fr ww1227.hunter (final report) · 1. summary of final report ... cabernet sauvignon, richter 110...

WW 1227 JJ Hunter ARC Infruitec-Nietvoorbij

CFPA Canning Fruit Producers’ Assoc.

Submit to: Wiehahn Victor

Tel: +27 (0)21 872 1501 [email protected]

SAAPPA / SASPA / SAT Fruitgro Science

Submit to: Louise Liebenberg Tel: +27 (0)21 882 8470/1

[email protected]

DFTS Dried Fruit Technical Services

Submit to: Dappie Smit

Tel: +27 (0)21 870 2900 [email protected]

Winetech Submit to:

Jan Booysen Tel: +27 (0)21 807 3324

[email protected]

X

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

FINAL REPORT

2011/2012

PROGRAMME & PROJECT LEADER INFORMATION

Programme leader Project leader

Title, initials, surname Dr J Steenkamp Dr JJ Hunter

Present position Research Leader: Viticulture Specialist Scientist

Address

ARC Infruitec-Nietvoorbij Private Bag X5026 Stellenbosch 7599

ARC Infruitec-Nietvoorbij Private Bag X5026 Stellenbosch 7599

Tel. / Cell no. (021) 809 3200/ 083 629 5959 (021) 809 3057

Fax (021) 809 3002 (021) 809 3002

E-mail [email protected] [email protected]

PROJECT INFORMATION

Project number WW 12/27

Project title Factors involved in abnormal graft union development

Industry programme

CFPA

Deciduous

DFTS

Winetech Cultivation

Other

Fruit kind(s) Winegrapes

Start date (dd/mm/yyyy) 1/04/2008

End date (dd/mm/yyyy) 31/3/2012

Progress report 2

WW1227/JJ Hunter/ARC Infruitec-Nietvoorbij

FINAL REPORT

1. Summary of final report The purpose of the project was to provide answers on the origin and prevention of the phenomenon of graft union abnormality. In vineyards where the phenomenon occurs, plants apparently developed normally in the nursery, but as soon as they were exposed to the vineyard environment, the graft union started to increase in size and the rootstock development was retarded. The scion then became visibly thicker than the rootstock and the graft union excessively large. It was assumed that this led to death of the whole plant. The project is carried out at the KWV Grondves farm in Stellenbosch. Material from Sauvignon blanc, Cabernet Sauvignon, Richter 110 and 101-14 Mgt was collected and combinations of Sb/R110, CS/R110, Sb/101-14 Mgt, CS/101-14 Mgt were warm and cold callused, whereas a hot water treatment/no treatment process was also followed for each combination. Grafted stocks were planted in commercial nurseries. After the nursery phase, vines were planted at Grondves farm using a vine-by-pole training system (1.5 x 1.0 m), in heavy (clayey) and sandy soils, with normal and overly wet (by means of irrigation) seasonal conditions, and restricted and unrestricted root volume availability (by means of planting hole) for each soil type. Vines were evaluated after the nursery phase and during growth in the vineyard.

After the nursery phase, warm callused vines had noticeably thicker graft unions and diameters of both the rootstock and graft scion were larger. Irrespectively, graft union quality between warm and cold callused vines was similar. In general, below- and above ground growth and graft union mass were stimulated by warm callusing. Graft scion mass was higher for cold callused vines. There seemed to be no obvious effect related to hot water treatment. Rootstock 101-14 Mgt realised lower root mass compared to R110, particularly under warm callusing conditions. These differences were induced during callusing and/or during the nursery phase. After the first growth season, no obvious changes occurred below the graft union for any factor under clayey soil conditions. Graft union size and the area above the graft union were stimulated by warm callusing under both normal and wet soil water conditions. Graft union size and development above the graft union were apparently stimulated by hot water treatment. Shoot length appeared to be reduced by hot water treatment under warm callusing conditions, but stimulated under cold callusing conditions. Under unrestricted, wet, sandy soil conditions, a general reduction in rootstock diameter occurred with hot water treatment. Hot water treatment reduced the diameter size of the graft union under unrestricted soil conditions. Similar to what was found in clayey soil, warm callusing stimulated the diameter of the area above the graft union. No clear patterns seemed to occur for the different cultivars and rootstocks. At this stage, it seemed that graft union size was not related to canopy growth stimulation; the graft union may restrict transport of nutrients if good fusion and vascular development did not occur, in which case the area above the graft union is likely to increase in diameter because of a swelling of the phloem. During the second growth season, it was evident that rootstock 101-14 Mgt was also affected by treatment. Sauvignon blanc had a smaller graft union size than C. Sauvignon, irrespective of rootstock used. It appeared that hot water treatment and warm callusing in particular, do affect graft union development; warm callusing increased graft union size under clayey and sandy, restricted and unrestricted as well as normal and wet conditions. As found previously, cane mass seemed indeed more stimulated by warm callusing. The detrimental effect of root restriction on cane mass was evident; surplus water was not successful to reduce this effect. In general, largest increases in graft union diameter from the first to the second season occurred in the sandy soil under normal water conditions. During the third growth season, the data showed that in clayey soil with normal water conditions, C. Sauvignon had larger graft unions than S. blanc for both rootstocks and all other treatments. These differences were less pronounced under wet conditions. Warm callusing again stimulated graft union size, but had no effect on rootstock size. This appeared to be a carry-over effect, already induced during the callus and nursery

Progress report 3


phases. The difference between rootstock diameter and graft union (and above) size may reach such proportions that physical translocation restrictions in the vascular tissue may result. Similar patterns were found under sandy and clayey soil conditions. General trends over the three seasons, analysed by means of principle component analysis of the means over three years, showed that the cultivars could be clearly separated, with C. Sauvignon having thicker graft unions and rootstock diameters than S. blanc. Warm callus tended to result in thicker graft unions and thinner rootstocks. Further analyses of the data of each cultivar-rootstock combination over the three year period of the experiment showed all treatments most likely associated with thicker or thinner graft unions and the rootstock; it seemed highly likely that warm callusing would lead to the thickest graft unions and thinnest rootstocks, irrespective of the graft combination, while cold callusing is likely to result in the thinnest graft union and thickest rootstock, and therefore a more balanced vine. Regressions of graft union and rootstock diameter with cane mass also showed that rootstock diameter per se is better associated with aboveground growth than graft union diameter. It seemed that most vine deaths occurred during the second growth season and did not increase after that. Large increases and highest numbers were found in the clayey soil under normal and wet conditions. Under clayey soil conditions most vines died under wet conditions, whereas under sandy soil conditions most vines died with normal irrigation. Cane starch contents were similar. Visual evaluation of the fusion/integration of the vascular system of the graft union as well as measurements of graft union size and cane size above the graft union indicated no recognisable relationship between vascular system restriction and a normal or over-sized graft union. The size of the graft union seemed not to be related to a restriction inside the graft union. The root system generally preferred to grow under normal water conditions in clayey soil and under wet conditions in sandy soil. Under normal water conditions generally more roots occurred in the clayey compared to the sandy soil, whereas under wet conditions root growth performance seemed similar in clayey and sandy soils. The study was meant to provide answers on the origin and prevention of the phenomenon of graft union abnormality (over-sized graft union). It indirectly addressed the economic viability of young vineyards as well as the sustainability of production and grape and wine quality. It investigated the impact of various grafted plant material production techniques and vineyard management factors, the idea being to start with a broad investigation in order to find impact factors. The latter of which warm callusing being the most important clearly surfaced. Focus areas were evident and subjects for further study could be identified. 2. Problem identification and objectives

1. To determine physiological, viticultural and pedological factors that may play a role in abnormal enlargement of graft unions.

2. To contribute to the optimisation and sustainability of production and grape quality. 3. To contribute to the optimal use of terroir potential. 4. To improve the economic viability of plantings. OBJECTIVES CURRENT YEAR 1. Maintain the vineyard, currently established using the vine by pole training system (1.5 x

1.0 m), in heavy (clayey) and sandy soils (at KWV Grondves, Stellenbosch) with normal and overly wet seasonal conditions as well as restricted and unrestricted root volume availability, for each soil type. Treatment combinations are as follows: Sb/R110, CS/R110, Sb/101-14 Mgt, CS/101-14 Mgt; Warm/Cold callus per cultivar-rootstock combination; Hot water/No treatment per cultivar-rootstock combination per callus procedure; Clayey/sandy soil per cultivar-rootstock combination per callus procedure per water treatment; Normal/overly wet conditions (6 hrs/week vs 12 hrs/week drip irrigation) per cultivar-rootstock combination per callus procedure per water treatment per soil type; Restricted/unrestricted root volume per cultivar-rootstock combination per callus procedure per water treatment per soil type and per soil water condition.

