a study of the vegetative and reproductive …...c - reproductive morphology and growth 12 1 -...
TRANSCRIPT
Copyright is owned by the Author of the thesis. Permission is given for a copy to be downloaded by an individual for the purpose of research and private study only. The thesis may not be reproduced elsewhere without the permission of the Author.
A STUDY OF THE VEGETATIVE AND REPRODUCTIVE MORPHOLOGY OF
GRASSLANDS HUlA WHITE CLOVER (7�itofium �epen� L.) WITH
EMPHASIS ON THE EFFECTS OF DEFOLIATION AND PARAQUAT
ON SEED YIELD AND QUALITY
CARLOS EDUARDO ROMERO MALDONADO
1985
Depicting vegetative and floral parts of white
clover plant.
Inflorescence
Seed Pod Single Seed
ABSTRAC T
The p r e s ent s t udy e x amined t h e e ffect of management s y s t ems , p ar t i cul ar l y
cl osi ng dat e and paraquat app l i ca t i on, o n t h e vege t a t i ve and r e product i ve
morphol ogy of'Gr a s s l and s Hui a' whi t e clover (Tri fol i um repens L. ) ove r
two succe s s i ve y e a r s i n a fi e ld mi x e d (gra s s and clover ) sward s i t uat i on.
More d e t ai l e d s tudi e s i nvolv i ng two di f fe rent genoty p e s of 'Gr a s s l ands
Hui a' whi t e clover grown i n monocul ture were al so carri ed out to e x am i ne
the e f fect s of cut t i ng and paraquat app l i cat i on.
The mi x e d sward s t udi e s cl ear l y showe d t h at N ovember closing d at e s
r e s u l t e d i n h i gh e s t s e e d y i e l d s. I n gr a s s/clover swards the clos i ng
of crQp s i n November accomp ani ed by p araquat s pray i ng to remove gra s s
comp e t i t i on e i t h e r i n mi d Oct obe r or at clos i ng , enhance d seed y i e l d.
Lat e r grazi ng and s p r ay i ng was d e l e t e r i ou s t o s e e d y i e l d unle s s c l i m at i c
condi t i ons al l ow e d cont i nued vege t at i ve grow t h into December. I n t h i s
lat t e r cas e s p r ay i ng i n November and clos i ng i n December gave h i gh s e e d
yi e l d s . Tr e atment s i nvol v i ng closing i n Se p t ember and October and
spray i ng 30 day s before , at clos i ng or 30 day s a f t er closi ng , alway s
gav e l e s s s e e d y i e l d t han November t r e atme nt s spray e d 30 day s be fore or
at closing t i me.
Closing t i m e and s p r ay i ng t i me had a mar k e d e ffect on seed y i e l d component s.
The mos t cons i s t ent and major ef fect of c l os i ng and s p r aying t r e atment s
i n t h e two m i x e d sward experiment s was on i nf l ore sce nce number s. O t h e r
component s such a s s e e d s e t , s e e d weigh t , and f l or e t numbers w e r e not
cons i st ent l y i nf l uenced by management but di d v ary according to e nvi ron
men t a l condi t i ons.
Studi e s on the e f fect s of cut t i ngs and p ar aquat ap p l i cat i on on p l ant
s t ructure and on s e e ding pot ent i al and y i e l d of 'Gr a s s l ands Hui a' whi t e
clove r cl e ar l y showe d t h a t t here i s a p a r t i t i oni ng between v e ge t at i v e
grow t h and r e product i ve d e v e l opment. The v e ge t a t i v e proce s s w a s charac
t eri s e d by a h i gh p ercent age of t h e nod e s on mai n s t olons formi ng l at eral
s t olons i n t h e wi nt e r and ear l y s pri ng. R e product i ve deve l opment i n l at e
spr i ng and summe r showed t h a t approxi mat e l y 80% o f i nf l ore scence s were
forme d on mai n s t o lons . High e s t i nf l ore scence number s were p roduced
from nodes forme d i n Octobe r and Novembe r , a l t hough f l oral i ni ti at i on
s t ar t e d duri ng l a t e wint e r (August ) . The two genot y p e s used i n t h i s
s t udy show e d consi derabl e vari a t i on i n r e l at i on t o reproduct i ve d e v e l op
ment . Di f ference s of 47% i n i nflore scence number s , 25% i n s e e d s p e r
f l or e t and 13% i n s e e d w e i gh t w e r e obs e r v e d between genotype s.
