The effect of summer pruning on growth and grape composition of Vitis vinifera L. cv. Cape Riesling

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ANDRE CHARLES DE LA HARPE

Dissertation presented for the Degree of Doctor of Philosophy at the University of Stellenbosch

Promoter: Prof. Dr. J.H. Visser

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CONTENTS

1 I nt r oduc t i on 1

2 The Det er mi nat i on of t he Homogenei t y of a Vi t i s vi ni f er a L.

cv. Cape Ri esl i ng Vi neyar d 3

3 Gr owt h Char act er i st i cs of Vi t i s vi ni f er a L. cv. Cape Ri esl i ng

4 Tr ansl ocat i on of 14C- l abel l ed Phot osynt het at e i n Vi t i s

vi ni f er a L. cv. Cape Ri esl i ng

5 Accumul at i on of Sugar s i n t he Ber r y of Vi t i s vi ni f er a L. cv.

Cape Ri esl i ng 68

6 A Rapi d Met hod f or t he Anal yses of t he Maj or Or gani c Aci ds i n

t he Gr ape Ber r y 83

7 Devel opment of Or gani c Aci ds i n- t he Ber r y of Vi t i s vi ni f er a

L. cv. Cape Ri esl i ng 94

8 Mi ner al Composi t i on of t he Ber r y of Vi t i s vi ni f er a L. cv.

Cape Ri es l i ng. I . Ni t r ogen 113

9 Mi ner al Composi t i on of t he Ber r y of Vi t i s vi ni f er a L. cv.

Cape Ri es l i ng. I I . Phos phor ous , Pot as s i um, Cal c i um and

Magnesi um 124

10 Summar y and Conc l us i on 136

Acknowl edgement s 141

Appendi x

A. Tabl e of c or r el at i ons 142

" 6 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

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I NTRODUCTI ON

Toppi ng i s a s ummer pr uni ng v i t i c ul t ur al pr ac t i c e and i s c ommonl y us ed i n Sout h

Af r i c a as a pr ac t i c al mani pul at i on t o enabl e t he pr oduc er t o ent er r ows of v i

-gor ous l y gr owi ng v i nes . I n s ome c as es , howev er , f or e. ampl e Mus c at d' Al e. andr i e,

t oppi ng i s us ed t o i mpr ov e ber r y s et . Toppi ng i s al s o done t o mi ni mi z e wi nd

damage and t o c r eat e mor e uni f or m v i nes ( Ther on, 1944) .

Thi s pr ac t i c e c ompr i s es t he r emov al of t he api c al 25 c m or mor e of t he s hoot

ape. The r at i onal e behi nd t oppi ng i s a di s pl ac ement of t r ans l oc at i on s i nk s .

The s i nk s f or phot os y nt het at e ar e nor mal l y c ons i der ed t o be t he api c al mar l

-s t em, bunc he-s , -s t em and t oot -s . Compet i t i on bet ween bunc he-s and ot her -s i nk -s

c oul d eas i l y r es ul t i n al t er ed qual i t y of t he gr apes .

Thus t oppi ng i s a mani pul at i on t o ef f ec t t he t r ans l oc at i on of phot os y nt het at e

i n t he v i ne and i s of i mpor t anc e i n pr ac t i c al v i t i c ul t ur e due t o t he f ac t t hat

t he t r ans l oc at i on of phot os y nt het at e pl ay s an i mpor t ant r ol e i n t he quant i t at i v e

and qual i t at i v e c ompos i t i on of t he bunc h.

The i Mpor t and ex por t of phot os y nt het at e i n t he l at er al s hoot s of v i nes ar e

af f ec t ed by c l i mat i c c ondi t i ons ( Kobl et ; 1977) . Res ul t s obt ai ned f r om t he

nor t her n hemi s pher e s howed t hat j uv eni l e l eav es of l at er al s hoot s ar e s i nk s

and r emai n s i nk s unt i l at l eas t t wo l eav es r eac h mat ur i t y ( Hal e a Weav er , 1962;

Kobi et , 1977) . The l at er al s hoot s wi l l t hen s t ar t e. . . . por t i ng phot os y nt het at e.

Ac c or di ng t o Kobl et & Per r et ( 1971; 1972) onl y bas i pet al t r ans l oc at i on of

phot os y nt het at e oc c ur s ar i d l at er al s hoot s ex por t t hei r pr oduc t s t o s ur r oundi ng

bunc hes . Howev er , i t i s i mpor t ant t o k now how t he t r ans l oc at i on pat t er n of

phot os y nt het at e i s af f ec t ed by Sout h Af r i c an c ondi t i ons bef or e any r ec

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LI TERATURE

HALE, C. R. & WEAVER: R. J . 1962. The ef f ec t of dev el opment al s t age on di r ec t i on

of t r ans l oc at i on of phot os y nt het at e i n Vi t i s v i ni f er a. Hi l qar di a 33, 89- 131.

KOBLET, W. 1977. Tr ans l oc at i on of phot os y nt het at e i n gr apev i nes . Pr oc . I nt .

Sy mp. on t he qual i t y of t he v i nt age. l a- 21 Febr . 1977, Cape Town, 45- 52.

KOBLET, W. & PERRET, P. 1971. Fohl ehy dr at wander ung i n Gei z t r i eben. Wei n- Wi s s .

26, 202- 211.

KOBLET, W. & PERRET, P. 1972. Wander ung v on As s i mi l at en i nner hal b der Rebe.

Wei n- Wi ss. 27, 146- 154.

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CHAPTER 2

The Oet er mi nat i on of t he Homogenei t y of a Vi t i s vi ni f er a L. cv. Cape Ri esl i ng

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ABSTRACT

The val ue of Pr i nci pal Component and St epwi se Di scr i mi nant anal yses i n sel

ec-t i ng uni f or m pl anec-t s For eper i menec-t al pur pos es i s di s c us s ed. Twenec-t y - s ev en

v ar i abl es wer e t aen i nt o ac c ount t o es t abl i s h t he homogenei t y ( uni f or m pl ant s ) 4

of 297 Vi t i s v i ni f er a L. c v . Cape Ri es l i ng v i nes . A det ai l ed s t udy of t he r e-

l at i onshi p and i nt er r el at i onshi p of t hese var i abl es r esul t ed i n 208 vi nes

be-i ng sel ect ed as an unbe-i f or m popul at be-i on. Thbe-i s sel ect be-i on pr ovbe-i des t he possbe-i bbe-i l be-i t y

f or t he r esear cher i n vi t i cul t ur e t o use si ngl e vi nes as e. per i ment al uni t s,

but i t must be poi nt ed out t hat Pr i nci pal Component and St epwi se Di scr i mi nant

anal yses can onl y be used as an ai d t o nor mal st at i st i cal eval uat i on of exper i

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I NTRODUCTI ON

The mai n s t at i s t i c al t ool s i n c ompens at i ng For v ar i abi l i t y ar e r epl i c at i on,

r andomi s at i on and bl oc k i ng ( Hammer , 1981) . Repl i c at i on nor mal l y i nv ol v es

mul t i pl e i s per i ment al uni t s and t oget her wi t h r andomi s at i on i t r es ul t s i n

v al i d es t i mat es of t he ex per i ment al er r or ( v ar i anc e) . Bi ol ogi c al v ar i at i on c an

be dec r eas ed by s el ec t i ng mor e uni f or m pl ant s at t he pr et r eat ment s t age and

t hen us i ng r epl i c at i on and r andomi s at i on f or t r eat ment appl i c at i ons ( Hammer ,

1981) . Ac c or di ng t o Hammer ( 1981) t hi s wi l l al l ow t he s c i ent i s t t o det ec t

di f f er enc es bet ween t r eat ment s wi t h f ewer r epl i c at i ons . The c ompl ex i t y of

bi ol ogi c al mat er i al , wi t h i nt er c or r el at i ng v ar i abl es , has as r es ul t t hat s i ngl e

v ar i abl es c annot be t r eat ed as i ndependent c omponent s of a f ac t or ( Br os c hat ,

1979) .

The pr obl em of i dent i f i c at i on of uni f or m pl ant s bef or e t r eat ment s ar e appl i ed

c oul d t her ef or e be s ol v ed by meas ur i ng t he appr opr i at e v ar i abl es and s

ub-s equent l y per f or mi ng a Pr i nc i pal Component anal y ub-s i ub-s ( PCA) dec r eaub-s i ng t he di mens i onal i t y of t he dat a.

PCA has been s uc c es s f ul l y us ed i n ps y c hol ogy ( Hot el l i ng, 1936) and i n t he

bi ol ogi c al. and hor t i cul t ur al sci ences f or a number of year s ( Or l ocki , 1967;

Sneat h & Sol - al , 1973; Gl adon & St aby , 1976; Ol i v er , Si ddi qi &. Gowar d, 1978;

Leegwat er & Leegwat er , 1981 ; Van Rooy en & Tr omp, 1962) .

The pur pos e of t hi s s t udy was t o s el ec t r el at i v el y uni f or m v i nes i n a Vi t i s

v i ni f er a L. c v . Cape Ri es l i ng v i ney ar d by means of di f f er ent gr owt h and qual i t y

par amet er s wi t h t he ai d of St epwi s e Di s c r i mi nant anal y s i s ( SDA) and PCA i n

or der t o dec r eas e t t -Le l ar ge number of vi nes per t r eat ment needed f or physi

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pl ant s i n t he v i ney ar d made t he nor mal r andomi s ed bl oc k des i gn wi t h a l ar ge

number of ex per i ment al uni t s per r epl i c at i on i mpos s i bl e.

