Botany

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Browsing Botany by Author "Buthelezi, Lungelo Given"

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    Agro-morphological, nutritional variability and heritability studies of Lagenaria siceraria landraces in northern KwaZulu-Natal, South Africa
    (University of Zululand, 2019) Buthelezi, Lungelo Given; Ntuli, N.R.
    Lagenaria siceraria (Molina) Standley of the Cucurbitaceae family is one of many underutilised ancient cultigens with great economic potential. Its nutritious tender shoots, flowers, fruits, and seeds are of culinary use and widely consumed in rural communities as a vegetable relish. It has abundant nutrients and minerals essential for human health. However, research on morphological and nutritional variation among L. siceraria landraces from South Africa is very marginal. Therefore, the objective of this study was to characterise variability in growth, yield and nutritional composition among L. siceraria landraces from northern KwaZulu-Natal. L. siceraria landraces with various fruit and seed morphology, collected from different agro-ecological areas of northern KwaZulu-Natal were grown in a randomised complete block design with three replications over two summer seasons. Seedling, vegetative and reproductive traits were compared among landraces, while pulp of the mature fruit was analysed for nutrient composition. Analysis of variance, correlation, principal component analysis, cluster analysis and heritability estimates were conducted on morphological traits and nutrient content. Landraces with different fruit and seed morphology, from different areas varied significantly in seedling, vegetative and reproductive traits as well as nutrient content. Significant positive correlations were mainly recorded among reproductive traits and also among the majority of nutrients. The first five and three informative principal components were responsible for 74.393% and 80.270% of the total variability in morphological traits and nutrient composition, respectively. First components (PC1) with 26.635% and 42.076% variability were positively associated with most of morphological traits and nutrients, respectively. In morphological trait and nutrient analyses, biplot and dendrogram grouped landraces mainly according to fruit and seed morphology and then their origin. High heritability estimates were recorded among fruit and seed traits as well as among various nutrients. Therefore, this study can be the foundation for strategic improvement, direct production or conservation of the Lagenaria siceraria using these landraces.
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    Variation in growth, nutrition and phytochemicals of sequentially harvested shoots and fruits, and genetic studies of Lagenaria siceraria landraces in South Africa
    (University of Zululand, 2024) Buthelezi, Lungelo Given; Ntuli, N.R. Mavengahama, S. and Sibiya, J.
    Lagenaria siceraria (Molina) Standley, a member of the Cucurbitaceae family, is valued for its many uses, serving as a crucial food source with edible plant parts such as leaves, shoots, fruit pulp, and seeds. However, studies on L. siceraria regarding the relationship between shoot, peduncle and fruit traits during growth; nutritional and phytochemical composition of sequentially harvested shoots and fruits; as well as genetic diversity among landraces using single nucleotide polymorphism (SNP) markers, are limited. These studies are crucial for enhancing plant physiological understanding, optimizing crop yields, improving nutritional value, and preserving genetic diversity in L. siceraria. Therefore, the objectives of this study were to correlate shoot, peduncle, and fruits’ traits during growth; compare the nutritional composition of shoots and fruits, and phytochemical profile of fruits harvested at different maturity stages; and assess the genetic variability using SNP markers in L. siceraria landraces sourced from northern KwaZulu-Natal and Limpopo, South Africa. Multivariate analyses were conducted along with the estimations of heritability. Harvested shoot, peduncle, and fruit traits showed significant variation (p < 0.05) within each growth period and at different growth stages. Peduncles of all landraces became shorter and thicker when fruits were elongating and widening, from 0–5 days after anthesis (DAA). Positive correlations were notable among all shoot traits (shoot length, shoot width, shoot fresh mass, shoot dry mass, and shoot moisture content), and peduncle width correlating with fruit length and width. The first three principal components explained 85% of the total variability. Clustering identified three main groups, with singlets for landraces KRI and NSRC. Landraces were clustered according to peduncle and fruit sizes, as well as availability of harvestable shoots. High heritability estimates were recorded for peduncle length (55.2%) and shoot width (60.2%). Differences in nutrient attributes were significant within and among landraces where shoots and fruits were harvested at various growth stages. Nutritional traits correlated either positively or negatively with each other based on their translocation modes and similar chemical properties. The first five principal components explained 90.218% and 89.918% total variability in shoots and fruits, respectively. Micronutrients Ca, Mg, K, P, and N in shoots and macronutrients Fe, Zn, Cu, and Al in fruits, were the primary contributors of variability. Shoot nutrient content associated landraces into three major clusters, based on landraces with superior and inferior levels of specific nutrients at different growth stages, as well as those with distinctive nutrient profiles. Fruit nutrient status also grouped landraces into two major clusters, reflecting variations in nutrient content at different growth stages. Phytochemical analysis identified five isoprenoids in fruits harvested at 7 DAA across all landraces, namely 1-Dodecene, 2,3-Dimethyldodecane, E-15-Heptadecenal, Eicosane, and Tridecane, 6-propyl. Lighter metabolites in molecular mass displayed shorter retention rates (9.08-16.29 min) with lower relative peak areas (1.09-6.97%), while heavier compounds exhibited longer retention rates (13.42-18.00 mins) with higher relative peak areas (2.25-11.41%). Landraces were grouped into five clusters based on fruit and seed attributes and significant isoprenoid units. Terpenoids were the predominant phytochemicals commonly identified among landraces’ fruits at different stages of growth, where 1-Dodecene; Decane,3,7-dimethyl-; 1-Octadecane; 1-Pentadecene; E-14-Hexadecenal; E-15-Heptadecenal; Eicosane; Tetradecane, 4-methyl; and Tridecane, 6-propyl-, were the highest contributors to variation. Correlation in phytochemicals was predominantly based on their availability at different fruit growth stages. Three distinct clusters grouped landraces according to the unique presence of phytochemicals at different stages of growth, as well as landraces with similar fruit traits and phytochemical availability at different growth stages. Genetic variation at a single nucleotide base was identified among studied landraces, where the sequencing of 16 landraces revealed variations in the target genes ACS27 and CmFIS8. Molecular variance analysis and phylogenetic tree construction indicated variations among landraces. Sequenced landraces showed an average of 1.75 alleles, effective alleles at 0.419, Shannon’s information index at 0.403, expected heterozygosity at 0.265, gene flow at 6.80, and genetic differentiation at 0.082. Sequence variations were observed, and landraces were clustered based on genetic differences. Analysis of Molecular Variance (AMOVA) indicated 100% variation among landraces of different origins.
University of Zululand