CFPA DFPT DFTS Winetech Canning Fruit Producers’ Assoc. Deciduous Fruit Producers’ Trust Dried Fruit Technical Services Submit to: Submit to: Submit to: Submit to: Wiehahn Victor Louise Liebenberg Dappie Smit Jan Booysen PO Box 426 Suite 275, Postnet X5061 PO Box 426 PO Box 528 , 7620 , 7599 Paarl, 7620 Paarl, 7624 Tel: +27 (0)21 872 1501 Tel: +27 (0)21 882 8470/1 Tel: +27 (0)21 872 1501 Tel: +27 (0)21 807 3324

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Indicate (X) client(s) to whom this final report is submitted. Replace any of these with other relevant clients if required.

FINAL REPORT

FOR 2009 WW AD 09-01

PROGRAMME & PROJECT LEADER INFORMATION

Programme leader Project leader Title, initials, surname Prof A. Deloire 1 & Prof. K. Hunter 2 C. Howell Present position Professor researcher Address 1Department of and ARC-Infruitec Oenology, Stellenbosch Stellenbosch University 2ARC-Infruitec Stellenbosch Tel. / Cell no. 021- 808-2747 021-809-3343 Fax 021-808-3771 E-mail [email protected] [email protected] [email protected]

PROJECT INFORMATION

Project number WW AD 09/01

Project title Understanding of ripening, determination and prediction of harvest date of by studying the relationship between berry composition and berry skin colour evolution, measured biochemically and instrumentally (Dyostem).

Industry CFPA programme DFPT DFTS Winetech X Other

Fruit kind(s) Start date (dd/mm/yyyy) 1/1/2009 End date (dd/mm/yyyy) 31/12/2009

FINAL SUMMARY OF RESEARCH PROJECT

PROGRAMME & PROJECT LEADER INFORMATION

Programme leader Project leader Title, initials, surname Prof A. Deloire 1 & Prof. K. C. Howell Hunter 2 Institution 1Department of Viticulture and ARC-Infruitec Oenology, Stellenbosch Stellenbosch University 2ARC-Infruitec Stellenbosch Tel. / Cell no. 021- 808-2747 021-809-3343 E-mail [email protected] [email protected]

PROJECT INFORMATION

Project number WW AD 09/01

Project title Understanding of ripening, determination and prediction of harvest date of Sauvignon blanc by studying the relationship between berry composition and berry skin colour evolution, measured biochemically and instrumentally (Dyostem).

Fruit kind(s) Wine grapes

Start date (dd/mm/yyyy) 1/1/2009 End date (dd/mm/yyyy) 31/12/2009

The aim of this study were therefore to compare two different climatic regions in , Overberg and Stellenbosch, according to tempo of berry ripening using new indicators in conjunction with classical maturity indices. The mean temperature for the 2008/09 growing period (September to March) showed that the Overberg region was cooler than the Stellenbosch region. Bonnardot et al. (2002) showed that Stellenbosch falls in region IV and Overberg in region II according to the Winkler index. The colour of berries from the Overberg region was greener than berries from Stellenbosch. The tempo of colour evolution was more regular for berries from the Overberg region. Furthermore, berries from the cooler Overberg region never attained the yellow colour of berries from Stellenbosch. Brix°: It is quite difficult to reason properly with this indicator which is dependent on the berry fresh mass versus the berry sucrose content for a considered period. No direct relationship was found between brix° and berry colour evolution. The berry sucrose content evolution (sugar per berry) and in parallel for the same dates, the berry fresh mass evolution were more regular for the Overberg vineyard. Malic acid degradation is an irreversible process during berry ripening, and the results show clearly that it is irrespective of the berry fresh mass. The rate of malic acid respiration seems mainly related to a certain temperature accumulation (GDD), irrespective of the regions.

Berry colour evolution (versus the tint angle) reading by Dyostem  tool, was related indirectly to the style of wine, mainly on the following principles: at a certain stage of their ripening process if the berries are still green, the wine will express green characters related to pyrazines; if the berries turn yellow the wine will express more tropical fruit characters related to thiols (Deloire et al ., 2008). This study has allowed to begin the calibration of Dyostem  tool, on Sauvignon blanc cultivar. For South Africa, it was the first experimentation on the theme of berry colour evolution in relationship with the possible style of wine. At the moment and since five years, eighty Dyostem have been successfully calibrated worldwide in the main viticulture regions (mainly , , New Zealand, France, Spain).