Progress report 4


2. Prune the experiment and determine cane mass. (Aug. 2011) 3. A root distribution study and starch analyses of roots and canes. (Sept. – Oct. 2011) 4. Final research report. (June 2012)

3. Amended work plan (materials & methods)

None 4. Performance chart, results and discussion

Milestone Achievement

Rootstock and trunk diameters, graft union evaluation, graft union circumference, shoot and root growth of grafted vines before planting

Done

Rootstock diameter, graft union diameter, scion above graft union diameter, and aboveground growth – cane mass in winter (after first summer)

Done

Roo Rootstock diameter, graft union diameter, graft union circumference, cane mass (after second and third summers) – clear trends evident

Done

Roo Root distribution study Done Background The phenomenon of abnormal graft union enlargement seems to increasingly occur in the South African Wine Industry. Although there are cases where symptoms already appear in the nursery, vines usually develop normally in the nursery and as soon as they are exposed to the vineyard environment, the graft union starts to increase in size and the rootstock shows retarded growth or declines. The rootstock then appears visibly thinner than the scion and the graft union excessively thick; such vines eventually die. The reason for this is not clear and information regarding prevention is needed. It was observed that the phenomenon seems to be mainly rootstock cultivar related and occurs mostly when Ruggeri 140, Richter 110, Richter 99 and Paulsen 1103 are used; these rootstocks all have relatively high vigour. It seems not to occur when 101-14 Mgt and Ramsey are used; these rootstocks are mostly used with water supply since 101-14 Mgt is considered drought sensitive and Ramsey is often used under sandy conditions to sustain vigour and reduce the risk of nematode infection. It apparently occurs for all scion cultivars, but mostly for Pinot noir, P. gris, Merlot, Sémillon and Sauvignon blanc; these cultivars are more often grown under cooler climatic conditions. Cultivars with different inherent properties are therefore involved, although similarities in preferred growth conditions are evident. The same cultivars in cooler areas also seem to show more pronounced symptoms. Rootstocks of the same clone, but from two different sources also show different levels of the symptom. It appears as if there could be a soil, climate and/or cultivation influence.

Regarding the grafting procedure being followed in South Africa, it appears that the most dramatic change introduced during the last years was the use of hot water treatment (30 minutes @ 50 0C) of the plant material before grafting in order to reduce the risk of diseases. The phenomenon seems not to occur for cold callused graft combinations. Cultivars do indeed differ in their callusing reaction towards warm and cold callus procedures, depending on the rootstock used. For example, in a previous study it was found that when S. blanc and Cabernet Sauvignon were grafted onto 101-14 Mgt, the reaction of the two scions and the reaction of the scions towards the two callusing procedures were similar, but when they were grafted onto Richter 110, the reaction of the scions as well as the reaction of the scions towards warm and cold callusing procedures differed; with C. Sauvignon the callusing was more detrimentally affected. From our research we also got strong indications that cold callus stimulates root mass, whereas warm callus stimulates cane mass (for both S. blanc and C.

Progress report 5


Sauvignon) – the deduction was that this may result from a better graft union being formed (reserve-dependent callus formation) and better ripening of the graft union wood. It was found previously in our research that hot water treatment can reduce the reserve (starch) content of material by up to 60 %.

Similar symptoms than those described above occur in other countries, but all are ascribed to viruses. However, in South Africa, no harmful viruses could be found, either in the stocks collected or the sources from where it was collected.

Experiment layout An experiment that includes various factors envisaged to play a role in abnormal graft union development was started at Grondves Farm (KWV, Stellenbosch) during the 2008/2009 season. The vineyard was established during spring 2008 using the Vine-by-pole training system (1.5 x 1.0 m), in heavy (clayey) and light (sandy) soils with normal and overly wet (double than normal) seasonal conditions and restricted and unrestricted root volume availability, for each soil type (PHOTO 1). Treatment combinations are as follows: Sb/R110, CS/R110, Sb/101-14 Mgt, CS/101-14 Mgt; Warm/Cold callus per cultivar-rootstock combination; Hot water/No treatment per cultivar-rootstock combination per callus procedure; Clayey/sandy soil per cultivar-rootstock combination per callus procedure per water treatment; Normal/overly wet conditions per cultivar-rootstock combination per callus procedure per water treatment per soil type; Restricted/unrestricted root volume per cultivar-rootstock combination per callus procedure per water treatment per soil type and per soil water condition (TABLE 1).

Photo 1

After the nursery phase (TABLE 2), warm callused vines had noticeably thicker graft unions. The diameter of the rootstock of warm callused vines as well as that of the graft scion was also larger. No clear pattern emerged for graft union quality between warm and cold callused vines and the thicker graft unions of the warm callused vines therefore had no effect on the strength of the graft union. In general, the root-, cane-, rootstock- and graft union mass was clearly stimulated by warm callusing. The graft scion mass was higher for cold callused vines. There seemed to be no obvious effect related to hot water treatment. Rootstock 101-14 Mgt realised lower rootstock and root mass compared to R110, particularly under warm callusing conditions. As the original material from the mother block was divided into two bundles for the different

Progress report 6


treatments during callusing, these differences were clearly induced during callusing and/or during the nursery phase.

Table 1. Treatment combinations established at Grondves Farm (KWV, Stellenbosch) for each of

the two soil types and under normal and overly wet soil conditions.

Treatment no

Root Volume Callus

method* Water

treatment Cultivar Rootstock

1 Unrestricted Warm Hot water Sb 101-14 Mgt 2 Unrestricted Warm None Sb 101-14 Mgt 3 Unrestricted Warm Hot water CS 101-14 Mgt 4 Unrestricted Warm None CS 101-14 Mgt 5 Unrestricted Warm Hot water Sb R110 6 Unrestricted Warm None Sb R110 7 Unrestricted Warm Hot water CS R110 8 Unrestricted Warm None CS R110 9 Unrestricted Cold Hot water Sb 101-14 Mgt

10 Unrestricted Cold None Sb 101-14 Mgt 11 Unrestricted Cold Hot water CS 101-14 Mgt 12 Unrestricted Cold None CS 101-14 Mgt 13 Unrestricted Cold Hot water Sb R110 14 Unrestricted Cold None Sb R110 15 Unrestricted Cold Hot water CS R110 16 Unrestricted Cold None CS R110 17 Restricted Warm Hot water Sb 101-14 Mgt 18 Restricted Warm None Sb 101-14 Mgt 19 Restricted Warm Hot water CS 101-14 Mgt 20 Restricted Warm None CS 101-14 Mgt 21 Restricted Warm Hot water Sb R110 22 Restricted Warm None Sb R110 23 Restricted Warm Hot water CS R110 24 Restricted Warm None CS R110 25 Restricted Cold Hot water Sb 101-14 Mgt 26 Restricted Cold None Sb 101-14 Mgt 27 Restricted Cold Hot water CS 101-14 Mgt 28 Restricted Cold None CS 101-14 Mgt 29 Restricted Cold Hot water Sb R110 30 Restricted Cold None Sb R110 31 Restricted Cold Hot water CS R110 32 Restricted Cold None CS R110

*Warm callusing was done at Vititec and cold callusing at Groenvlei nursery After the first growth season (PHOTO 2) (TABLES 3a & 3b), no obvious changes seemed to occur below the graft union for any of the different factors under clayey soil conditions. Graft union size and the area above the graft union were stimulated by warm callusing under both normal and wet soil water conditions. Graft union size also appeared to be stimulated by hot water treatment, particularly under normal soil water conditions. Hot water treatment also generally stimulated development above the graft union. Shoot length, however, appeared to be reduced by hot water treatment under warm callusing conditions, but stimulated under cold callusing conditions. This indicates that graft union size was not related to canopy growth stimulation, but that the graft union could even restrict transport of nutrients if a good fusion and vascular development did not occur, in which case a thickening above the graft union is likely to occur because of a swelling of the phloem as a result of downward pressure and build-up of water and nutrients (mainly sucrose). Under unrestricted, wet, sandy soil conditions, a general reduction in rootstock diameter occurred with hot water treatment. Other than that, there seemed to be no clear pattern emerging below the graft union for any factor. Hot water treatment reduced the diameter size of the graft union under unrestricted soil conditions, which may indicate that increased flow occurred through the graft union. Similar to what occurred in clayey soil, warm callusing stimulated the diameter of the graft scion and the area above the graft union. No clear pattern occurred for shoot length. At this stage, no clear patterns seemed to occur for the different cultivars and rootstocks.