The e f fe c t s of defoli at i on by cut t i ng i nvolved a re ducti on i n stolon
e l ongat i on and a gener a l i ncr e a s e i n l at eral s t ol on product i on ,
part i cul a r l y when t ermi nal bud s w e r e a l so removed. Both l i gh t and
he avy cut t i ng t r e atment s r e sul t e d i n s e e d yi e l d s whi ch were 70 to 90 kg/ha l e s s t han the 657 kg/ha produce d by uncut p l ant s. The e f f ect of
p araquat app l i cat i on was al so d e t rimental to s e e d yi e l d , mai nly t hrough
a di rect e ffect on whi t e clover morphology. A l though p ar aquat reduce d
t h e amount o f l at eral branchi ng on t h e main s t olon t h e de s t ruct i on of
s t ol on t i s sue by t h e h erbi ci de r e duce d p l ant r e covery and r e su l t e d i n
a s e e d y i e l d o f onl y 392 kg/ha compare d wi t h 657 kg/h a from unspray e d
p l ant s. Thi s e f f ect was mos t pronounce d in pure swar d s of whi t e clover
and was l e s s obvious when the gra s s component of a mi x e d sward provi d e d
some prot ect i on for t h e whi t e clover by re ducing t h e e x t ent o f di rect
cont act wi t h t h e herbi ci de.
Some pot e nt i al are a s for future r e s e arch and t h e p ot e nt i al for whi t e
clover s e e d producti on i n Colombi a are also di s cu s s ed.
ii
ACKNOWLEDGEMENTS
There are many people I wish to thank for thei r understanding and
s upport during my studies in New Zealand .
but I thank them al l .
I can mention on ly a few
Those pr incipa l l y invol ved were :
Dr Murray H i l l , Di rector
beginning of my research
read and corrected the
constructive cr iticism .
o f the Seed Technology Centre who s i nce the
ha s been a source of he lp and support . He
manus cript improving my e ngl i sh a nd making
Professor B . R . Watki n , Head of the Department of Agronomy who guided
and instructed me during the first part of the research work .
Dr M . P . Rol ston , of the Gra s s lands Divis ion , DSI R , who provided guidance
a nd he lp during the programme .
Professor R . G . Thoma s for hi s inva luable and constant help during the
preparation of this thesis . His support is very much apprec iated .
I a l so thank Mrs D . Meech , Mrs K . Johnstone , Mr s R . Ca lton,
Johnstone and Mr G . Wa l ter for their technical a ssistance
l aboratory work and in the s canning electron mi crographs .
Mr R . C . Seddon for his help in computing the data .
Mr C . R .
i n the
Sta f f and students of Seed Technology Centre and the technicians of
the Agronomy Department , especi a l l y Mr T . J . Lynch, Mr M. C . Thomson
and Mr R . F . Battersby for the i r support and the use of the ir technica l
faci lities .
Mrs Anne Davies for her patience a nd care in typing the draft of
the manuscr ipt .
Mrs Veronica Fi.e ldsend for her care in the f ina l typing of the manuscript .
i i i
My gratitude i s a l so expressed to the New Zeal and a nd Colombia n
Governme nts who al lowed me t o complete m y study programme .
