Shaobing PengIRRI Rice Seminar Series

Current position: Senior Crop PhysiologistEducation and training

1983, B.S. in Agronomy, Huazhong Agriculture University, China 1986, M.S. in Agronomy, University of California, Davis, USA1990, Ph.D. in Crop Physiology, Texas Tech University, USA1991, PDF, University of Florida, USA

Work experience1991-1993, Visiting Scientist, IRRI1993-1997, Associate Crop Physiologist, IRRI1997-2001, Crop Physiologist, IRRI 2001-present, Senior Crop Physiologist, IRRI

Career highlights1996, The CGIAR Science Award for Promising Young Scientist2004, Fellow, American Society of Agronomy2005, Fellow, Crop Science Society of America2005, The CGIAR Science Award for Outstanding Scientific PaperEditorial Board: Field Crops Res., Crop Sci., and Plant Production Sci.

TwoTwo decadesdecades of crop physiology of crop physiology research on irrigated rice at IRRIresearch on irrigated rice at IRRI

Shaobing PengShaobing PengInternational Rice Research InstituteInternational Rice Research Institute

IRRI Thursday Seminar IRRI Thursday Seminar 2 December 2010, Los 2 December 2010, Los BaBaññosos, Philippines, Philippines

Crop PhysiologyCrop Physiology studies studies plantplant processesprocesses to to understand the functioning of the plant at understand the functioning of the plant at crop levelcrop level in its in its interactioninteraction with other plants with other plants in the crop and with its in the crop and with its environmentenvironment..

((Paul C. Paul C. StruikStruik))

DefinitionDefinition of crop physiologyof crop physiology

Two faces of crop physiologyTwo faces of crop physiology

One looks towards agronomyOne looks towards agronomyImproving the efficiency of water and fertilizerImproving the efficiency of water and fertilizermanagementmanagement

The other looks towards plant breedingThe other looks towards plant breedingIdentifying and analyzing the processes which Identifying and analyzing the processes which limit the advance in crop yieldslimit the advance in crop yields

(Evans, 1992)(Evans, 1992)

Twin pillars of CGIARTwin pillars of CGIAR--supported researchsupported research

ProductivityProductivityPlant breeding, crop improvement, yield Plant breeding, crop improvement, yield potentialpotential

Natural resource managementNatural resource managementResource use efficiency, crop management,Resource use efficiency, crop management,cultivation, farming systemcultivation, farming system

(Mission and Objectives of CGIAR, 2004)(Mission and Objectives of CGIAR, 2004)

RiceRice cropcropphysiologyphysiology

Crop/resourceCrop/resourcemanagementmanagement

Crop Crop improvementimprovement

High yield High yield and highand high

resource use resource use efficiencyefficiency

Road map: Road map: RResearch areas and objectivesesearch areas and objectives

Rice physiologyRice physiology

PhotosynthesisPhotosynthesis, RUE, and , RUE, and leaf senescenceleaf senescenceTranspiration and WUETranspiration and WUENitrogen nutrition and metabolismNitrogen nutrition and metabolismGrain filling and Grain filling and plant plant hormonehormoneLodging resistanceLodging resistanceCrop modeling Crop modeling QTL mapping of morphoQTL mapping of morpho--physiological traitsphysiological traits15 t/ha rice crop in Yunnan province15 t/ha rice crop in Yunnan provinceClimate change (night temperatureClimate change (night temperature and UVand UV--B)B)

CropCrop and and resource managementresource management

RealReal--time nitrogen managementtime nitrogen managementSiteSite--specific nutrient managementspecific nutrient managementSheath blight/healthy canopy managementSheath blight/healthy canopy managementAWD x N interactionAWD x N interactionCrop Crop establishmentestablishment (direct seeding)(direct seeding)System of rice intensification (SRI)System of rice intensification (SRI)Zero tillage and straw managementZero tillage and straw managementControl of golden snailsControl of golden snails

Crop improvementCrop improvement

New plant typeNew plant type//ideotypeideotypeHybrid riceHybrid riceAerobic riceAerobic riceGrain yield of historical IRRI cultivarsGrain yield of historical IRRI cultivarsCold toleranceCold toleranceGenotypic variation in NUEGenotypic variation in NUEGreen super riceGreen super rice

Research highlightsResearch highlights

Rice leaf N nutrition and N managementRice leaf N nutrition and N management

High night temperature: a hidden stressHigh night temperature: a hidden stress

Yield decline in IR8 and possible causes Yield decline in IR8 and possible causes

Yield stability of aerobic riceYield stability of aerobic rice

Development of new plant type linesDevelopment of new plant type lines

Rice leaf N nutrition and N managementRice leaf N nutrition and N management

Chlorophyll meterChlorophyll meter

Leaf color chartLeaf color chart

Ndw

(g k

g-1)

Pool y = 6.56 + 33.66x

MT

0.4 0.6 0.8 1.0 1.220 30 40 5020

30

40

50

SPAD SPAD/SLW

r2 = 0.93

r2 = 0.77r2 = 0.80

r2 = 0.54

PI

FL

Pool

MT

r2 = 0.49

r2 = 0.58r2 = 0.84

PoolFL

PI

r2 = 0.74

Effect of leaf thickness on SPAD readingsEffect of leaf thickness on SPAD readings

(Peng et al., 1993(Peng et al., 1993,, AgronAgron.. JJ..))

