Crop Growth and Phenology
–
Species Variability
Crop Growth and Development and Environment
Species Variability
9 Effects of multiple environmental factor effects on
crop growth and phenology across many important
crop species.
9 Can we use environmental productivity index
concept across the species to quantify the responses
and to develop functional relationships?
K. Raja Reddy
Mississippi State University
Mississippi State, MS
Crop
Area,
Million ha
Production,
Million Mt.
Productivity,
Mt. ha-1
224
161
159
97
57
45
37
31
30
28
690
823
685
231
158
65
36
66
58
20
3.0
5.1
4.3
2.4
2.8
1.5
0.96
2.1
1.9
0.73
Wheat
Maize/corn
Rice
Soybeans
Barley
Sorghum
Millets
Seedcotton
Rapeseed
Beans, dry
Environmental and Cultural Factors
Influencing Crop Phenology
¾ Atmospheric Carbon Dioxide (indirect)
¾ Solar Radiation (indirect)
¾ Photoperiod (direct on flowering, no effect on
modern cotton cultivars)
¾ Temperature (direct)
¾ Water (indirect)
¾ Wind (indirect)
¾ Nutrients (N, P and K) (direct & indirect)
¾ Growth Regulators (PIX) (indirect)
Rice Production Statistics
Rice – Some Crop Statistics
200
0
India
25
0
China
8% Deep-water
50
25
Indonesia
12% Rainfed upland
•
50
Bangladesh
•
75
Vietnam
27% Rainfed lowland
100
75
Thailand
•
125
100
Myanmar
53% Irrigated flooded-paddy
125
Brazil
•
150
Philippines
• 2004 stats are: Area = 151 Million ha, production = 606
Million Mt, and average yield = 4.02 t ha-1.
175
150
Japan
Provides the dietary needs of 1.6 billion with another
400 million rely on rice for one-quarter or one-half of
their diet.
200
Area
Production
Year 2004
USA
•
Rice production area, Mha
175
Rice production, MMt
Crop Growth and Development and Environment
Major Crops – Global Statistics - 2008
1
Rice Production Statistics
Rice Production Statistics
35
35
8
Year 2004, Area = 151.3 Mha, Production = 605.8 MMt
World 2004 average = 3.97 t ha-1
30
Area
Production
15
5
Indonesia, r2 = 93, 77 kg yr1
4
World, r = 0.98, 53 kg yr
3
India, r = 0.92, 42 kg yr
1
Myanmar
India
0
China
0
Indonesia
2
Vietnam
5
Bangladesh
5
Thailand
10
Philippines
2
2
10
2
-1
0
1960
1970
1980
1990
2000
2010
Year
Phenology - Species Variability
Temperature - Rice
Phenology and Temperature – cv IR 30
700
12
A)
Sowing to Panicle Emergence, d
REPRODUCTIVE
10
Phyllochron Interval
d leaf-1
1
-1
Thailand, r = 0.82, 21 kg yr
Phenology – Species Variability – Rice
8
6
VEGETATIVE
4
2
B)
85
Days to 50 %
Panicle Appearance
-1
-1
6
Rice yield, t ha-1
20
15
Rice production, %
20
Brazil
2
Japan, r = 0.51, 32 kg yr
2
25
USA
USA, r2 = 0.90, 70 kg yr-1
7
China, r = 96, 102 kg yr
25
Japan
Rice production area, %
30
80
75
IR 36
600
500
400
Carreon
300
200
100
70
0
65
60
20
0
25
30
35
40
TEMPERATURE, °C
5
10
15
20
25
30
35
Temperature, C
S.K. Leong and C.K.Ong. 1983. J. Expt. Bot. 34: 1551-1561.
Phenology – Species Variability – Rice
Phenology and Temperature –Photoperiod
Corn or Maize, Zea mays L.
Corn is the 3rd most important food crops globally in
terms of energy and protein (FAO, 2004).
Area:
147 Million ha
Total production: 721 Million Mt
Average yield:
4.93 t ha-1
2
Corn or Maize, Zea mays L.
Corn or Maize, Zea mays L.
Area
Production
250
250
200
200
150
150
100
100
45
50
Year 2004, Area = 147.02 Mha, Production = 721.4 MMt
40
45
40
Area
Production
35
35
30
30
25
25
20
20
15
15
10
10
5
5
0
0
Corn or Maize, Zea mays L.
