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dc.contributor.advisor Mathaba, N.
dc.contributor.advisor Mafeo, T. P.
dc.contributor.author Sibuyi, Hazel
dc.date.accessioned 2019-09-12T07:53:32Z
dc.date.available 2019-09-12T07:53:32Z
dc.date.issued 2018
dc.identifier.uri http://hdl.handle.net/10386/2608
dc.description Thesis (M.Sc. (Horticulture)) --University of Limpopo, 2018 en_US
dc.description.abstract ‘Hass’ avocado fruit changes skin colour from green to purple and then black during ripening. However, markets importing South African avocado fruit have been complaining about the ‘Hass’ skin colour not changing to purple/black during ripening. Thus, the study aimed to investigate the effect of tree girdling, harvest time and ripening temperature on ‘Hass’ avocado fruit skin colour development during ripening. The mature ‘Hass’ avocado fruit were harvested from girdled and non-girdled trees during early (April), mid- (May) and late (June) harvest times. Upon arrival, in the laboratory fruit were cold stored at 5.5°C for 28 days. After storage, fruit were ripened at 25, 21 and 16°C for 8, 6 and 4 days, respectively. After withdrawal from clod storage fruit were evaluated for skin colour development, ripening and physiological disorders (chilling injury). Fruit from girdled trees showed high maturity (low moisture content) when compared with fruit from non-girdled trees during early and mid-harvest. With respect to skin colour development, the results indicate that skin eye colour development of fruit from girdled and non-girdled trees minimally increased from emerald green (1) to olive green (3) across all harvest times, ripening temperature and ripening duration. However, late season fruit from non-girdled trees improved to purple (4) when ripened at 21°C when compared with fruit from girdled trees. In terms of objective colour, lightness, hue angle and chroma decreased for fruit from girdled and non-girdled trees, across all harvest times, ripening temperature and ripening duration. Lightness and hue angle of fruit from girdled trees were slightly reduced when compared with fruit from non-girdled trees, throughout all harvest times, ripening temperature and duration. Early and mid-season fruit harvested from girdled trees showed rapid decrease of chroma when compared with fruit from non-girdled trees, throughout ripening temperature and x duration. In terms of softening, fruit from girdled trees showed higher firmness loss and ripening percentage within 6 (16°C) and 4 (21 and 25°C) days when compared with fruit from non-girdled trees during early and mid-harvest, whereas, late harvest fruit from girdled trees reached higher ripening percentage and firmness loss within 4 days throughout ripening temperatures. With respect to cold damage, late harvested fruit from girdled trees showed higher external chilling injury when compared with non-girdled trees, throughout ripening temperature. In general, girdling treatment improved fruit maturity, ripening rate and firmness loss. However, the incidence of variable skin colouring of ‘Hass’ avocado fruit during ripening was also prevalent in early harvested fruit from girdled tree, irrespective of ripening temperature. Keywords: girdling, harvest time, physiological disorder, ripening temperature, variable colouring en_US
dc.format.extent x, 56 leaves en_US
dc.language.iso en en_US
dc.relation.requires PDF en_US
dc.subject Girdling en_US
dc.subject Harvest time en_US
dc.subject Hass avocado variable colouring en_US
dc.subject Avocado ripening temperature en_US
dc.subject.lcsh Avocado - Harvesting time en_US
dc.subject.lcsh Fruit - Ripening en_US
dc.subject.lcsh Avocado - Effect of temperature on en_US
dc.title Effect of tree girdling, harvest time and ripening temperature on "hass" avocado fruit skin colour development during ripening en_US
dc.type Thesis en_US


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