MATERI AL AND METHODS

Ex per i ment al v i ney ar d: A 15 y ear ol d v i ney ar d c ons i s t i ng of 297 v i nes of

V. v i ni f er a c v . Cape Ri es l i ng gr af t ed ont o 99 Ri c ht er , pl ant ed i n a v i

ne-y ar d c ons i s t i ng of f our s oi l t ne-y pes namel ne-y a Sout hwol d, Av al on, Gl enc oe and

Kanonk op s er i es ( s oi l s er i es as des c r i bed by Mac v i c ar , C. N. & Soi l Sur v ey St af f ,

1977) on t he ex per i ment al f ar m, Ni et v oor bi j , St el l enbos c h, Sout h Af r i c a was

us ed i n t hi s s t udy . The v i nes wer e t r el l i s ed on a Per ol d s y s t em ( Zeeman, 1981)

and s pur pr uned t o 16 buds per k i l ogr am s hoot mas s . Rai nf al l was s uppl ement ed

by t wo 200 mm i r r i gat i ons dur i ng Nov ember 1 981 and J anuar y 1982, r es pec t i v el y .

Var i abl es : The i nv es t i gat i on was ex ec ut ed i n t wo phas es . I n phas e I , t he zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

22 gr owt h v ar i abl es depi c t ed i n Tabl e 1 wer e meas ur ed on t wo s hoot s per c ol :

-don and t he mean of t hes e meas ur ement s wer e us ed as dat a poi nt s . The l eaf

ar ea of a v i ne was det er mi ned by meas ur i ng t he ar ea of i ndi v i dual l eav es wi t h

a model LI - 3000 Li - Cot Por t abl e Ar ea Met er and s ummat ed. Leaf dr y mas s was

det er mi ned af t er dr y i ng t o c ons t ant mas s at 80°C. The v i nes wer e v i s ual l y

ev al uat ed by f i v e j udges i nt o t hr ee c at egor i es : s i c k and poor l y dev el oped

v i nes t ak en as 100; nor mal l y dev el oped v i nes as 500 and wel l dev el oped v i nes

as 900. Al l meas ur ement s wer e c ar r i ed out at har v es t i ng t i me.

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TABLE 1

Variable ured in a Vitis zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBAv -Lnifera L. ov. Cane Rieslimo, vineyard

Variable

Number Variables Nnit

Phase I

1. Shoot length cordon 1 co snoot. cordon 1-1

11. Total leaf area per shoot of cordJon 2 "on2zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA. shoot -1

12. Total loaf area of both shoots cm2 . zhosots

13. Mein area per leaf of the shoots of cordon 1 *om2. leaf-1 14. Mean area per leaf of the shoots of cordon 2 "cm2. leaf -1

20. 17. 18. 19.

Total 1132 dry ma sa per :hoot of cordon 2 Total leaf dry mazz of both Ehocz

Mean dry mass per 1:af of the shoots of cordon 1

"Etalafel fI lleat numb:7-1

a

_g.leasg.total leaf number

-1 ,-1

15. Total mean Are.r. _{per leaf of both shots}

16. Total leaf dri maze per shoot of cordon 1 *g.total leer number -1

Mess_ dry mass per leaf of the shoots of cordon 2. 21. Total moon dry mass pr leaf of the shoots of both

cordons g.leaf -1

22. Evaluation of the vines

Phase II

Phase I plus the following

5

variables 23. Total voluble solids of must

24. Total titrable acids of must

25. PH

26. Yield per vine

27. Number of bunches per vine

Mean of the two shoots of the 2nd spur on cordon 1

I N _{Mean of the two shoots of the 2nd spur on cordon 2}

I n phas e 11 f i v e qual i t y v ar i abl es war e meas ur ed addi t i onal l y , namel y . t ot al

s ol ubl e mus t s ol i ds i n °Bal l i ng ( °B) , pH, t ot al t i t r at abl e must aci di t y ( TTA)

( g. dm- 3) , as wel l as t he t ot al number of bunc hes per v i ne and y i el d per v i ne,

as pr ac t i s ed i n t he l abor at or i es of t he VORI ( Anon, 1981) .

Dat a pr oc es s i ng: The dat a was pr oc es s ed us i ng a BD- 07M SDA pr ogr amme ( Heal t h

Sc i enc es Comput i ng Fac i l i t y , UCLA) and a PCA pr ogr amme f or mi ng par t of t he

pat t er n r ec ogni t i on s y s t em " Ar t hur " ( Har per , Duewer & Kowal s k i , 1977) . The

s ubr out i nes us ed i n' t he " Ar t hur " pr ogr amme ar e l i s t ed i n Tabl e 2.

-1

2. Shoot length cordon 2 cm shoot. cordon 2

-1

3. Total shoot length of both cordons cm shoot. cordons

4. Spurs cordon 1 5. Spurs cordon 2 6. Spurs per vine

7. Number of leaves per shoot of cordon 1 8. Number of leaves per shoot of cordon 2

9. Total number of laves of the shoot or variables

7 and 8

-1

10. Total leaf area per shoot of cordon 1 shoot

-1

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8

zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

TABLE 2

Pr ogr amme of Ar t hur as per f or med on t he dat a s et

Pr ogr amme Pr ogr amme f unc t i on

Phas e I

I nput Cr eat es a dat a mat r i : : as out put t o a ' Anar y f i l e t hat i s

c ompat i bl e wi t h al l ot her r out i nes i n Ar t hur .

Ut i l i t Pr ov i 3es a l i ne pr i nt er l i s t i ng of t he dat a mat r i x and/ or

t he di s t anc e mat r i x .

Sc al e Sc al es t he dat a t o s ome pr opor t i ons . The s c al i ng f ac t or s

ar e der i v ed f r om t he u dat a v ec t or s or t he t r ai ni ng s et and appl i ed t o al l t he dat a.

Cor r el Cal c ul at es al l f eat ur e - f eat ur e and f eat ur e - pr oper t y

c ov ar i anc es and c or r el at i ons .

Kapr i n The ex t r ac t i on of t he ai genv Al ues aad ei genv ec t or s of t he

dat a di s per s i on mat r i x as per f or med.

Kat r an Cr eat es a new dat a mat r i x f r om t he f i r s t E f ac t or s of zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBAthe

dat a.

Var v ar Pr oduc es l i ne pr i nt er pl ot s or a dat a mat r i x .

Kapr i n- Kav ar i - Per f or m a pr i nc i pal c omponent anal y s i s pl us r ot at i on of

Kat r an- Var v ar ei genv al ues wi t h pl ot t i ng.

Phas e I I

I nput Same as phas e T

Sc al e Same as phas e

Kapr i n Same as phas e I

Kat r an Same as phas e I

Var v ar Same as phas e I

Kav ar i Ex ec ut es a V3ri0E1% r ot at i on on : qt z . ei genv ec t or s .

Kat r an Az phas e I but wi t h Kav ar i r es ul t s .

1/92•VIr Same as phas e I

The B10- 0711 pr ogr amme was ex ec ut ed on a Bur r oughs 7800 c omput er of t he Depar t ment

of Agr i c ul t ur e and t he " Ar t hur " pr ogr amme on a Uni v ac 1100 c omput er of t he

Uni v er s i t y of St el l enbos c h. zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

Pr ior t o PCA all t he dat a w er e scaled t o a st andar d dev iat ion one and 1)

z er o mean. The nor mal i s ed s t andar d dev i at i on i s def i ned as

S. =

1

. wher e a =- s t andar d dev i at i on

x.

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and - zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

wher e u. . i s t he uncer t ai nt y associ at ed wi t h t he f eat ur e zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA ••••

9

-

11

and wher e n = t ot al number oF dat a v ec t or s i n t he t r ai ni ng dat a s et , and x i s

t he i t h f eat ur e as s oc i at ed wi t h t he j t h dat a v ec t or .

RESULTS AND DI SCUSSI ON

Phas e I : Tabl e 3 r epr es ent s t he s c al ed dat a wi t h t he mean, s t andar d dev i at i on,

nor mal i s ed s t andar d dev i at i on as pr ev i ous l y def i ned as wel l as mi ni mum and

max i mum v al ues .

Thr ee of t he PCA Fac t or s hav e ei genv al ues ( t he s um of t he v ar i anc es ) gr eat er t han one and ar e r et ai ned f or di s c us s i on ( Tabl e 4) . They ac c ount f or 65% of

t he v ar i anc e i n t he or i gi nal v ar i abl es wi t h t he r emai ni ng 35% c aus ed by r andom

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TABLE 3

The scaled data of phase I with the mean

standard doviation, normalised standard deviation and minimum and

M5YAMUffl values Maximum Variable Number Variables Mean Standard Deviation Normalised Std. Deviation Minimum Phase I 1.

Shoot length cordon 1

* 140,110 96,31 0,68 0,00 514,00 2.

* 128,56 92,07 0,72 6,00 603,00 3.

Total shoot length of both cordons

zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA '266,40 146,36 . 0,5 0,00 768,00 4.

Spurs per cordon 1

2,70 1,07 0,39 0,00 6,00 5.

Spurs per cordon 2

2,73 1,03 0,39 1,00 5,00 6.

Spurs per vine

5, 4 3 1,59 0, 2 9 0,00 10,00 7.

Number of leaves per shoot of cordon 1

*2 4,76 15,16 0,61 0,00 64,00 8.

* 19,51 -14,51 0,74 0,00 59,00 9.

Total number of leaves of the shaots of variables " and 8

4 44,42 21,5h 0,48 0,00 102,00 10.