15 20 25 30 35 40 452

3

4

5

6

7

8

20 25 30 35 402

3

4

5

6

7

8IRRI

20 25 30 35 402

3

4

5

6

7

8ZAU UCD

20 25 30 35 400.02

0.05

0.08

0.11

0.14

0.17IRRI

20 25 30 35 400.02

0.05

0.08

0.11

0.14

0.17ZAU

20 25 30 35 400.02

0.05

0.08

0.11

0.14

0.17UCD

r2 = 0.25r2 = 0.39r2 = 0.76r2 = 0.46Pool

PIPI+9dFL

r2 = 0.39r2 = 0.46r2 = 0.65r2 = 0.46Pool

PIPI+9dFL

r2 = 0.50r2 = 0.45r2 = 0.73r2 = 0.46Pool

PIPI+9dFL

r2 = 0.81r2 = 0.96r2 = 0.91r2 = 0.84Pool

PIPI+9dFL

r2 = 0.83r2 = 0.95r2 = 0.88r2 = 0.89Pool

PIPI+9dFL

r2 = 0.86r2 = 0.94r2 = 0.93r2 = 0.88Pool

PIPI+9dFL

NNdwdw (g kg(g kg--11))

LCC

sco

reLC

C s

core

LCC

/SLW

LCC

/SLW

Effect of leaf thickness on LCC readings

(Yang et al., 2003(Yang et al., 2003,, AgronAgron.. JJ..))

N a (g m -2)

N d w (g k g -1)

S L W (g m -2)

D a y s a fte r tra n s p la n tin g

S P A D

Sing

le le

af tr

aits

1 0 2 0 3 0 4 0 5 0 6 0 7 00 .8

1 .2

1 .6

2 .0

2 .4

1 0 2 0 3 0 4 0 5 0 6 0 7 02 0

2 5

3 0

3 5

4 0

4 5

5 0

5 5

6 0

Changes in single leaf traits during crop growthChanges in single leaf traits during crop growth

(Peng et al.(Peng et al.,, 19961996,, FCR)FCR)

FixFix--time N management using Kjeldahl N (%)time N management using Kjeldahl N (%)

15 D

AT

Flow

erin

g

Days after transplanting (DAT)Days after transplanting (DAT)

Leaf

N %

Leaf

N %

Multiple Kjeldahl N% threshold values are needed for timing N Multiple Kjeldahl N% threshold values are needed for timing N topdressing for a given cultivar.topdressing for a given cultivar.

Mid TMax T

PI

MidtilleringMidtilleringMaximum tilleringMaximum tilleringPanicle initiationPanicle initiation

3.03.02.62.62.42.4

3.03.0--4.04.02.82.8--3.63.62.62.6--3.23.2

Growth stageGrowth stage CriticalCriticalvaluevalue

AdequateAdequaterangerange

(Mikkelsen, 1971)

RealReal--time N management using SPAD or LCCtime N management using SPAD or LCC

SPAD = 35 or LCC = 3.2Na = 1.4 g m-2

15 D

AT

Flow

erin

g

Days after transplanting (DAT)Days after transplanting (DAT)

Leaf

N st

atus

Leaf

N st

atus

A single SPAD or LCC value could be used as a threshold forA single SPAD or LCC value could be used as a threshold fortiming N topdressing for a given cultivar.timing N topdressing for a given cultivar.

Feed the plant need!

Inorganic fertilizer

N

Climate

Crop need for nitrogen

Manure

Indigenous nitrogen supply

Irrigation water Crop residues

Soil

The siteThe site--specific nitrogen management approach specific nitrogen management approach

(R.J. Buresh)(R.J. Buresh)

Determining N rate at each growth stageDetermining N rate at each growth stage

N appl. 1N appl. 1

N appl. 2N appl. 2

N appl. 3N appl. 3

N appl. 4N appl. 4

TotalTotal

PrePre--plantplant

MidtilleringMidtillering

PIPI

HeadingHeading

00

1515--2020

3535--4040

5555--6565

35%35%

20%20%

30%30%

15%15%

100%100%

5050

30 30 ±± 1010

40 40 ±± 1010

(20)(20)

100100--160160

**

****

******

Growth stage DAT % split N rate If SPADGrowth stage DAT % split N rate If SPAD

* If SPAD * If SPAD > 36, apply 20 kg/ha; between 34 and 36, apply 30 kg/ha; > 36, apply 20 kg/ha; between 34 and 36, apply 30 kg/ha; < 34, apply 40 kg/ha.< 34, apply 40 kg/ha.

** If SPAD ** If SPAD > 36, apply 30 kg/ha; between 34 and 36, apply 40 kg/ha; > 36, apply 30 kg/ha; between 34 and 36, apply 40 kg/ha; < 34, apply 50 kg/ha.< 34, apply 50 kg/ha.

*** In favorable season and If SPAD *** In favorable season and If SPAD < 36, apply 20 kg/ha.< 36, apply 20 kg/ha.

(Witt and Dobermann, 1996)(Witt and Dobermann, 1996)

These seven provinces occupy 50% of rice plantingThese seven provinces occupy 50% of rice plantingarea in Chinaarea in China

IRRIIRRI--ChinaChina ccollaboration on ollaboration on SSNMSSNM

HeilongjiangHeilongjiang

HubeiHubei

HunanHunan

GuangdongGuangdong

JiangsuJiangsu

ZhejiangZhejiang 19971997

20012001

20032003

20052005LiaoningLiaoning

20082008

Research, demonstration, and Research, demonstration, and extension continuumextension continuum

OnOn--farm farm field trialsfield trials

OnOn--farm farm demonstrationdemonstration

Participatory Participatory farmer farmer

researchresearch

LargeLarge--scale scale extensionextension

Key research findingsKey research findingsRelatively high indigenous N supply capacity comparedRelatively high indigenous N supply capacity comparedwith other major ricewith other major rice--growing countries.growing countries.

Yield response to NYield response to N--fertilizer application is low (aroundfertilizer application is low (around1.5 t/ha).1.5 t/ha).

Most rice farmers apply excess NMost rice farmers apply excess N--fertilizer, especially fertilizer, especially atatearly vegetative stage.early vegetative stage.