Nigeria
South Africa
Indonesia
Argentina
India
Romania
France
Brazil
Mexico
USA
China
Nigeria
0
South Africa
Indonesia
Romania
Argentina
India
France
Mexico
USA
Brazil
50
China
50
0
50
300
Corn production area, %
Year 2004, Area = 147 Mha, production = 721 MMt
World average = 4.93 t ha-1
Maize production, MMt
Maize production area, Mha
300
350
Corn production, %
350
Phenology – Species Variability
12
10
2
Maize yield, t ha-1
France, r = 0.88, 138 kg yr
2
-1
USA, r = 0.84, 114 kg yr
-1
8
2
Argentina, r = 0.87, 99 kg yr
2
-1
China, r = 0.96, 100 kg yr
6
Phenology – Leaf Appearance
Rates (Phyllochrons);
Maize or Corn.
•
Notice the base temperature
which is much different than
that of cotton.
•
The rate of development is
also linear across a wide
range of temperatures.
-1
World, r2 = 0.95, 62 kg yr-1
4
2
Brazil, r = 0.83, 47 kg yr
2
-1
India, r2 = 0.79, 24 kg yr-1
2
-1
Nigeria, r = 0.29, 10 kg yr
0
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
Year
Phenology – Species Variability
Corn Growth – UV-B Radiation – Species Variability
1.0
•
0.8
•
Notice the base temperature
which is much different than
that of cotton, but similar to
maize leaf appearance rates.
The rate of development is
also linear across a wide
range of temperatures (10 to
30°C).
UV-B Indices
Phenology and Silking to
Maturity: Maize or Corn
0.6
0.4
Stem extension
leaf area expansion
Leaf development
Biomass
0.2
0.0
0
5
10
15
-2 -1
UV-B radiation, kJ m d
3
Sorghum – Cultivar Differences
Phenology – Species Variability
Sorghum, Sorghum bicolor (L.) Moench
Phenology – Panicle
Initiation.
Sorghum is the 4th most important food crops globally in terms
of energy and protein (FAO, 2004).
2004 stats are:
Area:
43.1 Million ha
Total production: 57.8 Million Mt
Average yield:
1.3 t ha-1
United States = 2.64 Mha, 4.4 t ha-1, 11 MMt
India = 9.4 Mha, 0.8 t ha-1, 7.53 MMt
Nigeria = 7.1 Mha, 1.13 t ha-1, 8.03 MMt
China = 0.57 Mha, 4.1 t ha-1, 2.34 MMt
Mexico = 1.91 Mha, 3.35 t ha-1, 6.4 MMt
Sudan = 6.0 Mha, 4.33 t ha-1, 2.6 MMt
•
Notice the base
temperature which
is almost similar to
corn.
•
The rate of
development can be
described by a
bilinear model.
Sorghum – Vegetative Growth and Development
18
80
12
40
6
Internode length (cm)
0
C
20
4.0
15
3.0
10
2.0
5
1.0
0.0
36/26
40/30
44/34
32/22
36/26
40/30
44/34
Air te mperature (°C)
(daytime maximum/nighttime minimum)
40
12
20
6
0
0
D
20
0.3
15
0.2
10
0.1
5
0.0
0
40/30
44/34
32/22
36/26
40/30
Air te mpe rature (°C)
(daytime maximum/nighttime minimum)
44/34
-1
700 µ mol CO 2 mol
-1
350 µ mol CO 2 mol
A
30
A 32/22°C
700 µ mol CO 2 mol
-1
350 µ mol CO 2 mol
-1
1500
20
1000
-1
500
0
100
B
75
50
25
Seed size
-1
(mg seed )
C
0.4
2000
Individual seed weight (mg seed )
18
Pollen production
-1
(no. anther )
24
In-vitro pollen germination
(%)
30
Sorghum – Reproductive Growth and Development
Pollen viability
(%)
B
Seed dry weight
-1
(g plant )
-1
36/26
D
32/22
60
32/22
-1
Plant height (cm)
24
0
700 µmol CO 2 mol
-1
350 µmol CO 2 mol
80
30
120
Sorghum – Vegetative and Reproductive Growth
and Development
A
B
0
The rate of
development can be
described by a
bilinear models.
Also, notice the
genotypic
variability.
Total dry weight
-1
(g plant )
•
Notice the base
temperature which
is almost similar to
corn.
Harvest index
•
-1
700 µmol CO 2 mol
-1
350 µmol CO 2 mol
A
160
Stem diameter (cm)
Phenology – Leaf
development.