Total leaf area per shoot of cordon 1

* 1312,00 952,66 6,68 6,00 6136,00 11.

iv113,66 4 .84:' .;,66 0,7 6 . 0 . 00 3933, 0 0 12. os

Total leaf area of both shot

* 2 508,00 1309,00 0,52 0,00 7966,00 13.

Mean area per leaf of the shoots of cordon 1

*4 8,99 2 3,95 0,4 9 0,00 *3 04,50 14.

4 46,13 27,35 0 ,59 0,00 171,50 15.

Total mean area per leaf of both shoots

..57,79 18,16 0 ,3 11 0,00 146,80 16.

Total leaf dry mass per shoot of ccrdon 1

' 7, 0 5 4,89 0,69 0,00 32,41 17.

Total leaf dry mass per shoot of cordon 2

* 5,22 4,52 0 ,78 :::: 20,67 13.

Total leaf dry mass of both shoots

* 12,85 IE,38 0,53 37,3 1 19.

Mean dry mass per leaf of the shoots of cordon 1

'0 ,3 8 0,5 0 0,22 0,00 2000,00 20.

* 0, 2 4 0,13 0,57 0,00 0,49 21.

Total average dry

rises

per leaf of the shoots of both cordons

* 0,27 0,09 0,32 0,00 0,53 22.

Evaluation of the vines

2537,00

655,20

0,26

1000,00

3000,00

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TABLE 4

Fac t or l oadi nga f or t he f i r s t 3 Ei genv al uea f or 22 v ar i abl es

( Pr ogr ammes us ed: I nput , Ut i l i t , Seal e, Cor r al , Kapr i n, Kat r an, Var v ar )

Var i abl e

Number Var i abl es Fac t or 1 Fac t or 2 Fac t or 1 .

Phas e I

1. Shoot l engt h c or don 1 - 0, 1819 - 0, 0187 ' - 0, 0198

2. Shoot l engt h c or don 2 - 0, 1658 - 0, 0462 - 0, 0915

3. Tot al s hoot l engt h of bot h c or deul s - 0, 2229 - 0, 0428 - 0, 0689

4. Spur s per c or don 1 _0, 1167 +0, 0043 - 0, 3900

5. Spur s per c or don 2 - 0, 1364 - 0, 0837 - 0, 3501

6. Spur s per v i ne -0,1672 - 0, 0516 - 0, 4901

7. Number of l eav es per s hoot of c or don 1 _{- 0, 1 972} +0, 3836 +0, 1089.

8. Number of l eav as per s hoot of cordon 2 - 0, 2367 - 0, 2877 +0, 2254

9. Tot al number of l eav es of t he s hoot s of v ar i abl es 7 and 3 - 0, 2976 +0,0677 +0, 2146

10. Tot al l eaf ar ea per s hoot of cordon 1 - 0, 2061 +0, 4049 +0, 0395

11. Tot al l eaf ar ea per s hoot of c or don 2 - 0, 2527 +0, 2991 +0, 2031

l e. Tot al l eaf ar ea of bot h s hoot s - 0, 71 33 e0, 0975 +0, 1621

13. Mean ar ea per l eaf of t he s hoot s of c or don 1 - 0, 2010 +0, 2236 - 0, 1987

14. Mean ar ea Der l eaf of t he s hoot s ef c or don 2 _0, 2+151 - 0, 2868 - 0, 0302

15. Tot al mean ar ea per l eaf of bot h s hoot s _0, 2190 4. 0, 0714 - 0, 2584

16. Tot al l eaf dr mass par s hoot of c or don 1 - 0, 2050 +0, 3928 +0, 1050

17. Tot al dr j l eaf mas s Der s hoot of c or don 2 - 0, 2480 +0, 3004 +0, 2098

18. Tot al l eaf dr y mass of bot h s hoot s - 0, 3089 +0, 0819 +0, 2119

19. Mean dr y mas s per l eaf of t he s hoot s of c or don 1 - 0, 0046 - 0, 0614 +o, 1666

20. i ' f aM dr y mas s pee l eaf of t he s hoot s of cordon 2 - 0, e204 - 0, 7061 - 0, 0625

21. Tot al mean dr y mass per l eaf of t he s hoot s of bot h c or dons _0, 2349 +0, 0494 -0,1882

22. Ev al uat i on of t he v i c ar - 0, 0647 - 0, 0104 - 0, 1137

Ei genv al uas _8,7 _{3, 5} 2, 1

Fac t or per c ent age r es pons i bl e f or v ar i anc e _{39, 6} 15, 3 9, 5

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The f i r s t PCA Fac t or wi t h an ei genv al ue of 8, 7 ac c ount For 39, 6% of t he v ar i anc e

of t he or i gi nal v ar i abl es . Thi s f ac t or has r s l at i v el y hi gh f ac t or l oadi ngs on

t he t ot al number of l eav es , l eaf ar ea and l eaf dr y mas s of al l meas ur ed s hoot s

i ndi c at i ng t hat l eaf c anopy v ar i abl es domi nat e t hi s Fac t or . Fac t or 2 has an

ei genv al ue of 3, 5 ex pl ai ni ng 15, 8% of t he t ot al v ar i anc e. The v ar i abl es wi t h

t he hi ghes t f ac t or l oadi ngs ar e t he number of l eav es per s hoot of c or don 1,

t he t ot al l eaf ar ea and t he t ot al l eaf dr y mas s of c or don 1 whi c h i s al s o l eaf

c anopy v ar i abl es r es pec t i v el y .

Fi gur e 1 r epr es ent s a pl ot of Fac t or 1 ( r epr es ent i ng mai nl y t ot al l eaf c anopy )

agai ns t f ac t or 2 ( r epr es ent i ng mai nl y t ot al l eaf ar ea) . Fr om t hi s pl ot i t c an

be deduc ed t hat t he v i ney ar d c ons i s t s of t wo gr oups of v i nes , s epar at ed mai nl y

by f ac t or 2. Y MAX 0, 4692 FACTOR 2 Y MI N - 0, 2527 X MI N - 0, 5946 X MAX 0, 5239 FACTOR 1

Fi g. 1. PCA of 297 v i nes wi t h 22 v ar i abl es of a Vi t i s v i ni f er a L. c v . Cape Ri es l i ng v i ney ar d. Fac t or l oadi ngs f or gr owt h c omponent s f ar PCA I and I I ( * vi nes consi der ed homogeneous; • and 4. vi nes consi der ed t o be het er : ganaous t o t he homogeneous gr oup ) .

Fac t or 3 has an ei genv al ue of 2, 1 r epr es ent i ng 9, 5% of t he v ar i anc e i n t he

or i gi nal v ar i abl es . The hi ghes t l oadi ngs i n t hi s Fac t or ar e t he s pur v ar i abl es

( Tabl e 4) . Thi s may be i nt er pr et ed as bei ng a gener al gr owt h f ac t or or c

ompo-nent .

(15)

I n Fi g. 2 f ac t or 1 ( X- Fl i ) and f ac t or 3 ( Y- ax i s ) ar e pl ot t ed. I t i s ev i dent

t hat t he l eaf c anopy f ac t or ( f ac t or 1) c or r el at es wi t h t he gr owt h f ac t or ( f ac

-t or 3) and -t ha-t -t he gr oupi ng of -t he v i nes i s wel l def i ned. I n Fi g. 3 -t he l eaf

Y MAX 0, 3491

FACTOR 3

Y MI N - 0, 2780

X MI N - 0, 5948 X MAX 0, 5239

FACTOR 1

Fi g. 2. PC, of 297 v i nae wi t h 22 v ar i abl es of a Vi t i s v i ni f er e L. c v . Cape Ri es l i ng v i ney ar d. Fac t or l oadi ngs f or gr owt h and l eaf c anopy c omponent s f or PCA I and I I I ( * homogeneous and • het er ogeneous ) .

canopy of cor don 1 ( f act or 2, ' i : . - axi s) i s pl ot t ed agai nst t he gr owt h f act or ( f

t or 3, Y- ax i s ) . Onc e agai n t he v i nes s eem t o be wel l gr ouped i nt o c l us t er s

i ndi c at i ng uni f or m v i nes as Far as t he l eaf c ov er i ng and ot her gr owt h par

a-met er s ar e c onc er ned. A f ur t her i ndi c at i on of t he gr oupi ng i s gi v en i n t he t

o-t al s on o-t he Y- ax i s s howi ng o-t he o-t oo-t al of pl oo-t o-t ed v i nes on o-t he 2- di mens i onal pl ane.

(16)

Y MAX 0,3491 FACTOR 3 Y MI N -0,2730 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA 1zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA4 X MI N -0,2522 X MAX 0,4892 FACTOR 2

Fig. Z. PCA of 297 vi nes wi t h, 22 v ar i abl es of a ! i i s v i ni f er a L. c v . Cepa

Ri es l i ng v i ney ar d. Fact or l oadi ngs f or l eaf canopy and gr owt h component s f or

ACA I I and I I I ( * homogeneous and• het er ogeneous ) .

