Table grape rootstocks in South Africa

TABLE GRAPE ROOTSTOCKS IN SOUTH AFRICA A compilation of evaluations spanning 27 years

J.H. Avenant

Table grape rootstocks in South Africa A compilation of evaluations spanning 27 years Copyright (c) 2021 Agricultural Research Council (ARC) 1134 Park Street, Hatfield, Pretoria, 0028 P.O. Box 8783, Pretoria, 0001 Tel +27 (0) 427 9700 Email: enquiry@arc.agric.za Copyright (c) 2021 South African Table Grape Industry (SATI) 63 Main Street, Paarl, 7646 P.O. Box 2932, 7620 No part of this book may be reproduced or transmitted in any form or by any electronic, photographic or mechanical means, including photocopying and recording on record, tape or laser disk, on microfilm, via the Internet, by email, or by any other information storage or retrieval system, without prior written permission by the author. First Edition 2018 Second Edition 2021 ISBN: 978-0-620-93467-1(printed) Tel: +27 (0) 21863 0366 Email: info@satgi.co.za

Disclaimer: While reasonable care has been taken to ensure the accuracy of the information in this book, the author and publishers accept no responsibility for the consequences that may arise from any error and / or omission. COMPILED FOR THE SOUTH AFRICAN TABLE GRAPE INDUSTRY

By JH Avenant October 2021

Set in describe text DESIGN and LAYOUT by Bespoke Media

This book is dedicated to every person who was involved in these trials and assisted with data collection over the 27 year period. – J.H. Avenant

About this publication This book has been made possible through support from SATI. The content of this book is primarily based on research findings of the ARC.

Table Grape Rootstocks in South Africa 1

I met Jan Avenant in 1989. We worked together for more than a decade in the Viticulture Division of the ARC Infruitec-Nietvoorbij. Since the beginning of his research career, in 1980, he has made various meaningful research contributions to the South African table and raisin grape industries. He is still involved in research in these fields. Between 1980 and 1993, while stationed on the Roodeplaat Experimental Farm outside Pretoria, he was responsible for establishing basic viticultural principles for the northern provinces, including planting his first table grape rootstock trials on different trial sites in these provinces. Since 1994, Mr Avenant has been stationed at Nietvoorbij, outside Stellenbosch. His research remains focused on viticultural aspects of table and raisin grape cultivation. Since the beginning of his research career, rootstock evaluation has been one of his main research focus areas. For 27 years, he has conducted rootstock evaluation trials in all five of the table grape production regions and the two primary raisin grape regions in South Africa. This book provides a compilation of research results obtained from his evaluation of table grape rootstocks. The book contains results from his research and other relevant work conducted in South Africa and internationally. The use of rootstocks in viticulture in South Africa became a practice about 140 years ago, after phylloxera from FOREWORD

Europe caused large-scale degeneration among local vineyards. For many years, this soilborne insect was considered the primary cause of deficient vigour and poor grape quality. Today, growers know that many factors determine the performance of their vineyard. Scientists have shown through research that various soilborne organisms impair the vine’s growth. Soil conditions also play a significant role in grapevine performance. If we also add to this the inherent characteristics of the scion and rootstock cultivars and the varying degree of compatibility and affinity that exists between scion and rootstocks, we realise that the choice of which rootstock to use for a new planting is a complex task. Research conducted over many years in South Africa and the experience and results of many field trials provide comprehensive information that enables producers to make informed decisions. This book addresses viticultural aspects such as current rootstock use and rootstock characteristics, including adaptability to soil conditions. It contains valuable information that will enable table grape producers to make rootstock choices for their specific cultivars, soil conditions and climate. At an academic level, lecturers can also use this book as study material for their students. The author succeeds in presenting many research results in an informative, visual and easy-to-interpret way and gives practical guidelines about decision-making in rootstock choices.

Dr Jan Loubser

2 Table Grape Rootstocks in South Africa

Table Grape Rootstocks in South Africa 3

RESEARCH & DEVELOPMENT FRAMEWORK

>>

>>

MISSION SATI delivers service excellence to create a progressive, equitable and sustainable South African table grape industry.

VISION South Africa is the preferred country of origin for table grapes and will provide every table grape producer with as wide a choice as possible of profitable markets.

TOOLS Market Access & Development Information, Systems & Communication Transformation & Training Research & Technical

VALUES Science-based Agility and Flexibility Transparency Outcome-driven

DRIVERS Market Access:

“Market Preparedness” “Market Accessibility”

<<

AVANT-GARDE_0218633165

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CREATING A PROGRESSIVE, EQUITABLE AND SUSTAINABLE TABLE GRAPE INDUSTRY

63 Main Street | Paarl 7646 Western Cape | South Africa

Tel: +27 21 863 0366 | Fax: + 27 21 863 0339 Email: info@satgi.co.za | Website: www.satgi.co.za

ACKNOWLEDGEMENTS

Thanks is extended to the following roleplayers: SATI, THRIP (Technology and Human Resources for Industry Programme of the Department of Trade and Industry - the dti) and the ARC for their support and funding of table grape rootstock research. The farms of Karsten Boerdery (Rooiwal, Kromhout and Fulham) in the Lower Orange River region and the farm Malanot (La Ferme Derik) in the Agter-Paarl region for the availability and management of the trial sites. The ARC Infruitec-Nietvoorbij staff stationed at Stellenbosch, Hex River Valley and Upington for their technical support over 27 years. SATI for information from the National Vine Census and PlantSA for rootstock data. Abraham Vermeulen of ARC Infruitec-Nietvoorbij for diagnostic data. Tarryn Wettergreen of SATI for input, organisation and liaison to enable publication of the book. Dr Jan Loubser and Eunice Avenant for their editing of this publication, including translation thereof.

