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The effect of pollen quality on blueberry fruit yield
Thesis (PhD)--Stellenbosch University, 2022.
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| Format: | Thesis |
| Language: | English |
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Stellenbosch : Stellenbosch University
2022
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| _version_ | 1867613813936750592 |
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| access_status_str | Open Access |
| author | Martin, Keanu |
| author2 | Anderson, Bruce |
| author_browse | Anderson, Bruce Martin, Keanu |
| author_facet | Anderson, Bruce Martin, Keanu |
| author_sort | Martin, Keanu |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (PhD)--Stellenbosch University, 2022. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/126350 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:42:06.574Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2022 |
| publishDateRange | 2022 |
| publishDateSort | 2022 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/126350 The effect of pollen quality on blueberry fruit yield Martin, Keanu Anderson, Bruce Minnaar, Corniele De Jager, Marinus Stellenbosch University. Faculty of Science. Dept. of Botany and Zoology. Blueberries -- Breeding -- South Africa Blueberries -- Varieties -- Pollination -- South Africa Pollination by bees Blueberry industry -- South Africa UCTD Thesis (PhD)--Stellenbosch University, 2022. ENGLISH ABSTRACT: Substantial evidence suggests that pollination is an integral part of blueberry fruit production. However, there is little knowledge on the different aspects of blueberry pollination outside the native range of blueberries (North America), with the vast majority of knowledge coming from the Northern hemisphere. Due to the differences in pollinators and varieties used, this knowledge cannot be directly applied to pollination issues in areas such as South Africa. This thesis uses five commonly planted blueberry varieties in South Africa to investigate the various aspects of blueberry pollination and the effect of pollen quality on blueberry fruit production. My first data chapter (Chapter 2) set out to determine whether cross-pollination between varieties (inter-varietal pollination) resulted in increased fruit production, quality and decreased ripening time relative to pollination within varieties (intra-varietal pollination), and if so, what the optimal crossing combinations of these varieties are. Results revealed that intra-varietal pollination often produced fruit, however, these fruit resulted in decreased fruit production, quality and increased ripening time compared to inter-varietal pollination. The benefit of inter-varietal pollen also differed between varieties, suggesting that varietal combinations are not trivial, and highlights the importance of determining optimal co-planting schemes as an avenue to increase yield. In Chapter 3, I determined the effect of honey bee pollination on blueberry fruit production, quality and ripening time and whether there was any room for improvement. In this chapter, I show that honey bee pollination was consistently beneficial in terms of fruit production, quality and ripening time, however, the magnitude of this benefit differed across varieties. Likewise, the pollination deficit (difference between optimized hand-pollination and honey bee pollination) also differed considerably across varieties with certain varieties performing relatively close to their maximum potential (small pollination deficit), and others where optimized hand-pollination differed vastly from honey bee pollination (large pollination deficit). This demonstrates that honey bees can be effective pollinators of blueberries in areas that lack the native pollinators of blueberries and that consideration should go into growing varieties that favour the commercial pollinators of a country. Chapter 4 determined whether fruit yield differed depending on whether pollen was moved within plants compared to pollen movement between clonal plants of the same variety. By comparing fruit production, quality and ripening times among within-plant and between-plant donors I show that despite blueberry varieties being clones, fruit production and quality increased and ripening times decreased when pollinated with between-plant intra-varietal pollen compared to within-plant pollen. Although the effect size of these differences differed between varieties. By observing honey bees foraging in a blueberry orchard and recording their movements, my fifth chapter demonstrates for the first time in blueberries that honey bees forage primarily along rows and infrequently switch between rows in blueberry orchards. This has important implications for planting design in blueberry orchards as these results show that planting design is likely to have a large impact on fruit yield. In my last chapter (Chapter 6), I combine the effects of pollen source and honey bee foraging movements in a model to estimate blueberry fruit yield in a theoretical orchard. I show that the traditional method of alternating varieties by rows is likely to result in decreased fruit yield compared to alternating varieties within a row. This has large implications for the blueberry industry as a whole as this model has the potential to inform blueberry growers of their estimated yield depending on their planting design, and can inform them of which varieties may be better suited to their pollination climate. This thesis is likely to have a large impact on the South African blueberry industry, as it provides the first detailed look into the effects of pollen quality on commonly planted blueberry varieties in South Africa. Although this thesis was not done on all the blueberry varieties planted in South Africa, it provides insight that can be applied further than the varieties investigated. Despite the pressure to import bumble bees into South Africa, I show that honey bees are effective pollinators of blueberries in South Africa. Such empirical evidence has been lacking until now. Although certain varieties show pollination deficits, I provide various strategies which have the potential to decrease those pollination deficits. An important discovery, which has been previously unexplored, is that of pollinator foraging movement in blueberry orchards. Various aspects of the plant in terms of pollen received are often taken into account, however, one equally important aspect is pollinator foraging behaviour, as this determines both the amount of pollen deposited as well as the quality of pollen deposited. I show that pollinator foraging movement likely has large effects on blueberry fruit production and that taking this into account has the potential to increase blueberry fruit yields. AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar. Doctoral 2022-11-23T20:13:09Z 2023-01-23T06:53:30Z 2022-11-23T20:13:09Z 2022-12 Thesis http://hdl.handle.net/10019.1/126350 en Stellenbosch University v, 161 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Blueberries -- Breeding -- South Africa Blueberries -- Varieties -- Pollination -- South Africa Pollination by bees Blueberry industry -- South Africa UCTD Martin, Keanu The effect of pollen quality on blueberry fruit yield |
| title | The effect of pollen quality on blueberry fruit yield |
| title_full | The effect of pollen quality on blueberry fruit yield |
| title_fullStr | The effect of pollen quality on blueberry fruit yield |
| title_full_unstemmed | The effect of pollen quality on blueberry fruit yield |
| title_short | The effect of pollen quality on blueberry fruit yield |
| title_sort | effect of pollen quality on blueberry fruit yield |
| topic | Blueberries -- Breeding -- South Africa Blueberries -- Varieties -- Pollination -- South Africa Pollination by bees Blueberry industry -- South Africa UCTD |
| url | http://hdl.handle.net/10019.1/126350 |
| work_keys_str_mv | AT martinkeanu theeffectofpollenqualityonblueberryfruityield AT martinkeanu effectofpollenqualityonblueberryfruityield |