Out l y i ng v i nes , whi c h ar e not c ons i der ed par t of t he c l us t er s , wer e el i mi nat ed

f r om f ur t her ex per i ment at i on. Thes e ar e t he v i nes wher e t he r el at i v e di s

-t anc e be-t ween any -t wo v i nes i s -t oo l ar ge i n r el a-t i on -t o -t he av er age di s -t anc e

of t he ot her v i nes t o one anot her . The as s es s ment of t he di s t anc es i s a

s ubj ec t i v e c hoi c e of t he aut hor s and t hi s may l ead t o c r i t i c i s m as f ar as t he

obj ec t i v i t y i s c onc er ned. Howev er , i t mus t be k ept i n mi nd, t hat t hi s gr oupi ng

was done t o gat an i ndi c at i on of t he homogenei t y of t he dat e s et and i t gi v es

t he r es ear c her s uf f i c i ent s c ope t o us e hi s own i ni t i at i v e as Far as t he c hoi c e

of s qoer i ment s 1 uni t s goes . Emphas i s mus t be pl ac ed on t he f ac t t hat t hi s i s

not a s t at i s t i c al anal y s i s f or eac h v ar i abl e al one but an anal y s i s f or t he

c ompl et e s et of v ar i abl es .

Af t er t he v i nes wer e c l as s ed i nt o a homogeneous gr oup A ( t he 245 v i nes c ons i

-der ed i n t he c l us t er ) and a het er ogeneous gr oup B ( t he 52 v i nes not c ons i -der ed

(17)

• • • • • • • - • • • • • zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA UzyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBAzyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA. S. • N U M B E R O F V IN E S P E R C A T E G O R Y 200 150 100 50

means and s t andar d dev i at i on of t he v ar i abl es f or t he t wo gr oups ar e gi v en i n

Tabl e 5.

The r es ul t s of t he SOA s howed t hat 208 of t he or i gi nal 245 v i nes c ons i der ed t o be

homogeneous ( 85%) c oul d be r et ai ned as c at egor y A v i nes whi l e 34 of t he or i gi nal

52 v i nes c ons i der ed t o be het er ogeneous v i nes ( 65%) wer e r et ai ned i n c at egor y 8

( Fi g. 4) . Al t hough t he per c ent age gr oupi ng f or c at egor y 8 i s l ow, t he v i nes ex

-c l uded f r om t hi s gr oup had not been t ak en i nt o -c ons i der at i on f or -c at egor y A

be-c aus e of t he r el at i v el y l ar ge di s t anbe-c es bet ween t hes e v i nes and t hos e v i nes of

c at egor y A. Thi s l ow per c ent age may be bec aus e of s ome unex pl ai ned v ar i anc e i n

t he dat a s at . Af t er es t abl i s hi ng t he homogeneous gr oup of v i nes ( A) anot her

SDA was per f or med on t he dat a, t hi s t i me c l as s i ng t he v i nes ac c or di ng t o t he

f our s oi l t y pes . Tabl e 6 gi v es t he means and s t andar d dev i at i on of t he 22 gr owt h

par amet er s .

A Al 8 81

CATEGORI ES

Fi g. 4. Vi nes gr ouped i nt o homogeneous and het er ogeneous c at egor i es by PCA end 501 t ec hni ques . ( A . v i nes s el ec t ed by PCA az homogeneous ; Al = v i nes s el ec t ed by 501 as homogeneous ; 8 = het er ogeneous v i nes ; 81 = het er ogeneous v i nes gr ouped by 50A) .

Fr om t he Sout hwol d s er i es 58 v i nes ( 73%) , t he Av al on s er i es 102 v i nes ( 79%) ,

(18)

TABLE

5

The means and standard deviation of the two categories

zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

as

classified by stepwise discriminant analyeis

' Variable Means Means Grand Means Standard Standard 22 222 Number Variables Category A Category D over Categories Deviation A Deviation II Phase I ) 6 ,'. 0 1140,84 165,56 145,09 1 34,38 1. Sleet length cordon 1 2.

Shoot langth oordon 2

* 128,50 169,07 135,47 14s,' 33 3.

Total shoot length

o of both cordons 1 266,41 338,56 278,80 92,06 _146,31 219,99 4. Spurs per cur -dz.:n ..1 2,70 2,47 2,66 1,06 1,27 5. Spurs per cordon 2 2,73 2,49 2,69 1,03 1,36 6.

Spurs per vine

5, 4 3 4,96 5,35 1,58 16 , 2,11 7. Number of r

leaves pet' shoot

zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA o f cordon '. 7-' 1 4 '4,7 8,45 --'5, -'.9 15 23,79 8.

Number of laavoe per ahoot of cordon 2

* 19,50 25,49 20,53 14,51 24,00 9.

Total number of leaves of the shoots of variables

7 and 8'44,41 53,94 46,05 21,53 3 0,57 10.

11 1 392,20 1 851,02 1 1Z:4 9 95 2 ,56 1 711,11 11.

Tots]. leaf area per shoot of cordon 2

* 1 131s,71 1 777,97 2 867 ; 59 1 665,91 12. Total leaf or 2 la of both shoote 4 2 507,85 3 585,67 692,93 1 309,05 2 267,65 13.

1 18,98 47,79 48,78 23,94 30,37 14.

* 46,13 5t: . ,28 47,37 1:211;!: 71,16 15. Total mean a r

ea per leaf of both shoots

'53,78 62,11 9 5, 1 30,77 16.

Total leaf dry mass par shoot of Lordon 1

4 7, 0 4 9, 70 7,43 3,25 1 ,2 17.

Total leaf dry mass par shoot

o f cordon ' 2' 4 5,82 8,61 6,30 81'674 13.

N 1=',C4 17,92 1 3,72 19.

Mean dor mass per leaf of the eboot

s of cordon 1 '8,37 0, 2 4 (,98 0,14 20.

Dean dry mass

per

leaf of the shoots of cordon 2

* 0,23 0,22 0,23 0,13 0,17 21.

Total mean dry mess per leaf of the shoots of both cordons

* 0,27 0,30 0,27 0,08 0,10 22.

Evaluation of the Vines

2 53 6 ,5 8 2 392,15 2 511,78 665,18 723,23

* Discrepancies in the data

s

e

t

!ar,1

attributable to computer rounding off.

1

2

Category A homogeneous group

2

"

Category 13

(19)