Table Grape Rootstocks in South Africa 7

CONTENT

Foreword

2 7

Acknowledgements

Introduction

10 10 12 18 23 24 26 28 30 32 34 36 38 40 42

About the trials

1 Rootstock use

2 Compatibility and affinity of scion-rootstock combinations 3 Viticultural characteristics of the 10 major rootstocks used for table grapes

• Ramsey

• Paulsen 1103 • Richter 110 • Richter 99 • Ruggeri 140 • Dog Ridge • US 8-7

• SO4

• Freedom • Harmony

4 Adaptability of rootstocks to soil conditions (physical, chemical and biological) as determined in trials for the period 1989-2016

46 57

5 Guidelines for rootstock selection

References

60

APPENDICES Appendix 1

61

Summary of major findings of rootstock trials concluded from 1989-2016

61

1.1 The status of different table grape rootstock trials in South Africa for the period 1989-2016 1.2 Yield data of South African table grape rootstock trials for the period 1997-2016 1.4 Cane mass data for South African table grape rootstock trials for the period 1997-2016

62

64

66

Appendix 2

68

Poster: The effect of grapevine rootstocks on the performance of Regal Seedless List of figures

69 69

List of tables

8 Table Grape Rootstocks in South Africa

Photo: Jan Avenant

Table Grape Rootstocks in South Africa 9

INTRODUCTION R ootstocks offer producers a strategy to improve grapevine performance. Although ungrafted vines may produce acceptable yields of high quality grapes, there are risks because Vitis vinifera vines roots are sensitive to soilborne pests such as nematodes and phylloxera, as well as diseases and unfavourable soil conditions (such as low nutrient status or salinity). Using the correct rootstocks helps overcome many of these problems in the root zone. Recommending the most suitable rootstock is complicated because scion cultivar, soil type and climatic conditions differ. Consequently, each situation is unique. Research results from 27 years of evaluation, indicate performance differences between different scion cultivars on the same rootstock on the same site. Long-term trial results show that rootstock performance and the ranking of rootstock performance vary from one season to the next. Consequently, the cumulative performance of each scion and rootstock combination must be evaluated over time, to make reliable recommendations. The evaluation trials have demonstrated that a minimum of eight seasons of cumulative production evaluation results is required to provide scientifically sound recommendations. Inferior grape quality caused by excessive vigour can occur when rootstocks with inherently strong growth are combined with strongly growing scions. Therefore, rootstock evaluation trials must focus on identifying and developing rootstocks with vigour qualities that are compatible with the scion cultivar of interest to deliver economic yields of optimum quality. Rootstocks have a noticeable effect on the performance of table grape cultivars. Trials have already shown there is no universal rootstock that performs best with every scion cultivar. It is, therefore, worth noting that little or no information is available about rootstock influence on newly developed cultivars. In the rootstock evaluation trials conducted by the ARC Infruitec-Nietvoorbij in the Western and Northern Cape, rootstock performance for specific cultivars, soil types and site suitability were compared. The objectives of the trials were: • table grapes in terms of: - growth yield and quality

- provision of high yields without negatively affecting quality • to make recommendations regarding the best rootstocks for: - different soil types - specific scions, especially newly bred cultivars All trials were laid out according to the standard statistical design. In all trials, treatments (rootstocks) consisted of experimental unit sizes ranging from four to six vines per unit. Treatments were allocated randomly over the trial site in blocks and repeated five to six times. The trials, which were not performed on experimental farms, were cultivated and managed by the various participating producers. Viticultural practices applied in trial blocks were according to standard cultivation guidelines for the cultivar in the area. To explain the outcome of the trials, the following was determined: soil samples were taken to determine the pH balance, plant nutrient status and chemical properties of the soil and determine and quantify the presence of soilborne pests and diseases. The nutrient content of petioles was determined at berry set. The virus status of all scion-rootstock combinations was also determined. The names of rootstocks as used in this publication are according to the South African Varietal List for fruit crops as maintained by the Registrar of Plant Improvement of the Department of Agriculture, Forestry I n 1982, table grape research done at the FFTRI (Fruit and Food Technology Research Institute, or Infruitec) was transferred to the VORI (Viticultural and Oenological Research Institute, or Nietvoorbij). At the takeover of viticultural research by VORI, there were several rootstock trials in different phases of development at the Bellevue experimental farm, the Hex River Valley experimental farm, and several commercial farms. These trials consisted mainly of rootstock hybrids developed by Stellenbosch University (US hybrids), which were compared to and Fisheries (Anon, 2017) About the trials

10 Table Grape Rootstocks in South Africa

rootstocks commonly used in the table grape industry (Jacquez, Rupestris du Lot, Richter 110, Richter 99 and Ramsey). The data and conditions of all these trials were evaluated and those trials which were to be discontinued or concluded, were identified (Deist, 1997). During this period, evaluation of rootstocks for table grape vines was identified as a high priority. A new generation of rootstock trials was laid out using a split plot design. In these trials, “new” rootstocks, which had been included in wine grape trials, some US hybrids, and rootstocks being used in the table grape industry at the time, were included (Deist, 1997). One of the limitations of the “old” concept trials was that they only supplied answers to a specific scion cultivar. In the “new” rootstock trials, the split plot design allowed several scions to be compared. Researchers could obtain answers for more than one scion cultivar on various rootstocks in the same experimental block. ARC Infruitec-Nietvoorbij conducted a very successful trial of this nature at the Roodeplaat Research Station outside Pretoria (four scion cultivars grafted onto eight different rootstocks – a total of 32 scion-rootstock combinations). This was the first rootstock trial in the northern part of the summer rainfall region (Deist, 1997). Two similar trials were planted in the Western Cape, one on the Hex River Valley experimental farm (five scion cultivars grafted onto 16 different rootstocks; 80 scion rootstock combinations, and another on the Nietvoorbij experimental farm near Stellenbosch (seven scion cultivars onto 24 different rootstocks; 168 scion-rootstock combinations). In 1996, the data and vigour performance of all these trials were evaluated. Those trials that could be concluded, or had to be terminated, were identified and it was decided to end the trial at Nietvoorbij. The trial at the Hex River Valley experimental farm was continued until 2002. With the release of two new promising table grape cultivars from the ARC Infruitec-Nietvoorbij’s breeding programme in 1997, the question arose which rootstock should be used. In 1997, Regal Seedless and White Gem were established in two separate localities on the commercial farm Malanot (later La Ferme Derik)