Progress report 7


Table 2. Growth parameters measured before planting in vines obtained from nurseries.

Treat-ment

Graft union circumference

Diameter Quality of

graft union

Mass/vine Graft union

Root- stock*

Graft scion

Roots Canes Root-stock

Graft scion

Graft union

1 65.20 18.48 9.45 11.57 3.57 23.93 18.15 22.50 4.70 3.79

2 67.77 19.83 8.76 11.30 4.20 21.52 17.10 19.93 4.60 4.00

3 66.43 19.22 8.64 11.45 3.83 19.91 15.58 18.95 4.40 4.06

4 67.30 19.00 9.57 12.77 3.87 24.67 20.49 23.01 4.78 4.19

5 65.93 19.17 9.73 11.82 4.07 22.89 16.01 25.06 3.78 4.12

6 66.17 19.47 9.81 11.77 4.03 26.45 15.24 25.91 3.48 4.00

7 65.00 18.95 9.13 12.15 4.37 24.39 17.22 22.15 4.39 4.06

8 66.07 19.53 9.14 12.20 4.30 30.61 20.31 22.42 4.59 4.23

Ave 66.23 19.21 9.28 11.88 4.03 24.30 17.51 22.49 4.34 4.06

9 47.23 12.20 8.42 8.33 4.03 12.73 11.03 14.16 5.09 4.66

10 51.60 14.57 8.38 8.83 3.63 12.32 10.21 15.63 3.86 3.20

11 53.73 14.93 8.26 8.35 4.07 8.47 13.05 13.44 4.67 3.81

12 54.63 14.65 8.44 8.88 4.00 10.41 12.24 14.75 5.02 3.68

13 48.07 13.00 7.96 8.03 4.10 13.36 9.00 14.01 4.38 2.90

14 48.33 13.55 8.65 8.52 4.43 18.10 9.01 11.88 4.68 4.19

15 55.39 15.34 8.53 9.56 4.61 10.50 17.75 16.02 6.48 4.66

16 49.90 14.13 7.81 8.40 4.47 9.74 10.94 12.87 4.09 3.36

Ave 51.11 14.05 8.31 8.61 4.17 11.95 11.65 14.10 4.78 3.81

Treatment numbers 1 – 8 refer to warm callused vines and 9 – 16 to cold callused vines Average of 30 nursery stocks (3 Replications x 10 vines; Diameters were measured in two directions - averages are presented; *Measured in 2 internodia; Quality of graft unions was evaluated by cutting the union and scoring the extent of vascular system fusion of graft scion and rootstock from 1 to 5 (best)

Photo 2

Progress report 8


Table 3a. Growth parameters measured after the first growth season in a normal irrigated and double than normal irrigated (wet), clayey soil at Grondves, Stellenbosch.

CLAYEY SOIL Treatment Below graft union Graft union Above graft union Longest shoot length

Normal Wet Normal Wet Normal Wet Normal Wet

1 13.96 13.79 25.71 24.42 21.04 18.92 88.42 82.42 2 17.79 15.71 26.54 24.92 21.75 18.54 103.50 90.17 3 15.58 17.54 26.83 29.38 21.67 23.54 90.67 124.92 4 17.71 12.58 29.00 23.63 26.71 18.00 117.83 72.75 5 13.08 15.42 23.79 26.50 21.21 19.96 68.17 104.25 6 15.29 14.75 24.71 26.88 21.50 18.13 75.58 105.50 7 16.25 15.63 27.79 26.29 24.38 22.79 112.08 110.17 8 16.38 13.25 31.42 23.96 27.75 20.46 132.33 94.92

Ave 15.76 14.83 26.97 25.75 23.25 20.04 98.57 98.14

9 16.08 17.58 21.25 24.83 15.79 18.58 77.75 134.58 10 13.71 12.25 20.08 17.50 14.17 12.58 71.08 65.75 11 19.83 14.63 25.13 24.46 19.63 17.04 120.58 111.08 12 14.58 15.50 22.25 24.17 16.63 16.71 85.67 108.17 13 13.96 13.92 22.33 21.04 14.58 14.79 85.08 106.17 14 16.21 11.33 22.88 17.83 17.17 11.75 100.92 63.58 15 16.04 12.38 25.71 21.50 19.63 14.29 113.75 77.75 16 15.83 12.33 24.42 18.83 19.96 13.63 100.25 70.42

Ave 15.78 13.74 23.01 21.27 17.19 14.92 94.39 92.19

17 15.71 15.17 26.04 26.21 21.00 19.50 101.67 99.83 18 15.21 12.08 25.29 23.29 18.50 15.04 84.42 62.33 19 15.54 14.67 25.33 25.38 21.13 18.17 115.08 77.92 20 15.83 14.29 26.71 23.79 22.75 18.04 110.58 86.00 21 13.67 14.33 23.92 26.79 21.88 20.54 71.67 113.67 22 13.63 12.75 23.92 23.88 18.46 17.33 80.17 75.92 23 15.25 15.54 26.00 27.46 22.58 22.08 97.00 120.33 24 15.50 13.54 27.08 25.29 20.79 18.25 99.75 90.58

Ave 15.04 14.05 25.54 25.26 20.89 18.62 95.04 90.82

25 16.08 12.50 22.00 17.08 14.58 11.58 113.83 55.50 26 16.04 13.75 21.50 21.08 14.79 14.71 79.33 85.42 27 16.38 12.38 24.67 20.33 18.71 12.92 130.00 70.50 28 16.00 14.04 22.17 21.75 15.29 15.13 86.83 90.58 29 14.58 13.08 23.21 21.13 16.08 13.25 111.58 76.75 30 14.96 14.67 20.75 21.71 16.92 13.67 89.83 91.17 31 16.08 16.21 24.75 22.83 19.25 16.21 105.83 95.00 32 14.17 14.25 20.25 22.71 15.67 14.63 64.08 84.83

Ave 15.54 13.86 22.41 21.08 16.41 14.01 97.67 81.22

Diameters were measured in two directions – averages are presented

During the second growth season (PHOTOS 3 & 4) (TABLES 4a & 4b), rootstock 101-14 Mgt was also affected by treatment, showing changes in graft union size (Tables 4a & 4b). Sauvignon blanc had a smaller graft union size than C. Sauvignon, irrespective of rootstock, pointing to generally more vigorous growth. Trends of results seemed to exclude involvement of viruses on graft union size. Hot water treatment and warm callusing appeared to affect graft union development and warm callusing increased graft union size under clayey and sandy, restricted and unrestricted as well as normal and wet conditions. As found, cane mass seemed more stimulated by warm callusing. A restricted planting hole confirmed the detrimental effect of root restriction on cane mass. Surplus water did not alleviate this. In general, largest increases in graft union diameter from the first to the second season occurred in sandy soil under normal water conditions.

Progress report 9


Table 3b. Growth parameters measured after the first growth season in a normal irrigated and double than normal irrigated (wet), sandy soil at Grondves, Stellenbosch.

SANDY SOIL Treatment Below graft union Graft union Above graft union Longest shoot length


1 11.71 13.79 23.33 25.25 17.50 19.17 81.25 106.83 2 12.79 14.83 23.75 26.25 16.79 19.88 70.83 101.00 3 12.63 14.67 22.83 28.21 16.75 23.21 67.75 123.42 4 13.67 15.21 24.17 26.96 19.17 20.63 78.17 108.67 5 14.13 13.75 23.75 23.29 17.96 18.75 82.75 89.08 6 12.21 15.42 22.00 27.83 17.04 21.38 79.92 120.17 7 14.46 14.83 24.83 26.25 19.67 22.92 90.58 109.67 8 14.46 17.83 26.33 30.13 21.92 20.42 76.42 115.67

Ave 13.26 15.04 23.87 26.77 18.35 20.79 78.46 109.31

9 12.29 15.42 16.54 19.54 10.79 14.21 50.58 94.92 10 11.54 17.13 18.67 24.67 11.71 16.79 56.83 109.42 11 13.58 13.96 21.79 23.13 14.75 17.13 84.33 84.25 12 14.75 16.67 22.71 24.63 16.25 18.33 76.58 117.25 13 13.79 13.38 22.00 19.79 15.29 13.38 101.42 77.75 14 13.50 13.58 21.08 20.67 13.25 14.54 64.50 74.83 15 12.13 13.96 20.75 22.79 13.38 17.13 63.92 95.33 16 13.63 14.71 22.38 24.00 16.58 17.79 112.08 117.75