Final report 4

FINAL REPORT (Completion of points 1-4 is compulsory)

1. Problem identification and objectives State the problem being addressed and the ultimate aim of the project. All wine producers need to characterise and monitor ripening to determine the optimal harvest date for a specific style of wine. Although there are several methods to assist producers in selecting this date, with classical biochemical indicators (Brix, titrable acidity, pH) and/or method as berry tasting. It is generally difficult to establish accurate relationships between these indicators and the desired style of wine in terms of wine aromatic profile. It would, therefore, be of enormous benefit for the industry if the harvest potential, prediction and selection of the harvest date could be done according to berry potential, specifically integrating aroma profile (berry potential according to the desired style of wine) and bearing in mind the specific style of wine that is being targeted. This one year pilot project has therefore been initiated to evaluate new technology that has been developed in France, using Dyostem  tool (Vivelys, France). The aim of this project is to gain an understanding of berry tint evolution (berry colour evolution) in relation (or in parallel) to berry composition, comparing two different viticulture regions (Overberg and Stellenbosch). This project was a first step which has been continued in 2010 and 2011, mainly with Distell collaboration.

2. Workplan (materials & methods) List trial sites, treatments, experimental layout and statistical detail, sampling detail, cold storage and examination stages and parameters. Experiment vineyards Bunches of Sauvignon blanc were sampled from two vineyards. One of these vineyards was located in the Stellenbosch region whilst the other vineyard was situated in the Overberg region. Based on heat summation over the growing period (September until March), the Stellenbosch locality is a class IV and the Overberg locality a class II climatic region. Since the localities have a Mediterranean type of , only 25% of the total rainfall occurs from October until March. The Stellenbosch vineyard is located at an altitude of approximately 196 m. This vineyard, planted in 1983, is growing on soil that is representative of the fertile deep soils typical of the Stellenbosch region and is classified as a duplex gravelly, yellow brown Tukulu (Soil Classification Work Group, 1991) with approximately 25% clay. The parent material is granite. The vineyard is orientated south and experiences a sea breeze at approximately 12:00. Sauvignon blanc, grafted onto R99, was used. These grapevines were planted at a spacing of 2.7 m x 1.8 m and trained onto a single cordon VSP training system. The vineyard is irrigated by means of drip irrigation and irrigation is applied only once through the growing season as the canopy is vigorous. The Overberg vineyard is located at an altitude of approximately 308 m. This vineyard, planted in 2004, is growing on soil that is derived from shale. The vineyard is orientated south west and is situated on top of a hill, experiencing much wind. Sauvignon blanc, grafted onto R99, was used. These grapevines were planted at a spacing of 2.5 m x 1.5 m and trained onto a double cordon VSP training system. The vineyard is irrigated by means of drip irrigation and irrigation is applied only if deemed necessary. Sampling For the Stellenbosch vineyard, bunches were sampled from 23 January to 25 March. Samples were therefore taken well after commercial harvest, which, for this region is approximately mid February. Bunches were sampled ten times during this period. In the Overberg region, sampling started on 10 February and also ended on 25 March. In this region, sampling took

Final report 5 place seven times during this period. Approximately 12 bunches were randomly sampled for colour measurements and 15 bunches were sampled for measuring ripening parameters. Measurements Berry colour was measured using the Dyostem® instrument developed by Vivelys society (France). This instrument indicates the berry colour change from green to yellow, which may be related to skin pigment evolution and a change in berry composition. In addition, total soluble solids (TSS), titratable acidity (TA), pH, malic and tartaric acids of grape must were measured. Tartaric and malic acid were determined using HPLC. Fresh berry weight was also determined. Sugar loading into berries was calculated to indirectly quantify the source- sink (vine-fruit) relationships (Deloire et al ., 2008). Temperature data from automatic weather stations were provided by the Institute for Soil, Climate and Water of the Agricultural Research Council (ARC-ISCW) and Distell. Statistical analysis As this project was a comprehensive industry directed study on Sauvignon berry ripening evolution, no repetition for measurements were performed and therefore no statistical analysis can be performed. Nevertheless, a statistical comparison of sub ripening periods per group of dates is possible.