in Agter-Paarl. Each scion cultivar was grafted onto 11 different rootstocks. For practical reasons, a single scion cultivar was included for evaluation on each of these sites. Researchers did this to simplify the viticultural management of the trial block within a commercial configuration. The first table grape trials in the Lower Orange River region were planted in 2008. The climate and soil in this area differ substantially from that of the Western Cape. The success of a suitable scion cultivar would depend on the success with which a chosen rootstock would adapt to the hardy climatic conditions in this region. Margarodes was one of the known soilborne pests which were causing severe damage in the area at that stage. Surveys before the start of these trials showed that margarodes had destroyed three of the best phylloxera resistant rootstocks (R 99, 101-14 Mgt and Rupestris du Lot) (De Klerk, 1975). New vineyards planted in the Lower Orange River region were also established on the warmer soils along the river west of Kakamas. Replanting of vineyards also took place on a large scale in the Lower Orange River region. According to Burger et al . (1972) indications were that the replanting problem occurs in drier areas and on heavier soils types under alkaline and saline conditions. With Ramsey’s establishment on soils on which this rootstock was used before, producers experienced fewer problems. However, the success rate of replanting vineyards with most other rootstocks was unknown. At that stage, it was accepted that rootstock evaluation is a long-term process and that field trials should continue for between 10 to 15 seasons before reliable recommendations could be made. In a trial on raisin grapes conducted over 18 years, 28 rootstocks with Sultanina H5 as scion were evaluated. This trial was also used to determine the minimum number of seasons necessary for scientifically acceptable recommendations to be made. This investigation has shown that reliable evaluation of rootstocks over a shorter period is possible, namely at least eight seasons of production data (Avenant, 2014). A shorter evaluation process will significantly benefit the table grape industry, mainly because new cultivars are becoming available more regularly.

Table Grape Rootstocks in South Africa 11

1 Rootstock use Rootstock use for table grapes in South Africa (planting per rootstock)

In 2017, 82% of table grapes planted in South Africa were grafted onto the rootstock Ramsey, followed by R 110 (10.8%) and P 1103 (4.4%). The use of R 99 and US 8-7 was

less than 2% (Figure 1). Only about 0.3% of table grape vineyards are planted on their own root (data not shown).

RAMSEY

R 110

P 1103

R 99

US 8-7

10.8%

4.4%

1.7% 1.1%

2017

82.0%

FIGURE 1: The five most planted rootstocks for table grapes in South Africa in 2017.

Source: Compiled from 2017 SATI National Vine Census Information. *Rootstocks with a graft success rate of < 0.1% and indicated as unknown are excluded in the data processing.

12 Table Grape Rootstocks in South Africa

Availability of certified grafted table grape vines per rootstock type: A comparison over two five-year periods

According to the data in Figure 2 (a and b), it is evident that the rootstock cultivars used for table grapes have changed markedly over the past 15 years. A comparison of data for the two periods shows a significant change in the use of each rootstock type.

In the period 2002-2006, Ramsey and R 110 represented nearly 90% of the available certified, grafted vines. From 2012 to 2016, the available and certified grafted Ramsey and R 110 vines markedly decreased (collectively 78%), while the availability of US 8-7 increased. The availability of 143 B Mgt and R 99 declined to below 1% during the same period.

RAMSEY

R 110

P 1103

143 B Mgt

R 99

US 8-7

OTHER

(a)

(b)

18.0%

17.0%

3.5%

13.7%

2002 - 2006

2012 - 2016

2.3% 0.7% 3.1% 1.2%

65.5%

3.3% 0.3% 0.2%

71.3%

FIGURE 2: Certified grafted table grape vines available according to rootstock type as reported by grapevine nurseries to PlantSA, listed as a percentage of the total number of vines over two five-year periods: 2002-2006 (a) and 2012-2016 (b).

Source: Compiled from data made available by (a) SAWIS (2002-2006) and by (b) PlantSA (2012-2016). Where availability of rootstocks is < 0.1% is included under “Other”

Table Grape Rootstocks in South Africa 13

Figure 3 provides evidence that in recent years P 1103 has become more popular to the detriment of R 110. The

demand for Ramsey remained relatively constant, while the demand for US 8-7 did not increase and remained low.

P 1103

RAMSEY

R 110

US 8-7

100 90 80

70 60 50 40 30 20 10 0

AVAILABLE VINES (%)

2012

2013

2014 YEAR

2015

2016

FIGURE 3: Trends of available certified table grape vines according to rootstock type (2012-2016).

Source: Compiled from data made available by PlantSA

Trends in rootstock use for two of the most planted table grape cultivars in South Africa

R 110 initially increased gradually with Crimson Seedless plantings (a naturally vigorous scion cultivar). P 1103 then became more popular – initially at the expense of Ramsey, but later mainly at the cost of R 110 (Figure 4).

The demand for Ramsey remained relatively constant, while the demand for US 8-7 did not increase and remained low. Prime (moderately vigorous scion cultivar) is virtually only used in combination with Ramsey and there is currently no indication that this is going to change (Figure 5).