Nodes (no. plant )
Sorghum – Phenology – Cultivar Differences
0
100
C
10
0
30
B 36/26°C
20
10
0
30
C 40/30°C
75
20
50
25
0
10
32/22
36/26
40/30
44/34
Air temperature (°C)
(daytime max imum/nighttime minimum)
0
0
10
20
30
40
Time after tagging (d)
4
Wheat – Production Trends
Wheat – Some Crop Statistics
100
100
Wheat – Production Trends
Pakistan
France
Wheat – Production Trends
20
20
10
15
15
8
10
10
5
5
0
0
Year 2004, Area = 215.8 Mha, Production = 627.1 MMt
Year 2004
Wheat production, MMt
0
Turkey
0
Ukraine
20
Canada
20
Australia
40
Germany
Average yield = 2.84 t ha-1.
40
USA
Production = 633 Million Mt
60
Russian Fed.
Area = 217 Million ha
80
60
India
• 2004 stats are:
Area
Production
80
China
• Provides 20% of the energy and 25% of the protein
requirements of over 6 billion population.
N.a.N.
Wheat production area, Mha
Year 2004, Area = 215.8 Mha, Production = 627.1 MMt
Wheat yield, t ha-1
Wheat production, %
Wheat production area, %
Area
Production
2
6
2
Kazakhstan
Pakistan
Argentina
Turkey
Ukraine
Canada
Australia
France
Germany
USA
Russian Fed.
India
China
-1
China, r = 0.97, 87 kg yr
4
USA, r2 = 0.81, 26 kg yr-1
World, r2 = 0.97, 42 kg yr-1
2
-1
India, r = 0.97, 50 kg yr
2
N.a.N.
-1
Germany, r = 0.94, 111 kg yr
2
-1
France, r = 0.93, 114 kg yr
0
1955
Australia, r2 = 0.40, 18 kg yr-1
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
Year
Wheat and Phenology
Temperature Effects on Flowering to maturity
Soybean Production Statistics
Soybean the most important protein and oilseed crop
globally (FAO, 2004).
Area:
91.4 Million ha
Total production: 204.4 Million Mt
Average yield:
2.23 t ha-1
5
Soybean Production Statistics
Soybean Production Statistics
Soybean Production Statistics
15
10
10
5
5
0
0
Italy
20
15
Bolivia
25
20
Indonesia
0
30
25
Canada
Italy
Indonesia
Bolivia
Canada
Paraguay
India
China
USA
0
Brazil
20
Argentina
20
35
30
Paraguay
40
40
35
India
40
40
China
60
45
Area
Production
Argentina
60
50
Year 2004
USA
80
Soybean production area, %
80
45
Soybean production, MMt
Soybean production area, Mha
50
Area
Production
Soybean production, %
100
Year 2004, Area = 91.44 Mha, Production = 204.3 MMt
Brazil
100
Temperature and CO2 Effects on Soybean
Developmental Rates
5
4
26/19
4.2
Final node
number, no.
plant-1
10.3
2
-1
31/24
3.3
11.5
2
-1
36/29
3.2
12.0
26/19
3.9
11.2
31/24
2.7
11.4
36/29
2.6
12.1
2
Soybean yield, t ha
-1
Italy, r = 0.81, 47 kg yr
CO2, ppm Temp. °C Plastochron interval, d
leaf-1
-1
300
3
USA, r2 = 0.81, 26 kg yr-1
Brazil, r 2 = 0.95, 36 kg yr -1
World, r = 0.95, 26 kg yr
2
China, r = 0.92, 26 kg yr
2
India, r = 0.58, 14 kg yr
1
0
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
-1
2010
Year
Crop Growth and Development - Environment
600
Rangeland grass – Big bluestem (Andropogon gerardii)
Response to temperature - Soybean biomass and seed yield
Biomass / seed yield (g/plant)
40
4-week old cotton Biomass
seedlings
35
CO2 = 700 ppm
•
C4 photosynthetic pathway
30
•
Clump forming perennial grass
25
•
Grows 3 to 6 feet tall but occasionally up to 9 feet.
20
•
Lower stems are a purplish or bluish color
15
•
Leaves are 1/2 inch wide and up to 20 inches long.
•
Arrangement of the flowers in three dense
elongate clusters is the reason for the common
name of turkey-foot grass.
•
Grows best in moist well drained soil in full sun and
is a major component of the tallgrass prairie.
