Concepts and theory: Spectral reflectance, canopy temperature

and chlorophyll content

SWIM - Sustainable Water Integrated Management Demonstration Project

Aridity Index

Aridity index in the Mediterranean basin calculated from 1961 to 1990 (source EEA, 2003).

Water status projected to 2025

Water status projected to 2025 at Mediterranean area basin (adapted from IWMI, 2000).

Bring durable improvement in agricultural water management and economic

development of six Mediterranean areas in the context of adaptation to

climate change, increasing water scarcity, and desertification risk.

Maru research station - 2012

Adapted from IWMI, 2000.

Best performing genotypes; water WP3 – IMPLEMENTATION

Best performing genotypes; water and management practices

WP5 TRAINING AND DISSEMINATION WP5 – TRAINING AND DISSEMINATION Courses; Field days; Brochures;

Guidelines; Videos, Website

WP1 – STARTUP

Offices/ Stations; Demonstration fields Varieties * Management; Equipment

WP4 SUSTAINABILITY WP4 – SUSTAINABILITY Economical; Social;

Environmental

WP2 – DEMONSTRATION Genotypes; Irrigation;

Conservation tillage; Nitrogen

WP2 – DEMONSTRATION Genotypes; Irrigation;

Conservation tillage; Nitrogen

http://www.aclimas.eu/

SPAD-502Plus (Konica Minolta)

Chlorophyll content

Visual Senescence Scoring

Stay-green

Infrared Thermometer INF151 (UEI)

Canopy temperature

Greenseeker® 505 Handheld

(NTech Industries, Inc.)

NDVI

• Help to interpret the results:

– Explain yield variation (across sites and seasons),

– Quantify the impact of drought on yield (pre-/ post-anthesis

water use).

• Help to optimise inputs to the expected yield:

– Optimize water use;

– Fine tune N application.

• Link physiology to a predicted Ideotype.

• Better demonstrate to the farmers.

Adapted from: Monteith & Unsworth (2008) Principles of Envornmental Physics 3rd ed.

Greenseeker HandHeld

Wheat canopy reflectance

(NW Mexico - CYMMIT)

Adapted from: Reynolds M, Pask A, Mullan D (2012) Physiological breeding I: Interdisciplinary approaches to improve crop adaptation.

Influenced by the canopy optical properties

Leaf level: • Pigments, • Proteins, • Cell Walls, • Leaf cuticles, • Lignin, • Cellulose, • Sugars, • Starch, • Water, etc.

Canopy level: • Leaf Area Index (LAI), • Leaf angles, • Plant height. Physical & Environment: • Soil (not dense foliage), • Latitude & Longitude, • Season & time, • Clouds, • Wind.

Index Name Physiological process Type Calculation

NDVI Normalized difference vegetation index Green area, photosynthetic capacity, N status

VI [R900-R680]/[R900+R680]

R-NDVI Red normalized difference vegetation index Green area, photosynthetic capacity, N status

VI [R780-R670]/[R780+R670]

G-NDVI Green normalized difference vegetation index

Green area, photosynthetic capacity, N status

VI [R780-R550]/[R780+R550]

SRa Simple Ratio Green biomass VI [R800/R680] and [R900/R680]

RARSa Ratio analysis of reflectance spectra chlorophyll a

Chlorophyll a content PI [R675/R700]

RARSb Ratio analysis of reflectance spectra chlorophyll b

Chlorophyll b content PI R675/[R650xR700]

RARSc Ratio analysis of reflectance spectra carotenoid

Carotenoid content PI [R760/R500]

NPQI Normalized pheophytinization index Normal chlorophyll degradation; can be used to estimate phenology, pests and diseases

PI [R415-R435]/[R415+R435]

SIPI S tructural independent pigment index Senescence related to stress PI [R800-R435]/[R415+R435]

PRI Photochemical reflectance index WI Water index

Dissipation of excess radiation PI [R531-R570]/[R531+R570]

WI Water index Plant water status WI [R970/R900]

NWI-1 Normalized water index 1 Plant water status WI [R970-R900]/[R970+R900]

NWI-2 Normalized water index 2 Plant water status WI [R970-R850]/[R970+R850]

NWI-3 Normalized water index 3 Plant water status WI [R970-R880]/[R970+R880]

NWI-4 Normalized water index 4 Plant water status WI [R970-R920]/[R970+R920]

NDVI Normalized difference vegetation index

Green area, photosynthetic capacity, N status

VI [R900-R680]/[R900+R680]

Adapted from: Reynolds M, Pask A, Mullan D (2012) Physiological breeding I: Interdisciplinary approaches to improve crop adaptation.

NDVI=RNIR-R

RED

RNIR+R

RED

=R

900-R

680

R900+R

680

• Green area

• Photosynthetic capacity

• N status

A – High Biomass B – Low Biomass

Adapted from: Reynolds M, Pask A, Mullan D (2012) Physiological breeding I: Interdisciplinary approaches to improve crop adaptation.