Yield reduction is often observed under excessive N Yield reduction is often observed under excessive N input due to great pest damage and lodging.input due to great pest damage and lodging.

Improved N management such as SSNM increases bothImproved N management such as SSNM increases bothgrain yield and NUE.grain yield and NUE.

Improved N management did not cause yield reduction Improved N management did not cause yield reduction in subsequent rice crops.in subsequent rice crops.

((Peng et al.,Peng et al., 2010, ASD)2010, ASD)

SSNM technology has been officially evaluated SSNM technology has been officially evaluated by an expert panel in China on June 25, 2005by an expert panel in China on June 25, 2005

On average, the fertilizer On average, the fertilizer for SSNM was 20for SSNM was 20--30% 30% lower than that of FFP. lower than that of FFP. Grain yield of SSNM was Grain yield of SSNM was 55--8% greater than FFP. 8% greater than FFP.

High night temperature: a hidden stressHigh night temperature: a hidden stress

Annual mean temperature, 1979Annual mean temperature, 1979--2009, IRRI2009, IRRI

(IRRI Climate Unit)(IRRI Climate Unit)

Year1975 1980 1985 1990 1995 2000 2005 2010

Max

imum

tem

pera

ture

(C)

29.0

29.5

30.0

30.5

31.0

31.5

32.0y = 7.5 + 0.012x (r2 = 0.13)

Year1975 1980 1985 1990 1995 2000 2005 2010

Min

imum

tem

pera

ture

(C)

22.0

22.5

23.0

23.5

24.0

24.5

25.0y = -61.8 + 0.043x (r2 = 0.74)

0.37ºC increase in 31 years 1.33ºC increase in 31 years

P > 0.05 P < 0.01

Year1975 1980 1985 1990 1995 2000 2005 2010

Max

imum

tem

pera

ture

(C)

28.0

28.5

29.0

29.5

30.0

30.5

31.0

31.5

32.0y = 16.5 + 0.0068x (r2 = 0.01)

Year1975 1980 1985 1990 1995 2000 2005 2010

Min

imum

tem

pera

ture

(C)

20.5

21.0

21.5

22.0

22.5

23.0

23.5

24.0

24.5y = -78.5 + 0.0507x (r2 = 0.55)

Dry season temperature, 1979Dry season temperature, 1979--2010, IRRI2010, IRRI

(IRRI Climate Unit)(IRRI Climate Unit)

1.62ºC increase in 32 yearsDry season = Jan. - April

P > 0.05 P < 0.01

22.0 22.5 23.0 23.5 24.0 16 17 18 19 20 21 2229.0 29.5 30.0 30.5 31.0 31.5 32.0

Gra

in y

ield

(ton

s ha

-1)

6.5

7.0

7.5

8.0

8.5

9.0

9.5

10.0y = -436.7 + 40.11x - 0.902x2 (r2 = 0.73) y = -9.4 + 1.71x - 0.0397x2 (r2 = 0.30)

Minimum temperature (C) Radiation (MJ m-2 day-1)Maximum temperature (C)

Relationship between grain yield and climate Relationship between grain yield and climate 19921992--2010 dry season, IRRI2010 dry season, IRRI

Update on Peng et al. 2004 (PNAS) with data from 7 more yearsUpdate on Peng et al. 2004 (PNAS) with data from 7 more years

22.0 22.5 23.0 23.5 24.0 16 17 18 19 20 21 2229.0 29.5 30.0 30.5 31.0 31.5 32.0Abo

vegr

ound

bio

mas

s (g

m-2

)

1500

1550

1600

1650

1700

1750

1800

1850

1900y = 4691 - 131.5x (r2 = 0.76) y = -1511 + 323.8x - 8.108x2 (r2 = 0.26)

Minimum temperature (C) Radiation (MJ m-2 day-1)Maximum temperature (C)

Relationship between biomass and climate Relationship between biomass and climate 19921992--2010 dry season, IRRI2010 dry season, IRRI

Update on Peng et al. 2004 (PNAS) with data from 7 more yearsUpdate on Peng et al. 2004 (PNAS) with data from 7 more years

Biomass declined by about 10% for each oneBiomass declined by about 10% for each one--degree degree increase in growingincrease in growing--season minimum temperatureseason minimum temperature

Minimum temperature22.0 22.5 23.0 23.5 24.0

Rad

iatio

n (M

J m

-2 d

-1)

16

17

18

19

20

21

229.37

9.07

9.30 9.03

9.31

9.58 9.55 9.11

9.00

8.71

7.72

7.06

8.05

7.772001

1999

2000

2004

2005

1996

1993 19971998

2003

1995

1992 2002 1994

9.30

8.86

7.78

Critical night temperature and radiation for Critical night temperature and radiation for grain yield, 1992grain yield, 1992--2006 dry season, IRRI2006 dry season, IRRI

•8.282006

Dry Season - IRRI Farm

Year1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

Gra

in y

ield

(t h

a-1)

6

7

8

9

10

11

IR729.6

9.49.1 9.1 9.0

8.4

9.0

8.1

7.1

7.8

Year1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

Gra

in y

ield

(t h

a-1)

6

7

8

9

10

11

Best entry9.6 9.7

9.3

10.39.9

10.7

9.0

8.3 8.3

7.8

IR72

IR60

819-

34-2

-1

IR59

682-

132-

1-1-

2

IR68

284H

IR65

469-

161-

2-2-

3-2-

2

IR68

284H

IR72

IR68

284H

IR71

622H

IR72

A

B

Dry Season - IRRI Farm

Year1992 1994 1996 1998 2000 2002

Rad

iatio

n (M

J m

-2 d

ay-1

)

16

17

18

19

20

21

22

23

A

Year1992 1994 1996 1998 2000 2002

Min

imum

tem

pera

ture

(C)