Seed yield
10
5
0
28/18 32/22 36/26 40/30 44/34 48/38
Day/night temperature, °C
6
Rangeland grass – Big Bluestem, A. girardii
Reproductive Response – Panicle initiation
Rangeland grass – Big Bluestem, A. girardii
Growth and Developmental Responses
0.016
3.0
y = 0.0056 + 0.0002781X; R2 = 0.99 for T = <26°C
-1
-1
0.014
0.012
2.0
1.5
77
88
-1
0.010
96
99
0.008
15
20
1.0
-1
360 µL L
0.5
2 2
y = -3.672+0.523x+-0.011x ; R = 0.96
-1
760 µL L
2 2
y = -2.118+0.396x+-0.009x ; R = 0.92
0.0
85
Leaf addition rate (no. d )
Panicle initiation rate, 1/d
y = 0.0207 - 0.00030009X; R2 = 0.97 for T = >26°C
[CO2]
*
T
***
[CO2] x T NS
2.5
Stem elongation rate (cm d )
-1
360 µL L
-1
700 µL L
25
30
35
40
[CO2]
*
T
***
[CO2] x T *
0.30
0.25
360 µL L-1
0.20
2 2
y = -0.130+0.027x+-0.001x ; R = 0.94
720 µL L-1
2 2
y = -0.057+0.013x+-0.001x ; R = 0.92
Temperature, °C
0.15
15
20
25
30
35
40
o
Temperature ( C)
Rangeland grass – Big Bluestem, A. girardii
Rangeland grass – Big Bluestem, A. girardii
Growth and Developmental Responses
30
Tillers
Leaf
2 2
360 µL L-1; y = 30.004-2.425x-0.059x ; R = 0.98
2 2
760 µL L-1; y = 12.957-0.871x+0.027x ; R = 0.92
20
-1
360 µL L ; y = -3.752-0.427x; R2 = 0.97
760 µL L-1; y = -7.881-0.677x; R2 = 0.87
20
200
10
5
5
0
0
Tillers with panicles
4
Nodes with panicles
-1
2 2
360 mL L ; y = -34.595+3.425x-0.065x ; R = 0.98
-1
2 2
720 mL L ; y = -29.201+2.974x-0.058x ; R = 0.96
10
[CO2]
*
T
***
[CO2] x T NS
8
Dry weight (g plant-1)
Number (plant-1)
0
12
NS
[CO2]
T
***
[CO2] x T NS
15
10
1
5
0
Panicle
-1
360 µL L ; y = -7.227+0.754x-0.014x2; R2 = 0.97
760 µL L-1; y = -4.538+0.514-0.009x2; R2 = 0.94
3
20
-1
360 µL L ; y = -87.732+8.004x-0.149x2; R2 = 0.94
-1
760 µL L ; y = -75.556+6.902x-0.129x2; R2 = 0.93
NS
[CO2]
T
***
[CO2] x T NS
15
0
10
15
15
20
25
30
Temperature, °C
35
40
25
30
35
40
Temperature ( C)
0.28
720 µL L-1
-1
360 µL L
0.26
0
20
25
30
35
40
0.24
o
Root
360 µL L-1; y = -26.37+2.886x-0.053x2; R2 = 0.91
-1
760 µL L ; y = -3.143+1.452x-0.032x2; R2 = 0.92
15
[CO2]
T
[CO2] x T -
10
0.22
0.20
0.18
0.16
0.14
5
0
20
o
10
5
50
-1
360 µL L ; y = -59.272+7.245x-0.134x2; R2 = 0.95
760 µL L-1; y = -21.178+4.796x-0.093x2; R2 = 0.94
0
Panicles
NS
[CO2]
T
***
[CO2] x T NS
100
30
Temperature ( C)
0
20
-1
2 2
760 µL L ; y = -483.020+50.557x-1.052x ; R = 0.98
150
40
15
1
2
25
NS
[CO2]
T
***
[CO2] x T NS
50
-1
360 µL L ; y = -378.860+42.571x-0.898x2; R2 = 0.84
NS
[CO2]
T
***
NS
[CO2] x T
2
6
4
60
-1
760 µL L ; y = -25.561+3.759x-0.082x2; R2 = 0.95
20
[CO2]
**
T
***
[CO2] x T NS
2
14
360 µL L-1; y = -22.788+3.158x-0.065x2; R2 = 0.91
Stem
-1
2 2
360 µL L ; y = -4.331+0.576x-0.011x ; R = 0.96
-1
2 2
720 µL L ; y = -5.4296+0.673x-0.014x ; R = 0.90
3
Total weight response
[CO2]
***
T
***
[CO2] x T **
Total biomass (g plant-1)
[CO2]
**
T
**
NS
[CO2] x T
10
Seeds (no. panicle-1)
15
15
Seed weight, g
25
Seed number and weight response
25
0.12
0.10
15
0
15
20
25
30
35
40
20
25
30
35
Temperature, °C
Temperature (oC)
Chickpea is a cool-season crop grown
substantially in South and West Asia, the
Mediterranean region, and South
and Central America.