14 Table Grape Rootstocks in South Africa

RAMSEY

R110

US 8-7

AND

P1103

80 90 100

CRIMSON SEEDLESS

R 110

P 1103 RAMSEY

US 8-7

OTHER

0 10 20 30 40 50 60 70 70 60 50 40 30 20 10 0

AVAILABLE VINES (%)

2012

2013

2014 YEAR

2015

2016

FIGURE 4: Trends in rootstock use for available certified Crimson Seedless vines (2012-2016). Source: Compiled from data made available by PlantSA

PRIME

P1103

RAMSEY P 1103 RAMSEY

RU140 Ru 140

0 10 20 30 40 50 60 70 80 90 100 100 90 80 70 60 50 40 30 20 10

AVAILABLE VINES (%)

2012

2013

2014 YEAR

2015

2016

FIGURE 5: Trends in rootstock use for available certified Prime vines (2012-2016) . Source: Compiled from data made available by PlantSA

Table Grape Rootstocks in South Africa 15

The state of rootstock use in the various South African table grape regions is indicated in Figure 6 and Table 1. Figure 6 shows the contribution of the six most cultivated rootstocks, with Ramsey by far in the first position in all regions. The Western Cape has the highest percentage of plantings with Ramsey as rootstock, followed by the Lower

Orange River region and the Northern Provinces R 110 is in the second position in all regions, with the largest plantings (25%) found in the Northern Provinces. This can be attributed to favourable growing conditions regarding climate and soil in these provinces. R 99 still plays a significant role in the Olifants River region, while the use of US 8-7 is limited.

Use of rootstocks per region for the cultivation of table grapes

RAMSEY

R 110

P 1103

R 99

US 8-7

OTHER

80 100 90 80

90 100

70 60 50 40 30 20 10 0

50 60 70

40

HECTARE (%)

30

20

0 10

Berg River

Hex Rivier Valley

Olifants River

Lower Orange River

Northen Provinces

FIGURE 6: Rootstock use in South African table grape production regions (2017).

Source: Compiled from 2017 SATI National Vine Census information

16 Table Grape Rootstocks in South Africa

Rootstock Total 5 078.3 100 6 174.3 100 1 737.9 100 1 339.2 100 6 011.9 100 20 341.6 100 Table 1. Distribution of rootstock use (area) in South Africa according to table grape production region (2017). cultivar Berg River (ha) (%) Hex River Valley (ha) (%) Northern Provinces (ha) (%) Olifants River (ha) (%) Lower Oragne River (ha) (%) Ramsey 4 047.5 79.70 5 301.0 85.86 1 032.7 59.42 1 040.6 77.71 4 345.0 72.27 15 766.7 77.51 R 110 386.4 7.61 307.5 4.98 433.8 24.96 189.1 14.12 758.7 12.62 2 075.6 10.20 P 1103 261.2 5.14 242.2 3.92 58.4 3.36 17.8 1.33 274.4 4.56 854.0 4.20 R 99 97.9 1.93 70.6 1.14 40.7 2.34 60.6 4.52 58.5 0.97 328.1 1.61 US 8-7 29.9 0.59 24.9 0.40 1.0 0.06 5.5 0.41 142.1 2.36 203.4 1.00 101-14 Mgt - - 19.4 0.31 6.0 0.35 4.0 0.30 6.0 0.10 35.4 0.17 143 B Mgt - - 2.0 0.03 - - - - 21.7 0.36 23.7 0.12 Ru 140 - - 1.7 0.03 - - - - 7.0 0.12 8.7 0.04 SO4 - - - - - - 2.9 0.22 - - 2.9 0.01 Jacquez 4.6 0.09 9.9 0.16 - - - - - - 14.5 0.07 Own roots - - - - - - - - 62.5 1.04 62.5 0.31 Unknown 250.9 4.94 195.2 3.16 165.4 9.52 18.7 1.40 335.9 5.59 966.1 4.75 Total (ha) (%)

Source: Compiled from 2017 SATI Natonal Vine Sensus information

Table Grape Rootstocks in South Africa 17

Successful grafting in the nursery is an essential step in the production of table grapevines. Reports of several problems relating to the grafting of vines in the nursery and with vines that die after vineyard establishment have increased in recent years. The problem is sometimes referred to as incompatibility and sometimes as poor affinity. Compatibility refers to the ability of the rootstock and scion cultivar to combine anatomically and physiologically after grafting (i.e. to unify successfully), thereby producing a strongly growing, grafted vine. Affinity refers to the long-term productive capacity of the graft combination. Therefore, although a rootstock and scion cultivar can be compatible, poor affinity could cause the graft combination to deteriorate after a few years and eventually die. Problems with compatibility are expressed within the same year as when the grafting was done (in the nursery following bench grafting or the vineyard after aerial grafting). Affinity is expressed after establishment in the vineyard, two or more years after grafting or one or more years after planting. Unsuccessful grafting has a major negative impact on both the nursery and producer. A scarcity of grafted plant material of a specific scion-rootstock combination causes these vines to be more expensive than abundant combinations. This situation leads to producers using scion-rootstock combinations that are merely available and not necessarily the best combination for a relevant vineyard site. Unsuccessful grafting inevitably influences the availability of certain scion-rootstock combinations of new and newly imported scion cultivars. In establishing six semi-commercial trials with Merbein Seedless and Sultanina H4 on different rootstocks, the graft success rate for Merbein Seedless and Sultanina was 20.7% and 21.2%, respectively. Two clones of 143 B Mgt were grafted with Merbein Seedless as scion cultivar, with a success rate of 20.7% and 47.4%, respectively. The graft success rate of both the above scion cultivars with Ramsey as rootstock was 50%. Reasons for such failures of Merbein Seedless and Sultanina with 143 B Mgt as a rootstock are largely unclear. Poor graft success rates are often attributed 2 Compatibility and affinity of scion-rootstock combinations

to the quality of the graft material, the graft technique used, callus formation and environmental factors.

COMPATIBILITY is expressed within the same year in which grafting was performed (in the nursery through bench grafting or in the vineyard after aerial grafting).

