for enhancing their domestication, production, and utilization. It is recommended that follow-up studies be carried to identify specific sociocultural and geographic factors affecting the use of spider plants.

Increased public awareness of healthy foods and healthy living, coupled with escalating medicinal costs and recent advances in research and technology, has sparked a paradigm shift to nutraceuticals, which guarantee human health and disease prevention. Spider plant (Gynandropsis gynandra) contains dietary phytochemicals with high nutritional and medicinal properties that can contribute to healthy living. A study was conducted to identify spider plant (Gynandropsis gynandra (L.) Briq.) accessions with superior levels of dietary phytochemicals and anti-oxidative activity for use in nutraceutical breeding. Thirty-three accessions of spider plant, representing a wide genetic diversity based on geographic areas of origin (Asia, East Africa, Southern Africa, and West Africa), were used. Total phenolic acids, tannins, and anthocyanins were extracted and quantified using the Folin-Ciocalteau colorimetric, spectrophotometric, and pH differential methods, respectively. Antioxidant activity was determined using phosphomolybdenum method. Results showed significant variation in levels of total phenolic compounds, tannins, anthocyanins, and antioxidant activity (P < 0.05) amongst the spider plant accessions and regions of origin; ODS-15-037 (464 mg TAE/g DW), ODS-15-053 (270 mg GAE/g DW), and BC-02A (127 mg cyanidin-3-glucoside/g DW) had the highest levels of total tannins, phenolic compounds, and anthocyanins, respectively. Antioxidant activity was high in ODS-15-053 (492.2 mg AAE/100 g DW), NAM 2232 (445.3 mg AAE/100 g DW), and NAM-6 (432.5 mg AAE/100 g DW). On average, West African accessions had significantly high tannin concentrations (239 mg TAE/g DW), while Southern Africa accessions contained significantly high anthocyanin content (58.9 mg cyanidin-3-glucoside/g DW). The superior accessions are potential candidates for use in nutraceutical breeding, while the regions of origin could be used as gene pools for specific phytochemicals for improving dietary supplements of nutraceuticals. The strong antioxidant activity exhibited by spider plant accessions suggests the presence of compounds responsible for scavenging free oxygen or nitrogen radicals. Further studies are recommended to identify the chromosomal regions that contain genes controlling the dietary nutraceuticals in the genetic materials and to determine their association with foliage yield and other phenotypes, which can be utilized in spider plant improvement.

Knowledge on the diversity and domestication levels of the spider plant (Gynandropsis gynandra) has the potential to affect pre-breeding for client-preferred traits, yet information is scarce in Namibia due to limited research. We investigated indigenous knowledge on the species diversity and domestication levels in the regions of Kavango West, Ohangwena, Omusati, Oshana, and Oshikoto of northern Namibia. Semi-structured interviews involving 100 randomly selected farming households, four key informant interviews, and a focus group discussion were conducted. Descriptive and chi-square tests were conducted using IBM SPSS version 20. Out of the possible four morphotypes, the results suggested that only one with green stem and green petiole existed and was associated with soils rich in organic manure. Spider plant abundance was reported to be on the decline, due to declining soil fertility. On a scale of 0 (wild species) to 6 (highest level of domestication), an index of 1.56 was found and this implied very low domestication levels. Furthermore, the study found significant differences in the trends of domestication across the sociolinguistic groups (χ2 (12, N = 98) = 46.9, p < 0.001) and regions studied (χ2 (12, N = 100) = 47.8, p < 0.001), suggesting cultural and geographical influences. In conclusion, the findings constituted an important precedent for guiding subsequent pre-breeding efforts.

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The influence of organic hydroponic nutrient solution on tomato growth and yield was studied using a randomized complete block design (RCBD) with three treatments (organic nutrient solution, conventional hydroponic fertiliser (as positive control) and plain tap water (as negative control)) replicated three times. Determinate tomato seeds were germinated and transplanted into the 3 treatments. Twenty days after transplanting, vegetative response variables were recorded at fifteen days intervals from each treatment. Vegetative response variables included plant height, number of leaves and stem diameter. The reproductive parameters included number of flowers per plant, number of fruits per plant, average fruit weight (g), yield (kg) per plant and yield (kg) per treatment. Furthermore, the organic nutrient solution formulated from goat manure positively improved plant growth and yield performance of a tomato crop, and provided a technique feasible and alternative to conventional hydroponics. These results open further possibilities for other crops currently grown in hydroponics using conventional fertilisers.