T A B L E 6 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA T I ,, . ._ o n o a n d o t o n d o r d & v ia l: o n o o f t h e f iv e c o t a g o r ie o o f w in c n a o d e fi n e d b y l lo n f o u r c o il t y p e c a n d h e t e r o g e n e o u o g r o u p a n p o in t e d o u t b y D C A i n w h ic h t h e y a r e g r o w in g a , c l0 0 0 lf le d b y a t e p w io s d io c r im in a n t o n a t i2 is . V a r ia b le B e n n o 1 M a n n a -B e a n o , H e n n a H e a r n D r o n d H a n n a S ta n d a r d S ta n d a r d S ta n d a r d S tn n d a r d S ta n d 4 5 B u n d le r V o r ia b le o C a te g o r y A C a t e g o r y 0 C a te g o r y zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA C C a te g o r y D C a t e g o r y E o f C a t e g o r is e D e v ia t io n A D O V IA 1 6 1 1 D D e v ia t io n C D e v ia t io n P D e v ia P h a s e I I . S h o o t l e n g t h c o r d o n 1 ' 2 1 1 , 0 4 1 3 3 , 8 6 8 7 , 1 8 1 6 5 , 5 6 1 4 5 , 0 9 1 0 7 , 2 ? ? 6 , 7 8 ' :34 1 1 6 , 4 6 11 : i7 °9.2C9 2 . S h o o t l e n g t h c o r d o n 2 ' 1 0 5 , 0 6 1 6 9 , 0 1 3 5 , 4 7 1 2 9 . 3 1 E, 6! 7: ; 7: 1: :: '3 1 0 1 ,9 1 3 . T o t a l s h o o k Le n g t h o f b o t h c o r d o n a ' 3 9 1, 30 ? 5 5 , 2 6 175 ;6' .. 93 32 3 3 0 . 5 2 1 4 . S p u r n p e r c o r d o n 1 ' 2 , 9 3 2 : 7 5 2 , 9 1 2 , 1 0 2 . 4 7 2 7 8 , 3 0 2 , 6 6 16 71 .. 51 67 0 , 9 7 0 , 9 4 5 . S p u r s p e r c o r d o n 2 ' 2 , 6 2 3 , -3 2 2 .6 3 1 , 9 0 2 . 4 9 2 , 6 9 0 , 9 2 0 , 6 8 0 , 7 6 1 8 i 1 189 175 1 , 0 3 6 . S p u r s p e r v in e ' 5 , 6 0 6 , 0 7 5 . 5 5 4 , 0 0 4 , 9 6 5 . 3 5 1 , 4 8 1 , 3 8 11 471 ,:;3. 8; 1 , 4 ? 2 5 , 1 9 1 1 9 2 ,72 8 7 H u m b e r o f le a v e n p e r a b o u t o f c o r d o n 1 ' 2 5 , 0 8 26 , 5 3 2 1. 5 5 2 4 , 9 2 15 . 7 1 1 4 , 2 6 1 3 , 7 5 2 0 . n o u b c r o f le a v e ° p e r o h o o t o f c o r d o n 2 ' 2 0 . 8 8 4 6 . ) 2 : 0 , 4 5 2 6 , 8 7 7. 9. 1 2 5 .1 9 2 8 , 4, 6 1 4 7173 006., ,o, 595 5 1 2 . 0 1 9 . T o t a l n u s h o r o f lc a v o ° o f t h e o h o o t o o f v a r io li le o 7 a n d 6 4 7 , 6 4 4 9 , 4 3 2 1 , 4 7 1 9 , 3 7 1 9 , 7 0 2 4 , 1 5 2 31 1 0 . T o t a l lo a f a r e a p e r o h o o t o f c o r d o n 1 '1 5 1 3 , 4 1 1 4 0 6 , 6 7 1 17 2, 51 / 4, (3 ,: . 5 3 . 9 4 7 5 4 . 2 ! 7 2 8 . 7 3 7 1 5 , 9 6 2 3 2 . 4 9 1 7 1 1 C 5 1 , 0 1 1 2 4 4 , 3 4 1 18 154 : 7 : 1 6 9 , 3 8 1 1 . T o t a l lo a f a r e a p a r s h o o t o f c o r d , . 2 '1 2 6 3 , 3 ? i 1 ? -0 ,! 8 '2 1^ 9. 61 ,6 7, 6 2 2 , 6 6 0 2 9 . 7 3 6 0 0 , 3 5 1 7 7 7 . 9 7 1 4 2 9 .4 2 9 9 3 , 0 7 12 (2 ;;3. 'I ? . T o t a l lc a a r e a o f b o t h o h o o f n ' 2 7 7 6 , 7 6 1 9 4 3 , 1 : 3 7 9 5 , 6 ? 4 3 5 , 0 0 2 4 8 4 , 8 7 2 6 9 2 , 3 3 4 8 , 7 3 223 053 ... 769 :3 1 3 . M o n : w o o p e r l e a f o f t h o o h o o t o o f c o r d o n 1 " 4 9 . 9 6 5 1 , 1 s 5 1, 4 9 4 1, 3 3 4 7 , 7 9 1 7 , 4 6 15 , 7 3 2 8 , 3 9 2 8 , 0 2 2 0 , 4 2 4 7 , 8 7 2 2 . 7 ? 7 1 4 . M a n n a r e a p e r l e a f o f t h e a h o o la o f c o r d o n 2 ' 5 1 , 3 2 5 1 , 1 0 5 6 . 2 ? 5 6 , 2 8 4 6 , 2 0 Z I II : 1 5 . T o lo t a e o n n r c a p e r l e a f o f b a t h n h o o t o ' 5 7 . 9 9 5 6 . 9 9 5 5 , 2 1 1 2 , 6 6 2 5 . 9 1 5 3 . 5 9 6 2 , 1 1 1 6 . T o ln i le a f d r y 1. 14 .. p e r 01 10 01 o f .o r d a n 1 ' 6 , 9 6 7 , 1 1 6 , 2 9 7 . 6 7 9 . 3 9 . 7 , 4 3 4 , 8 9 4 , 0 1 3 . 9 4 6 , 8 7 3: 1 7 . T o t a l le a f d r y m o o n p e r ° h 5 o o t o f c o r d o n 2 ' 6 , 1 6 8 , 7 1 : , 2 5 6 , 6 1 6 , 3 0 4 , 2 5 3 , 6 5 4 , 6 1 ' 3 , 5 5 1 8 . T o t a l h o o f d r y m a n n o f b o t h c h a o t o ' 1 3 , 0 4 1 2 ,2 2 8 4 1 5 ,0 0 1 0 , 1 5 1 7 , 9 2 1 3 , 7 1 6 , 7 2 6 , 1 7 6 , 1 7 8 , 1 4 1 1 9 . n a n o d r y m o o n p e r l o a f o f t h e n h o o t o o f c o r d o n 1 ' 0 , 2 3 0 , 2 5 3 4 0 , 2 4 , 7 6 0 , 2 2 6 , 9 8 0 , 1 2 0 , 1 7 0 , 1 5 2 0 . n e o n d r y m o a n p e r l e a f o f t h e o h o o t ° o f c o r d o n 2 ' 0 . 2 5 0 , 2 5 6 , 3 0 0 ,1 0 0 , 2 2 0 . 2 3 0 , 1 2 0 , 1 9 2 6 :: 6 1 10 0 .1 4 2 1 . T o t a l 4 . 2 4 1 1 d r y A lc o a p e r l o a f o f t h e ° h o o t : : o f b o t h c o r d p o e ' 0 , 2 7 0 , 2 6 0 . 3 6 0 , 2 3 0 . 3 0 0 , 2 7 0 , 1 8 0 ,1 4 0 , 0 6 0 ,1 3 6 4 1 , 7 4 2 2 . E v a lu a t io n o f lh e v i n e ° 2 4 6 6 , 0 6 2 68 9, 1". 6 2 5 8 o , o 0 :2 3 9 2 , i s 2 5 1 1 , 7 0 7 6 1 . 5 7 C h i , 6 4 5 6 8 . 3 7 2 45 4, .0 , 7 2 1 . C a t e g o r y A l S o o t h w o ld G a r in ° 2 . C ,t e g o r y D . A v a lo n c a r t o n 3 : C a t e g o r y C : G le n c o e n c r ie n 4 : C a te g o r y DI K o n o n k o p o e r io n 5 : C a te g o r y 5 .% B o tc r o g e n z o n o g r o u p D ir c r o p o n c le o i n t h e d a t e ., c o t a r c a t t r ib u t a b le t o c o m p u t e r r o u n d in g o ff .

(20)

18

s el ec t ed t o be par t of t he homogeneous gr oup s howi ng t hat i n t hi s s pec i f i c v i

ne-y ar d t he f our s oi l t ne-y pes had - l i t t l e or no ef f ec t on t he gr owt h par amet er s of

t he v i nes dur i ng t hi s s eas on.

Phas e I I : As a s uppl ement t o t he e, i s t i ng dat a, Fi v e addi t i onal par amet er s i

n-c l udi ng s ome gr ape qual i t y par amet er s wer e det er mi ned. The Ar t hur pr ogr amme

was us ed on t he dat a s et i nc l udi ng t he f i v e addi t i onal par amet er s and t he r es ul t s

ar e l i s t ed i n Tabl es 7 and 8.

Sev en of t he PCA f ac t or s hav e ei genv al ues gr eat er t han one and wer e r et ai ned

i n t he anal y s i s . They ac c ount For 100% of t he v ar i anc e i n t he or i gi nal v ar i

a-bl es . Af t er t he dat a was r ot at ed by t he Var i max r ot at i on al gor i t hm KAVARI , t he

f i r s t PCA f ac t or ex pl ai ns 24, 8% of t he v ar i anc e of t hs or i gi nal v ar i abl es ( Tabl e

8) . Thi s f ac t or has r el at i v el y hi gh f ac t or l oadi ngs on l eaf c anopy ( s ur f ac e)

and gr owt h v ar i abl es s uc h as t ot al number of l eav es - , t ot al l eaf ar ea per

s hoot on bot h c or dons , s i mi l ar t o f ac t or 1 i n phas e I wher e l eaf c ov er and

gr owt h v ar i abl es pl ay ed an i mpor t ant r ol e i n t he c l us t er i ng of t he v i nes .

Fad-t or . 2 has an ei genv el ue of 4, 97 and i s, pl ai ns 13, 6% of Fad-t he Fad-t oFad-t al v ar i anc e. The

v ar i abl es wi t h t he hi ghes t f ac t or l oadi ngs ar e t ot al l eaf ar ea of t he s hoot s

on c or don 2, t he t ot al dr y l eaf mas s of t he s hoot s on c or don 2 and t he av er age

l eaf mas s per l eaf of t he s hoot s on c or don 2. Thi s f ac t or may t her ef or e be

i nt er pr et ed t o be r el at i ng t o l eaf c ov er i n gener al and t o gr owt h par amet er s

of t he v i nes .

Fi g. 5 r epr es ent s t he pl ot of t he t ot al l eaf c ov er ( f ac t or 1, X- ax i s ) t o t he

(21)

TABLE 7

The scale data Lf phase I Ek II with the mean, standard deviation, normalised standard deviation, and minimum and mayimum values

Standard Normalised Variable Moan Number ' Variables Deviation Phase I 104,10 101 1 20 162,10 1,11 1,09 9 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA ( 1 7 1 16 6,, 2 9 23 23,43 13o,00 040,0o 539, 6 0 25,25 20 , 9 8 5,66 5,33 7,8 4 116,60 0,14 0,09 . 659,30 2,16 1,16 0,30 2,25 10,86

" Discrepancies in the data set are attributable to computer rounding off.

Std. Deviation Minimum Maximum 0,71 0.75 0,5g 0,42 0,00 0,00 0,00 0,00 514,00 664,00 769,00 6,00 0,40 0,00 0,32 0,00 1:::: 0,67 0,00 9,00 0,79 0,00 72,00. 0,51 0,00 117,00 0,76 0,00 6 340,00 o,84 0,00 5 956,00 0,57 0,00 8 419,00 0,52 0,00 204,50 0,81 0,00 458,10 0 , 3 8 0 , 0 0 m 0,76 0,00 32,41 0,85 0,00 26,70 0 ,57 0,00 38,75 1 6 ,55 0,00 2 000,00 0,66 0,00 0,61 0,32 0,00 0,53 0,26 1 3 oo000 000,00 0,11 0,00 23,10 0,15 0,00 131; 0,09 0,00 3,69 0,45 0,40 11,10 0,41 0,00 74,00 1. 2. 3. 4. 5. 6. 7.

Shoot length cordon 1 Shoot length cordon 2 Total shoot length of both cordons Spurs per cordon 1 Spurs per cordon 2 Spurs per vine Number of leaves per shoot of cordon 1 N "146,00 11 3 4 ,7 0 "278,90 2,66 2,70 5, zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA3 6 "25,51 C.

Number of leaver per shoot of cordon 2 Numb

'

20,39

9.

Total number of leaves of the shoots of variables 7 and 8

1

46,03

lo.

Total leaf area par shoot of cordon 1

"1 430, o0

1

11.

Total leaf arse, par shoot of cordon 2

'1 2

7.7,00

1

12.

