Phytochemical composition of Lagenaria siceraria fruits from KwaZulu-Natal and Limpopo, South Africa.

Lagenaria siceraria (Molina) Standley is a food and medicinal source with anti-proliferative, anti-fertility, anti-HIV and anti-cancerous properties. The current study investigated the phytochemical constituents of L. siceraria fruits using gas chromatography/mass spectrometry (GC-MS). Five isoprenoids present in all investigated landraces were 1-Dodecene, 2,3-Dimethyldodecane, E-15-Heptadecenal, Eicosane, and Tridecane, 6-propyl. Lighter metabolites such as 1-Dodecene and 2,3-Dimethyldodecane were recorded at a shorter retention time range of 9.08-16.29 min over a lower relative peak area ranging from 1.09 to 6.97%. However, heavier compounds (E-15-Heptadecenal, Eicosane and Tridecane, 6-propyl) had a longer retention time range of 13.42-18.00 mins over a higher relative peak area range of 2.25-11.41%. Cluster analysis grouped landraces into 5 clusters (I -V) according to their fruit and seed attributes, and isoprenoid units significant to each cluster. Terpenoids were the prominent phytochemicals present in fruits. This is the most comprehensive study on the fruit phytochemical constituents of different L. siceraria landraces to date.

Nutritional Quality and Popability of Popcorn (Zea mays L. var. everta) in Response to Compost and NPK 20-7-3 Application under Dryland Condition of South Africa.

The dietary value of popcorn, an important snack, depends on its proximate and nutritional constituents, while the economic worth is based on popability and expansion traits of the kernels. There is paucity of information on how soil fertility influences or relates with popping potentials as well as quality of popcorn kernel in semi-arid region. Therefore, the proximate composition and popping parameters of popcorn in response to organic and inorganic fertilizers were investigated. The field trial was conducted in 2017-2019, and it comprised five amendment rates including 90 and 180 kg ha-1 NPK fertilizer and 4 and 8 t ha-1 compost and unamended treatment as the control. The trial was arranged in randomized complete block design in triplicate. Data on kernel yield, biomass, and harvest index were evaluated. Kernels were analysed for proximate composition and popping indices using standard procedures. Across the two seasons, mean protein (8.1%) and fibre (10.2%) contents were highest in kernels from plots fertilized with NPK at 180 kg ha-1, while grains from plots fertilized with 8 t ha-1 compost had the highest moisture (19.3%) and starch (50.1%) contents. The highest kernel expansion of 54.18 cm3 g-1 and 77.6% popped kernels were obtained in plots fertilized with 4 t ha-1 compost. Most of the kernels (61%) were small-sized caryopsis. Popability is significantly associated with volume expansion (r = 0.696). Proximate components and popability improved greatly in compost-augmented field relative to the unfertilized plots. Application of 4 or 8 t ha-1 sorted municipal solid waste compost to Luvisol enhanced growth and nutritional quality of popcorn. In view of promoting nutrient cycling towards improving soil fertility without compromising environmental health, compost is comparable and a good alternative to fossil-based mineral fertilizers.

First report of aeroponically grown Bambara groundnut, an African indigenous hypogeal legume: Implications for climate adaptation.

Global agricultural production is currently limited by negative climate-related hazards such as drought, uneven rainfall and rising temperatures. Many efforts have been put in place by government and non-government agencies to mitigate the challenges of climate change in the sector. However, the approaches do not seem feasible due to the growing demand for food. With these challenges, climate-smart agricultural technologies such as aeroponics and underutilised crops have been projected as the future of agriculture in developing African countries to reduce the risk of food insecurity. In this paper, we present the cultivation of an underutilised indigenous African legume crop, Bambara groundnut, in an aeroponics system. Seventy Bambara groundnut landraces were cultivated in a low-cost climate-smart aeroponics system and in sawdust media. The results showed that Bambara groundnut landraces cultivated in aeroponics performed better than those cultivated in a traditional hydroponics (sawdust/drip irrigation) technique in terms of plant height and chlorophyll content, where the landraces cultivated in sawdust had a higher number of leaves than those cultivated in aeroponics. This study also demonstrated the feasibility of introducing a generic Internet of Things platform for climate-smart agriculture in developing countries. The proof-of-concept and the successful cultivation of a hypogeal crop in aeroponics can be useful for cost-effective adaptation and mitigation plans for climate change, particularly for food security in rural African agricultural sectors.

Variation in Shoot, Peduncle and Fruit Growth of Lagenaria siceraria Landraces.

