A survey of traditional leafy vegetables and studies of genetic diversity of Cucurbita landraces in northern KwaZulu-Natal, South Africa
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Date
2013
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University of Zululand
Abstract
Traditional leafy vegetables (TLVs) are commonly herbaceous plants with
relatively high nutrition and health significance. They have formed part of food
security in rural-based communities for generations. The utilization of TLVs; the
diversity in morphology, yield and genetics of highly preferred vegetable species
was investigated. The objectives were to identify the known and preferred TLVs,
and determine morphology, yield and genetic diversity of most preferred
Cucurbita landraces in northern KwaZulu-Natal. In a total of 72 recorded species,
the following were recorded for the first time as TLVs: Commelina erecta,
Deinbollia oblongifolia, Erythroxylum delagoense, Galinsoga ciliata, Ipomoea
wightii, Limeum sulcatum, Priva meyeri var. meyeri, Trachyandra asperata var.
asperata and Trachyandra cf. saltii var. saltii. High species diversity was
recorded at Umkhanyakude district when compared with others. Most vegetables
were collected from the wild, during rainy seasons, and were consumed daily to
every two days. Cucurbita species were predominantly grown in spring and
summer, from the seeds that were saved from the previous harvest. Leafy shoots
were harvested in less than two months from seeding.
Diversity in morphology and yield was evident in landraces within the same and
among different Cucurbita species. Cucurbita pepo landraces had the highest
shoot, fruit and seed yields. In all Cucurbita landraces, harvest-pruning initiated
at six weeks from planting resulted in longer vines and higher numbers of: lateral
branches; leaves; pistillate and staminate flowers. Dendrogram from molecular
analysis using random amplified polymorphic DNA (RAPD) markers primarily
grouped C. pepo landraces according to the fruit colour change at maturity, while
both RAPD and simple sequence repeat (SSR) markers also grouped them
according to their agro-ecological origin. Some unique RAPD and SSR bands
discriminated the self-pollinated C. pepo landraces from the unselfed ones.
The newly documented TLVs have formed the basis for future research of their
growth, yield as well as improved palatability. Also the results of diversity in
morphology and genetics of Cucurbita landraces can be used to improve these
vegetable species.
Description
Submitted to the Faculty of Science and Agriculture in fulfillment of the
requirements for the degree of Doctor of Philosophy in the Department of
Botany at the University of Zululand, South Africa, 2013.
Keywords
Traditional leafy vegetables, Cucurbita landraces