Spider plant (Gynandropsis gynandra (L.) Briq.) is among the most important African Leafy Vegetables (ALVs) as a source of essential nutrients with the potential of contributing significantly to household food and nutritional security and mitigation of hidden hunger. Nevertheless, the vegetable is considered an orphan crop and its production is challenged by inadequate research to identify and improve traits preferred by smallholder farmers. The research was conducted to identify the main challenges impacting the production of spider plants and identify traits preferred by smallholder farmers in northern Namibia and central Malawi for use in demand-led crop improvement. Semi-structured interviews involving a random selection of 197 farming households from five regions of northern Namibia and three districts of central Malawi were conducted. In addition, six key informant interviews and four focus group discussions were conducted to triangulate the findings. Data were analyzed using IBM SPSS version 20. Fischer's exact test was used to test for independence in the ranking of production constraints and agronomic traits, while Kendall's Coefficient of Concordance (W) was used to measure agreement levels in the ranking across the countries. Farmers indicated lack of seed, poor soil fertility, poor seed germination and drought as the main production challenges across the two countries. Production constraints were ranked differently (p &lt; 0.001) across the study sites suggesting the influence of biophysical and socio-economic factors associated with production. High yield and drought tolerance were considered the most important agronomic traits among the smallholder farmers in both countries. The findings of this study are useful for designing demand-driven pre-breeding trials that prioritize the needs of the end-users. Demand-led breeding has the potential to stimulate the production and utilization of spider plant, hence contributing to household food and nutritional security.

For many years, the generation of nitrates from organic sources in order to create nutrient solutions for hydroponics had proved a challenge until lately when microorganisms were introduced to perform this task. The objectives of the current study therefore were to use local microbial consortium to nitrify goat manure in water and to determine microbial diversity in the inoculated consortium. Therefore, microorganisms were sourced from garden soil and natural compost at the Sam Nujoma Marine resources Research Centre (SANUMARC) in Henties Bay Namibia to convert organic nitrogen in goat manure from Utuseb farm near Walvis Bay into nitrates. Results show that microbial consortium from the compost source produced significantly (P< 0.05) more nitrates followed by the garden-soil source, suggesting that it is necessary to add inoculum in order to generate nitrate from goat manure. The ammonia oxidising bacteria (AOB) community from the compost sample's was dominated by uncultured ammonia-oxidising species followed by uncultured bacterium (both not identified), with the least being Nitrosomonas species. The AOB community from the garden source was dominated by uncultured bacterium, followed by uncultured ammonia-oxidising species and the least being Nitrosomonas species. NOB community from the compost source was dominated by uncultured bacterium, followed by Nitrobacter winogradskyi and Nitobacter vulgaris with the least being Nitrococcus mobilis and Nitrospira moscovensis. For the garden soil microbial source, uncultured nitriteoxidising bacteria dominated followed by uncultured bacterium, whereas the least species were N. moscovensis and Nitrobacter alkalicus. Moreover, community composition of the compost sample was more diverse than the community from the garden sample. These results maintain that there are other unculturable yet important microbes doing the same job if not better than the known ones, in this case suggesting that there may be other local nitrite-oxidizing bacteria responsible for oxidizing ammonia other than the traditionally known Nitrobacter, Nitrospira and Nitrococcus species.

Cereals constitute a food staple in the African bread (Ugali) form. Overdependence on maize as a predominant staple is partly blamed on the constricting indigenous cereal phyto-diversity. Strategies rekindling interest in their restoration remain few and disconnected. Thus, the objectives were to: (1) search for micronutrient density information among accessions of sorghum, finger millet, pearl millet and maize on the basis of 'where-they-were-as they-were' (free-call diversity); (2) determine micronutrient densities linked to eco-nutrametric variation for distinguishing differences among accessions. The accessions were collected in 2003/04 from the Bungoma-Maseno-Kibwezi (BMK) phyto-regions and subjected to Energy Dispersive X-ray Fluorescence (XRF) analysis. A nested design was used for sampling in which the cereal species were nested within sites and sites nested within phyto-regions. For each accession with its soil, a gamut of element concentrations was XRF-generated. The data were subjected to a Clustered Bar Graphing (CBG) test for identifying variation-picking element(s). By CBG test, a given element's concentration data range was placed along the X-axis upon which species/accessions' density categories along the Y-axis were graphed as series in rows giving way to density variation comparisons. Where no such density variations were visible, the element was disregarded as non-variation-picking. The CBG test revealed that all accessions were 'imperfect' in that none of them had the gamut elements (density as subject score) inall-top or in-all-low density, i.e. none of the accessions scored high 'As' or low 'Cs' in every elemental density case. This implied that a phenotypic characterization as a whole would have required describing an accession in as different (number of) ways as the number of the variation-picking elements included. A soil-to-plant mineral flow (elemental uptake-ability or EU) was further calculated as a single value [plant ppm]/[soil] x 100. In sorghum the EUs were as follows: 2.4% for Fe (in accession tC74), 211% for Zn (in tC65), 332% for Cu (in tC36) and 408% for K in (tC70). The CBG test among the cereal accessions is invaluable for distinguishing within and between accessions in respect of their single element uptake-ability. A single nutrametric value (NMV) or grade, on the other hand, appears useful in describing a nutrametric phenotypic variant as it bypasses the genotype-environment interaction dilemma. Its robustness is its ability to distinguish various phenotypic mineral micronutrient diversity grading and offers opportunities for mineral micronutrient mapping across phyto-regions.