Ave 13.15 14.85 20.74 22.40 14.00 16.16 76.28 96.44

17 13.33 13.96 24.79 23.58 17.33 18.83 86.75 83.67 18 11.17 12.21 20.71 23.96 14.33 15.88 50.42 82.00 19 10.71 14.67 22.33 26.21 15.00 20.67 53.67 102.17 20 13.29 15.88 23.46 28.25 19.00 20.46 80.83 110.08 21 12.92 14.50 22.83 27.79 16.83 22.67 66.42 127.67 22 12.13 14.08 22.58 23.13 17.46 18.17 72.92 75.75 23 13.04 16.00 23.38 28.13 18.88 22.13 70.17 122.83 24 13.54 15.38 24.96 30.79 18.63 23.58 82.00 99.67

Ave 12.52 14.58 23.13 26.48 17.18 20.30 70.40 100.48

25 12.00 16.04 19.58 21.75 11.96 15.75 62.92 96.92 26 13.46 14.58 21.13 21.83 13.83 15.67 89.08 94.00 27 12.67 15.75 19.33 23.25 13.79 17.54 77.08 106.58 28 11.46 15.21 18.79 23.54 11.33 17.25 54.08 101.00 29 11.25 15.54 19.13 23.46 11.92 17.21 63.00 108.00 30 11.92 16.08 18.88 22.21 12.29 17.92 56.50 111.75 31 12.75 13.46 20.17 23.17 13.63 15.67 76.67 84.08 32 12.58 17.33 18.46 25.96 12.58 19.63 73.67 115.58

Ave 12.26 15.50 19.43 23.15 12.67 17.08 69.13 102.24


Photo 3

Progress report 10


Photo 4

Table 4a. Growth parameters measured after the second growth season in a normal irrigated and double than normal irrigated (wet), clayey soil at Grondves, Stellenbosch.

CLAYEY SOIL Treatment Below graft union

diameter (mm) Graft union

circumference (cm) Graft union diameter

(mm) Cane mass(kg)


1 18.60 17.95 9.67 9.75 31.21 26.93 1.00 0.70 2 21.20 18.95 9.83 10.04 33.96 30.42 0.75 0.48 3 18.61 21.19 10.28 11.18 33.18 34.67 1.13 1.04 4 21.19 15.49 10.26 9.02 33.97 24.70 1.65 0.53 5 16.40 20.03 8.93 9.49 29.62 30.10 0.52 1.32 6 20.35 19.61 9.49 10.02 31.47 28.87 0.70 1.02 7 21.81 20.29 10.55 10.65 32.82 32.07 1.56 1.20 8 22.82 17.39 11.56 9.83 36.47 28.13 1.94 1.58

Ave 20.12 18.86 10.07 10.00 32.84 29.49 1.16 0.98

9 17.60 23.18 7.45 9.92 23.53 30.87 0.63 1.79 10 15.68 16.62 7.20 7.76 22.18 20.34 0.47 0.31 11 22.42 19.06 9.73 9.68 31.94 31.47 1.31 1.20 12 21.75 19.88 9.09 10.08 29.31 31.99 0.82 1.24 13 17.85 18.21 8.43 8.43 26.85 28.19 0.56 0.66 14 20.69 17.05 8.51 7.68 27.44 20.43 0.88 0.18 15 22.66 16.12 10.94 8.96 34.78 25.38 1.26 0.30 16 21.46 15.91 10.25 8.61 33.37 27.07 1.08 0.36

Ave 20.01 18.25 8.95 8.89 28.68 26.97 0.88 0.76

17 20.25 16.95 10.83 9.45 33.88 30.33 1.03 0.47 18 17.08 14.77 8.42 8.18 26.28 23.23 0.51 0.20 19 22.41 18.21 9.47 10.47 30.56 30.07 1.05 0.35 20 20.91 16.86 10.65 10.09 34.56 29.92 1.17 0.40 21 18.18 18.69 9.32 10.58 30.33 29.29 0.51 0.74 22 17.30 17.97 14.38 9.94 27.94 27.13 0.54 0.46 23 23.87 22.68 11.31 10.02 37.08 29.10 0.93 1.92 24 19.52 17.53 10.86 10.81 33.03 32.22 1.16 0.56

Ave 19.94 17.96 10.66 9.94 31.71 28.91 0.86 0.64

25 18.65 13.78 8.34 7.31 26.73 20.35 0.88 0.16 26 18.54 17.40 8.46 7.72 26.45 23.80 0.48 0.82 27 21.67 16.26 9.98 7.99 32.16 22.74 1.45 0.27 28 18.73 18.73 8.78 8.88 28.26 26.03 0.46 0.62 29 18.58 18.12 8.82 14.86 27.34 25.45 0.74 0.23 30 20.12 19.56 8.57 9.10 26.84 26.52 0.61 0.96 31 23.99 26.28 12.26 9.76 34.23 24.34 1.11 0.41 32 18.95 17.46 9.11 9.23 28.75 26.44 0.60 0.35

Ave 19.90 18.45 9.29 8.36 28.85 24.46 0.79 0.48


Progress report 11


Table 4b. Growth parameters measured after the second growth season in a normal irrigated and

double than normal irrigated (wet), sandy soil at Grondves, Stellenbosch.

SANDY SOIL Treatment Below graft union

diameter (mm) Graft union

circumference (cm) Graft union diameter

(mm) Cane mass


1 18.63 14.80 10.88 9.58 32.99 29.04 0.78 0.53 2 18.67 14.61 11.11 9.41 33.08 27.99 0.55 0.86 3 20.94 16.26 11.99 10.18 35.06 30.02 0.67 0.56 4 19.48 16.37 12.48 10.61 37.43 32.23 1.01 0.57 5 19.25 17.86 11.36 11.01 34.34 32.62 0.53 0.71 6 19.09 17.38 11.69 9.76 34.83 30.82 0.77 0.52 7 21.03 19.33 12.35 11.68 37.00 34.70 0.71 1.03 8 24.78 18.23 14.26 11.31 43.89 35.54 0.90 0.95

Ave 20.23 16.86 12.02 10.44 36.08 31.62 0.74 0.72

9 19.06 13.00 8.95 6.51 27.93 19.76 0.42 0.24 10 20.92 15.33 11.06 7.06 30.11 22.08 0.50 0.31 11 21.74 19.45 10.07 9.79 31.01 29.20 0.38 0.46 12 20.79 19.46 10.84 9.36 33.62 28.19 0.55 0.51 13 17.79 18.15 9.64 9.18 29.17 27.74 0.38 0.90 14 19.92 17.55 8.88 8.56 27.68 26.40 0.31 0.47 15 19.61 16.89 10.83 9.20 31.58 29.23 0.52 0.20 16 21.09 19.74 11.03 9.96 34.67 29.58 1.02 0.84

Ave 20.12 17.45 10.16 8.70 30.72 26.52 0.51 0.49

17 16.93 16.58 10.01 9.48 30.22 28.87 0.42 0.44 18 17.41 12.55 9.26 8.87 27.63 24.03 0.49 0.20 19 21.00 12.98 11.59 9.06 33.84 26.19 0.86 0.40 20 20.31 15.38 12.04 10.96 36.81 31.32 1.12 0.80 21 20.15 16.29 12.14 9.61 36.06 28.67 1.19 0.44 22 17.93 14.94 10.64 9.24 31.91 26.94 0.34 0.41 23 20.52 17.57 13.38 9.95 36.38 31.32 0.66 0.67 24 26.10 18.07 13.39 11.31 40.32 34.99 0.75 0.66

Ave 20.04 15.55 11.56 9.81 34.15 29.04 0.73 0.50

25 22.44 14.66 9.96 7.78 28.91 23.49 0.77 0.41 26 19.47 16.75 9.03 8.61 27.74 25.22 0.54 0.49 27 22.91 16.48 10.87 9.04 32.14 27.22 0.67 0.39 28 20.97 14.13 10.83 7.38 32.95 22.89 0.80 0.32 29 21.49 14.36 10.04 7.41 29.90 25.44 0.54 0.38 30 20.47 16.50 10.35 8.03 31.15 25.33 0.59 0.20 31 19.22 16.32 10.41 9.38 32.53 28.41 0.42 0.28 32 24.98 15.21 12.31 8.89 36.94 24.35 1.03 0.30

Ave 21.49 15.55 10.48 8.32 31.53 25.29 0.67 0.35

Diameters were measured in two directions – averages are presented During the third growth season (TABLES 5a & 5b), the trends became clearer. Under clayey conditions with normal water conditions, C. Sauvignon showed larger graft unions than S. blanc for both rootstocks and all other treatments, displaying the expected higher vigour of this cultivar. These differences were not so evident under wet conditions; the latter may lead to anaerobic conditions, especially in a clayey soil, restricting respiration and therefore growth. Warm callusing again showed a clear stimulating effect on graft union size, but had no effect on the size of the rootstock below the graft union. This phenomenon appears to be a permanent carry-over effect that was already induced during the callus and nursery phases. If this would continue, the difference between rootstock diameter and graft union (and above) may reach such proportions that translocation restrictions between scion and rootstock may

Progress report 12


result; this would be harmful to the vine. Although normal soil conditions had a more positive effect on graft union and below graft union diameters during all the seasons, this pattern was changed during the past season when growth in these areas was more stimulated by wet sandy soil conditions. Except for this, similar patterns were found under sandy soil conditions than under clayey soil conditions.