AFFINITY is expressed after establishment in the vineyard, two or more years after grafting or one or more years after planting.

Compatibility Table 2 and Figure 7 provide information on the compatibility of various table grape scion-rootstock graft combinations. This table and figure have been compiled from information collected from vine nurseries over five years (2012-2016). The graft success rates of certified vines in nurseries (bench grafting) were calculated and used as a benchmark for compatibility. Table 2 and Figures 7, 8, 9 and 10 show that many differences were present between rootstocks, cultivars and clones. Not one of the scion cultivars showed equally good compatibility with all rootstocks (e.g. P 1103 – 38.9%, Ramsey – 40.7%, R 110 – 36.2%, US 8-7 – 38% and R 99 – 36.3%, data not shown). Not one specific rootstock showed equally good compatibility with all the scion cultivars (e.g. Sultanina H5 – 40.1%, Prime – 42.2%, Crimson Seedless – 49.4%, data not shown). It seems as if rootstock choice has a greater influence than scion cultivar on compatibility. There are clear differences in the compatibility of clones of scion cultivars and rootstock. The average graft success rate over all scion cultivars showed that the compatibility for all rootstocks is less than 50%. Figure 7 shows that the best compatibility is obtained with R 110 and P 1103 and the poorest with Ramsey and R 99.

18 Table Grape Rootstocks in South Africa

TABLE 2. Compatibility between scion and rootstock cultivars for table grapes (average for the period from 2012-2016).

ROOTSTOCK CULTIVAR

Scion cultivar African Delight TM Arrathirteen® Arrafourteen® Arrafifteen® Arrasixteen® Autumn Royal Crimson Seedless Evans Delight TM Flame Seedless Arraten® Blagratwo

P 1103

Ramsey R 110

US 8-7

R 99

3 3 3 3 3 3 3 3 3 3 3 3 3 4 3 5 2 3 3 3 4 2 4 4 2 2 2 3 3 3 3 2 2 4 4 4 3 2 2 3 4 2

4 2 3 4 3 3 5 4 4 3 5 5 5 4 3 5 5 4 1 3 5 1 3

4

5

3 3

1

2

3

5 5

3 3 3 3 3 1

2

4

3 3

1

4 1

4

3

Early Sweet TM

3

IFG Nine

IFG Nineteen

IFG One IFG 31-077 IFG Seventeen

3

IFG Six IFG Ten

4

3 2 3 5

IFG Three IFG 68-175

3 5

Joybells®

Prime®

Ralli Seedless®

4 2

Redglobe

2 2

3

Sheegene-12 Sheegene-13 Sheegene-2 Sheegene-20 Sheegene-21 Sheegene-3 Stargrape-1 Stargrape-2 Starlight® Sugraone®

3

3

5 3 5

5

3

4 1 4 4

KEY

4

3 3 1 3

4

Sugrathirteen Sugrasixteen Sugranineteen Sugrathirtyfour Sugrathirtyfive Sugrathirtyeight Sundance Seedless Tawny Seedless® Tropical Delight TM Sultanina

3

4 Very good 5 Excellent

3 4 3 5 2 3 4

3

4

4 5

3 Good

3

1 Very poor 2 Poor

3 1

2

1

4

2

Source: Compiled from data made available by PlantSA

Average

3.5

3.0

3.2

3.0

3.3

Table Grape Rootstocks in South Africa 19

P 1103

RAMSEY

P 110

R 99

SO4

US 8-7

60

50

40

30

20

GRAFT SUCCESS RATE (%)

10

0

2012

2013

2014 YEAR

2015

2016

FIGURE 7: Compatibility of various rootstocks over all table grape scion cultivars (average over five seasons, 2012-2016).

Source: Compiled from data made available by PlantSA

CRIMSON SEEDLESS

10 15 20 25 30 35 40 45 50

R 99

R 110

P 1103

RAMSEY

SO4

US 2-1

US 8-7

GRAFT SUCCESS RATE (%)

0 5

ROOTSTOCK

FIGURE 8: Compatibility of different rootstocks with Crimson Seedless as scion cultivar (average over five seasons, 2012-2016). Source: Compiled from data made available by PlantSA

20 Table Grape Rootstocks in South Africa

SC 18AB

SC 18AE

10 15 20 25 30 35 40 45

GRAFT SUCCESS RATE (%)

0 5

2012

2013

2014 YEAR

2015

2016

FIGURE 9: Compatibility of two Ramsey clones over all table grape scion cultivars (average over five seasons, 2012-2016).

Source: Compiled from data made available by PlantSA

TAWNY SEEDLESS

60

51.2

50.5

50

46.2

44.9

40.5 39.4

39.5

38.1

40

29.6

30

23.3

20

GRAFT SUCCESS RATE (%)

10

P 1103-PS 28G

P 1103-PS 28I

Ramsey- SC 18 AB

Ramsey-SC18 AE

Ramsey-SC18 S

Ramsey-SC19 E

R 110-RQ20

R 110-RQ28C

R 110-RQ244D

US 8-7-UC274 A

0

ROOTSTOCK CLONE NUMBER

FIGURE 10: Compatibility of Tawny Seedless with different rootstock clones (average over five seasons, 2012-2016). Source: Compiled from data made available by PlantSA

Table Grape Rootstocks in South Africa 21

Affinity Table 3 provides information on the compatibility of various graft combinations of table grape scion cultivars and different rootstocks. This was compiled from reports of ARC Infruitec-Nietvoorbij investigations of plant material, as received from producers (from established vineyards) over the past few seasons. The results indicate that poor affinity occurs with several rootstocks and scion cultivars. If information regarding specific clones of these graft combinations were available; it might have been possible to determine whether there is a correlation between clone compatibility and poor affinity. This would have assisted in predicting potential affinity problems between scion-rootstock combinations.