Fina l l y , my warmes t thanks to Maria Isabel , Car los and Cami lo for thei r
patience , support and understanding .
iv
CONTENTS
PAGE
Abstract
Acknowledgements i i
List of Tables vi i i
List of Figures xii
List of Plates xiv
List of Appendices XV
INTRODUCTION �·
CHAPTER I - REVIEW OF LITERATURE 4
A - General Descr ipt ion of White Clover 4
B - Vegetative Morphology and Growth · 6
1 - Stolen Structure and Growth 6
2 - Branching 9 3 - Leaf and Petiole Growth 10
4 - Root Growth 11
C - Reproduct ive Morphology and Growth 12
1 - Inflorescence St ructure and Growth 12
2 - Fac� which af fect Inf lorescence Deve lopment 13
D - Ef f ect of Flowering on Vegetat ive Growth 16
E - Seed Structure and Development 16
F - Seed Yield Components and Seed Qua l i ty 20
G - Seed Crop Management 23
1 - Seed Product ion 23
2 - Effect of De fol iation on Vegetat ive Growth , Reproductive Growth and Seed Product ion 28
H - Paraguat Properties 32
CHAPTER II - EFFECT S OF CLOSING DATE AND TIMING OF PARAQUAT AP PLICATION ON VEGETATIVE AND REPRODUCTIVE GROWTH OF HUIA IN MIXED SWARD S 33
A - Field Experiment 1982 - 1983 33 1 - Int roduction 33
2 - Materia l s and Methods
a - Experimenta l Site and Field Procedures
b - Plant Measurements and Stati sti cal Ana lysis
3 - Results
a - Ef fect of Treatments on Dry Weight of grass and Dead Matter
b - Ef fect of Treatments on Whi te Clover Dry Wei ght
c - Ef fect of Treatments on Clover Lea f Area Index
d - Ef fect of Treatments on Number of Nodes and Terminal Buds
e - Ef fect of Treatments on the Date of Peak F l owering
f - Effect of Treatments on Seed Yield and Yield Components
g - E f f ect of Treatments on Seed Quality
h - Relationship Between Seed Y i eld and Yield Components
B - Field Exper iment 1983 - 1984
1 - Introduction
2 - Materia l s and Methods
a - Experimenta l Site and Field Procedure
b - Pl ant Measurements and Stati stical Ana lysis
3 - Re sults
a - Ef fect of Treatments on Gra s s and Dead Matter Dry Weight
b - E f f ect of Treatments on White Clover Dry We ight
c - Ef fect of Treatments on White C lover Leaf Area I ndex a nd Lea f let Area
d - Ef f ect of Treatments on Number of Nodes , Terminal buds and Stolon Length
e - Ef f ect of Treatments on Branch Production per Stolon
f - Re l ationship between Vegetat ive Characters
g - Ef fect of Treatment on the Number of I n f l orescences
h - Re lationship between Inf lorescences/m2
a:nd Vegetative Characters
i - Effect of Treatments on the Date of Peak F l owering
V
PAGE
33
3 3
37
3 9
3 9
42
4 5
47
50
50
61
65
67
6 7
6 7
6 7
70
·10
70
n
75
7 7
82
92
85
B:Z
90
j - Ef fect of Treatments on the Seed Yield and Yield Components
k - Ef fect of Treatment on Seed Qua l ity
l - Rela tionship between Seed Yield and Yield Components
C - Di scus sion
C HAPTER I ll - STUDY OF THE GROWTH PATTERN OF HUlA AND
THE EFFECT OF C UTTING AND PARAQUAT ON ITS
REP RODUCTIVE DEVELO PMENT AND SEED Y I ELD
A - The Importance of Pl ant Structure on Seeding Potent ial
and Yield
1 - Int roduction
2 - Materials and Methods
a - Experimenta l Site and Field Procedures
b - Plant Meas urements
3 - Res ults
a - Vegetative Growth and Development
b - The Morphology of I n f lorescence Initiat ion and Development
c - Seed Yield and Seed Y i e ld Components
4 - Di scuss ion
B - E f f ect of Paraquat Appl i cation and Cutting Intensity on
Reproductive Growth and Seed Y ield
1 - Materials a nd Methods
a - Exper imenta l Site and Field Procedures
b - Pl ant Measurements and Statistica l Ana lys i s
2 - Res ults
a - Ef fect of Defol iation Treatments on Wh ite Clover Vegetative Growth and Development
b - Ef fect of Defol iation Treatments on Wh ite Clover Reproduct ive Growth a nd Devel opment
c - Effect of Defoliat ion Treatments on \'lhi te Clover Yield Components and Seed Yield
d - Effect of De fol iation Treatments on White Clover Seed Qual ity
3 - Discussion
vi
PAGE
91
97
101
102
109
10':1
109
110
110
112
115
115
124
141
1 44
146
147
147
148
149
149
158
162
167
167
,•
- .