Chickpea - Cicer arietinum L.
Production and distribution
• Chickpea is a cool season food legume crop grown on >10
million ha in 45 countries of the world.
• Chickpea is either the first or the second most important,
rainfed, cool season food legume, grown mainly by small
farmers in the semi-arid tropics (SAT) and West Asia and
North Africa (WANA) regions.
• The crop is also grown in southern and eastern Africa
(particularly important in Ethiopia), Europe, the Americas
and, more recently, Australia.
• World production is 7 million tones.
• International trade in chickpeas has increased over the
years.
7
Phenology - Species Variability
Temperature - Sowing to First Flower
Chickpea Cultivars
Phenology - Species Variability
Temperature - Sowing to 50% Emergence
Chickpea Cultivars
Roberts et al., 1980. Expt. Agric.16:343-360.
Roberts et al., 1980. Expt. Agric.16:343-360.
100
Days from Sowing to First Flower
Days to 50% Emergence
10
8
6
4
2
0
10
Chaffa - Early = 10.1 - 0.26*X, R2=0.79
G 130 - Late = 11.3 - 0.30*X, R2=0.87
Rabat - Mid-late = 13.5 - 0.33*x, R2=0.61
15
20
25
30
Chafa-Early = 61-1.3*X, r2 =0.44
G 130 - Late = 102-1.9*X, r2 = 0.14
2
Rabat - mid-late = 86-1.1*X, r = 0.08
80
60
40
20
10
35
15
Phenology - Species Variability
Temperature - First Flower to Maturity
Chickpea Cultivars
Roberts et al., 1980. Expt. Agric.16:343-360.
30
35
Roberts et al., 1980. Expt. Agric.16:343-360.
200
Crop Duration (sowing to maturity), d
Days from First Flower to Maturity
25
Phenology - Species Variability
Temperature - Sowing to Maturity
Chickpea Cultivars
150
Chaffa-Early = 203 - 5.8*X, r2 = 0.69
G 130 - Late = 167 - 4.7*X, r2 = 0.77
2
Rabat - Mid-late = 173-4.8X, r = 0.63
125
100
75
50
25
10
20
Average Air emperature, °C
Average Air emperature, C
15
20
25
30
35
2
Chaffa - Early = 264 - 7.1*X, r = 0.72
2
G 130 - Late = 270 - 6.6*X, r = 0.64
2
Rabat - mid-late = 261 - 5.9*X, r = 0.64
175
150
125
100
75
50
25
10
15
20
Average Air Temperature, °C
Groundnut or Peanut
(Arachis hypogaea L.)
Groundnut, an important cash crop, is an
annual legume. Its seeds are a rich source
of edible oil (43-55%) and protein (2528%). About two thirds of world production
is crushed for oil and the remaining one
third is consumed as food. Its cake is used
as feed or for making other food products
and haulms provide quality fodder.
25
30
35
Average Air Temperature, °C
Groundnut or Peanut
(Arachis hypogaea L.)
1
2
3
7
4
WC
1 Mali
2 Niger
3 Nigeria
5
6
SEA
3 Kenya
4 Malawi
5 Zimbabwe
Asia
7 India
Semi-arid
tropic
The semi-arid tropics of Asia and Africa (WC = western and central Africa;
SEA = southern and eastern Africa (Source: http://www. cgiar.org/icrisat/)
8
Phenology - Species Variability
Temperature - Groundnut (Peanut, cv. Robut 33-1)
Distribution:
Groundnut originated in the southern Bolivia/north west
Argentina region in south America and is presently
cultivated in 108 countries of the world.
0.4
Leaf appearance
Important groundnut producing countries are China, India,
Indonesia, Myanmar, Thailand, and Vietnam in Asia;
Nigeria, Senegal, Sudan, Zaire, Chad, Uganda, Cote
d'Ivory, Mali, Burkina Faso, Guinea, Mozambique, and
Cameroon in Africa; Argentina and Brazil in South
America and USA and Mexico in North America.