3. Results and discussion State results obtained and list any benefits to the industry. Include a short discussion if applicable to your results. This final discussion must cover ALL accumulated results from the start of the project, but please limit it to essential information. The mean temperature for the 2008/09 growing period (September to March) showed that the Overberg region was cooler than the Stellenbosch region. Bonnardot et al. (2002) showed that Stellenbosch falls in region IV and Overberg in region II according to the Winkler index . The colour of berries from the Overberg region was greener than berries from Stellenbosch. The tempo of colour evolution was more regular for berries from the Overberg region. Furthermore, berries from the cooler Overberg region never attained the yellow colour of berries from Stellenbosch. In order to present classical ripening parameters in a different manner, and as example, the evolution of malic acid and the evolution of sugar per berry have been represented according to single berry fresh mass and versus the Growing Degree Days (GDD). The evolution of these compounds, on a per berry basis, was totally different in Overberg and Stellenbosch: • The balling evolution reflects the sugar concentration. It is quite difficult to reason properly with this indicator which is dependent on the berry fresh mass versus the berry sucrose content (sugar per berry) for a considered period. - The berry sucrose loading per date showed differences between Stellenbosch and the Overberg region. There were three distinct phases of sucrose loading in Stellenbosch whilst it seems that in the Overberg region, there was only one phase of sucrose loading before sugar loading plateaus. The average of sucrose loading for the three phases in Stellenbosch were respectively: 12, 6.8 and 7.6 mg.berry/day; the average of sucrose loading from 10 February to 11 March for the one phase before the plateau in Overberg was 8 mg.berry/day. These results on the dynamic of berry sugar loading indicated that, for both vineyards, the vines were balanced (appropriate ratio exposed leaves to fruits; no vine water stress; no mineral deficiency). The sugar loading curves showed as well that the dynamic of berry ripening was normal. - Malic acid degradation is an irreversible process during berry ripening, and the results showed clearly that it was irrespective of the berry fresh mass. The rate of malic acid respiration was mainly related to a certain temperature accumulation (GDD), irrespective of the regions.

Final report 6

Berry colour evolution reading by Dyostem  tool, was related indirectly to the style of wine, mainly on the following principles: at a certain stage of their ripening process if the berries are still green, the wine will express green characters related to pyrazines; if the berries turn yellow the wine will express more tropical fruit characters related to thiols (Deloire et al ., 2008). In this study, small scale experimental were made by Distell experimental cellar. Berry sucrose loading is related to grapevine functioning (mainly the efficiency of photosynthesis activity) and to bunch microclimate (Wang et al ., 2003; Deloire and Hunter, 2005). As shown by the results of berry sucrose evolution versus GDD, temperature was not the limiting factor involved in berry sucrose content: the plant photosynthesis activity was not limited and the bunch microclimate was balanced for both vineyards. The use of this indicator (Deloire et al ., 2004; Wang et al ., 2003; Deloire et al ., 2008 and 2009; Howell et al, 2009) could allow to establish a profile of grapevine and berry functioning and ripening for a particular vineyard. Malic acid degradation is mainly related to temperature at different levels: meso and micro climatic scales (Hunter et al ., 2004; Dokoozlian and Kliewer, 1995a, b). The observations made in this study confirmed the importance of temperature for the evolution of malic acid during the post-véraison period, and demonstrated that this process was not berry volume dependent. In general, the tartaric acid content is stable per berry as the tartaric acid is biosynthesised by the fruit pre-véraison (Ollat et al ., 2002). It seems, according to our study, that the tartaric acid content per berry was not directly correlated to the berry fresh mass (results not shown).

CONCLUSIONS The Overberg vineyard experiences a cooler climate due to altitude (308m) and latitude (southerner). The type of soil (deep soil with a 1.2 m deep root system) and the homogeneity thereof, the regularity of canopy management and the age of the vines (5 years old) are factors which, in interaction, could explain the regularity of the berry ripening, and the slower tempo of colour evolution. The Stellenbosch vineyard is more inland, not as high in altitude and therefore experiences a warmer climate, during the ripening period. The soil is deep soil (1.2 m root system) but the vines are fairly old (26 years old). These factors interact and could have affected the regularity of berry ripening. The location of this plot, in a warmer area could explain the progression of berry colour development from green to yellow. The tempo of the berry colour evolution, and ultimately the style of wines were mainly related to the temperatures of these regions (mesoclimate and bunch microclimate). The tempo of berry ripening has to be considered with a set of 3 to 5 parameters, on a per berry basis, and as well versus climatic factors evolution during the ripening period. This will then allow a more complete reasoning of harvest potentiality, than just considering the bailing evolution and/or the berry concentration effect.

Milestone Achievement

1. To choose the appropriate vineyard in The heliothermic climatic indices (Winkler, two different climatic regions Huglin, fresh night) were useful to select the appropriate vineyards. The help of Dr V. Bonnardot was much appreciated.

Final report 7

2. To establish the kinetic of Sauvignon Eight to ten sampling dates were needed to blanc berry ripening according to the achieve this target. In parallel, the classical berry colour evolution (Dyostem and berry ripening and composition parameters tint angle). were analysed.