Advantages

• Active NDVI

(“independent of light

conditions”)

• Integrative

• Non-destructive

• Quick

Disadvantages

• Training needed

• Saturation of NDVI

(may begin at LAI = 1,

insensitive to changes > 2)

Greenseeker HandHeld Canopy size/ Vegetative greenness:

• Ground cover

• Pre-anthesis biomass

• Nitrogen content

• Senescence/ Stay-green

• Yield

Adapted from; Cabrera-Bosquet L, Molero G, Stellacci AM, et al. (2011) NDVI as a Potential Tool for Predicting Biomass, Plant Nitrogen Content and Growth in Wheat Genotypes Subjected to Different Water and Nitrogen Conditions. Cereal Research Communications 39:147–159.

Glasshouse pot experiment:

• 4 Durum wheat genotypes;

• 3 Water treatments (well watered,

intermediate and severe water stress);

• Low and high N;

• NDVI at stem extension and anthesis.

Biomass

Green Area

N

Source of Variation

Above Ground DW

Total Green Area

Above Ground N

NDVIAnthesis NDVIStemExtension

Water Regime (WR)

*** *** *** *** ***

Nitrogen Supply (NS)

*** *** *** *** ***

Genotype (G) *** *** *** *** ***

WR x NS *** *** *** ** ***

WR x G *** ns *** *** *

NS x G *** ns *** ** **

WR x NS x G ns ns ** ns ns

ANOVA

Adapted from: Bellairs SM, Turner NC, Hick PT, Smith RCG (1996) Plant and soil influences on estimating biomass of wheat in plant breeding plots using field spectral radiometers. Aust J Agric Res 47:1017–1034.

Estimation of GAI Biomass of Wheat and Barley up to Anthesis

(Western Australia - 1992)

NDVI vs GAI NDVI vs DW

Adapted from: Cabrera-Bosquet L, Albrizio R, Araus JL, Nogués S (2009) Photosynthetic capacity of field-grown durum wheat under different N availabilities: A comparative study from leaf to canopy. Field Crops Research 67:145–152.

Durum wheat grown on Low and High N levels

(Southern Italy - 2006)

NDVI measurements 2 weeks after anthesis, 5 samples = 100 readings plot-1.

GY vs NDVI

Derkx AP, Orford S, Griffiths S, et al. (2012) Identification of Differentially Senescing Mutants of Wheat and Impacts on Yield, Biomass and Nitrogen PartitioningF. Journal of Integrative Plant Biology 54:555–566.

Effects of crop management

techniques on

Growth and Senescence

(Central Mexico - 2006)

6 Muted Wheat lines screened for fast

and slow canopy senescence under

low and high N

(Glasshouse)

Verhulst N, Govaerts B, Nelissen V, et al. (2011) The effect of tillage, crop rotation and residue management on maize and wheat growth and development evaluated with an optical sensor. Field Crops Research 120:58–67.

Adapted from: Plants in Action (http://plants inaction.science.uq.au/)

Chl a

Chl b

Chlorophyll extracted with acetone

Wikipedia (http://www.wikipedia.org/)

SPAD-502Plus (Konica Minolta)

650 nm 940 nm

Advantages

• Active (“independent of light conditions”)

• “Cheap”

• Quick/ Easy

SPAD Chlorophyll content of green tissues:

• Photosynthetic potential

• Effects of drought

• Nutrient deficiency

• Senescence/ Stay-green

Disadvantages

• Point measurement only:

Data needs to be integrated

across whole green canopy.

Uddling J, Gelang-Alfredsson J, Piikki K, Pleijel H (2007) Evaluating the relationship between leaf chlorophyll concentration and SPAD-502 chlorophyll meter readings. Photosynth Res 91:37–46.

Chlorophyll content and SPAD

(Sweden - 1999)

• 2 Wheat genotypes;

• leaves at different development stages

(including premature, fully mature and

senescent leaves)

Dragon: Chl = 0.467 e0.0416 SPAD, R2 = 0.81

Lantvete: Chl = 0.435 e0.0455 SPAD, R2 = 0.85

SPAD and Photosynthesis (Anthesis)

(Glasshouse 2007)

• Barley cv. Rum

• Irrigated and drought

• 3 N levels: 0, 50 & 100 Kg N ha-1

Adapted from: Cabrera-Bosquet L, Albrizio R, Araus JL, Nogués S (2009) Photosynthetic capacity of field-grown durum wheat under different N availabilities: A comparative study from leaf to canopy. Field Crops Research 67:145–152.

Durum wheat grown on Low and High N levels

(Southern Italy - 2006)

Flag leave SPAD measurements 2 weeks after anthesis, 3 readings per plot.

GY vs SPAD

Lopez-Bellido RJ, Shepherd CE, Barraclough PB (2004) Predicting post-anthesis N requirements of bread wheat with a Minolta SPAD meter. Eur J Agron 20:313–320.

Wheat grown on seven N levels

(South East, UK – 8 seasons

from 1993-2001)

Adapted from: Derkx AP, Orford S, Griffiths S, et al. (2012) Identification of Differentially Senescing Mutants of Wheat and Impacts on Yield, Biomass and Nitrogen PartitioningF. Journal of Integrative Plant Biology 54:555–566.

