Knowledge Resource Center for Ecological Environment in Arid Area
| Effect of climate and soil water status on Cabernet Sauvignon (Vitis vinifera L.) grapevines in the Swartland region with special reference to sugar loading and anthocyanin biosynthesis | |
| Mehmel; Tara Olivia; Van Heerden; Tara Olivia | |
| 出版年 | 2010 |
| 学位授予单位 | Stellenbosch : University of Stellenbosch |
| 英文摘要 | Thesis (MScAgric (Viticulture and Oenology))--University of Stellenbosach, 2010. ENGLISH ABSTRACT: Cabernet Sauvignon, the most planted red wine cultivar in South Africa, is prone to vigorous growth with low yields. The aim of the study was to describe how Cabernet Sauvignon grapevines react to climate and irrigation within the Swartland region. Such knowledge would assist growers in decisions regarding long term as well as short term cultivation practices. This study was part of a larger project carried out by the Infruitec-Nietvoorbij institute of the Agricultural Research Council at Stellenbosch to determine effects of soil type and climate on yield and wine quality of Cabernet Sauvignon. The larger project was carried out in selected grape growing regions, i.e. Stellenbosch, Swartland, Lower Olifants River and Lower Orange River. Due to the proximity to the Atlantic Ocean, the study area in the Swartland region could be divided into two climatic regions for viticulture. Grapevines near Philadelphia closer to the ocean experienced less water constraints compared to those further inland near Wellington. Variation in stem water potential could also be related to soil water matric potential. Climate tended to have a more pronounced effect on the grapevine response to water constraints further inland than closer to the ocean. Vegetative growth, berry size and yield depended on water constraints experienced by the grapevines. In the warmer climate, severe constraints reduced yield. In the warmer climate, grapes started to ripen earlier than those in the cooler climate. Sugar concentration (mg/mL) was highest where grapevines experienced moderate water constraints. These seemingly balanced grapevines had the highest sugar accumulation, probably due to optimum photosynthesis and carbohydrate utilization. Low water constraints increased vegetative growth which could have been a sink for sugar loading. In addition to sugar loading, degree Balling (°B) increases could also have been due to a concentration effect where water constraints reduced berry volume. Therefore, °B is probably not a representative indicator of grapevine functioning. Anthocyanin biosynthesis, as quantified on a per berry basis, showed that sugar and anthocyanin could be co-regulated, with anthocyanin biosynthesis reaching a plateau when the sugar content per berry reached 200 mg/mL to 220 mg/mL. At véraison, the most intense grape colour occurred where grapevines experienced moderate water constraints, i.e. single drip line at Wellington and no irrigation at Philadelphia. However, at harvest grapes from the cooler climate tended to have more intense colour and higher phenolics, indicating that lower temperatures favoured anthocyanin biosynthesis. These results supported earlier findings that grapevine water status influences berry volume and dynamics of berry ripening. Water constraints tended to increase sensorial wine colour intensity, as well as wine fullness. Moderate water constraints at both localities resulted in the best sensorial wine quality. Yet there were indications that too severe water constraints could be detrimental to wine quality. Irrigation can be used to manipulate grapevine growth in warmer climates, but might be less effective in cooler climates. In warmer climates, moderate water constraints required to achieve balanced grapevine functioning can be obtained with single drip irrigation, but this might not be the case in cooler climates. AFRIKAANSE OPSOMMING: Cabernet Sauvignon, die mees aangeplante rooiwynkultivar in Suid-Afrika, is geneig tot kragtige groei met lae opbrengste. Die doelwit van hierdie studie was om te beskryf hoe Cabernet Sauvignon-wingerdstokke reageer op klimaat en besproeiing in die Swartland-streek. Hierdie kennis sal kwekers help wanneer hulle besluite moet neem oor langtermyn sowel as korttermyn verbouingspraktyke. Hierdie studie was deel van ‘n groter projek deur die Infruitec-Nietvoorbij Instituut van die L |
| 英文关键词 | Sugar loading Anthocyanin biosynthesis Cabernet Sauvignon Theses -- Viticulture and oenology Dissertations -- Agriculture Vineyards -- Soils Soil water Theses -- Agriculture |
| URL | http://hdl.handle.net/10019.1/5292 |
| 来源机构 | University of Stellenbosch |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/245080 |
| 推荐引用方式 GB/T 7714 | Mehmel;Tara Olivia;Van Heerden;Tara Olivia. Effect of climate and soil water status on Cabernet Sauvignon (Vitis vinifera L.) grapevines in the Swartland region with special reference to sugar loading and anthocyanin biosynthesis[D]. Stellenbosch : University of Stellenbosch,2010. |
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