The information compiled for Table 3 suggests that Ramsey has affinity problems with several scion cultivars. It is generally assumed that R 99 has a good affinity with most scion cultivars. From this investigation, it was clear that the degree of affinity problems differed from one season to the next and that the graft technique used also influenced the results. Problems regarding affinity were more pronounced when using the omega grafting technique (Figure 11). This observation should probably be attributed to the graft technique used and not the poor physiological interaction between scion cultivar and rootstock.

TABLE 3. Affinity problems of different scion and rootstock combinations of table grapes (results recorded for plant material examined by ARC Infruitec Nietvoorbij).

ROOTSTOCK

R 110

143 B Mgt

P 1103

Ramsey

US 8-7

Early Sweet TM Sugranineteen Sugrathirtyfour

Sugrathirtyfour

Sugranineteen Sugrasixteen Sugranineteen Sugrathirtyfour

Arrafifteen®

Sugrathirtyfour

Crimson Seedless

LaRochelle Redglobe Sugrasixteen

Sugranineteen Sugrathirtyfour Sugrathirtyfive Tawny Seedless®

Source: Abraham Vermeulen, Diagnostic Services, ARC Infruitec-Nietvoorbij

How could compatibility and affinity problems be prevented? • Using plant material that is free of harmful viruses. • Using the best grafting technique and the best scion-rootstock combination. • Identifying the best scion-rootstock combinations can be done by grafting new cultivars onto different rootstocks

and establishing them in field trials and/or commercial vineyards. • Planting only certified vines obtained from registered nurseries.

22 Table Grape Rootstocks in South Africa

SCION

ROOTSTOCK

FIGURE 11: Poor graft union associated with an affinity problem. (Photo: Abraham Vermeulen, LNR Infruitec-Nietvoorbij).

3 Viticultural characteristics of the 10 major rootstocks used for table grapes

Reference key for text and tables: (1) Results obtained from rootstock trials undertaken by ARC Infruitec-Nietvoorbij and observations made in collection plantings and trial blocks (2) Storey (2013)

There are several publications and online rootstock selection applications/tools available, which describe the benefits of grapevine rootstocks. The following results were compiled from publications referenced below, results obtained from rootstock trials undertaken by ARC Infruitec-Nietvoorbij, observations made in collection plantings and experimental sites, the pamphlet series Farming in South Africa published by the ARC Infruitec-Nietvoorbij, as well as the publication by Loubser and Uys (1997).

(3) Kidman et al . (2014) (4) Christensen (2010)

Table Grape Rootstocks in South Africa 23

RAMSEY

V. champini (a natural crossing) Synonym(s): Salt Creek

Origin: Discovered by T.V. Munson in USA, in 1900

GENERAL CHARACTERISTICS Tolerances relating to: Phylloxera: Very good according to local research. Nematodes: Excellent against root-knot nematodes; moderate against dagger nematodes. Phytophthora: Good. Crown gall: Poor. Wet soils: Good. Dry soils: Excellent (3) . Saline soils: Good Calcareous soils: Weak to good; depending on quantity of free lime present.

• Most planted rootstock for table grapes in South Africa. • Strong vigour and good to excellent quality grapes recorded with most scion cultivars on a variety of soils. CULTIVATION CHARACTERISTICS Compatibility: Moderate; results vary with omega bench grafting. Affinity: Problems especially with muscat flavoured cultivars, Crimson Seedless, Redglobe and various new cultivars. Rooting: May give poor results; the use of rooting hormones to overcome problems is recommended. Vigour if not grafted: Excellent (1) . Vigour if grafted: Excellent; scion can be developed fully during the season of planting. More canopy management is needed than with other rootstocks due to strong vigour. Petiole nutrient status tendencies: High N and P uptake; low Na and Ca uptake.

GENERAL: • Primarily used for its excellent tolerance against nematodes. • Induces strong vigour in scion cultivars.

• Results in good to excellent quality table grapes with most scion cultivars in a variety of soil types. • Sometimes results in fertility problems and poor colour development of red and black grapes when used in combination with inherently strong scion cultivars on fertile soils.

24 Table Grape Rootstocks in South Africa

RAMSEY

Photos: Jan Avenant

Table Grape Rootstocks in South Africa 25

PAULSEN 1103

V. berlandieri x V. rupestris Synonym(s): P 1103 and 1103 P

Origin: Bred by F. Paulsen, in Sicily, Italy, in 1895.

GENERAL CHARACTERISTICS Tolerances relating to: Phylloxera: Very good to excellent. Nematodes: Moderate (2) against root-knot nematodes; poor against dagger nematodes. Phytophthora : Very poor; not recommended in soils that remain wet for long periods after irrigation or rain. Crown gall: Moderate. Wet soils: Very good (if Phytophthora is absent). Dry soils: Moderate (3) . Saline soils : Poor to very poor. Calcareous soils: Good; better than R 110, but poorer than Ru 140.

• Currently the third most planted rootstock for established table grape vineyards. • For new plantings, currently the second most popular rootstock following R 110. CULTIVATION CHARACTERISTICS Compatibility: Very good with most cultivars of V. vinifera . Good results obtained with both bench and aerial grafting. Omega bench grafting may occasionally result in problems (1) . Affinity: Problems with Redglobe in South Africa. Rooting: Very good. Vigour if not grafted: Moderate to good (1) . Vigour if grafted: Very good. Petiole nutrient status tendencies: High P and Fe uptake; low Na uptake (1) .

GENERAL: • The current demand for table grapes shows a shift to P 1103 at the expense of Ramsey and R 110. The expectation is that vine vigour will decrease and grapes of better quality will consequently be obtained (especially on fertile soils). • Popularity is increasing and P 1103 is currently second in demand, following Ramsey for new plantings. • Ramsey performed better in the majority of trials.