CHAPTER IV - GENERAL DISCUSSION
- CONCLUSIONS
APPENDI CES
BIBLIOGRAPHY
vii
PAGE
171
179
1 8 3
208
TABLE
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
1 6
LIST OF TABLES
Treatments used and their identification 1982/83
Effect of closing time a�d paraquat treatments on grass dry weight (g/m )
Effect of closing time and par�quat treatments on dead matter dry weight (g/m )
Effect of closing time and para�uat treatments on white clover dry weight (g/m )
Effect of closing time and paraquat treatments on white clover leaf area index
Effect on closing time an� paraquat treatments on the number of nodes/dm
Effect of closing time and paraqu�t treatments on the number of terminal buds/dm
Effect of closing time and paraquat treatments on the date of peak flowering
Effect of closing date and time of paraquat application on seed yield per unit area (kg/ha)
Effect of closing date and time of paraquat a�plication on the total number of inflorescences/ m present at each harvest
Effect of closing date and time of paraquat application on the number of florets per inflorescence at peak flowering
Effect of closing date and time of paraquat application on the seed number per floret present at each harvest
Effect of closing date and time of paraquat application on 1000 seed weight (g) at each harvest
Correlation coefficients between seed yield (kg/ha) and yield components
Treatments used and their identification
Effect of closing date and time of p�raquat application on grass dry weight (g/m )
viii
PAGE
37
40
41
4J
46
48
49
52
55
57
58 '
60
66
68
71
TABLE
17
18
19
20
21
22
23
24
Effect of closing date and time of paraqua� application on dead matter dry weight (g/m )
Effect of closing date and time of paraquat2 application on white clover dry weight (g/m )
Effect of closing date and time o� p�raquat application on leaf area index (m /m )
Effect of closing date and time2of paraquat application on leaflet area (mm )
Effect of closing date and time of pa2aquat application on the number of nodes/dm
Effect of closing date and time of paraquat applica1ion on the number of terminal buds/dm
Effect of closing date and time of paraquat application on the length (mm) of main stolon
Effect of closing date and time of paraquat application on the number of branches per stolon
25 Effect of closing date and time of paraquat application on the strength of2association between clover dry weight (g/m ) and some vegetative characters measured every 15 days after the completion of each treatment until harvest
26
27
28
29
3 0
Effect o f closing date and time o f paraquat application on t�e total number of inflorescences/m
Correlation coefficient for eac� treatment between inflorescence numbers/m emerged at different time of the year and several vegetative characters of white clover plants
Effect of closing date and time of paraquat application on the date of peak flowering
Effect of closing date and time of paraquat application on seed yield (kg/ha)
Effect of closing date and time of paraquat 2 application on the number of inflorescences/m at harvest
ix
PAGE
73
74
76
78
79
80
81
83
84
85
87
90
91
-93
TABLE
31
32
33
34
35
36
37
38
Effect of closing date and time of paraquat application on the number of florets per inflorescence at harvest ·�
Effect of closing date and time of paraquat application on the number of seeds per floret at harvest
Effect of closing date and time of paraquat application on 1000 seed weight (g)
Effect of closing date and time of paraquat application on normal seedling percentage
Effect of closing date and time of paraquat application on abnormal seedling percentage
Effect of closing date and time of paraquat application on hard seed percentage
Effect of closing date and time of paraquat application on dead seed percentage
Correlation coefficients between seed yield and yield components from plots closed at different dates and sprayed with paraquat
39 Total number of nodes, lateral stolons, lateral branches, axillary buds, and inflorescences present in February at the nodes, which emerged from terminal buds of main stolons from July to January