22.0

22.5

23.0

23.5

24.0

B

Year1992 1994 1996 1998 2000 2002

Max

imum

tem

pera

ture

(C)

29.0

29.5

30.0

30.5

31.0

31.5

32.0

C

Year1992 1994 1996 1998 2000 2002

Rai

nfal

l (m

m)

0

100

200

300

400

500

D

Yield decline in the last three dry seasons at IRRI(A report sent on August 14, 2001)

(August 14, 2001)(August 14, 2001)

WetWet--season rice of nine major riceseason rice of nine major rice--growing states in growing states in India as affected by OctIndia as affected by Oct--Nov minimum temperatureNov minimum temperature

((AuffhammerAuffhammer et al., 2006, PNAS)et al., 2006, PNAS)

Partial regression coefficient = Partial regression coefficient = --0.870.87

Predominantly rainfed rice

Most important factor: June-Sept rainfall

Minimum night temperature (oC)

12 14 16 18 20 22 24 26 28

Gra

in y

ield

(kg

m-2

)

0.0

0.2

0.4

0.6

0.8

1.0

Y=-0.049X2 + 2.418X – 29.22 R2=0.87

Night temperature beyond 22Night temperature beyond 22°°CC reduces rice yieldreduces rice yield

((NagarajanNagarajan et al., 2010, AEE)et al., 2010, AEE)

Weekly transplanting 6 June Weekly transplanting 6 June –– 24 August 200524 August 2005

Exp. Farm, IARI, New Delhi, India Exp. Farm, IARI, New Delhi, India

Impacts of temperature and radiation on yieldImpacts of temperature and radiation on yield

((WelchWelch et al., 20et al., 201010, , PNASPNAS))

(Based on 227 farmer(Based on 227 farmer--managed fields from 6 countries)managed fields from 6 countries)

Wheat yield in Mexico as affected by climate Wheat yield in Mexico as affected by climate

((LobellLobell et al., 2005, FCR)et al., 2005, FCR)

15-year historical data set (1988-2002) from two major wheat growing areasClimatic parameters were averaged during January-AprilRoughly 10% yield reduction for every 1˚C increase in Tmin

Field chamber to night temperature studyField chamber to night temperature study

Treat.Treat. Total DWTotal DW(g m(g m--22))

SpikeletsSpikelets mm--22

(x1000)(x1000)Grain yieldGrain yield

(t ha(t ha--11))

IR72IR72 IR8IR8 IR72IR72 IR8IR8 IR72IR72 IR8IR8

Low TLow T 10021002 11241124 26.926.9 20.520.5 5.125.12 4.644.64

High THigh T 959959 988988 25.625.6 18.918.9 4.794.79 3.453.45

AmbientAmbient 11991199 13171317 31.831.8 23.423.4 5.675.67 4.734.73

Diff. (%)Diff. (%) 55 1414 55 88 77 3535

Chamber experiment in the field, IRRI, 2007WS Chamber experiment in the field, IRRI, 2007WS

IR8 was more sensitive to high night temperature than IR72IR8 was more sensitive to high night temperature than IR72

N22 BRRI dhan29

OM2517 IR62

Cigeulis MTU1010

IR22

Varieties with tolerance to high night temperatureVarieties with tolerance to high night temperatureIRRI, 2009WS IRRI, 2009WS

Night temperature treatment: 43Night temperature treatment: 43--114 DAT with 4.9 114 DAT with 4.9 °°C increaseC increase

Sensitive varieties Sensitive varieties had reduced sink had reduced sink size and grain size and grain filling percentagefilling percentageuunder warm nightsnder warm nights

Yield decline in IR8 and possible causesYield decline in IR8 and possible causes

Year of release1960 1965 1970 1975 1980 1985 1990 1995 2000

6

7

8

9

10

11

y = -139 + 0.075xr 2 = 0.73

IR8

BPI76

IR20

IR26

IR30

IR36

IR50

IR60IR64

IR72

IR59682-132-1-1-2

IR65469-161-2-2-3-2-2G

rain

yie

ld (t

/ha)

Yield potential of Yield potential of inbredsinbreds stagnated at 10 t/hastagnated at 10 t/ha

(Peng et al.(Peng et al.,, 20002000,, Crop Sci.Crop Sci.))

N rate (kg ha-1)0 50 100 150 200

3

4

5

6

7

8

9

10

IR8

IR8

IR72

(1998 dry season)

(1998 dry season)(De Datta et al. 1968)

Gra

in y

ield

(t h

a-1)

Grain yield of IR8 grown in the late 60s and 1998Grain yield of IR8 grown in the late 60s and 1998

(Peng et al.(Peng et al.,, 19991999,, Crop Sci.Crop Sci.))

Grain yield of IR8 and best cultivar in 1996Grain yield of IR8 and best cultivar in 1996--9999

Cultivar 1996 DS 1997 DS 1998 DS 1999 DSCultivar 1996 DS 1997 DS 1998 DS 1999 DS

BestBest

IR8IR8

Yield potentialYield potential

9.9 a9.9 a

8.4 b8.4 b

10.010.0

9.7 a9.7 a

8.7 a8.7 a

10.210.2

9.1 a9.1 a

7.2 b7.2 b

9.59.5

8.1 a8.1 a

7.9 a7.9 a

8.38.3

IR8 seeds harvested in the dry IR8 seeds harvested in the dry seasons of 1968 and 1998seasons of 1968 and 1998

IR8(GB)IR8(GB) IR8(C)IR8(C)

IR8(GB) IR8(C)IR8(GB) IR8(C)

Nitrogen Response of IR8 Harvested in 1968 and 1998Dry Season 2000, IRRI

N input (kg ha-1)

0 50 100 150 200

Gra

in y

ield

(t h

a-1)

3

4

5

6

7

8

9

Col 6 vs Col 7 Col 6 vs Col 10

IR8(GB) IR8(C)