Table 5a. Growth parameters measured after the third growth season in a normal irrigated and

double than normal irrigated (wet), clayey soil at Grondves, Stellenbosch. CLAYEY SOIL

Treatment Below graft union diameter (mm)

Graft union circumference (cm)

Graft union diameter (mm)

Normal Wet Normal Wet Normal Wet

1 21.73 20.02 11.96 10.89 36.44 31.89 2 23.79 19.66 11.78 11.20 36.28 33.80 3 20.81 24.30 12.88 13.22 38.55 40.64 4 25.21 18.29 13.69 10.85 42.88 32.37 5 19.34 23.35 11.84 13.14 34.75 39.53 6 25.45 21.50 12.08 12.18 37.50 36.45 7 25.55 22.28 14.58 13.31 43.10 38.85 8 28.35 20.77 16.21 12.55 50.24 36.39

Ave 23.78 21.27 13.13 12.17 39.97 36.24

9 21.83 26.96 9.29 11.53 27.96 35.70 10 17.80 17.70 8.31 8.24 25.64 24.92 11 27.60 20.78 12.43 11.31 37.40 34.23 12 25.35 23.37 11.66 11.88 33.74 36.80 13 21.24 20.80 10.48 10.48 32.26 32.22 14 23.96 18.33 10.99 9.39 32.85 25.73 15 27.75 19.64 13.38 10.67 40.84 32.36 16 25.88 20.30 13.23 11.17 39.67 34.63

Ave 23.93 20.99 11.22 10.58 33.79 32.07

17 24.36 20.43 12.70 11.28 37.31 33.22 18 20.22 16.18 10.63 9.13 34.23 27.89 19 26.21 17.83 12.75 23.8 38.65 32.14 20 24.13 21.97 13.16 12.66 38.12 37.85 21 19.20 22.27 11.38 12.55 34.33 39.33 22 20.32 20.06 11.39 12.02 34.88 36.32 23 25.80 24.25 14.31 13.92 43.44 41.51 24 24.61 23.26 13.88 14.18 41.86 43.28

Ave 23.11 20.78 12.52 13.69 37.85 36.44

25 20.22 17.33 9.70 8.11 28.87 24.76 26 22.78 19.86 10.06 9.73 29.52 27.99 27 25.06 19.06 12.30 9.77 36.80 28.39 28 21.21 21.21 11.27 10.44 33.66 31.68 29 22.44 21.87 10.82 10.53 33.07 32.91 30 24.33 21.61 10.41 10.49 32.60 32.01 31 28.93 23.11 13.84 11.65 42.09 35.02 32 22.16 20.77 11.05 11.27 33.96 33.79

Ave 23.39 20.60 11.18 10.25 33.82 30.82


Trends over the three seasons It was clear from the principle component analysis (PCA) of the means over three years that PC1 (which explained 82% of the variation) separated mainly the cultivars, with C. Sauvignon having thicker graft unions and rootstock diameters than S. blanc. The PC2 separated warm and cold callus (explaining the additional 18% variation), with warm callus tending to result in

Progress report 13


thicker graft unions and thinner rootstocks and cold callusing increasing the size below the graft union (that of the rootstock) (FIG. 1).

Table 5b. Growth parameters measured after the third growth season in a normal irrigated and double than normal irrigated (wet), sandy soil at Grondves, Stellenbosch.

SANDY SOIL

Treatment Below graft union diameter (mm)

Graft union circumference (cm)

Graft union diameter (mm)

Normal Wet Normal Wet Normal Wet

1 18.08 21.96 11.37 12.74 34.05 37.32 2 20.02 21.79 11.31 12.68 34.34 37.67 3 19.56 24.32 12.51 13.59 36.25 40.07 4 20.69 22.81 12.71 13.92 39.07 42.16 5 22.69 22.94 12.85 12.94 39.26 39.35 6 18.96 22.68 11.71 12.69 34.33 39.89 7 22.46 24.39 13.13 14.59 40.55 44.45 8 21.55 26.78 13.98 16.19 43.42 50.55

Ave 20.50 23.46 12.45 13.67 37.66 41.43

9 15.47 21.48 7.37 10.17 22.64 31.22 10 17.97 21.99 9.05 11.26 26.38 34.38 11 23.34 22.42 11.87 11.30 35.08 34.43 12 22.05 23.80 11.06 12.46 33.59 37.87 13 21.76 21.32 10.94 11.14 33.03 34.23 14 20.18 23.46 10.88 11.23 31.18 31.71 15 19.81 22.39 11.04 12.61 33.38 37.48 16 22.49 22.24 11.96 12.21 35.94 37.72

Ave 20.38 22.39 10.52 11.55 31.40 34.88

17 20.89 19.90 11.63 11.02 34.88 33.70 18 15.50 20.00 9.41 10.64 28.05 32.48 19 16.52 22.36 10.80 13.08 30.79 40.27 20 19.02 22.95 12.40 13.65 37.83 41.39 21 18.87 24.67 11.18 14.54 32.30 43.60 22 18.07 22.48 11.54 12.54 33.00 37.63 23 17.86 24.12 12.19 15.36 35.51 46.33 24 20.36 24.07 13.84 15.55 40.77 46.08

Ave 18.39 22.57 11.62 13.30 34.14 40.18

25 18.77 25.12 8.78 11.14 27.56 35.49 26 20.93 22.10 10.36 10.28 31.48 31.75 27 20.29 26.32 10.28 13.10 31.76 39.32 28 15.47 23.12 9.12 11.75 26.26 36.29 29 17.40 23.85 9.09 12.12 26.27 35.39 30 19.44 23.87 9.77 11.38 29.28 34.74 31 20.46 22.99 11.01 12.36 33.31 37.91 32 20.85 26.23 11.26 14.03 33.49 42.83

Ave 19.20 24.20 9.96 12.02 29.93 36.72

Diameters were measured in two directions – averages are presented Data were therefore also analysed for each cultivar-rootstock combination over the 3-year period of the experiment in order to reduce the impact of the cultivar-rootstock combination on the data (masking the effects of the other treatments) and to determine which of the treatments, including soil type, could be best associated with graft union thickness and rootstock diameter (below the graft union). Results are displayed in FIGS 2a & b for C. Sauvignon/101-14 Mgt and C. Sauvignon/R110 and in FIGS 3a & b for S. blanc/101-14 Mgt and S. blanc/R110.

Progress report 14


In TABLE 6 the quadrant results of the PCA’s are shown, indicating the treatments most likely associated with thicker or thinner graft unions and the part of the trunk below the graft union (rootstock).

Biplot (axes F1 and F2: 99.91 %)

RCHC

RCHSRCNC

RCNS

RWHC

RWHS RWNC

RWNS

UCHC

UCHS

UCNC

UCNS

UWHC

UWHS

UWNC

UWNS

BelowGraftUnion

Thickness

GraftUnion

Circumference

GraftUnionThickness

-1.4

-1.2

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

-5 -4 -3 -2 -1 0 1 2 3 4

F1 (81.89 %)

F2 (18.0

2 %

)

Fig. 1. PCA of main effects impacting on graft union and rootstock size (means over 3 years) at

Grondves, Stellenbosch.