40
41
42
Changes in petiole and peduncle length, inflorescence size, and number of ovules per floret with the time of the year
Variation in yield components and seed yield between two 'Grasslands Huia' genotypes
Treatments used and their identification
43 Effect of defoliation treatments on the number of nodes emerging from the terminal bud per month on a main stolon from November to January
44 Effect of defoliation treatments on the increment in length (mm) of a main stolon during each month from November to January
X
PAGE
94
95
96
97
98
99
100
101
119
139
141
148
150
151
xi
TABLE PAGE
45 Effect of defoliation treatments on the number of leaf primordia per terminal bud
46 Effect of defoliation treatments on the number of lateral stolons present in February at nodes which emerged from teriminal buds of main stolons during each month from November to January
47 Effect of defoliation treatments on the number of lateral branches present in February at nodes which emerged from terminal buds of main stolons during each month from November to January
48 Effect of defoliation treatments on the number of rooted notes present in February at nodes which emerged from terminal buds of main stolons during each month from November to January
49 Effect of defoliation treatments on the number of inflorescences present in ten terminal buds of main stolons every 15 days from November to January
50 Effect of defoliation treatments on the time of inflorescence initiation in ten terminal buds of main stolons every 15 days from November to January.
51 Effect of defoliation treatments on the total number of inflorescences emerged
52
53
on main stolons plus lateral stolons, present in February at nodes which emerged from terminal buds during each month from November to January
Effect of defoliation treatments on white clover yield components
Effect of defoliation treatments on white clover seed yield (kg/ha)
54 Effect of defoliation treatments on white clover seed quality
154
156
157
158
159
160
161
164
166
168
FIGURE
1
2
3
4
5
6
7
8
9
10
11
LIST OF FIGURES
Vegetative and floral parts of a white clover plant
a) External and internal morphology of a legume seed and
b) Anatomical features of a legume seed coat
Trial layout. Field experiment 82/83
Effect of closing time on the percentage of normal seedlings, abnormal seedlings, hard seed, dead seed and viable seed at each harvest
Effect of paraquat spraying time on the percentage of normal seedlings, abnormal seedlings, hard seed, dead seed and viable seed at each harvest
Trial layout. Field experiments 83/84
Effect of closing t�me and paraquat treatments on seed yield .!g/m ) Two year experiments
Vegetative and floral organs of a white clover plant
Number of nodes emerging from the terminal bud on main stolons per month
Monthly incremental length increase in main stolons (July to January)
Total number of lateral stolons present in February at nodes which emerged from terminal buds on main stolons from July to January
12 Number of lateral stolons of different lengths present in February at nodes which emerged from terminal bud of twenty main stolons from July to January
13 Number of lateral branches and axillary buds present in February at nodes which emerged from terminal buds of main stolons from
14
July to January
Percentage of rooted nodes present in February at nodes which emerged from terminal buds of main stolons from July to January
xii
PAGE
17
35
62
63
69
106
111
116
117
118
121
122
123
FIGURE
1 5
1 6
1 7
1 8
1 9
2 0
Diagramatic representation of stages of inflorescence and node development in white clover relative to distance from stolon apex under natural spring conditions. Thomas ( 1 981 )
Estimated time of inflorescence initiation in 1 0 terminal buds on main stolon from July to February
Number of inflorescences present in ten terminal buds on main stolons from July to February
Number of inflorescences emerged on main stolons and lateral stolons from September to January