Grain yields of IR8 seeds from two sourcesGrain yields of IR8 seeds from two sources

Cultivar 2000 DS 2001 DS 2002 DS 2003 DSCultivar 2000 DS 2001 DS 2002 DS 2003 DS

BestBest

IR8(GB)IR8(GB)

IR8(C)IR8(C)

Yield potentialYield potential

8.1 a8.1 a

8.1 a8.1 a

8.0 a8.0 a

8.38.3

7.8 a7.8 a

7.6 a7.6 a

7.5 a7.5 a

7.97.9

9.6 a9.6 a

8.4 b8.4 b

7.9 b7.9 b

10.010.0

10.2 a10.2 a

8.7 b8.7 b

8.5 b8.5 b

10.410.4(Peng et al.(Peng et al.,, 20102010,, FCR)FCR)

Simple sequence repeat (SSR) analysis Simple sequence repeat (SSR) analysis

SSR detected variation in 12% of IR8(C) seedlings SSR detected variation in 12% of IR8(C) seedlings and none in IR8(GB). Among the 12 used markers, and none in IR8(GB). Among the 12 used markers, SSR detected variation marked by RM151, RM320, SSR detected variation marked by RM151, RM320, and RM333and RM333

Lanes 2Lanes 2--14 for RM151, among them, lanes 214 for RM151, among them, lanes 2--5 are IR85 are IR8(GB)(GB), lanes 6, lanes 6--14 are IR814 are IR8(C)(C), lane 12 is , lane 12 is variant; Lanes variant; Lanes 1155--25 for RM320, among them, lanes 1525 for RM320, among them, lanes 15--18 are IR818 are IR8(GB)(GB), lanes 19, lanes 19--25 are 25 are IR8IR8(C)(C), lanes 24 and 25 are variants; Lanes 26, lanes 24 and 25 are variants; Lanes 26--35 for RM333, among them, lanes 2635 for RM333, among them, lanes 26--29 are 29 are IR8IR8(GB)(GB), lanes 3, lanes 300--35 are IR835 are IR8(C)(C), lanes 30 and 35 are variants., lanes 30 and 35 are variants.

IR8 with and without SSR variationIR8 with and without SSR variation

IR8(GB)IR8(C)

without SSR variation

IR8(C) with SSR variation

Leaf photosynthetic rate of IR8 from Leaf photosynthetic rate of IR8 from difference sourcesdifference sources

SeedSeedsourcesource

IR8(GB)IR8(GB)

IR8(C)IR8(C)

IR8(C) with IR8(C) with SSR variationSSR variation

34.434.4

34.534.5

35.035.0

24.124.1

22.822.8

23.823.8

22.622.6

21.821.8

21.221.2

MidMid--tilleringtillering

PaniclePanicleinitiationinitiation

HeadingHeading

((µµmol COmol CO22 mm--22 ss--11))

Also no difference in plant height, panicle size, grain filling Also no difference in plant height, panicle size, grain filling %, seed %, seed weight, TDW, HI and grain yield.weight, TDW, HI and grain yield.

Why did the grain yield of IR8 decrease?Why did the grain yield of IR8 decrease?

Biotic stresses (Biotic stresses (changes in biotypes of diseases changes in biotypes of diseases and insects)and insects)

Abiotic stresses (Abiotic stresses (changes in climate such as changes in climate such as nighttime temperature and in soil quality)nighttime temperature and in soil quality)

Genetic changes in seeds (mutation)Genetic changes in seeds (mutation)

××

××

Implications of this studyImplications of this study

Importance of Importance of ““maintenance breedingmaintenance breeding””

Tolerance to abiotic stress also contribute toTolerance to abiotic stress also contribute to““maintenance breedingmaintenance breeding””

Climate change may erode genetic gain in cropClimate change may erode genetic gain in cropimprovementimprovement

Variety Variety deteriorationdeterioration may not existmay not exist

Yield stability of aerobic riceYield stability of aerobic rice

A mediumA medium--term experiment on aerobic riceterm experiment on aerobic rice

2001 2002 2003 2004 20051.0

2.5

4.0

5.5

7.0

8.5

10

20

30

40

50

60

70

80

2001 2002 2003 2004 2005

Yiel

d (t/

ha)

1.0

2.5

4.0

5.5

7.0

8.5

Diff

eren

ce (%

)

10

20

30

40

50

60

70

80

Aerobic Flooded Difference

Year

Yiel

d (t/

ha)

Diff

eren

ce (%

)

Year

Yield difference between aerobic and flooded riceYield difference between aerobic and flooded rice

Wet seasonWet season

Cultivar = Apo with N applicationCultivar = Apo with N application

Dry seasonDry season

10 25 40 55 70 85 100 115

Tota

l bio

mas

s (g

m-2

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0

300

600

900

1200

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1800AerobicFlooded

2001DS

Days after transplanting10 25 40 55 70 85 100 115

0

300

600

900

1200

1500

1800

2002DS

10 25 40 55 70 85 100 1150

300

600

900

1200

1500

1800

2003DS

10 25 40 55 70 85 100 1150

300

600

900

1200

1500

1800

2004DS

Biomass of flooded and aerobic rice in dry seasons Biomass of flooded and aerobic rice in dry seasons

Cultivar = Apo with N applicationCultivar = Apo with N application

2004 DS2004 DS

FallowFallow

77thth aerobic riceaerobic rice

11stst aerobic riceaerobic rice

Flooded riceFlooded rice

2004 DS2004 DS

FallowFallow

77thth aerobic riceaerobic rice

11stst aerobic riceaerobic rice

Flooded riceFlooded rice

2004 DS2004 DS

1st SeasonAerobic Rice

7th SeasonAerobic Rice

TreatmentTreatment 11stst seasonseason 77thth seasonseason DifferenceDifference

+N+N 6.326.32 3.773.77 51%51%

--NN 4.024.02 2.722.72 39%39%

Yield decline of continuous aerobic riceYield decline of continuous aerobic rice2004 dry season2004 dry season

