Botany
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Browsing Botany by Author "Ferreira, D.P."
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- ItemGenetic improvement of selected indigenous Cucurbitaceae species important for food and medicinal purposes in KwaZulu-Natal, South Africa(2007) Ntuli, Nontuthuko Rosemary; Ferreira, D.P.; Hannweg, K.; Zobolo, A.M.Coccinia palmata (Cogn.) and Lagenaha sphaerica (Sond.) Naud. are indigenous Cucurbitaceae species widely distributed in pantropical to tropical regions of Southern Africa. They are widely used for food and medicinal purposes, in nature these species exist as diploids, with their basic haploid (n) chromosome numbers being 12 and 11 for C. palmata and L sphaerica respectively. However, in higher plants nuclear DNA endoreduplication often occurs during their growth and differentiation which causes polysomaty in their tissues. For both C. palmata and L sphaerica, the optimum germination conditions were 25°C under light. Growth was either in the nursery (in pots/bags) or in the field (with and without bags). Colchicine treatment of seeds before and after incubation for germination was used to induce polyploidy in both of these Cucurbitaceae species. The effectiveness of colchicine in inducing polyploidy (genetic improvement) in the roots and shoots of both species was established. In both species treated roots had higher tetraploid and octoploid ratios than leaves. Colchicine treatment lowered the germinability (germination percentage), induced dwarfism, enhanced stem branching, reduced leaf area and number of stomata, and increased guard cell length and leaf chlorophyll content in both species. In C. palmata, colchicine treatment increased root fresh and dry weight but reduced shoot fresh and dry weight. However, colchicine treatment inhibited female plants' flowering and therefore fruiting in both species.
- ItemMorphology and selection of high yielding cashew (Anacardium occidentale L.) Strains for Maputaland, South Africa(2001) Vololoniana, Ramiakato; Ferreira, D.P.; de Wet, H.The Industrial Development Corporation (IDC) and Ithala Development Finance Corporation Limited (ITHALA) are in the process of establishing a cashew industry in South Africa at Coastal Cashews, Maputaland. This study concentrated on the morphology and yield characteristics of most of the strains already planted at Coastal Cashew farm. One hundred and thirty different strains, originating from various countries such as Zambia and Brazil, have been studied. Morphological and yield characteristics were considered for suggestions about strains for inclusion in a propagation program. Most morphological characteristics such as apple size and colour, leaf surface area and others, varied between strains, reflecting the diverse origin of plant material. Similarly, most of the yield characteristics such as nut production, nut size and others, varied between strains and within strains between seasons. Based on the morphological (number of panicles per tree, number of perfect flowers per panicle, and others) and the yield characteristics (nut per panicle, nut size, and others), a model has been proposed where the number of panicles per tree and the number of perfect flowers per panicle are used to predict the yield of a tree (strain).