Number of white inflorescences present per unit area
Number of white inflorescences produced in paraquat and cutting treatments
xiii
PAGE
125
132
133
1 3 5
1 3 7
1 6 3
LIST OF PLATES
PLATE
1 Knapsack sprayer used for paraquat application
2 Portable shearing machine used in cutting treatments
3
4
5
6
7
8
9
10
11
Damage caused by paraquat in white clover leaves one week after spraying
Damage caused by paraquat application to white clover inflorescence one week after spraying
Scanning electronmicrograph showing the morphological appearance of a leaf primordium (x 550)
Scanning electron micrograph showing flower initiation (x 430)
Scanning electron micrograph showing floret initiation (x 300)
Stage of growth of an inflorescence at early emergence (x 60)
Stages of development of inflorescences after emergence
Differences in flowering density between the two genotypes in December 1984
Ovules present in an unfertilised floret (x 60)
12 X-ray photograph showing changes in the number of ovules forming seeds in individual florets
13
14
Effect of heavy cut and paraquat treatments on main stolons of white clover 7 days after treatment application
Recovery growth of white clover stolon after paraquat application
xiv
PAGE
34
36
89
89
126
127
128
130
130
136
140
142
152
155
LIST OF APPENDICES
APPENDICES
1
2
3
4
5
6
7
8
9
10
1 1
12
13
Soil analysis of the experimental field
Basic weather data for Palmerston North; mean values for each month over the experimental period 1 982 - 1983
Effect of closing time and paraquat treatment on soil moisture content 1982-1983
Effect of closing time and paraquat treatment on normal seedling percentage 1 982-1983
Effect of closing time and paraquat treatments on abnormal seedling percentage 1982-1983
Effect of closing time and paraquat treatments on hard seed percentage 1 982-1983
Effect of closing time and paraquat treatments on dead seed percentage 1982-1983
Effect of closing time and paraquat treatments on viable seed percentage 1982-1983
Basic weather data for Palmerston North: mean values for each month over the experimental period 1983-1984
Effect of closing time and paraquat treatments on soil moisture content 1 983 - 1 984
Variation in number of florets in ten inflorescences at harvest 1983-1984
Basic weather data for Palmerston North: mean values for each month over the experimental period 1 984 - 1985
Increase in length of main stolons from July to January 1984-1985
14 Number of lateral stolons of different sizes present in February on main stolons from July to January 1 984-1985
1 5 Percentage of rooted nodes present in February at nodes which emerged from terminal buds of main stolons from July to January 1984-1985
XV
PAGE
1 83
184
185
1 86
187
188
189
190
191
192
193
194
195
196
197
APPENDICES
16
17
1 8
1 9
20
21
22
23
24
25
Estimated time of initiation of inflorescences in 10 terminal buds of main stolons from July to January 1984-1985
Number of inflorescences present in ten terminal buds on main stolons from July to January 1984-1985
Number of inflorescences on main and lateral stolons, present in February, on nodes which emerged from terminal buds on main stolons from September to January 1984-1985
Number of white inflorescences per unit 1 984-1985 area
Changes in petiole and peduncle length, inflorescence size, number of ovules per ovary, and seed numbers per pod in Genotype I and Genotype II 1984-1985
Effect of defoliation on the number of inflorescences per main stolon present in February at nodes which emerged from terminal buds of main stolons from November to January 1984-1985
Effect of defoliation on the number of inflorescences on lateral stolons present in February at nodes which emerged from terminal buds on main stolons from November to January 1984-1985
Effect of defoliation on the number of florets per inflorescence 1984-1985
Effect of defoliation on the number of ovules per ovary 1984-1985
Effect of defoliation on the number of seeds per floret 1984-1985
�i
PAGE
198
199
200
201
202
203
204
205
206
207