6 Muted Wheat lines screened for fast

and slow canopy senescence under

low and high N

(Glasshouse)

Mutant lines with a range of flowering and physiological maturity dates.

Surface temperature of the canopy is related to

transpiration – Evaporative cooling

Adapted from: Reynolds M, Pask A, Mullan D (2012) Physiological breeding I: Interdisciplinary approaches to improve crop adaptation.

Infrared Thermometer

INF151 (UEI)

Infrared Thermometer

• Measure the energy (E) emitted by a surface.

• E = εσ T4 (Stefan’s Law), where:

σ = 5.68 x 10-8 Joules m-2 s-1(Stefan-Boltzman constant) and

ε = “emittance efficiency factor” (plants 0.95 – 0.98).

Advantages

• Integrative

• Non-destructive

• Quick/ Easy

• “Cheap”

IRT Canopy Temperature/ Temperature Depression

CTD (°C) = Tair – Tcanopy

• Stomatal conductance

• Plant water status

• Rooting

• Yield

Disadvantages

• Very susceptible to environmental conditions:

Needs cloudless sunny conditions and interacts

with time of the day.

Wheat Genotypes NW Mexico 2011

Adapted from: Reynolds M, Pask A, Mullan D (2012) Physiological breeding I: Interdisciplinary approaches to improve crop adaptation.

Adapted from: Blum A, Shpiler L, Golan G, Mayer J (1989) Yield stability and canopy temperature of wheat genotypes under drought-stress. Journal of Integrative Plant Biology 22:289–296.

Evaluation of 15 Wheat landraces and 2 improved cultivars

(Israel in 1986/87 – 1987/88)

• Rainout shelter

• Drought and Full irrigation

• Canopy temperature measured weekly, better correlations when the stress was higher.

Syield = (1-Yielddrought/Yieldirrigation)/(1-Xdrought/Xirrigation), X yield for all genotypes

Drought Susceptibility Index

Sbiomass = (1-Biomassdrought/Biomassirrigation)/(1-Zdrought/Zirrigation), Z biomass for all genotypes

Evaluation of Wheat genotypes to drought

(NW Mexico 2006 and 2007)

• Drought and Irrigated treatments

• 8 genotypes

Adapted from: Reynolds M, Pask A, Mullan D (2012) Physiological breeding I: Interdisciplinary approaches to improve crop adaptation.

Root DW and Canopy temperature

Canopy Temperature Depression

CTD (°C) = Tair – Tcanopy

Adapted from: Fischer RA, Rees D, Sayre KD, et al. (1998) Wheat yield progress associated with higher stomatal conductance and photosynthetic rate, and cooler canopies. Crop Science 38:1467–1475.

Evaluation of 8 wheat Cultivars

(NW Mexico)

• Hot, Irrigated conditions

• Grain Yield 1990 – 1995

• Stomatal Conductance 1993 – 1995

• CTD 1993 – 1995

Adapted from: Reynolds MP, Balota M, Delgado MIB, et al. (1994) Physiological and Morphological Traits Associated With Spring Wheat Yield Under Hot, Irrigated Conditions. Aust J Plant Physiol 21:717–730.

Evaluation of 16 wheat Cultivars

(Mexico, Egypt, India, Sudan and Brazil in 1990/91 – 1991/92)

• Yield on the 5 sites

• CTD measured in Mexico

(before and after irrigation when canopy cover was before and in 1992/93)

• Average photosynthetic rate of flag leaves measured in Mexico

(flag leaves at booting, anthesis and grain filling in 1991/92)

CTD Photosynthetic rate

score = p0 + p1 x (1 – exp(( -p2 x STA/ p1)) + (10 – p1 – p0/ (1 + exp(-4 x p3 (STA – p4)/ (10 – p1 – p0)))

Fitting the senescence data

Score: visual senescence score

STA: thermal time after anthesis (°C days)

p0: score at anthesis

p1: score at the end of the slow phase

p2: maximum rate of the slow phase

p3: maximum rate at rapid phase (SenRate)

p4: date at which p3 is reached.

SenOnset: onset of senescing phase date.

Stay-green associated with SenOnset and

SenRate.

Advantages

• Non-destructive

• “Cheap”

• Quick/ Easy

• “Precise”

Visual Senescence Scoring

Photosynthetic Area

• Light interception

• Photosynthetic performance

• Transpiration surface

• Crop biomass and yields

Disadvantages

• Subjective to user errors

• Time consuming

Green Leaf vs SPAD Wheat (Cap Horn) High N (Glasshouse - 2006)

NutE Onset of post-anthesis Senescence (2006/7 and 2007/8) • 16 Wheat cultivars; • 4 sites: Sutton Bonington and Norwich, UK; Estrees-Mons and Clermont-Ferrand, France.

Yield

Gaju O, Allard V, Martre P, et al. (2011) Identification of traits to improve the nitrogen-use efficiency of wheat genotypes. Field Crops Research 123:139–152.