Total leaf area of both shoots

"2 693,00

1

13.

n 1

eaf of the shoots of cordon

Mean area per l

o

'4894

,

14.

Mean area par leaf of the shoots of cordon 2

T.8,7

0

"48,60

15.

"55,41

1

.

Total leaf dry mass par shoot of cordon 1

' 7, 4 8 17.

Total leaf dry

m

a

s

c

.

per shcot of cordon 2

N6 ,,

.

18.

'13,71

19.

Mean dry mass per leaf of

zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA th e shoots of cordon 1 M 7, 0 5 20.

Mean dry mars per leaf of the shoots of cordon 2

0,23

21.

Total maan dry

11056E

per leaf of the shoots of both cordons

7,2

8

22.

2 920,00

Phase II Phase I plus the following C variables

23.

Total soluble solids

19,77 21+. Total till-able acids 7,90 25. pH 3,45 26.

Yield per vine

4,99

27.

Number of bunches per vine

(22)

TABLE 8

Factor loadir.gs

for the first 4 Eigenvaluea after rotation for 27 variables

(Programmee used: Input, Milli,. Scale, Corral, gaprin, Yatran, Eavan, Varvar) Variable Number

Variables Factor 1 Factor 2 Factor 3 Factor 4 Phase I 1.

-0,1205

+0,1501

-0,0400

-0,0644

2.

-0,1172

+0,0469

-0,0699

-0,0348

3.

Total shoot length of both cord:,ne

-0,1516

+0,1236

-0,0642

-0,0606

4.

Spurs per cordon 1

-0,0323

+0,0456

-0,1120

-0,5037

5.

Spurs per cordon 2

-0,0227

+0,0500

-0,0171

-0,4559

6.

Spurs per vine

-0,0356

+0,0618

-0,0839

-0,6206

7.

-0,4146 -0,c085 +0,0058 -0, 0 7.37 3.

-0,0176

-0,4315

+0,0098

-0,0596

9.

Total number of leaves of the shoots of variables 7 and 8

-0,3083

+0,2921

+0,0202

-0,0738

10.

-0,4119

10,0279

-0,1210

-0,0224.

11.

-0,0087 10,4185 -0, 1 55h -0,0139 12.

Total leaf area of both shoots

-0,3048

+0,2552

-0,1976

-0,0293

13.

Mean area par leaf of the shoots of cordon 1

-0,2646 -0,0291 -0 .33 0 9 -0,1828 14.

Mean area per loaf of the shoots of cordon 2

-00 . 0 395 +0,220e -0,4160 -0,0328 15.

-0,1313 +0,0713 -0 .5 6 55 -0,0962 16.

Total leaf dry maze per shoot of cordon 1

_0,4183

-0,6177

-0,0506

+0,0042

17.

Total leaf dry macs per shoot of cordon 2

-0,0213

+0,4314

-0,0398

-0,0409

13.

Total leaf dry saes of both shoots

-0,3164

+0,2810

-0,0643

-0,0240

19.

Mean dry mass per leaf of the shoots of zordon 1

-0 . 0 7 48 +0,0272 40,0215 -0,0649 20.

+0,0273

+0,3121

-0,2346

-0,1963

21.

Total mean dry mass per leaf of the shoots of both cordons

-0,1809

+6,1130

-0.3729

-0,1336

22.

+0,0129

+0,0062

-0,2258

+0,0049

Phase II Phase I plus the following 5 variables

23.

Total soluble solids

-0,0124 +0,0446 -0,1170 +0,0279 24. Total titratable acids +0,0718 -0,3303 +0,1380 -0,0811 25. PH +0,0165 +0,0408 -0,0427 +0,0061 26.

Yield per vine

7 0,06c9 +0,0416 +0,0217 -0,0744 27.

Number of bunches per vino

-0,0540 10,0353 -0,0009 -0 , 0 777 Eigenvalues 5 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA , 11 6,9 ..),h 2,3

Factor percentage responsible for variance

24,3

23,6

11,2

11,1

Cumulative percentage of variance

24,3 48,4 59,6 7 0 ,7

(23)

Y MAX 0, 3987 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA • FACTOR 2 Y MI N - 0, 3147 X MI N - 0, 5469 . x MAX 0, 3356 FACTOR 1

Fi g. 5. PCA of 245 v i nes wi t h' 27 v ar i abl es of a Vi t i s v i ni f er a L. c v . Cape Ri es l i ng v i ney er d. Fac t or l oadi ngs Par t ot al l eaf c ov er and t ol l eaf c ov er of c or -don 2 f ar PCA I and I I ( * vi nes consi der ed homogeneous and • and i . het er ogeneous) .

gr oups of v i nes whi c h wer e pr es ent i n c l us t er 1 ( Fi g. 1) of phas e I i s s t i l l

ev i dent al t hough t he c l us t er s eems t o be mor e c ompac t wi t h muc h s mal l er r el

a-t i v e di s a-t anc es bea-t ween gr oups ( Fi g. 6) . Thi s i s bec aus e of a-t he addi a-t i onal

c l us t er i ng ef f ec t of t he added par amet er s meas ur ed.

Y MAX 0, 4042

FACTOR 3

Y MI N - 0, 5398

X MI N - 0, 5469 X MAX 0, 3356

FACTOR 1

Fi g. 6. ' PCA of 245 v i nes wi t h .27 var i abl es of a Vi t i s vi ni f er a L. cv. Cape Ri

es-l i ng v i ney ar d. Fac t or es-l oadi ngs f or t ot aes-l Leaf zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBACOV31' and av age l eaf c ov e: f or

(24)

Fac t or 3 has an ei genv al ue of 2, 35 ex pl ai ni ng 11, 2% of t he t ot al v ar i anc e i n

t he or i gi nal dat a s et . The hi ghes t f ac t or l oadi ngs i n t hi s f ac t or ar e t he

ar ea per l eaf of t he s hoot s on c or don 1, c or don 2 and bot h c or dons as wel l as

t he av er age l eaf dr y mas s of t he v i ne. Thi s may onc e agai n be i nt er pr et ed as

bei ng a gr owt h f ac t or .

I n Fi g. 6 f ac t or - 1 was pl ot t ed ( X- ax i s ) agai ns t f ac t or 3 ( Y- ax i s ) . Compar ed t o

c l us t er 1 ( Fi g. 1) t he addi t i onal c l us t er i ng ef f ec t of t he Fi v e added par amet er s

i s ev i dent . I n Fi g. 7 Fac t or 2 ( Y- ax i s ) was pl ot t ed agai ns t Fac t or 3 ( X- ax i s ) . 22 Y MAX 0, 3987 FACTOR 2 Y MI N - 0, 3147 X MI N - 0, 5339 X MAX 0, 4042 FACTOR 3

Fi g. 7. PCA af 245 v i nes wi t h 27 v ar i abl es of a 1l i t i s v i ni f er a L. c v . Cape Ri es -l i ng v i ney ar d. Fac t or -l oadi ngs f or t ot a-l -l eaf c ov er of c or don 2 and av er age -l eaf cover f or POP I I and I I I ( • vi nes consi der ed homogeneous and • het er ogeneous) .

Fac t or s 4 and 7 r epr es ent 11, 1% and 9, 4% ( not s hown) r es pec t i v el y of t he v ar i

an-c e i n t he or i gi nal v ar i abl es and hav e ei genv al ues of 2, 3 and 1, 9. The hi ghes t

f ac t or l oadi ngs ar e on t he gr owt h par amet er s namel y s pur s and s hoot l engt h and

may be i nt er pr et ed as gr owt h f ac t or s .

Fac t or s 5 and 6 hav e ei genv al ues of 2, 2 and 2, 0 . ( not s hown) r es pec t i v el y wi t h

r el at i v el y hi gh l oadi ngs on t he par amet er s s uc h as pH, y i el d per v i ne and number

(25)

CONCLUSI ON

I n mos t PCA f ac t or s t he l eaf ar ea pl ay ed an i mpor t ant r ol e i n t he c l us t er i ng

pr oc es s al t hough a number of f ac t or s af f ec t s t he f i nal s el ec t i on. The mor e

uni f or m v i nes wer e t hos e wi t h mor e or l es s t he s ame l eaf s ur f ac e and gr owt h

v ar i abl es , wher eas t hos e r ej ec t ed For ex per i ment al pur pos es wer e t hos e

de-v i at i ng f r om t he abode-v e. I n t he s el ec t i on of homogeneous de-v i nes i t appear s t hat

i ns t ead of meas ur i ng 27 f ac t ur , z , uni t Loul d c onc ent r at e on v ar i abl es f or det er

-mi ni ng l eaf c anopy .

When al l meas ur ed v ar i abl es wer e t ak en i nt o ac c ount i t i s ev i dent t hat t he f our

s oi l t y pes had l i t t l e or no ef f ec t on t he homogenei t y of t he di f f er ent v i nes

i n t he v i ney ar d dur i ng t hi s gr owt h s eas on. Qual i t y v ar i abl es s uc h as oB, TTA

and pH r es ul t ed i n bet t er def i ned c l us t er s and s houl d t her ef or e be us ed i n

f ut ur e s t udi es of t hi s nat ur e. The pr ogr amme us ed i n t hi s s t udy ar e power

-f ul and handy t ool s i n t he hands o-f t he v i t i c ul t ur i s t enabl i ng hi m t o s i mul t

an-eous l y t ak e i nt o ac c ount gr oups of v ar i abl es and t hei r r el at i ons hi ps wi t h ot her

gr oups and c ombi ned wi t h t he nor mal s t at i s t i c al t ool s s uc h as r andomi s at i on

and r epl i c at i on hel p t o gi v e a bet t er under s t andi ng of t he dat a.