26 Table Grape Rootstocks in South Africa

PAULSEN 1103

Photos: Jan Avenant

Table Grape Rootstocks in South Africa 27

RICHTER110

V. berlandieri x V. rupestris Synonym(s): R 110 and 110 R

Origin: Bred by F. Richter in France, in 1902

GENERAL CHARACTERISTICS Tolerances relating to: Phylloxera: Very good. Nematodes: Moderate (2) against root-knot and dagger nematodes. Phytophthora : Moderate; better than R 99, but not recommended for soils that remain wet for long periods after irrigation or rain. Crown gall: Moderate. Wet soils: Sensitive to fairly resistant.

• Currently, the second most planted rootstock used in established table grape vineyards. • In new plantings, currently the second most popular rootstock following P 1103.

CULTIVATION CHARACTERISTICS

Compatibility: Very good; sometimes poor results are obtained with bench and aerial grafting. Grafting more problematic than with R 99. Affinity: No problems known or observed in trials. Rooting: Good. Vigour if not grafted: Good (1) . Vigour if grafted: Widely considered as being good, but less vigorous than R 99; local table grape trials indicated differences between scion cultivars. Petiole nutrient status tendencies: Low Na, Mn, Mg and Fe uptake (1) .

Dry soils: Very good (3) . Saline soils: Moderate. Calcareous soils: Good.

GENERAL: • Since the year 2000, the popularity of R 110 has increased at the expense of R 99. This is mainly attributed to the pursuit of better quality grapes. • Currently the third most popular rootstock in the country, preceded by P 1103 and Ramsey for new plantings. • Currently the second most popular roostocks being planted.

28 Table Grape Rootstocks in South Africa

RICHTER 110

Photos: Jan Avenant

Table Grape Rootstocks in South Africa 29

RICHTER 99

V. berlandieri x V. rupestris Synonym(s): R 99 and 99 R

Origin: Bred by F. Richter in France, in 1902

GENERAL CHARACTERISTICS Tolerances relating to: Phylloxera: Very good to exceptional. Nematodes: Moderate against root-knot nematodes; Susceptible to dagger and ring nematodes (2) . Phytophthora : Very poor; not recommended on soils that remain wet for an extended period after

Minimally used for new table grape plantings in South Africa

CULTIVATION CHARACTERISTICS Compatibility: Very good bench and aerial grafting results are obtained. Poor to good according to own results (1) . Affinity: No problems known or observed in trials. Rooting: Very good. Vigour if not grafted: Very high (1) . Vigour if grafted: Good. Petiole nutrient status tendencies: High P uptake; low Ca and Na uptake (1) .

irrigation or rain. Crown gall: Poor. Wet soils: Susceptible. Dry soils: Poor (3) . Saline soils: Moderate. Calcareous soils: Good.

GENERAL: • Minimal use for new table grape plantings in South Africa. • Performance average to poor regarding production and quality in rootstock trials. • Use not recommended for table grapes.

30 Table Grape Rootstocks in South Africa

RICHTER 99

Photos: Jan Avenant

Table Grape Rootstocks in South Africa 31

US 8-7

Richter 99 x Jacquez Synonym(s): USVIT 8-7

Origin: Bred by Prof. C.J. Orffer, Stellenbosch University, in 1949

GENERAL CHARACTERISTICS Tolerances relating to: Phylloxera: Moderate. Nematodes: Moderately susceptible (2) to root-knot nematodes; moderate to dagger nematodes. Phytophthora : Unknown.

• Not widely used for table grapes. • No indications that demand is increasing.

CULTIVATION CHARACTERISTICS Compatibility: Reasonable (1) to moderate. Affinity: No problems known or observed in trials. Rooting: Not available. Vigour if not grafted: Moderate (1) . Vigour if grafted: Very good, but less vigorous than Ramsey and Dog Ridge in local trials. More inputs regarding canopy management practices of the scion cultivar are required than for most other rootstocks because of their strong vigour. Petiole nutrient status tendencies: High Ca uptake and low Mn uptake.

Crown gall: Unknown. Wet soils: Unknown. Dry soils: Moderate to good. Saline soils: Unknown. Calcareous soils: Unknown.

GENERAL: • Rootstock trials performed on loamy and sandy loam soils. • Long-term trial results showed production and quality performance of Crimson Seedless grafted to US 8-7 to be very good, but that of Regal Seedless only average.

32 Table Grape Rootstocks in South Africa

US 8-7

Photos: Jan Avenant

Table Grape Rootstocks in South Africa 33

RUGGERI 140

Origin: Bred by A. Ruggeri in Palermo, Sicily, Italy in 1896

V. berlandieri x V. rupestris Synonym(s): Ru 140 and 140 Ru

GENERAL CHARACTERISTICS Tolerances relating to: Phylloxera: Moderate. Nematodes: Poor (2) against root-knot and dagger nematodes. Phytophthora : Moderately sensitive. Crown gall : Poor. Wet soils: Poor. Dry soils: Poor (3) . Saline soils : Moderate. Calcareous soils : Excellent (up to 35% free lime).

• Tested on a wide spectrum of soils. • Performance not as good as Ramsey. • Poor nematode tolerance.

CULTIVATION CHARACTERISTICS Compatibility: Excellent. Bench grafting often delivers a fairly low percentage take; good results with aerial grafting. Poor (1) . Affinity: No problems observed or reported in South Africa. Problems observed in other countries with Redglobe. Problems observed with wine grapes. Rooting: Relatively problematic. Vigour if not grafted: Good to very good (1) . Vigour if grafted: Good to moderate under local conditions. Petiole nutrient status tendencies: No exceptionally high or low levels (1) .

GENERAL: • Can be used on a wide range of soils. • Included in several rootstock trials. • Long-term trial results showed that under local conditions, production of table grapes grafted to Ru 140 varies from good to poor, with mostly average performance.