CRCHNCRCHW

CRCNN

CRCNW

CRWHN

CRWHW

CRWNN

CRWNW

CUCHW

CUCNN

CUCNW

CUWHN

CUWHW

CUWNNCUWNW

SRCHN

SRCHW

SRCNN

SRCNW

SRWHN

SRWHW

SRWNN

SRWNW

SUCHNSUCHW

SUCNN

SUCNW

SUWHN

SUWHW

SUWNN

SUWNW

BelowGraftUnion

Thickness

GraftUnionThickness

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

-4.5 -4 -3.5 -3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5

F1 (82.89 %)

F2 (

17

.11

%)


CRCHN

CRCHW

CRCNN

CRCNWCRWHN

CRWHW

CRWNN

CRWNW

CUCHN

CUCHW

CUCNN

CUCNW

CUWHN

CUWHW

CUWNNCUWNW

SRCHNSRCHW

SRCNN

SRCNW

SRWHN

SRWHW

SRWNN

SRWNW

SUCHN

SUCHW

SUCNN

SUCNW

SUWHN SUWHW

SUWNN

SUWNW

BelowGraftUnion

Thickness

GraftUnionThickness

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

-3 -2 -1 0 1 2 3 4

F1 (87.65 %)

F2

(1

2.3

5 %

)

Fig. 2a - C. Sauvignon/101-14 Mgt Fig. 2b - C. Sauvignon/R110

Progress report 15



CRCHN

CRCHW

CRCNN

CRCNW

CRWHN

CRWHW

CRWNN

CRWNW

CUCHN

CUCHW

CUCNN

CUCNW

CUWHN

CUWHW

CUWNN

CUWNW

SRCHN

SRCHW

SRCNN

SRCNW

SRWHN

SRWHW

SRWNN

SRWNW

SUCHN

SUCHW

SUCNN

SUCNW

SUWHN

SUWHW

SUWNN

SUWNW

BelowGraftUnion

Thickness

GraftUnionThickness

-0.7

-0.5

-0.3

-0.1

0.1

0.3

0.5

-3.5 -3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 3 3.5

F1 (83.01 %)

F2

(1

6.9

9 %

)


CRCHNCRCHW

CRCNN

CRCNW

CRWHN

CRWHW

CRWNN

CRWNW

CUCHN

CUCHW

CUCNN

CUCNW

CUWHN

CUWHW

CUWNN

CUWNW

SRCHN

SRCHW

SRCNN

SRCNW

SRWHN

SRWHW

SRWNN

SRWNW

SUCHN

SUCHW

SUCNN

SUCNW

SUWHN

SUWHW

SUWNNSUWNW

BelowGraftUnion

Thickness

GraftUnionThickness

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

-4 -3 -2 -1 0 1 2 3 4

F1 (77.59 %)

F2

(2

2.4

1 %

)

Fig. 3a - S. blanc/101-14 Mgt Fig. 3b - S. blanc/R110

Table 6. Treatment combinations best associated with thicker or thinner graft union or below

graft union (rootstock) occurrence (means over 3 years) at Grondves, Stellenbosch.

Treatment combinations in quadrants for all cultivars/rootstocks

C. Sauvignon/101-14 Mgt C. Sauvignon/R110 S. blanc/101-14 Mgt S. blanc/R110

Thinnest graft union

Thickest below graft

union (rootstock)



union (rootstock)



union (rootstock)



union (rootstock)

CRCNW CUCHN CRCHW CRCHN CUCHN CUCHW SUCNW CRCNN

CRCHW CUCNN CRCNN CUCHN CUCNW SRCHW CRCNW CUCNN

SUCNN SRCHW SUCNN SRCNW CRCNW CRCNN CUCNW SRCHW

CRCNN CRWHN CRCNW CUCNN CUCNN SUCHW CRCHW SRCNW

SUCHN CRCHN SRCNN CRWHW CRCHW CRCHN CUCHN CUWNN

SRCHN SUCHW SUCHW CUWHN SUCHN SRCNW SUCHN CRCHN

SRCNN SRCNW CRWHN SUCNN SUCNW CUCHW

SUCNW SUCNW SRCNN CUWNN SUCNN

CUCNW SRCHN SRCNN

SUCHW

Thinnest below

graft union (rootstock)

Thickest graft union

Thinnest below



Thinnest below



Thinnest below



CUCHW CRWNN CUCHW CRWNN SRWNW CUWHW SRCHN CUWHW

CUWNW CUWNN SRCHN CUWNN CRWNW CRWHN CRWNN CUWNW

CRWNW CUWHW CUWHW SUWHN SRWNN CRWNN CRWNW SRWNW

CRWHW SRWHW CUCNW SUWHW SUWNN CUWNW CRWHN CRWHW

SUWHN SUWHW SRCHW SUWNW SUWHN CRWHW SRWHN SUWHW

SRWHN CUWHN SUCHN SRWHW SRWHW SUWNN SUWHN

SUWNN SRWNW CUWNW SUWNN CUWHN CUWHN SUWNW

SRWNN SUWNW CRWNW SRWNW SRWHN SRWNN SRWHW

SRWHN SUWNW

SRWNN SUWHW

In order of letter occurrence from left to right: S = Sandy soil or C = Clayey soil; U = Unrestricted planting hole or R = Restricted planting

hole; W = Warm callus or C = Cold callus; N = No hot water treatment or H = Hot water treatment; N = Normal soil water conditions or W = Overly wet soil conditions

Progress report 16


The data show that it is highly likely that warm callusing would lead to the thickest graft unions and the thinnest rootstocks, irrespective of the graft combination, while cold callusing is likely to result in the thinnest graft union and the thickest rootstock. The latter in particular may be an indication that better growth and a more balanced development with less xylem and phloem translocation restrictions may be expected with cold callusing. Regressions of graft union and rootstock diameter with cane mass during the three years of the experiment indeed showed that the rootstock diameter per se is better associated with aboveground growth than the graft union diameter (FIG. 4). Observations regarding growth potential of a graft combination may therefore be more accurate if focused on the diameter of the rootstock (below the graft union).

y = 12.414x + 12.301

R2 = 0.6134

y = 18.04x + 20.473

R2 = 0.4715

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

0.00 0.20 0.40 0.60 0.80

Below graft

Graft union

Linear (Below graft )

Linear (Graft union)

Fig. 4. Regressions of graft union and rootstock diameter with cane mass (average of 3 seasons) From TABLE 7 it is clear that most vine deaths occurred during the second growth season, where after numbers were stable. Large increases from the first to the second season and highest numbers were found in the clayey soil under normal and wet conditions. This is in contrast to the largest increases in graft union diameter found from the first to the second season in sandy soil under normal water conditions. Sandy, wet soil seemed overall the better conditions for survival, followed by the sandy soil conditions with normal irrigation. Under clayey soil conditions most vines died under wet conditions, whereas under sandy soil conditions most vines died with normal irrigation; this is comprehensible given the fact that water logging (e.g. in a wet, clayey soil) and drought (e.g. in a dry, sandy soil) may both lead to poor growth or death. Although the use of rootstock R110 under clayey soil conditions seemed to have caused more vine deaths, no factor can be singled out as causing the deaths. Three years of data on cane starch contents also showed no major differences between treatments (data not shown). A root study (limited to the treatments with unrestricted planting holes) was done to further elucidate the effect of graft union and rootstock diameter, as induced by the treatments, on growth (PHOTOS 5 & 6). The fusion/integration of the vascular system of the graft union was visually evaluated by means of longitudinal cuts (to obtain quarters). In addition, the graft union size and cane size above the graft union were measured. The data (not shown) indicated no recognisable relationship between vascular system restriction and a normal or

Progress report 17


over-sized graft union. The size of the graft union seemed not to be related to a restriction inside the graft union. It should be noted that these vines survived the critical phases of development and environmental impact and are therefore not expected to show serious abnormalities. Efficiency of translocation through the graft union could be a subject of investigation in further studies.

Table 7. Number of dead vines found in the different seasons in a normal irrigated and double than normal irrigated (wet), clayey and sandy soil at Grondves, Stellenbosch.

