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Frost tolerance of various Pinus species and hybrids
Thesis (MScFor)--Stellenbosch University, 2017.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2017
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| _version_ | 1867613773547700224 |
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| access_status_str | Open Access |
| author | Mabaso, Fanelesibonge Sthabile |
| author2 | Ham, Hannel |
| author_browse | Ham, Hannel Mabaso, Fanelesibonge Sthabile |
| author_facet | Ham, Hannel Mabaso, Fanelesibonge Sthabile |
| author_sort | Mabaso, Fanelesibonge Sthabile |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScFor)--Stellenbosch University, 2017. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/101471 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:41:28.315Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2017 |
| publishDateRange | 2017 |
| publishDateSort | 2017 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/101471 Frost tolerance of various Pinus species and hybrids Mabaso, Fanelesibonge Sthabile Ham, Hannel Nel, Andre Stellenbosch University. Faculty of Agrisciences. Dept of Forest and Wood Science. Pinus hybrids -- Frost resistance -- South Africa Frost tolerance Electrolyte leakage Pine -- Frost resistance -- South Africa Pine -- Hybridization UCTD Thesis (MScFor)--Stellenbosch University, 2017. ENGLISH ABSTRACT: Pinus species covers a large area in South African Forestry and are utilised by forestry companies for pulp, paper and sawlog products to achieve financial returns. Although P. patula is the most popular commercial Pinus species, studies have shown that field trials of P. patula are affected by frost after establishment, and the introduction of many pests and diseases, such as Fusarium circinatum. Other Pinus species such as P. tecunumanii LE and HE have been crossed with P. patula and used to replace plantings of P. patula since these species have increased tolerance to frost and F. circinatum. The study objectives were to review and develop a reliable laboratory screening technique to assess frost tolerance of a range of Pinus pure species and hybrid families planted in South Africa. In-field climatic data was collected to construct a 24-hour circadian model, mimicking in vivo (day and night) temperature fluctuations to be simulated in vitro with electrolyte leakage and whole-tree freezing techniques. Rooted cuttings from a range of genotypes supplied by Sappi were tested in vitro at different target temperatures to determine their frost tolerance. These genotypes included pure species (P. patula seedlings and cuttings, P. tecunumanii LE, P. tecunumanii HE, P. oocarpa, P. taeda, P. caribaea, P. elliottii, P. maximinoi and P. greggii), three interspecific hybrids (P. patula x P. tecunumanii LE, P. patula x P. tecunumanii HE, and P. elliottii x P. caribaea) and a three-way cross (P. patula x (P. patula x P. oocarpa). The results indicated that pure species P. greggii, P. elliottii, P. patula seedlings and cuttings, P. tecunumanii HE and P. taeda were more frost tolerant than other Pinus pure species employed in this study. In addition, the interspecific hybrids of P. patula x P. tecunumanii HE were more frost hardy than P. patula x P. tecunumanii LE. There is variation in frost tolerance of PPTH families, therefore, a more comprehensive factorial mating design with more PTH families need to be screened in future studies. Also the number of replications need to be improved from six to 10 to limit experimental errors. In vitro screening for frost tolerance must be done before the establishment of field trials to determine the temperatures at which plants can survive and make informed decisions before planting. AFRIKAANSE OPSOMMING: Pinus spesies dek ‘n groot oppervlakte van Suid Afrikaanse Bosbou en word deur Bosbou maatskappye gebruik vir pulp, papier en saaghout om finansiële inkomstes te genereer. Alhoewel P. patula die mees aangeplante kommersiële Pinus spesies is, het vorige studies aangedui dit is vatbaar vir koue, asook peste en siektes soos Fusarium circinatum, na aanplantings. Ander Pinus spesies, bv. P. tecunumanii LE en HE is alreeds met P. patula gekruis en sal in die toekoms vir P. patula vervang aangesien dit beter koue en F. circinatum weerstand het. Hierdie studie se doelwitte was om ‘n betroubare labaratorium tegniek te evalueer en te ontwikkel om die koue weerstand van Pinus spesies en hibried families, aangeplant in Suid Afrika, se koue weerstand te toets. Klimaatsdata is versamel om die veld toetstande te verteenwoordig en sodoende ‘n 24-uur circadian model op te stel. Hierdie model kan dag en nag in vivo temperature dus in vitro, met elektron lekkasie en heel-plant eksperimente, naboots. Bewortelde saailinge en steggies is vanaf Sappi verkry en in vitro getoets by verskillende teiken temperature om die koue weerstand daarvan te bepaal. Hierdie genotipies het ingesluit verskeie Pinus spesies (P. patula saailinge en steggies, P. tecunumanii LE, P. tecunumanii HE, P. oocarpa, P. taeda, P. caribaea, P. elliottii, P. maximinoi en P. greggii), drie interspesifieke hibriede (P. patula x P. tecunumanii LE, P. patula x P. tecunumanii HE, en P. elliottii x P. caribaea), en ‘n drie-ledige kruising (P. patula x (P. patula x P. oocarpa). Resultate het aangedui dat die spesies P. greggii, P. elliottii, P. patula (saailinge en steggies), P. tecunumanii HE en P. taeda meer koue weerstandig as die ander spesies was. Verder was die interspesifieke hibried van P. patula x P. tecunumanii HE meer koue weerstandig as P. patula x P. tecunumanii LE. Variasies in die koue weerstand van die PPTH families het aangedui dat ‘n meer volledige faktoriale teelontwerp wat meer PTH families insluit, in die toekoms ge-evalueer moet word. Die aantal herhalings moet ook van ses na 10 vermeerder word om verdere eksperimentele foute uit te skakel. In vitro skandeering van koue weerstand moet gedoen word voor aanplantings om sodoende die temperatuur waarby hierdie genotipes optimal sal funksioneer, te bepaal. Masters 2017-02-21T17:17:22Z 2017-03-29T21:04:43Z 2019-03-31T03:00:09Z 2017-03 Thesis http://hdl.handle.net/10019.1/101471 en_ZA Stellenbosch University xii, 63 pages ; illustrations, maps application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Pinus hybrids -- Frost resistance -- South Africa Frost tolerance Electrolyte leakage Pine -- Frost resistance -- South Africa Pine -- Hybridization UCTD Mabaso, Fanelesibonge Sthabile Frost tolerance of various Pinus species and hybrids |
| title | Frost tolerance of various Pinus species and hybrids |
| title_full | Frost tolerance of various Pinus species and hybrids |
| title_fullStr | Frost tolerance of various Pinus species and hybrids |
| title_full_unstemmed | Frost tolerance of various Pinus species and hybrids |
| title_short | Frost tolerance of various Pinus species and hybrids |
| title_sort | frost tolerance of various pinus species and hybrids |
| topic | Pinus hybrids -- Frost resistance -- South Africa Frost tolerance Electrolyte leakage Pine -- Frost resistance -- South Africa Pine -- Hybridization UCTD |
| url | http://hdl.handle.net/10019.1/101471 |
| work_keys_str_mv | AT mabasofanelesibongesthabile frosttoleranceofvariouspinusspeciesandhybrids |