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Manipulation of flowering in Protea cynaroides cv. Arctic Ice
Thesis (MScAgric)--Stellenbosch University, 2021.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2021
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| _version_ | 1867613843689046016 |
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| access_status_str | Open Access |
| author | Hattingh, Naomi |
| author2 | Hoffman, E. W.
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| author_browse | Hattingh, Naomi Hoffman, E. W. |
| author_facet | Hoffman, E. W.
Hattingh, Naomi |
| author_sort | Hattingh, Naomi |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScAgric)--Stellenbosch University, 2021. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/110287 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:42:35.472Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/110287 Manipulation of flowering in Protea cynaroides cv. Arctic Ice Hattingh, Naomi Hoffman, E. W. O’Brien, C. J. Louw, E. L. Protea cynaroides -- South Africa Protea -- Flowering time Arctic Ice Inflorescences -- Development Harvesting time Protea cynaroides -- Effect of temperature on Proteaceae -- Climatic factors Pruning UCTD Thesis (MScAgric)--Stellenbosch University, 2021. ENGLISH ABSTRACT: Commercial cultivation of Protea cynaroides has received renewed interest due to high variation occurring in its aesthetic qualities such as flower size, shape, and colour, but also in harvesting times, where year-round flowering may occur in some variants. P. cynaroides ‘Arctic Ice’ is of commercial importance, due to its large, pure white inflorescence that is harvested mainly within two peak general flowering times, coinciding with autumn (April–May), and spring (October–November), under southern hemisphere conditions. ‘Arctic Ice’ primarily initiates inflorescences either on a summer shoot growth flush to result in the autumn harvest peak and/or on an autumn shoot growth flush to result in harvestable flowers in spring. Our study indicated that ‘Arctic Ice’, unlike most medium-head size proteas, does not preform most of the final number of appendages within terminal buds before flush extension. Commitment to flowering was shown only to be fixed with the formation of florets, thus rendering ‘Arctic Ice’ prone to floral reversion until late within its reproductive development, a phenomenon that impacts negatively on its management and productivity. Pruning ‘Artic Ice’ plants back to bearers in the winter, spring and summer of 2017 established baseline shoot regrowth and flushing characteristics. Episodic shoot extension growth in ‘Arctic Ice’ occurred as separate shoot flushes during autumn, spring, in addition to early and late summer. The minimum number of shoot growth flushes per shoot complex as well as the minimum stem diameter required for flower production could be determined for ‘Arctic Ice’ grown in Piket-Bo-Berg and Stellenbosch in the Western Cape as well as Hilton in KwaZulu Natal. Most inflorescences are subtended by either four-or five shoot flushes, except for three-flush flowers occurring at Piket-Bo-Berg and six or more flushes, often subtending inflorescences cultivated at Stellenbosch and Hilton. The observed increase in shoot diameter, as a function of biomass increase upon regrowth after pruning, significantly differed between flowering and non-flowering shoots. For a vegetative shoot measured in mid-January, a minimum stem diameter of 10–20 mm was required for flowering at Piket-Bo-Berg, while 20 mm and more was required at Stellenbosch. The prevalent climatic conditions, particularly relating reduced number of cloudless days, were suggested to be the primary determinant of the success in the accumulation of leaf non-structural carbohydrates (NSC) and the eventual capacity of the subtending shoot to support floral growth and development. Polysaccharides were dominant in the NSC pool in shoots from the winter rainfall region, Piket-Bo-Berg, while shorter chain mono-and oligosaccharides were predominantly found in leaves from shoots obtained from the summer rainfall region of Hilton. This, while leaf starch levels were relatively stable, irrespective of phenological stage or production region and were therefore considered to be a lesser contributor to leaf NSC. This study contributes novel information on the flowering phenology of Protea cynaroides in general and for ‘Artic Ice’ in particular. The requirement for a basic understanding of vegetative and reproductive phenology is illustrated for the effective implementation of probative studies to promote the management of ‘Arctic Ice’ for greater profitability. AFRIKAANSE OPSOMMING: Die groot variasie in estetiese eienskappe van Protea cynaroides het tot hernude