34 Table Grape Rootstocks in South Africa

RUGGERI 140

Photos: Jan Avenant

Table Grape Rootstocks in South Africa 35

DOG RIDGE

V. champini (a natural crossing) Synonym(s): Dogridge

Origin: Discovered by T.V. Munson on Dog Ridge mountain, Texas, USA, in 1900

GENERAL CHARACTERISTICS Tolerances relating to: Phylloxera: Moderate. Nematodes: Good against root-knot nematodes; susceptible to dagger and ring nematodes (2) . Phytophthora : Very good. Crown gall: Unknown. Wet soils: Very good. Dry soils: Very good (1) . Saline soils: Good to very good. Calcareous soils: Very poor to moderate, depending on the quantity of free lime in the soil.

White cultivars, performs as well as and sometimes better than Ramsey, especially on sandy soils.

CULTIVATION CHARACTERISTICS Compatibility: Weak; grafts with difficulty. Affinity: No problems known or observed in trials. Rooting: Poor; should be treated with rooting hormones. Vigour if not grafted: Very strong to excellent. Vigour if grafted: Very strong; vines can be developed fully within the first year. Costs of canopy management practices higher than with other rootstocks due to vigorous growth. Petiole nutrient status tendencies: High P, Ca, Mg and B uptake (1) .

GENERAL: • Performance in trials mostly and sometimes even better than Ramsey, especially with white cultivars. • Induces strong vigour in scions and is usually associated with good to excellent quality table grapes with most scion cultivars and in a wide spectrum of soils. • With inherently vigorous scion cultivars, it may sometimes result in problems regarding fertility, as well as colour development problems with red and black cultivars in very fertile soils.

36 Table Grape Rootstocks in South Africa

DOG RIDGE

Photos: Jan Avenant

Table Grape Rootstocks in South Africa 37

SO4

Origin: Bred by the Viticultural School in Oppenheim, Germany and selected by S. Telekei en H. Fuhr, 1896

V. berlandieri x V. riparia Synonym(s): Selection Oppenheim No. 4

GENERAL CHARACTERISTICS Tolerances relating to: Phylloxera: Moderate. Nematodes: Good (2) against root-knot and poor against dagger nematodes. Phytophthora : Poor. Crown gall: Moderate. Wet soils: Good. Dry soils: Poor to moderate. Saline soils: Poor. Calcareous soils: Moderate to good (4) .

Should be evaluated on a semi-commercial scale for use with table grapes in South Africa.

CULTIVATION CHARACTERISTICS Compatibility: Good (1) . Affinity: No problems known or noted in trials. Rooting: Good. Vigour if not grafted: Moderate to good (1) . Vigour if grafted: Mostly moderate; but poor in some trials (1) . Petiole nutrient status tendencies: High Ca uptake and low Na uptake (1) .

GENERAL: • Long-term trial results under South African conditions showed that production and quality performance with table grapes are good to very good (even better than Ramsey). • Trials were conducted over a wide range of soils (sandy loam, loamy sand, loam and sandy clay loam). • Colour manipulations are, however, still necessary.

38 Table Grape Rootstocks in South Africa

SO4

Photos: Jan Avenant

Table Grape Rootstocks in South Africa 39

FREEDOM

Origin: Bred by J.H. Weinberger and F.N. Harmon, USA, released in 1974

1613 Couderc x Dog Ridge Synonym(s): None

GENERAL CHARACTERISTICS Tolerances relating to: Phylloxera: Moderate. Nematodes: Good against root-knot nematodes; susceptible to dagger and ring nematodes (2) . Phytophthora : No information and/or data available. Crown gall: Moderate. Wet soils: No information and/or data available. Dry soils: Moderate (4) . Saline soils: Poor. Calcareous soils: Moderate (4) .

• Performs well in terms of production and quality. • Should be evaluated semi-commercially for table grapes. CULTIVATION CHARACTERISTICS Compatibility: Good. Affinity: No problems known or observed in trials. Rooting: No information and/or data available. Vigour if not grafted: Good to very good (1) . Vigour if grafted: Moderate to poor, but mostly better than Harmony according to the results of local trials. Petiole nutrient status tendencies: High K uptake (1) .

GENERAL: • Long-term research trials results under local conditions show that Freedom performs well to moderately well in relation to the production of table grapes. • Trials were conducted in a range of soils (sandy loam and loam), climatic (Western Cape and Lower Orange River region) and cultivation conditions.

40 Table Grape Rootstocks in South Africa

FREEDOM

Photos: Jan Avenant

Table Grape Rootstocks in South Africa 41

HARMONY

Origin: Bred by J.H. Weinberger and F.N. Harmon in California, USA, released in 1965

1613 Couderc x Dog Ridge Synonym(s): None

GENERAL CHARACTERISTICS Tolerances relating to: Phylloxera: Moderate. Nematodes: Good against root-knot nematodes; poor against dagger and ring nematodes (2) . Phytophthora : No information or data available.

Performance regarding production is poor under South African conditions.

CULTIVATION CHARACTERISTICS Compatibility: Good; problems with Sultanina and Merbein Seedless reported overseas. Affinity: No problems known or observed in trials (1) . Rooting: Good. Vigour if not grafted: Good (1) . Vigour if grafted: Moderate to poor, but less vigorous than Freedom according to local table grape trials (1) . Petiole nutrient status tendencies: Low N and Fe uptake (1) .

Crown gall: Moderate. Wet soils: Moderate. Dry soils: Moderate to poor (4) . Saline soils: Good. Calcareous soils: Moderate (4) .

GENERAL: • Long-term research trials show that Harmony performs poorly with table grape cultivars under South African conditions. • The trials were conducted in a wide range of soils (sandy loam and loam), climatic (Western Cape and Lower Orange River region) and cultivation conditions.

42 Table Grape Rootstocks in South Africa