Cultivar = ApoCultivar = Apo(Peng et al.(Peng et al.,, 20062006,, FCR)FCR)

AerobicOven heat

FloodedOven heat

FloodedZero input

AerobicZero input

Effect of oven heating on plant growth Effect of oven heating on plant growth in aerobic and flooded soilsin aerobic and flooded soils

Cultivar = Apo without fertilizer (11Cultivar = Apo without fertilizer (11thth--season aerobic soil)season aerobic soil)

Oven heat Zero input (NH4)2SO4 CO(NH2)2 NH4Cl NH4NO3 KNO3 Untreated

Zero input

Cultivar = ApoCultivar = Apo

Plant response to N sources supplied to Plant response to N sources supplied to the untreated 11the untreated 11thth--season aerobic soilseason aerobic soil

N rate = 1.2 g NN rate = 1.2 g N((NieNie et al.et al.,, 20082008,, FCR)FCR)

Possible cause of yield decline in Possible cause of yield decline in continuous aerobic ricecontinuous aerobic rice

N deficiencyN deficiency

N availabilityN availability N uptake abilityN uptake ability

Soil propertiesSoil properties NHNH33 toxicitytoxicity NematodeNematode

Development of new plant type linesDevelopment of new plant type lines

Development of new plant type at IRRIDevelopment of new plant type at IRRI19891989 Identification of donorsIdentification of donors

1990 DS1990 DS HybridizationHybridization

1990 WS1990 WS FF11 were grownwere grown

1991 DS1991 DS FF22 were grownwere grown

1991 WS1991 WS Pedigree nurseryPedigree nursery

1994 DS1994 DS First agronomic trialFirst agronomic trialIR65598IR65598--112112--22

Dr. G.S. KhushDr. G.S. Khush

Pros and cons of new plant type linesPros and cons of new plant type lines

Increased sink sizeIncreased sink sizeImproved lodging resistanceImproved lodging resistanceReduced unproductive tillersReduced unproductive tillers

Poor grain fillingPoor grain fillingLow biomass productionLow biomass productionLess compensation abilityLess compensation abilitySusceptible to diseases and insects Susceptible to diseases and insects Difficult to thresh/poor germinationDifficult to thresh/poor germinationPoor grain qualityPoor grain quality

(Peng et al.(Peng et al.,, 20082008,, FCR)FCR)

Impact of IRRIImpact of IRRI’’s NPT breedings NPT breeding

A few NPT lines have been released in Indonesia,A few NPT lines have been released in Indonesia,China, and PhilippinesChina, and Philippines..

Breeders in NARES have used NPT lines as parentsBreeders in NARES have used NPT lines as parentsin their breeding programin their breeding program..

Stimulated by Stimulated by IRRIIRRI’’ss NPT work, China established a NPT work, China established a nationwide mega project on the development of nationwide mega project on the development of ““supersuper”” rice in 1996rice in 1996..

IRRI NPT lines have been distributed through INGER IRRI NPT lines have been distributed through INGER to more than 90 countries for evaluation.to more than 90 countries for evaluation.

Is it possible to increase rice yield Is it possible to increase rice yield potential by 15% in the tropics? potential by 15% in the tropics?

Panicle number per mPanicle number per m22 = 275= 275

Spikelets per panicle = Spikelets per panicle = 175175

Grain filling percentage = 80%Grain filling percentage = 80%

10001000--grain weight = grain weight = 2727 gg

Grain yield = 275 x 175 x 0.8 x 27 = 1,039.5 g/mGrain yield = 275 x 175 x 0.8 x 27 = 1,039.5 g/m22

Grain yield = 1,039.5 / 0.9 / 100 = 11.55 t/haGrain yield = 1,039.5 / 0.9 / 100 = 11.55 t/ha

Is it possible to increase rice yield Is it possible to increase rice yield potential by 15% in the tropics? potential by 15% in the tropics? Mean daily radiation = 18 MJ/mMean daily radiation = 18 MJ/m22

Crop growth duration in main field = 110 daysCrop growth duration in main field = 110 days

Mean light interception = Mean light interception = 70%70%

Radiation use efficiency = Radiation use efficiency = 1.5 g/MJ1.5 g/MJ

Harvest index = 50%Harvest index = 50%

Grain yield = 18 x 110 x 0.7 x 1.5 x 0.5 = 1,039.5 g/mGrain yield = 18 x 110 x 0.7 x 1.5 x 0.5 = 1,039.5 g/m22

Grain yield = 1,039.5 / 0.9 / 100 = 11.55 t/haGrain yield = 1,039.5 / 0.9 / 100 = 11.55 t/ha

New strategiesNew strategiesFollow Chinese experience in donor selection andFollow Chinese experience in donor selection andutilization of heterosis.utilization of heterosis.

Emphasize more Emphasize more on the top three leaves and theon the top three leaves and theposition of panicle within canopyposition of panicle within canopy..

Use multiple traits instead of single trait. ConsiderUse multiple traits instead of single trait. Considercompensation among various traits. compensation among various traits.

Impose selection pressure in early generations.Impose selection pressure in early generations.

Develop measurable indicators to use in selectionDevelop measurable indicators to use in selection. .

Expand and standardize multiExpand and standardize multi--location yield trials.location yield trials.

Proposed plant traits for improvementProposed plant traits for improvement

Early Early vigorvigor, moderate tillering capacity, and thin, moderate tillering capacity, and thinleaves at vegetative stages.leaves at vegetative stages.

Taller plants, lower panicle height, thicker andTaller plants, lower panicle height, thicker andstronger stems.stronger stems.