Lagenaria siceraria (Molina) Standley is a prominent food source as almost all its plant parts are edible. However, no studies have recorded the changes in shoots, peduncles and fruits during its growth. Hence, this study aimed to record changes in shoot traits and relate the peduncle to the fruit traits of L. siceraria landraces across different growth stages. Changes in shoots, peduncles and fruits during growth were compared within and among landraces using analysis of variance, correlation, principal component analysis, cluster analysis and heritability estimates. Almost all landraces had harvestable shoots at 42 days after sowing. Peduncles became shorter and wider as the fruits elongated. Shoots, peduncles and fruits correlated positively with each other. The informative principal components had a total variability of 84.488%, with a major contribution from shoot traits. The biplot and dendrogram clustered landraces with similar growth habits and the harvestable shoot and fruit attributes into three clusters, but KRI and NSRC formed singlets. Shoot width (60.2%) and peduncle length (55.2%) had high heritability estimates. The general low heritability estimates and genetic advances indicated the presence of non-additive gene action. This study is the first report on changes in harvested shoots and the relationship between peduncles and fruits during growth.

Morpho-Agronomic Evaluation of Lagenaria siceraria Landraces and Their F1 Populations.

Lagenaria siceraria is one of the most important cucurbitaceous vegetables due to its prolific bearing habit, its edibility as a cooked vegetable, and its low cost of cultivation. The objective of this study was to evaluate variation in the morpho-agronomic traits among selected landraces and their F1 populations. The landraces were crossed based on the North Carolina II genetic design to develop F1 populations. The twelve F1 populations along with seven parental landraces were grown in a randomized complete block design with three replications. Significant differences (p < 0.05) were observed among quantitative traits suggesting considerable genetic variability. The genotypes displayed significant variation in most qualitative traits of fruits and seeds. The first five principal components of quantitative traits among the evaluated 19 genotypes contributed 74.84% of the variability. The biplot and dendrogram clustered the genotypes into five clusters according to their vegetative, fruit, and seed traits. The highest value for the broad-sense heritability estimate was recorded for days to edible harvest maturity trait. The F1 progenies were more variable than the landraces and can therefore be used for further Lagenaria siceraria genetic improvement.

Agronomic, Genetic and Quantitative Trait Characterization of Nightshade Accessions.

Nightshades are among many underutilized and neglected African indigenous leafy vegetable (AILVs) species, and if adequately exploited, they could improve food, nutrition and income among the rural population. Morphological characterization of available accessions is key for the breeder to identify and select superior accessions as parents for utilization in breeding programs. Fifteen accessions of nightshade were evaluated for morpho-agronomic variation in an open field trial implemented in a randomized complete block design with three replicates across the two growing seasons. The accessions exhibited significant (p < 0.0001) differences in all quantitative traits. The data analysis showed that Scabrum (805.30 g/plant) followed by Ncampus (718.60 g/plant) produced the highest fresh leaf yield; for fruit fresh yield, the accession NigSN18 (1782.00 g/plant) recorded the highest, followed by ManTown (1507.90 g/plant). The accession N5547 had the tallest plants (66.83 cm), followed by accession Timbali (62.31 cm). The first four principal components (PCs) accounted for 86.82% of the total variation, which had an eigenvalue greater than 1. The cluster analysis grouped the accessions into 14 clusters based on their genetic similarity. Results of genetic studies revealed that phenotypic coefficient variation was higher than genotypic coefficient of variation for all parameters evaluated, indicating the environmental influence on the expression of these traits. Both GCV and PCV were higher for the largest leaf area, moderate to high for the remaining characters and low for leaf fresh yield per plant. High heritability coupled with genetic advance as a mean percentage (H2-70.59%, GAM-142.4%), indicating the presence of additive gene effects. Hence, selection can be employed for the improvement of this trait in nightshades. The study revealed sufficient genetic variability in the nightshade accessions, which can be exploited for crop improvement.

Phenotypic description of elite cowpea (Vigna ungiculata L. Walp) genotypes grown in drought-prone environments using agronomic traits.