3. To harvest at three different periods, This was achieved with the help of Distell for both vineyards, according to the tint experimental cellar. The results have shown angle values and to elaborate the a relationship between the berry colour tint wines (six mini-vinifications in total). angle value and the style of wine. The Stellenbosch commercial wine was tasted as a tropical fruit profile wine for a tint angle value of 75° (23 Brix°, 6.94 g/l TTA), harvested 4 March 2009. The Overberg commercial wine was tasted as a green – tropical wine for a tint angle of 78° (21 Brix°, 9.11 g/l TTA) , harvested 25 march 2009.

4. To utilize Dyostem to understand the The main variability between berries from a variability within the Sauvignon blanc bunch is due to the bunch’s shape (a bunch bunch. is a cone) and the bunch orientation within the canopy (exposed side versus shaded side of the bunch) which will create different berry microclimate. Then it could be recommended to sample berries in the middle of the bunch if one had to compare berry composition between different situations.

4. Accumulated outputs List ALL the outputs from the start of the project. The year of each output must also be indicated.

Technology developed First year (2009) calibration of the Dyostem tool for the area.

Human resources developed/trained One Honours student (M. E. Terblanche) graduated in 2009.

Patents none

Final report 8

Publications (popular, press releases, semi-scientific, scientific) The GiESCO poster presentation has been associated with a written article for the proceedings. At the end of 2009, it was too early to publish in Wyneboer.

Presentations/papers delivered

These preliminary results have been presented, by Prof A. Deloire, to the RSA wine industry in various manners, and mainly towards conferences or training sessions (VINPRO, Distell, Cape Wine Master Guild, Stellenbosch University BSc and post graduate students and to various estates). These first results have as well been presented overseas in Conegliano (Italy) for a training session of post graduate students and to a group of winemakers and viticulturists from the Venice region.

Scientific oral and poster presentations at conferences . Lectures 2009 Deloire, A.J. 2009. Preliminary results on the effect of macro climatic temperatures on Sauvignon blanc berry ripening. Comparison of different wine regions of the Western Cape coastal area of South Africa. Fourth International Viticultural and Oenology Conference, International Convention Centre, Cape Town, South Africa. (28 – 30 July). Deloire, A.J. 2009. The importance of climate for viticulture. Fourth International Viticultural and Oenology Conference, Cape Town International Convention Centre, Cape Town, South Africa. (28 – 30 July). Posters 2009 -Deloire, A.J., C.L. Howell, I. Habets, M.P. Botes, V. Bonnardot & M.G. Lambrechts. 2009. Preliminary results on the effect of macro climatic temperatures on Sauvignon blanc ( L.) berry ripening. Comparison of different wine regions of the Western Cape Coastal area of South Africa. Fourth International Viticultural and Oenology Conference, Cape Town International Convention Centre, Cape Town, South Africa. (POSTER ) (28 – 30 July) -Howell, C.L., E.L.A. Terblanche, J.J. Hunter & A.J. Deloire. 2009. Using Dyostem® berry colour technology to investigate the effect of bunch exposure on ripening of Sauvignon blanc ( Vitis vinifera L.) in the Stellenbosch wine of origin district. Fourth International Viticultural and Oenology Conference, Cape Town International Convention Centre, Cape Town, South Africa. (POSTER ) (28 – 30 July) -Howell, C.L., I. Habets, M.P. Botes, V. Bonnardot, M.G. Lambrechts & A.J. Deloire. 2009. Progression of Sauvignon blanc ( Vitis vinifera L.) ripening for two regions of the Western Cape Coastal area of South Africa. Preliminary results on berry colour, malic acid and sucrose evolution in relation to temperature. Sixteenth International Symposium GiESCO 2009, UC Davis, California, U.S.A. (POSTER ) (12 – 16 July) -Terblanche, E.L.A., C.L. Howell, J.J. Hunter & A.J. Deloire. 2009. Preliminary results on Sauvignon blanc (Vitis vinifera L.) berry variability in bunches. Fourth International Viticultural and Oenology Conference, Cape Town International Convention Centre, Cape Town, South Africa. (POSTER ) (28 – 30 July).

Final report 9

4. Total cost summary of project

Year CFPA DFPT DFTS Winetech THRIP Other TOTAL Total cost in real terms for year 1 2009 200000 200000 Total cost in real terms for year 2 Total cost in real terms for year 3 Total cost in real terms for year 4 Total cost in real terms for year 5 TOTAL