TRMT*

1st Season 2nd Season 3rd Season

(2008/09) (2009/10) (2010/11)

Clayey Soil Sandy Soil Clayey Soil Sandy Soil Clayey Soil Sandy Soil

N W N W N W N W N W N W

1 0 0 0 0 1 2 0 0 1 2 0 0

2 0 0 0 0 0 0 0 0 0 0 0 0

3 0 0 0 0 0 0 0 0 0 0 0 0

4 0 0 3 0 1 0 3 0 1 0 3 0

5 2 0 0 0 7 1 0 0 7 1 0 0

6 1 0 0 0 6 11 0 0 6 11 0 0

7 1 0 0 0 6 6 0 0 6 6 0 0

8 0 0 0 1 0 5 0 1 0 5 0 1

4 0 3 1 21 25 3 1 21 25 3 1

9 0 1 1 0 3 1 1 0 3 1 1 0

10 0 2 3 0 2 1 3 0 2 1 3 0

11 0 1 1 0 1 1 5 0 1 1 5 0

12 0 2 2 1 0 1 2 2 0 1 2 2

13 0 0 1 1 0 0 1 1 0 0 1 1

14 0 0 1 0 3 9 2 0 3 9 2 0

15 0 0 0 0 0 3 0 0 0 3 0 0

16 3 1 0 1 5 11 0 2 5 11 0 2

3 7 9 3 14 27 14 5 14 27 14 5

17 0 0 0 0 0 1 1 0 0 1 1 0

18 0 2 2 0 0 3 1 0 0 3 1 0

19 0 0 1 0 0 1 1 0 0 1 1 0

20 0 0 0 0 0 2 0 0 0 2 0 0

21 0 0 0 0 2 3 0 0 2 3 0 0

22 0 1 2 0 4 1 1 0 4 1 1 0

23 0 1 0 0 1 5 0 0 1 5 0 0

24 1 1 1 0 3 1 0 0 3 1 0 0

1 5 6 0 10 17 4 0 10 17 4 0

25 0 1 1 1 0 1 1 2 0 1 1 2

26 0 0 0 0 0 0 1 0 0 0 1 0

27 0 1 0 0 0 6 0 1 0 6 0 1

28 0 1 1 2 0 1 3 2 0 1 3 2

29 4 1 2 0 5 3 4 0 5 3 4 0

30 2 0 0 1 7 0 0 1 7 0 0 1

31 0 2 0 0 1 3 0 0 1 3 0 0

32 0 0 1 0 2 8 0 0 2 8 0 0

6 6 5 4 15 22 9 6 15 22 9 6

Total 14 18 23 8 60 91 30 12 60 91 30 12

* For treatment descriptions refer to Table 1. N = Normal water conditions, W = Overly wet conditions.

The bulk density of the clayey and the sandy soils indicated variation in soil conditions over the surface area of the experiment (data not shown). It is clear that the root system generally

Progress report 18


preferred to grow under normal water conditions in clayey soil and under wet conditions in sandy soil (FIGS 5 & 6).

Photos 5 & 6

0

100

200

300

400

500

600

700

1 2 3 4 5 6 7 8 9 101112 13 141516

Clay Normal

(Total/profi le)

Clay Wet

(Total/profi le)

0

50

100

150

200

250

300

350

400

450

500

1 2 3 4 5 6 7 8 9 10111213141516

Sand Normal

(Total/profile)

Sand Wet

(Total/profile)

Figs 5 & 6. Comparison of normal water conditions and wet conditions for either clay soil or sandy soil, expressed as total number of roots per profile for each of the 16 treatments.

From the data in FIGS 7 & 8 it is evident that under normal water conditions generally more roots occurred in the clayey compared to the sandy soil. Under wet conditions, root growth performance seemed slightly better in sandy soils. These trends are also evident from the distribution of the different root sizes (FIGS 9 & 10). As found in other studies, the data also clearly show that fine and small-sized roots were present in largest quantities. Interestingly, 101-14 Mgt performed better in clayey and R110 better in sandy soil (FIGS 11, 12, 13 & 14).

0

50

100

150

200

250

300

350

400

450

500

1 2 3 4 5 6 7 8 9 10 11 1213 141516

Clay Normal

(Total/profi le)

Sand Normal

(Total/profi le)

0

100

200

300

400

500

600

700

1 2 3 4 5 6 7 8 9 10111213141516

Clay Wet

(Total/profile)

Sand Wet

(Total/profile)

Figs 7 & 8. Comparison of clay soil and sandy soil for either normal water conditions or wet conditions, expressed as total number of roots per profile for each of the 16 treatments.

Progress report 19


0

500

1000

1500

2000

2500

3000

3500

4000

4500

<0.5m

m

0.5-2

.0m

m

2.0-5

.0m

m

5.0-1

0.0m

m

>10.0

mm

Clay Normal

Clay Wet

Sand Wet

Sand Normal

0

500

1000

1500

2000

2500

3000

3500

4000

4500

Clay

Normal

Clay Wet Sand Wet Sand

Normal

<0.5mm

0.5-2.0mm

2.0-5.0mm

5.0-10.0mm

>10.0mm

Figs 9 & 10. Presence of different root sizes in clay soil and sandy soil for either normal water conditions or wet conditions, expressed as total number of roots per profile.

0

500

1000

1500

2000

2500

101-14 Mgt R110

Clay Normal

<0.5mm

0.5-2.0mm

2.0-5.0mm

5.0-10.0mm

>10.0mm

0

500

1000

1500

2000

2500

101-14

Mgt

R110

Clay Wet

<0.5mm

0.5-2.0mm

2.0-5.0mm

5.0-10.0mm

>10.0mm

0

500

1000

1500

2000

2500

101-14 Mgt R110

Sand Wet

<0.5mm

0.5-2.0mm

2.0-5.0mm

5.0-10.0mm

>10.0mm

0200400600800

1000120014001600

101-14

Mgt

R110

Sand Normal

<0.5mm

0.5-2.0mm

2.0-5.0mm

5.0-10.0mm

>10.0mm

Figs 11, 12, 13 & 14. Presence of different root sizes in clay soil and sandy soil and either normal water conditions or wet conditions for each rootstock, expressed as total number of roots per profile. General Any restriction in the graft union immediately after grafting and during callusing, whether from physical damage/improper grafting technique, poor callus formation or poor fusion/integration of vascular tissue of both scion and rootstock, would limit translocation in xylem and phloem tissue. Transport of mainly water, minerals and hormones such as cytokinins and abscisic acid (from the roots via the xylem) and sucrose, amino acids, minerals and hormones such as auxin and gibberellin (from the shoots via the phloem) would be affected. Of primary concern is the availability and quantities, at the graft union cut, of auxin and cytokinin. Presence of auxin is important for cambium development, differentiation of xylem and phloem cells and the formation of adventitious roots, whereas presence of cytokinin is a requirement for callus formation and differentiation; most importantly though, is the balance between these two hormones. In tissue culture, a relatively high auxin:cytokinin ratio would result in callus formation, a high auxin:cytokinin ratio in root formation and a low auxin:cytokinin ratio in shoot formation. Gibberellin is important for synthesis of starch breakdown enzymes, meaning that availability of reserve-energy for further callus formation, initial shoot growth and root development may be restricted either way if this hormone is deficient. During the early stages of callusing hormones for any development can only be sourced from existing quantities in the mother material wood. If they are present in deficient quantities or already in imbalanced quantities, this will impact negatively on callus and growth processes. Apart from the physiological impact of graft union restrictions, the mere physical restriction or disruption would primarily lead to a symptom that is similar to that of girdling (Hunter & Ruffner, 2001), i.e. a visual swelling of the area above the restriction because of the pressure that is created in the phloem by downward movement of solutes and water from the leaves and the accumulation above the restricted area. From this study it is clear that larger graft unions already developed during the nursery phase, e.g. for warm callused vines. Such graft unions are bound to develop further in the vineyard. The study also showed that the second growth season is most critical in survival of the young vines; this may be a carry-over effect from the