Erect, thick, dark green, and Erect, thick, dark green, and VV--shaped leaves, high shaped leaves, high LAI, and delayed leaf senescence in late stages. LAI, and delayed leaf senescence in late stages.

Large and compact panicles, heavy grain weight,Large and compact panicles, heavy grain weight,long grain filling duration.long grain filling duration.

No.No. TraitTrait ValueValue11 Panicles per mPanicles per m22 250250--30030022 SpikeletsSpikelets per panicleper panicle 150150--20020033 SpikeletsSpikelets per mper m22 45,00045,000--55,00055,00044 Grain filling percentageGrain filling percentage >80%>80%55 Grain weight (oven dry)Grain weight (oven dry) 2626--28 mg28 mg66 Panicle weight (oven dry)Panicle weight (oven dry) 44--5 g5 g77 Plant heightPlant height 115115--125 cm125 cm88 Panicle heightPanicle height 6060--70 cm70 cm99 Crop growth durationCrop growth duration 120120--130 days130 days

1010 Stem thickness (4th Stem thickness (4th internodeinternode)) 66--8 mm8 mm1111 Light interception (seasonal mean)Light interception (seasonal mean) >70%>70%

Group I: Important and easy to measureGroup I: Important and easy to measure

No.No. TraitTrait ValueValue11 Total biomass (oven dry)Total biomass (oven dry) >21 t/ha>21 t/ha22 Crop growth rate (seasonal mean)Crop growth rate (seasonal mean) >19 g/m>19 g/m22/d/d33 Leaf area index (maximum)Leaf area index (maximum) 77--101044 Leaf senescence (based on SPAD)Leaf senescence (based on SPAD)** >80%>80%55 Leaf N concentration at floweringLeaf N concentration at flowering 2.52.5--3.0%3.0%66 Radiation use efficiencyRadiation use efficiency >1.5 g/MJ>1.5 g/MJ77 Harvest indexHarvest index >50%>50%88 Translocation efficiencyTranslocation efficiency** 2020--30%30%99 Grain filling duration (cropGrain filling duration (crop--based)based) 3535--40 days40 days

1010 Lodging indexLodging index** <100<1001111 Total N uptakeTotal N uptake 200200--250 kg/ha250 kg/ha

Group II: Important and not easy to measureGroup II: Important and not easy to measure

Leaf senescenceLeaf senescence == 100 x100 xSPAD at 21 d after floweringSPAD at 21 d after flowering

SPAD at floweringSPAD at flowering

Translocation efficiencyTranslocation efficiency = 100 x= 100 xYield Yield –– (DW(DWMA MA -- DWDWFLFL ))

YieldYield

Lodging indexLodging index = = 100 x100 xBending momentBending moment

Breaking resistanceBreaking resistance

No.No. TraitTrait ValueValue11 Leaf numberLeaf number 1515--171722 Leaf length at flowering (top 3)Leaf length at flowering (top 3) 4545--5050--50 cm50 cm33 Leaf width at floweringLeaf width at flowering 1.51.5--1.8 cm1.8 cm44 Leaf shape at floweringLeaf shape at flowering 120120--150150°°55 Leaf erectness at flowering (top 3)Leaf erectness at flowering (top 3) 55--1010--2020°°66 Panicle lengthPanicle length 2626--30 cm30 cm77 Number of primary branchesNumber of primary branches 1212--151588 Number of secondary branchesNumber of secondary branches 2222--303099 Number of elongated internodesNumber of elongated internodes 55

1010 Days to floweringDays to flowering 8080--90 days90 days

Group III: Less important and easy to measureGroup III: Less important and easy to measure

No.No. TraitTrait ValueValue11 Leaf thickness (SLW at flowering)Leaf thickness (SLW at flowering) 5555--60 g/m60 g/m22

22 Maximum tiller number per mMaximum tiller number per m22 500500--60060033 Productive tiller percentageProductive tiller percentage 5050--60%60%44 SpikeletsSpikelets/panicle length (cm)/panicle length (cm) 66--8855 SpikeletsSpikelets on primary brancheson primary branches 6060--808066 SpikeletsSpikelets on secondary brancheson secondary branches 9090--12012077 High density grainsHigh density grains >70%>70%88 Grain filling rate (maximum)Grain filling rate (maximum) >2.5 mg/day>2.5 mg/day99 Number of large vascular bundleNumber of large vascular bundle 2222--2525

1010 Early vigor (at 14 DAT)Early vigor (at 14 DAT) >1.5 tillers/>1.5 tillers/pltplt

Group IV: Less important and not easy to measureGroup IV: Less important and not easy to measure

SecondarySecondary plant traitsplant traits

Secondary branchesSecondary branches

Primary branchesPrimary branches= 2.0= 2.0

SpikeletsSpikelets on primary brancheson primary branches

Total Total spikeletsspikelets= 0.4= 0.4

Large vascular bundlesLarge vascular bundles

Primary branchesPrimary branches= 1.8= 1.8

Lessons from Lessons from ““ssuperuper”” rice varietiesrice varietiesPoor nitrogenPoor nitrogen--fertilizer use efficiency because of its fertilizer use efficiency because of its tolerance to high nitrogen application.tolerance to high nitrogen application.

Reduced early vigor as reflected by low rate of tiller andReduced early vigor as reflected by low rate of tiller andleaf area production during early vegetative stage.leaf area production during early vegetative stage.

Poor compensatory abilityPoor compensatory ability to disease and insect damageto disease and insect damagedue to low tillering capacitydue to low tillering capacity..

Intensive crop management is required to demonstrateIntensive crop management is required to demonstrateyield advantage.yield advantage.

Scientific issuesScientific issues for increasing yield potentialfor increasing yield potential

How much room is left in plant type improvement forHow much room is left in plant type improvement forachieving greater yield potential? achieving greater yield potential?