LI TERATURE

ANONYMOUS. 1981. Ont l edi ngs met odes v an mos en wy n. Publ i s hed by t he Sout h

Af r i c an Soc i et y f or Enol ogy and Vi t i c ul t ur e, P. O. Box 2092, Dennes i g,

St el l enbos c h, 7600, Republ i c of Sout hAf r i c a.

BROSCHAT, T. K. 1979. Pr i nc i pal c omponent anal y s i s i n hor t i c ul t ur al r es ear c h.

(26)

GLADON, R. J . & STABY, G. L. 1976. Openi ng of i mmat ur e Chr y s ant hemums wi t h

s uc r os e and 8- hy dr ox y qui nol i ne c i t r at e. Hor t Sc i enc e 11, 206- 208.

HARPER, A. M. , DUEWER, D. L. & KOWALSKI , B. R. 1977. Ar t hur and ex per i ment al

dat a anal y s i s : The heur i s t i c us e of a Pbl y al gor i t hm. Doc ument at i on f or

Ar t hur , Ver s i on 1- 9- 77. Labor at or y For Chemomet r i c s , Dep. of Chemi s t r y ,

Uni v. Geor gi a, At hens, Geor gi a.

HAMMER, P. A. 1981. Cont r ol l i ng v ar i abi l i t y . hor t Sc i enc e 15 ( 6) , 818- 630.

HOTELLI NG, H. 1936. Anal y s i s of a c ompl ex of s t at i s t i c al v ar i abl es i nt o

pr i nc i pal c omponent s . 3. eMuc . Ps y c hol . 24, 417- 441, 498- 520.

LEEGWATER, D. C. & LEEGWATER, J . A. 1981. The us e of a mi c r oc omput er i n t he

cl assi f i cat i on of gr ape br andi es by pat t er n r ecogni t i on. J. Sci . Fd Abr i c.

32, 1115- 1118.

MACVI CAR, C. N. & SOI L SURVEY STAFF, 1977. Soi l c l as s i f i c at i on - A bi nomi al

s y s t em f or Sout h Af r i c a. Sc i . Bul l . 390, 152 pp Gov er nment Pr i nt er ,

Pr et or i a.

OLI VER, J . E. , SI DDI GI , A. H. & COWARD, S. N. 1978. Spat i al pat t er ns of c l i mat e

and i r r i gat i on i n Pak i s t an: A mul t i v ar i at e s t at i s t i c al appr oac h. Ar c h.

Met . Geophys. Bi okl i m. Ser . B. 25, 345- 357

ORLOCKI , L. 1967. An aggl omer at i v e met hod f or c l as s i f i c at i on of pl ant c ommuni

-t i es J. Ecol . 44, 193- 206.

(27)

SNEATH, P. H. A. & SOKAL, R. R. 1973. Numer i cal t axonomy. W. H. Feeman & Co. , San Fr anci sco.

VAN ROOYEN, P. C. & TROMP, A. 1982. Cheni n bl anc wi ne vol at i l es and t he i nt en-si t y of a guava- l i ke f l avour . S. Af r . J. Enol . Vi t i c. 3 ( 1) : 1- 7.

ZEEMAN, A. S. 1981. Opl ei . I n: Wi nger dbou i n Sui d Af r i ka 185. 198. Eds. J. D. Bur ger & J. Dei st . VORI . St el l enbosch, 7600.

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ABSTRACT

The ef f ec t of t oppi ng on a Vi t i s v i ni f er a L. c v . Cape Ri es l i ng v i ney ar d

was i nv es t i gat ed. Shoot and l eaf gr owt h of bot h t he t opped and unt opped

v i nes , r es pec t i v el y , c an be des c r i bed as s i gmoi dal . \ ,

gr owt h ( c m2 ) Of t he t opped v i nes wer e s i gni f i c ant l y mor e t han t hat of t he

unt opped v i nes and ar e at t r i but ed t o l at er al s hoot gr owt h i n t he c as e of

t he t opped v i nes . Toppi ng had no ef f ec t on bunc h . dev el opment . The dev el

op-ment or s k i n, pul p and s eed wi t h t i me of bot h t he t opped and unt opped v i nes

ex pr es s ed as a per c ent age dr y mas s per ber r y c an be des c r i bed by a hy per

-bol i c f unc t i on f or t he s k i n, l i near f or t he pul p and . par a-bol i c f or t he s eed. 27

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I NTRODUCTI ON

Gr owt h has been def i ned as " t he adv anc ement t owar ds or at t ai nment of f ul l

s i z e of mat ur i t y ; dev el opment ; a gr adual i nc r eas e i n s i z e and t he pr

o-c es s wher eby pl ant s and ani mal s i no-c r eas e i n s i z e by t ak i ng i n f ood" ( Bi

d-wel l , 1974; Sal i s bur y & Ros s , 1978) . Gr owt h may be ev al uat ed by meas ur

e-ment s of mas s , l engt h, hei ght , s ur f ac e ar ea or v ol ume ( Noggl e & Fr i t z ,

1976) . Gr owt h c ur v es of pl ant s ar e gener al l y s i gmoi dal ( Bi dwel l , 1974;

Noggl e & Fr i t z , 1976; Sal i s bur y & Ros s , 1978) _l ough doubl e and t r i pl e

s i gmoi ds hav e been r epor t ed ( Pr at t & Rei d, 1974; Coombe, 1976) . Si

g-mai ds and doubl e s i gmoi ds hav e been des c r i bed f or s hoot gr owt h and ber r y

dev el opment f or Vi t i s s pp. and c ul t i v ar s ( Coombe, 1960; 1973; 1976;

1980; Ni t s c h et al . , 1960; Hal e, 1968; Har r i s , Kr i edemann & Pos s i ngham,

1968; Coombe & Hal e, 1973; Kl i ewer & Sc hul t z , 1973) .

Remov al of t he di s t al 25 c m or mor e of t he gr owi ng s hoot t i p i s c al l ed

t oppi ng ( Wi nk l er et al . , 1974) and i s nor mal l y r ec ommended t o i nhi bi t

gr owt h of v i gor ous l y gr owi ng s hoot s r es ul t i ng i n uni f or m and upr i ght

gr owt h ( Ther on, 1944) . By r emov i ng 25 c m of t he apex , api c al domi nanc e

i s r emov ed, r es ul t i ng i n t he dev el opment of l at er al s hoot s .

Res ul t s obt ai ned i n t he nor t her n hemi s pher e i ndi c at e t hat t he j uv eni l e

l eav es of t he l at er al s hoot s ar e t he maj or s i nk s f or nut r i ent s ( Hal e a

Weav er , 1962; Kobl et , 1977) but af t er t wo t o t hr ee l eav es hav e mat ur ed,

bas i pet al t r ans l oc at i on of nut r i ent s t ak es pl ac e ( Kobl et & Per r et , 1971;

(30)

I t i s i mpor t ant t hat onl y v i gor ous l y gr owi ng v i nes s houl d be t opped

be-c aus e poor gr owt h wi l l be f ur t her aggr av at ed by t he ef f ebe-c t of t oppi ng

( Mal an, 1935; Ther on, 1944) . The t i mi ng of t oppi ng i s v er y i mpor t ant

bec aus e t he r emov al of l eav es at t he wr ong t i me wi l l r es ul t i n i ns uf f i

-c i ent gr ape nour i s hment . Le Roux & Mal an ( 1945) and Coombe ( 1959) r epor t ed

t hat r epeat ed t oppi ng ( t hr ee t o f our t i mes or mor e dur i ng one s eas on)

dec r eas ed ber r y mas s . Si mi l ar l y E1 7af t awi & Was t e ( 1970) f ound t hat a dr as

-t i c dec r eas e i n l eaf ar ea us ual l y c aus es a l os s i n ber r y mas s and s ugar c

on-c ent r at i on.

Si nc e 1944 no wor k on t he ef f ec t of t oppi ng on t he v i ne was done i n Sout h

Af r i c a. I t i s t her ef or e i mpor t ant t hat t he ef f ec t of t oppi ng on t he v i ne

under Sout h Af r i c an c l i mat i c c ondi t i ons s houl d be i nv es t i gat ed. The ai m of

t hi s i nv es t i gat i on was t o det er mi ne t he ef f ec t of t oppi ng on t he gr owt h

c har ac t er i s t i c s of Vi t i s v i ni f er a L. c v . Cape Ri es l i ng.

MATERI AL AND METHODS

Mat er i al : Fi f t een y ear ol d V. v i ni f er a c v . Cape Ri es l i ng v i nes gr af t ed on 99

Ri c ht er r oot s t oc k s end t r el l i s ed t o a Per ol d t r el l i s i ng s y s t em ( Zeeman, 1981)

wer e us ed i n t hi s i nv es t i gat i on. Homogeneous v i nes wer e s el ec t ed as des c r i bed

by De l a Har pe & Vi s s er ( 1983) and wer e s pur pr uned t o 16 buds per k i l ogr am

s hoot mas s . Rai nf al l Was s uppl ement ed by t wo ov er head s pr i nk l er i r r i gat i ons

of 200 mm eac h dur i ng Nov ember 1981 and J anuar y 1982, - r es pec t i v el y .