Progress report 20


first season that may already have started with a graft combination that was physiologically and physically under-developed and imbalanced. Assuming that warm, humid callusing conditions may lead to imbalances, it may be argued that warm conditions during callusing would firstly lead to faster root development and that young, actively growing roots may release large amounts of hormones such as cytokinins. As the roots will be actively absorbing water (in particular), this may create root pressure that would force premature and too fast movement of xylem sap towards an area (graft cut) that is not yet sufficiently developed (in terms of callus and cambium tissue) to ‘’receive’’ and ‘’transfer’’ (over the graft cut) such flow on the one hand and the contents of the sap on the other hand. Such sap would most likely contain cytokinin, which would then accumulate at the graft cut (if flow through or around the cut is restricted). Such situation may easily lead to hormone imbalances and finally an insufficiently developed graft union. Pressure may also result in an increase in cell size, swelling of the graft union area and finally a larger than normal graft union. Despite it not being certain/clear that an over-sized graft union would necessarily eventually be less efficient or lead to death of a young vine, it is possible that a larger than normal graft union may be the result of a combination of events during the callus period (increased size resulting from root activity) and during the nursery period (increased size resulting from high leaf activity forcing sap downwards in the phloem as described above – creating symptoms similar to that caused by girdling). Either way, it may be expected that neither the roots, nor the graft union or shoots would develop optimally if imbalances in abiotic and biotic factors already impact during early development of the graft combination. Any stressful event, during or after vineyard establishment, may worsen the situation and lead to death of a young vine. Abiotic factors may contribute to this when, for example, soils are still too cold in spring time, especially when the vineyard is established in heavy soils and after a wet winter. Under such circumstances, root activity would be delayed (our research already showed that root activity is dependent on soil temperature) and may result in a build-up of phloem-translocated substances at (above) the graft union (which is most likely a restriction to normal translocation under any circumstances). Further, when young vine establishment (e.g. preparation of planting holes) is not done judiciously in the first place, distribution of the root system will be restricted and more often lead to poor root development and distribution. Under such circumstances, the root system would be the restricting organ preventing or reducing phloem flow downwards in the plant (because of a lack of root activity and growth). A build-up of nutrients and therefore a thickening of the graft union would result, irrespective of a vascular system being formed during callusing and in the nursery. This may even lead to a situation where transpiration by the leaves is faster than water absorption (and movement across the graft union), the likely result being embolisms in the xylem and in worse cases desiccation, followed by death of the young vine. If such limitations or impacts on growth already occur during the first year after establishment, it is possible that the vines may survive during the first season, but when practices are applied during the second year, vines may not be able to withstand the additional stress caused by further physiological and physical imbalances. Final remarks The study was meant to provide answers on the origin and prevention of the phenomenon of graft union abnormality (over-sized graft union). It indirectly addressed economic viability of young vineyards as well as sustainability of production and grape and wine quality. It investigated the impact of various technical (during production of grafted plant material) and field (during establishment and management of vines in the vineyard) factors. The idea was to start with a broad investigation in order to find impact factors. Impact factors of which warm callusing being most important clearly surfaced. Focus areas were evident and subjects for further study identified.

Progress report 21


Relevant literature Ambrosi, H. & Kriel, A., 1958. Invloed van oplei van moederplantasies op die produksie en gehalte van enthout. Wynboer, June 1958, 16–17. Bartolini, G., Pestelli, P., Toponi, M.A. & Di Monte, G., 1996. Rooting and carbohydrate availability in Vitis 140 Ruggeri stem cuttings. Vitis 35, 11–14. Breen, P.J., 1975. Effect of peach/plum graft incompatibility on seasonal carbohydrate changes. J. Am. Soc. Hort. Sci. 100, 253–259. Buttrose, M.S., 1965. Use of carbohydrate reserves during growth from cuttings of grapevine. Aust. J. Biol. Sci. 19, 247–256. Fardossi, A., Mayer, C., Schober, V. & Mayer, S., 1996. Über die Einlagerung von Mineralstoffen im einjährigen Holz verschiedener Unterlagsrebsorten. Mitt. Klosterneuburg 46, 97–104. Goussard, P.G. & Van der Merwe, G.G., 1973. Ondersoek na bewortelingsprobleme van Salt Creek. Wynboer, Nov. 1973, 7–9. Guerrier-Julien, J., Deloire, A. & Coudret, A., 1996. Water relations in grapevine micro-cuttings grown in vitro. Biol. Plant. 38, 149–152. Hunter, J.J., 1999. Fisiese en fisiologiese gehalte van plantmateriaal. Handleiding, Kwekery Kortkursus, 14 April 1999, KWV, Paarl. pp. 7–30. Hunter, J.J., Le Roux, D.J. & Volschenk, C.G., 1996. Reserve nutrient status of Vitis graft material as related to callus success and growth during the callus period. In : J.M. Rantz (ed.). Proc’s Int. Symp. Table Grape Production, 28–29 June 1996, Anaheim, California. II-71–II-73. Hunter, J.J. & Ruffner, H.P., 2001. Assimilate transport in grapevines – effect of phloem disruption. Austr. J. Grape and Wine Res. 7, 118 - 126. Hunter, J.J., Volschenk, C.G., Le Roux, D.J., Fouché, G.W. & Adams, L., 2004. The physiological and morphological quality of plant material. ARC Infruitec-Nietvoorbij, Private Bag X5026, 7599 Stellenbosch, South Africa. Hunter, J.J., Volschenk, C.G., Tarricone, L. & Fouché, G.W., 2011. Factors involved in abnormal graft union development. Proc. 17th Int. Symp. GiESCO, Asti – Alba (CN), Italy, 29 Aug - 2 Sept 2011, 559 - 562. Kester, D.E., 1965. The physiology of grafting. Proc. Int. Propagators Soc., 261–273. Kolesnik, Z.V., 1963. Sugar and amino acid composition of vine grafts in relation to physiological compatibility. Fiziol. Rast. 10, 713–716. Schaefer, H., 1981. Physiologische Untersuchungen zur Veredlungsaffinität und Kallusbildung der Reben. In: Probleme der Rebenveredlung. Vorträge der XVI Geisenheimer Rebenveredlertagung 1981 – Internationales Symposium über Rebenveredlung. pp. 25–52. Van Schalkwyk, D., 1987. Entkombinasies by wyndruiwe. S.A. Kweker, Nov. 1987, 32–34. Zanathy, G., Löhnertz, O., Balogh, I. & Molnar, P., 1996. Effect of nitrogen on the carbohydrate content of grapevine canes. Hortic. Sci. 28, 75–78.

5. Accumulated outputs Technology development, products and patents 1. Improved cultivation practices 2. Improved grafting and callus processes 3. Improved sustainability as well as grape and wine quality Human resources development/training 1. Training in the establishment of a vineyard – vine by pole 2. New knowledge on the effects of grafting and callusing 3. New knowledge on the impact of the environment on graft union functioning and growth Publications (popular, press releases, semi-scientific, scientific) Hunter, J.J., Volschenk, C.G., Tarricone, L. & Fouché, G.W., 2011. Factors involved in abnormal graft union development. Proc. XVII GiESCO Conf., 29 Aug.–3 Sept. 2011, Italy. Presentations/papers delivered Poster: Hunter, J.J., Volschenk, C.G., Tarricone, L. & Fouché, G.W., 2011. Factors involved in abnormal graft union development. Proc. XVII GiESCO Conf., 29 Aug.–3 Sept. 2011, Italy.

© Agricultural Research Council, 2005. The content of this document may constitute valuable Intellectual Property and is confidential. It may not be read, copied, disclosed or used in any other manner by any person other than the addressee(s) and specifically not disclosed to another party submitting a proposal herein. Unauthorised use, disclosure or

copying is strictly prohibited and unlawful.

Progress report 22


6. Budget for the following year: None

CFPA Deciduous DFTS Winetech THRIP Other TOTAL

FUNDING REQUIRED FOR FOLLOWING YEAR: TOTAL

Overheads (only if part of project cost)

Personnel costs

Running costs

Local travel and accommodation

Local conferences (only specify separately for THIRP purposes)

Equipment (capital items*) [List capital items HERE]

Other

* Industries will only fund capital items under exceptional circumstances

6. Total estimated budget for project (insert actual cost when available)

Year CFPA Deciduous DFTS Winetech THRIP Other TOTAL

Total cost in real terms for year 1





TOTAL

Progress report 23


EVALUATION BY INDUSTRY This section is for office use only

Project number:

Project title:

Name of Subcommittee*:

Comments on project:

Committee’s recommendation: • Accepted. • Accepted provisionally if the subcommittee’s comments are also addressed.

Resubmit this progress report by ________________ • Unacceptable. Must resubmit progress report.

Chairperson: _____________________ Date: __________________ *SUBCOMMITTEES: Winetech Viticulture: Cultivation; Soil Science; Plant Biotechnology; Plant Protection; Plant Improvement Oenology: Vinification Technology; Bottling, Packaging & Distribution; Environmental Impact; Brandy and

Distilling; Microbiology Technology Transfer Training Deciduous Fruit Producer Research Advisory Committees (RAC’s): Pome fruit, Stone fruit, Table grapes Peer Work Groups (PWG’s): Biotechnology, Breeding & Evaluation (Pome Fruit), Breeding & Evaluation

(Stone Fruit), Entomology, Horticulture, Pathology, Post Harvest, Soil Science, Table Grape Production

fr ww1227.hunter (final report) · 1. summary of final report ... cabernet sauvignon, richter 110...

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