How much gain in yield potential is possible by delayed How much gain in yield potential is possible by delayed leaf senescence and extended grain filling duration? leaf senescence and extended grain filling duration?

Which one is more limiting, source or sink? How toWhich one is more limiting, source or sink? How toquantify sink strength?quantify sink strength?

Can improvement in RUE through high photosyntheticCan improvement in RUE through high photosyntheticrate contribute to high yield potential?rate contribute to high yield potential?

What are the real impact of advanced molecular techWhat are the real impact of advanced molecular tech--nologynology on breeding varieties with high yield potential?on breeding varieties with high yield potential?

Do we have a better chance this time? Do we have a better chance this time?

Better understanding of highBetter understanding of high--yielding plant yielding plant traits and some successes in traits and some successes in ideotypeideotype breeding breeding Wide range of Wide range of germplasmgermplasm with target traits with target traits become available as donor parents.become available as donor parents.All target plant traits are quantifiable and All target plant traits are quantifiable and measurable. measurable. MultiMulti--location yield trials will be expanded location yield trials will be expanded and standardized.and standardized.Better funding situation and more efforts of Better funding situation and more efforts of breeding work. breeding work.

RegretsRegrets……

Good understanding on N nutrition but weak in carbonGood understanding on N nutrition but weak in carbonassimilation and metabolism. assimilation and metabolism.

Focused on wholeFocused on whole--plant physiology but had limited useplant physiology but had limited useof molecular biology approaches.of molecular biology approaches.

Focused more in east Asia but had limited contributionFocused more in east Asia but had limited contributionto south and southeast Asia.to south and southeast Asia.

Emphasized on favorable ecosystems but neglected Emphasized on favorable ecosystems but neglected fragile ecosystems. fragile ecosystems.

Not successful in the application of large project fundsNot successful in the application of large project fundssuch as climate change.such as climate change.

Never achieve grain yield over 11 t/ha at IRRI farm.Never achieve grain yield over 11 t/ha at IRRI farm.

Future course of crop physiology researchFuture course of crop physiology researchon irrigated rice at IRRIon irrigated rice at IRRI

Continue to work with breeders in identifying plant typeContinue to work with breeders in identifying plant typettraits that increase rice yield potentialraits that increase rice yield potential. .

Study biological and genetic control of physiological Study biological and genetic control of physiological traits that determine the process of yield formation.traits that determine the process of yield formation.

Establish high throughput and precision Establish high throughput and precision phenotypingphenotypingsystem for both field and lab studies.system for both field and lab studies.

Understand the mechanism of varietal adaptation toUnderstand the mechanism of varietal adaptation toclimate change. climate change.

Explore strategies in increasing wetExplore strategies in increasing wet--season rice yieldseason rice yieldwith focus on shading tolerance.with focus on shading tolerance.

Increase RUE by improving photosynthesis at canopyIncrease RUE by improving photosynthesis at canopyand singleand single--leaf levels and by suppressing respiration.leaf levels and by suppressing respiration.

38 rice growing seasons38 rice growing seasons

169 field experiments169 field experiments

6,995 days with IRRI 6,995 days with IRRI ……

Some numbers to remember:Some numbers to remember:

Klaus Klaus LampeLampe

George George RothschildRothschild

Robert Robert HavenerHavener

Ronald Ronald Cantrell Cantrell

Robert Robert ZeiglerZeigler

Director General

Deputy Director General

(Research)

To Phuc To Phuc TuongTuong

Achim Achim DobermannDobermann

Kenneth Kenneth FischerFischer

MohabubMohabub HossainHossain

Ren Ren WangWang

Division Head

To Phuc To Phuc TuongTuong

Bas Bas BoumanBouman

Kenneth Kenneth CassmanCassman

James James HillHill

Osamu Osamu ItoIto

K.G. CassmanR.J. BureshA. DobermannB.S. VergaraB.A.M. BoumanA. IsmailJ.K. LadhaJ.E. SheehyC. Witt…

G.S. KhushS.S. VirmaniP. VirkF. XieJ. Bennett…

CESD divisionCESD division PBGB divisionPBGB division

Collaborating IRRI scientistsCollaborating IRRI scientists

Crop Physiology StaffCrop Physiology Staff

Shaobing Peng Romeo Visperas Ma. Rebecca Laza Bermenito Punzalan Pauline Jasmin Jacinta Evangelista

Anicio Macahia Onofre Mendoza Maximo Pelagio Eduardo Tandang Siena Calibo

Rowena Noblejas Joel Evangelista Yunbo Zhang Wanju ShiJenelyn Borgonia

FormerFormer sstafftaff membersmembersAlfredo "Fred" BernardoAlfredo "Fred" Bernardo

JovencitaJovencita "Joven" Biker"Joven" Biker

Arlene ChavezArlene Chavez

Florencio "Florencio "BindoyBindoy" " CanobasCanobas

Ernesto "Ernie" CuencaErnesto "Ernie" Cuenca

Jenny DagdagJenny Dagdag

Rodolfo "Rudy" Rodolfo "Rudy" delosdelos ReyesReyes

Venus Venus ““BingBing”” ElecElec

Nelzo ErefulNelzo Ereful

Emma FabianEmma Fabian

Felipe V. GarciaFelipe V. Garcia

GaundencioGaundencio ""TotiToti" " IndicoIndico

Ramon Ramon MasajoMasajo

EfrenEfren ManimtimManimtim

Arnel Arnel SanicoSanico

Eduardo "Eduardo "DodongDodong" " SuplacSuplac

NicanoNicanorr "Nick" "Nick" TuringanTuringan

Crop Physiology and Production Center (CPPC)College of Plant Science and TechnologyHuazhong Agricultural UniversityWuhan, Hubei 430070

Thank you!Thank you!