Met hods : The s el ec t ed v i nes wer e di v i ded i nt o t wo s ec t i ons of 104 v i nes eac h. 29

(31)

One s ec t i on was t opped by r emov i ng t he pr ox i mal 30 c m of eac h s hoot of t he

v i ne at pea ber r y s i z e dev el opment s t age ( 56 day s af t er bud br eak ) . For t he

pur pos e of t hi s i nv es t i gat i on bud br eak was def i ned as t hat s t age at whi c h

10% of t he v i nes had t wo l eav es . Toppi ng was done at t hi s dev el opment al s t age

t o ens ur e t hat t he t r eat ment was appl i ed bef or e t he l i near gr owt h phas e of

t he s hoot . The ot her s ec t i on was l ef t unt opped. Ten t opped and 10 unt opped

v i nes wer e r andoml y s el ec t ed and on eac h t he t wo s hoot s on t he s ec ond ac r

o-pet al s pur of eac h c or don wer e us ed f or det er mi nat i on of s hoot l engt h and

l eaf ar ea. Shoot l engt hs wer e det er mi ned f r equent l y at i r r egul ar i nt er v al s .

Leaf ar eas wer e det er mi ned wi t h a model LI - 3000 Li - Cor Por t abl e Ar ea Met er .

Whol e bunc hes on t he s ec ond s pur of bot h c or dons of t hr ee t opped as wel l as

of t hr ee unt opped v i nes wer e s ampl ed 69, 76, 82, 92, 97, 110, 117, 131, 138,

145 and 15' day s af t er bud br eak and s t or ed at - 20°C unt i l s ubs equent anal y s es .

Si x t y ber r i es per v i ne f r om eac h of t he t opped and unt opped v i nes wer e s ampl ed

69, 76, 82, 92, 97, 110, 117, 131, 138, 145 and 152 day s af t er bud br eak

and t he ber r y v ol ume det er mi ned by meas ur i ng wat er di s pl ac ement i n a meas ur i ng

c y l i nder . The f r es l-L and dr y mas s of t he ber r y , s k i n, pul p and s eed s epar at el y

wer e det er mi ned on 60 ber r i es per bunc h. Dr y mas s was det er mi ned by dr y i ng

at 80°C t o a c ons t ant mas s .

One way anal y s es of v ar i anc e wer e done by 8M0P- TV and SPSS s t at i s t i c al pr

o-gr amme and t he r eo-gr es s i on anal y s es by a l i near Leas t Squar es Cur v e f i t t i ng

(32)

WO I SO zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

TI ME ( DAYS AFTER BUD BREAK) zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

2_ R - 0 .9 9 4 0 0 A1 ‘ Prob. tad = 0 .0 3 .1 R2 = 0.99 • I 2 0 0 I P/ TOPPED UNTOPPED A V E R A G E S H O O T L E N GT H ( c m ) 4 0 [ 3 0 • : 1 I I I S H O OT G R O W T H (cm ) • 5 0 1 i0 0 1510

TI ME ( DAYS AFTER BUD BREAK) 2 0

1 0

31

RESULTS AND DI SCUSSI ON

The v eget at i v e gr owt h phas e

Shoot gr owt h: The av er age, f i nal s hoot l engt h f or t he unt opped v i nes was

267, 8 c m ( Fi g. 1) . The s hoot s s t ar t ed of f wi t h a s l ow el ongat i on r at e but

s hoot gr owt h i nc r eas ed f r om 60 day s af t er bud br eak i . e. s hor t l y af t er t oppi ng

( Fi g. 2) . Thi s s har p i nc r eas e l as t ed about t hr ee day s af t er whi c h t he gr owt h

r at e dr opped t o appr ox i mat el y t hr ee c m per day and dec l i ned s teadi l y unt i l

no el ongat i on c oul d be meas ur ed at 135 day s af t er bud br eak .

The av er age, f i nal t ot al . s hoot l engt h of t he t opped v i nes was appr ox i mat

e-l y 410 c m ( Fi g. 1) whi c h i s s i gni f i c ant e-l y mor e t han t hat of t he unt opped

v i nes mai nl y as a r es ul t of l at er al s hoot dev el opment . The s hape of t he

gr owt h c ur v e ( Fi g. 1) of t he t opped v i nes was al mos t i dent i c al t o t hat of

unt opped v i nes al t hough at a muc h hi gher l ev el Fr om 60 day s af t er bud br eak

onwar ds . Two day s af t er t oppi ng t he el ongat i on r at e i nc r eas ed s i gni f i c ant

-l y and r eac hed 37 c m per day f or t wo day s wher eaf t er i t dec -l i ned s har p-l y t o

about t hr ee c m per day ( Fi g. 2) . Gr owt h s t opped 155 day s af t er bud br eak

i n c ont r as t t o t he 135 day s of t he unt opped v i nes ( Fi g. 2) .

FI G. 1. Fi t t ed c uz v es and obs er v ed dat a f or

t opped ( 11 ) and unt opped Vi t i s vi ni f er a

L. cv, Cape Ri esl i ng vi nes. ( T = or t opping) .

FI G. 2. Dai l y s hoot elx igat icn for t opped and

unt opped Vit is yi n: f er e L. cv. Cape Ri esl i ng

v i nes . ( * s i gni f i c ant di f f er enc es ( p 0, 05) i n

(33)

A V E R A G E N U M O E R O F ,LE A U E S P E R S H O O T zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA ?c m = zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA .9 c4 d (N na s one 83 1J V Sk t1 0) N il pa na es qo p ue s en zn o zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA U ) ₀ C l A V E R A G E I N C R E A S E I N LE A F N U M B E R P E R S W O T uos ee s Elu Tm oz 5 ey q 5u Tz np uT e se ez ou i

T I ME ( OAYS AFTER BUD BREAK)

ez ajT uT A sT qT A p ed do 4 1 ' ° 1 n .1 ed T8 ee TT bu . ce p za d 58 A29 1

t hose obt ai ned b y Van der Wes t hui z en

(S 0' 0 = d) s sa T AT 41-1 20 TJ ✓t . C t U ) a ) 3 -CD sa uT A pe dd oor

t he unt opped v i nes was s i gni -

= I ! ;e s E4 e10

The l os s of l eav es i n t he t opped v i nes

t hr ee def i ni t e peak s namel y at 30 ,1 04

I nc r ease i n number of l eav es per day dur i ng t he gr owi ng

c1 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA • 3 j C O 1 1 ▪ 3 rt a to • H . C1 3 C L 3 < C 0 S 0 ) 0: 1 0 1 3 1-1 ) -C D X -E U 1 a -P . a H . 0 • (1 ) r r • < 3 CD CI ) O u ) zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA C L 3 ' 0 a r l-(D H . CD I-I -I) a M c-t • I-I O 0 a ) 0 3 (I ) r t H . 0 r t 1 0 I I CD O C L H . e l-C i H . -0 3 U ) W CD 3 a H . H . 3 3 • m I-j ( j) to U)• w tia zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA C D CD (D CD 0 3 ff i 0 C O -3 CD C O 13 ) CD _Lo zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA 3 ci- cr 6-j (C) 13) -17 _rt ₀ :y 4 mo ab j es i sa uT A pa dd oqw n e yq

(34)

32—

ow

i27 —

100 150 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

TI ME ( DAYS AFTER BUD BREAK)

sol i cb

TI ME ( DAYS AFTER 8U0 BREAK)

22

7I 1' • E ( DAYS AFTER BUD BREAK)

A V E R A G E L E A F A R EA P E R S H O O T ( c m 2 ) TOPPED UNTORPEO zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA 7 • .41..096 Prob. t ail -

Thr ee deFi ni t e peak s i n t he r at e of i nc r eas e i n l eaf ar ea wer e obs er v ed

i n t he c as e of t opped v i nes ( Fi g. 6) . Thes e peak s c oi nc i ded wi t h t he bur s t s

i n s hoot l engt h. The week l y t emper at ur e f r om bud br ea t o har v es t i s gi v en

i n Fi gur e 7.

FI G. S. Fi t t ed cur ves and obser ved dat a f or t he avsr sge i ncr ease i n l eaf S3 Fr om budbr esk t a har vest For t opped ( 41. ) and unt apped ( 41) Vi t i s

vi ni f er a L. cv. Cape Ri esl i ng vi nes. ( T = t i me of t appi ng) .

Repr oduc t i v e gr owt h phas e

FI G. 6. I ncr ease i n l eaf ar ea per FI G. 7. Weekl y t emper at ur e day dur i ng t he gr owi ng season f or Fr on bLd br eak t o har vest . t apped and unt apped Vi t l s vi ni f er a

L. cv. Cape Ri esl i ng vi nes OP si gni f i cant di f f er ences ( p =

i n t he dat a set ; T = t i me of t appi ng) .

Bunc hes : The dev el opment of t he bunc hes on t opped and unt opped v i nes i s

s hown i n Fi gs . 8, 9 and 10. No s t at i s t i c al l y s i gni f i c ant di f f er enc es ( P = 0, 05)

wer e f ound bet ween t he f r es h and dr y mas s per bunc h of t he t opped and unt opped

v i nes ( Fi gs . 8 & 9) . I t i s c l ear t hat t oppi ng di d not ef f ec t bunc h dev el op-

ment or t hat v ar i at i on was s o l ar ge t hat t he ef f ec t of t oppi ng c oul d not be

s hown s t at i s t i c al l y di f f er ent .

Ber r i es : The i nc r eas e i n ber r y v ol ume s howed a doubl e s i gmoYd c ur v e

( Fi g. -i i ) and c oul d be di v i ded i nt o t hr ee s t ages as des c r i bed by Coombe

( 1960; 1973; 1976 ; 1980) , Har r i s , Kr i edemann and Pos s i ngham ( 1968) ,