Identification and selection of cowpea genotypes possessing suitable agronomic attributes is key for cultivar development to increase production. The objective of this study was to evaluate cowpea genotypes using agronomic traits to aid selection and identification of best genotypes for adoption and breeding to develop high-yielding cultivars. Agronomic traits of 20 cowpea genotypes were evaluated under Tompi Seleka and Polokwane environments using a completely randomised block design. Significant (P ≤ 0.01) genotype effect was identified for agronomic traits, whereas environment effect was significant (P ≤ 0.05) for number of productive branches (NB), leaf width (LW), leaf length (LL), hundred-seed weight (HSW) and grain yield (GY). Significant genotype-by-environment interaction effect was observed for pod length (PL), pod width (PW) and number of seeds per pod (SPP). Correlation analysis revealed positive and significant associations between NB with LW (r = 0.58; P ≤ 0.01), LL (r = 0.67; P ≤ 0.01), number of pods per plant (PPP) (r = 0.56; P ≤ 0.01) and HSW (r = 0.47; P ≤ 0.05). LW was positively and significantly correlated with LL (r = 0.71; P ≤ 0.00), PPP (r = 0.56; P ≤ 0.01) and SPP (r = 0.58; P ≤ 0.01). Positive and significant correlation was observed between LL with chlorophyll content index (CCI) (r = 0.54; P ≤ 0.05), PPP (r = 0.68; P ≤ 0.01) and pod length (PL) (r = 0.52; P ≤ 0.05). PW was positively and significantly associated with PL (r = 0.68; P ≤ 0.01) and SPP (r = 0.61; P ≤ 0.01), whereas PL was positively associated with SPP (r = 0.82; P ≤ 0.01). Cowpea genotypes CH14, Embo buff, IT89D-349, IT96D-602, Veg cowpea 1, Veg cowpea 2, Veg cowpea 3 and Veg cowpea dakama red recorded high NB, plant height (PH), LL, LW, chlorophyll content index (CCI), number of pods per plant (PPP), HSW and GY. Also, genotypes 2460, IT96D-748, Oukawa, Ukaluleni, Veg cowpea dakama cream and Vigna Onb were associated with PL, SPP and PW. The identified genotypes possessing suitable agronomic traits are recommended for farmer-adoption and inclusion in breeding programs for cultivar development.

Heat Stress Effect on the Grain Yield of Three Drought-Tolerant Maize Varieties under Varying Growth Conditions.

A rise in global temperature will reduce maize yield, particularly in Africa, where maize is a staple food. Therefore, improving maize yield under heat stress will promote food security in the region. The objective of this study was to assess the influence of heat stress on the grain yield of drought-tolerant maize varieties under varied growth conditions. The experimental design used was a 2 × 3 × 3 × 2 factorial fitted into a completely randomized design with four replications. The factors were heat stress, maize variety, soil amendment, and soil type. The results showed a better yield from sandy clay loam over loamy sand soil. Varieties WE5323 and ZM1523 amended with poultry manure gave the best yield under the non-heat and heat-stressed environments, respectively. Heat stress reduced the cob weight, grain weight, grain number, and stover dry weight by 64, 73, 69, and 23%, respectively. Grain number, grain weight, and cob weight were the most informative yield attributes in this study and should be considered in a maize selection program. The ranking for the maize varieties was WE5323 > ZM1523 > WE3128. Drought-tolerant maize varieties can be useful in heat stress mitigation. This information is useful for the simulation of maize yields for heat stress-prone areas in Sub-Saharan Africa.

A chromosome-level Amaranthus cruentus genome assembly highlights gene family evolution and biosynthetic gene clusters that may underpin the nutritional value of this traditional crop.

Traditional crops have historically provided accessible and affordable nutrition to millions of rural dwellers but have been neglected, with most modern agricultural systems over-reliant on a small number of internationally traded crops. Traditional crops are typically well-adapted to local agro-ecological conditions and many are nutrient-dense. They can play a vital role in local food systems through enhanced nutrition (particularly where diets are dominated by starch crops), food security and livelihoods for smallholder farmers, and a climate-resilient and biodiverse agriculture. Using short-read, long-read and phased sequencing technologies, we generated a high-quality chromosome-level genome assembly for Amaranthus cruentus, an under-researched crop with micronutrient- and protein-rich leaves and gluten-free seed, but lacking improved varieties, with respect to productivity and quality traits. The 370.9 Mb genome demonstrates a shared whole genome duplication with a related species, Amaranthus hypochondriacus. Comparative genome analysis indicates chromosomal loss and fusion events following genome duplication that are common to both species, as well as fission of chromosome 2 in A. cruentus alone, giving rise to a haploid chromosome number of 17 (versus 16 in A. hypochondriacus). Genomic features potentially underlying the nutritional value of this crop include two A. cruentus-specific genes with a likely role in phytic acid synthesis (an anti-nutrient), expansion of ion transporter gene families, and identification of biosynthetic gene clusters conserved within the amaranth lineage. The A. cruentus genome assembly will underpin much-needed research and global breeding efforts to develop improved varieties for economically viable cultivation and realization of the benefits to global nutrition security and agrobiodiversity.