Rate of Development
0.3
Asia with 63.4% area produces 71.7% of world groundnut
production followed by Africa with 31.3% area and 18.6%
production, and North-Central America with 3.7% area and
7.5% production.
0.2
Branching
0.1
Flowering
Pegging
Podding
0.0
-0.1
5
10
15
20
25
30
35
Temperature, C
S.K. Leong and C.K.Ong. 1983. J. Expt. Bot. 34: 1551-1561.
Temperature – Pollen Germination
Phenology - Species Variability
Temperature - Groundnut (Peanut, cv. Robut 33-1)
Susceptible
Moderate
Tolerant
80
ICGV 92116
ICGV 92118
55-437
%
Event
Equation
CGDD
Leaf appearnce = 0.018*T - 0.183, r2 =0.79,
Branching = 0.0097*T - 0.0924, r2 =0.89,
Flowering = 0.00186*T - 0.0201, r2 =0.96,
2
Pegging = 0.00149*T - 0.0158, r =0.90,
2
Podding = 0.00139*T - 0.0158, r =0.98,
56
103
538
669
720
Tbase
10.0
9.5
10.8
10.6
11.4
Pollen germination (%)
70
Tb
Topt
Tmax
40 13.8 26.5 38.5
51.5 11.7 30.6 40.7
70.3 11.9 31.9 45.2
60
50
40
30
20
10
0
10
15
20
25
30
35
40
45
50
Temperature (°C)
Effect of temperature on percentage pollen germination of susceptible
(Topt < mean-LSD), moderately tolerant (Topt = ±mean) and tolerant
(Topt > mean+LSD) genotypes. Symbols are observed values and lines
are fitted values.
S.K. Leong and C.K.Ong. 1983. J. Expt. Bot. 34: 1551-1561.
Temperature – Pollen Tube Growth
ICGV 92116
ICGV 92116
55-437
%
16
Topt
Tmax
1280 16.0 36.4 45.5
1080 15.3 30.5 37.7
1410 14.5 37.6 45.1
14
12
Pollen tube length (102 m m)
Tb
Cowpeas (Vigna unguiculata belong to the family
Fabaceae.
Cowpeas were originally native to Asia and
are now an important forage and cover crop
in the southern United States. The seeds,
usually called black-eyed peas or black-eyed
beans, are cooked and eaten.
10
8
6
4
2
0
10
15
20
25
30
35
40
45
50
Temperature (°C)
9
Phenology – Species Variability – Cowpea Lines
Phenology – Species Variability
Sowing to Flowering
Horticultural Crops
Phenology – Species Variability – Crops and weeds
Phenology – Species Variability
Phenology – Species Variability
Phenology and Seed
Germination:
•
The minimum or the
base temperature, heat
sum (s) or the growing
degree days (GDD)
from that base
temperature for a
number of horticultural
crops.
Species
Maize
Sorghum
Pearl millet
Wheat
Barley
Rice
Soybean
Sunflower
Cowpeas
Sugar beet
Velvet leaf
Pigweed
Banana
Tmin or Tbase, °C
8
8
12
0
1
5
7
9
16
2
8
10
8
GDD per leaf tip
39
48
26
99
75
90
54
29
30
30
24
12
196
EPI Concept and Plant Growth and
Development
One way to quantify the effects of environmental factors on plant
growth and development is to use the EPI concept similar to the one
that we used in cotton as model crop.
EPI-phenology = Temperature (potential) * Nutrient Index (C, N, P,
K) * Water index * PPF Index * PGR Index etc.,
EPI-growth = Temperature (potential) * Nutrient Index (C, N, P, K)*
Water index * PPF Index * PGR Index etc.,
Once the potential is defined and quantified, then we can use EPI
concept to decrease that potential to account for the effects of
multiple environmental factors on given process such growth or
development of any plant/crop species as in cotton crop.
10
EPI Concept and Plant Growth and
Development
¾ Environmental productivity index concept, if applied, works
across species and locations.
¾ EPI also allows one to interpret and to understand stresses in
the field situations.
¾ If we know the factor that is limiting most at any point of time
during the growing season, then, we can make appropriate
management decisions to correct that limitation.
¾ EPI concept is the way to quantify the effects of multiple
environmental factors on plant growth and development
(photosynthesis, phenology, and growth) and thus productivity
of any species or crop.
11