Thesis (MSc)--Stellenbosch University, 2010. / Thesis presented in partial fulfillment of the requirements for the degree of
Master of Science in Zoology at Stellenbosch University. / ENGLISH ABSTRACT: Most modern deciduous fruit cultivars are self-incompatible, and require polliniser trees to be planted
in the orchard to provide the pollen necessary for cross-pollination, fertilization and fruit set. Polliniser
trees are either non-commercial cultivars interspersed in the orchard solely to provide pollen, or crosscompatible
cultivars inter-planted in the same orchard. 90% of the commercial crops dependent on bee
pollination are courtesy of a single species, Apis mellifera. Both polliniser planting pattern and honey
bee colony distance are known to influence crop production and crop quality, resulting in a rapid
decrease in fruit weight, fruit set and seed number with increasing distance from the polliniser or
honeybee colonies. However, the response of different crops and cultivars to polliniser and pollinator
proximity on optimal crop yield is not known for deciduous fruit crops in the Western Cape, South
Africa. The effect of polliniser position and honeybee colony distance on fruit set and weight was
investigated in plums, apples and pears on the Lourensford Estate. The relationship between fruit set
and fruit weight was investigated for deciduous fruit cultivars. In addition, fruit weight and seed
number was also investigated in apples and pears. Fruit set tended to increase on sides of trees closer
to the polliniser but not significantly so, except for apples. This suggests that there is probably better
pollination closer to the pollinisers but this does not equate to increased yield. In fact, smaller fruit was
produced on the sides of the trees closer to the polliniser for all orchards and significantly so for plum
and for ‘Packham’s Triumph’ in Hillside 1. This negative relationship between fruit set and weight may
indicate ‘over-set’ beyond the physiological limits of the trees. Fruits closer to the polliniser had
significantly more seeds for both pear and apple cultivars indicating sufficient pollination. A
significant relationship was found between the seed number in any particular fruit and the weight of
the fruit in all the cultivars except ‘Packham’s Triumph’ where the relationship was negative,
suggesting that ‘Packham’s Triumph’ set parthenocarpically. Colony distance had no effect on fruit
weight, fruit set and on seed number indicating that colonies were adequately distributed and that
there was no “pollination depression” in the centre of the orchards at Lourensford. In conclusion, the
fact that we did not get a yield gradient with increased distance from the colonies suggested that the
orchards at Lourensford Estate were sufficiently pollinated. / AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/5466 |
| Date | 12 1900 |
| Creators | Ramongalo, Boipelo Kgomotsego |
| Contributors | Wossler, Theresa C., Allsopp, Michael H., Stellenbosch University. Faculty of Science. Dept. of Botany and Zoology |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | 146 pages : illustrations |
| Rights | Stellenbosch University |
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