belangstelling in die kommersiële verbouing van variante daarvan gelei as gevolg van die teenwoordigheid van verskillende blomgrootte, -vorm en -kleur asook algemene blomtyd, waar sommige variante reg deur die jaar geoes kan word. Só ‘n toetredende produk, P. cynaroides ‘Arctic Ice’, is geselekteer vir kommersialisering weens sy groot, suiwer-wit bloeiwyse asook die voorkoms van twee algemene oestye in die suidelike halfrond se herfs (April–Mei), asook lente (Oktober–November). Blominisiasie in ‘Arctic Ice’ vind plaas óf op die somer groeistuwing waarna blomme tydens herfs geoes word óf op die lente groeistuwing vir lewering van bemarkbare blomme tydens herfs. Resultate het bevind dat ‘Arctic Ice’ nie aanhangsels binne die terminale knop preformeer voor groeistuwing verlenging soos gevind was by meeste medium-grootte protea blomtipes nie. Die verbintenis tot blomvorming vind eers plaas ten tye van die produksie van blommetjies en gevolglik is ‘Arctic Ice’ onderhewig aan die verskynsel van blom-omkering, tot en met ‘n gevorderde stadium van sy reproduktiewe ontwikkeling, ‘n verskynsel wat ‘n negatiewe invloed op bestuur en winsgewendheid het. Deur plante na draers terug te snoei tydens die winter, lente en somer van 2017 is die grondslag eienskappe rakende patrone van hergroei vasgestel. Episodiese lootverlengingsgroei in ‘Arctic Ice’ geskied as individuele loot groeistuwingsgebeurlikhede tydens herfs, lente, sowel as met vroë- en laat- somer. Die minimum vereiste episodiese groeistuwings vir blomvorming, sowel as die gepaardgaande minimum lootdikte is bepaal vir ‘Arctic Ice’ verbou te Piket-Bo-Berg en Stellenbosch in die Wes-Kaap, asook te Hilton in KwaZulu-Natal. Blomvorming geskied grotendeels op lote met vier-tot vyf- groeistuwings, met die uitsondering van blomme wat onderspan word deur drie groeistuwings by Piket- Bo-Berg, asook die gereelde ses- of meer groeistuwingslote wat waargeneem was te Stellenbosch en Hilton. Die waargenome toename in lootdikte as ‘n funksie van toename in biomassa met hergroei na snoei, toon beduidende verskille tussen vegetatiewe en blommende lote. Vegetatiewe lote, teen middel Januarie, benodig ‘n minimum lootdikte van 10–20 mm in Piket-Bo-Berg om te blom, terwyl ‘n minimum lootdikte van 20 mm vir Stellenbosch geld. Die heersende klimaatstoestande, veral rakende lae ligtoestande soos voorkom onder ‘n beperkte aantal sonnige dae, is as primêre bepalende faktor geidentifiseer vir die suksesvolle toename in blaar nie- strukturele koolhidrate (NSK), en die gevolglike geassosieerde kapasiteit vir blomproduksie. Polisakkariede was die dominante NSK fraksie in blare van lote vanaf Piket-Bo-Berg in die winterreënval streek, terwyl korter-ketting mono-en oligosakkariede oorheers het in blaarekstrakte van Hilton in die somerreënval streek. Blaar- styselinhoud is as relatief stabiel bevind, ongeag die fenologie stadium of produksie area en was dus as ‘n minder belangrike bydraende fraksie tot die blaar-NSK poel gesien. Hierdie studie bring nuwe inligting rondom die blom fenologie van Protea cynaroides in die algemeen, en meer spesifiek vir ‘Artic Ice’. Die noodsaaklikheid om die grondbeginsels van die vegetatiewe en reproduktiewe fenologie te verstaan word geillustreer vir die implementering van resultate van ondersoekende studies in die effektiewe bestuur van P. cynaroides ‘Arctic Ice’ vir verhoogde produktiwiteit en winsgewendheid. Masters 2021-03-06T12:35:36Z 2021-04-22T10:12:34Z 2021-03-06T12:35:36Z 2021-03 Thesis http://hdl.handle.net/10019.1/110287 en_ZA Stellenbosch University viii, 196 pages : illustrations (some color), maps application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Protea cynaroides -- South Africa Protea -- Flowering time Arctic Ice Inflorescences -- Development Harvesting time Protea cynaroides -- Effect of temperature on Proteaceae -- Climatic factors Pruning UCTD Hattingh, Naomi Manipulation of flowering in Protea cynaroides cv. Arctic Ice |
| title | Manipulation of flowering in Protea cynaroides cv. Arctic Ice |
| title_full | Manipulation of flowering in Protea cynaroides cv. Arctic Ice |
| title_fullStr | Manipulation of flowering in Protea cynaroides cv. Arctic Ice |
| title_full_unstemmed | Manipulation of flowering in Protea cynaroides cv. Arctic Ice |
| title_short | Manipulation of flowering in Protea cynaroides cv. Arctic Ice |
| title_sort | manipulation of flowering in protea cynaroides cv arctic ice |
| topic | Protea cynaroides -- South Africa Protea -- Flowering time Arctic Ice Inflorescences -- Development Harvesting time Protea cynaroides -- Effect of temperature on Proteaceae -- Climatic factors Pruning UCTD |
| url | http://hdl.handle.net/10019.1/110287 |
| work_keys_str_mv | AT hattinghnaomi manipulationoffloweringinproteacynaroidescvarcticice |