Physiological determination of oats yield: Physiological determination of oats yield: thoughts on promissory traits for further thoughts on promissory traits for further

genetic gainsgenetic gains

Daniel Daniel CalderiniCalderini

Universidad Austral de ChileUniversidad Austral de Chile

International Oat ConferenceInternational Oat ConferenceMinneapolis, 2008Minneapolis, 2008

This presentation has the objective of:

1. Review few aspects of the effect of plant breeding on oat grain yield and associated traits

2. Analyze major grain yield components (i.e., grain number and grain weight)

3. Propose traits that could be useful to continueincreasing yield potential

4. Propose a model of GW determination for temperatecereals

IntroductionIntroduction

Grain crops are facing important challenges:

- Expected increase of food demand

- Alternative uses (biofuels)

- Little opportunities for expanding arable land and

irrigated areas

- High grain production with low environmental impact

1.4

1.6

1.8

2

2.2

2.4

2.6

2.8

80 90 2000

Gra

in y

ield

(M

g ha

Gra

in y

ield

(M

g ha

-1))

OatOat

85 95

Years

WheatWheat

BarleyBarley RyeRye

Slafer and Peltonen-Sainio (2001)

In addition, some evidences are showingthat grain yield of temperate cereals areleveling off

IntroductionIntroduction

Plant breeding is the most cost effective, and environmentally safe, way of increasing grain yield

The knowledge of physiological bases of grainyield determination could provide useful tools toplant breeding programs aimed at increasingyield potential

1

2

3

4

5

6

1910 1930 1950 1970 1990 2010 1910 1930 1950 1970 1990 2010 1910 1930 1950 1970 1990 2010

Minnesota Finland Italy

Gra

in y

ield

(M

g ha

-1)

Year of release

y = 0.036x – 67.4(r = 0.71; p<0.01)

y = 0.099x – 15.7(r = 0.66; p<0.05)

y = 0.018x – 31.9(r = 0.96; p<0.001)

Oat breeding effect on grain yieldOat breeding effect on grain yield

BreedingBreeding

Adapted from Wych and Stuthman (1983);

Peltonen-Sainio (1990); Redaelli et al. (2008)

0

1

2

3

4

20 25 30 35 400

1

2

3

4

5

45 50 55 60

Gra

in y

ield

(M

g ha

-1)

Harvest index (%)

Minnesota Finland

y = 0.099x – 0.36(r = 0.90; p<0.001)

Relationship between grain yield and harvest indexRelationship between grain yield and harvest index

y = 0.114x – 2.2(r = 0.54; p<0.05)

BreedingBreeding

Adapted from Wych and Stuthman (1983);

Peltonen-Sainio (1990)

0

2

4

6

8

10

0 10 20 30 40 50 60

Oat

Wheat

Harvest index (%)

Gra

in y

ield

(M

g h

a-1)

Theoretical maximum HITheoretical maximum HI

Relationship between grain yield and harvest indexRelationship between grain yield and harvest indexin wheat and oatin wheat and oat

BreedingBreeding

DD SD SH

Plant height (cm)

Gra

in y

ield

70 100

Plant height optimumPlant height optimum

Richards (1992)

Miralles and Slafer (1995)

BreedingBreeding

Grain yield Grains m-2=Grain

Weightx

Grain yield will be increased by improvingGrain yield will be increased by improvingmajor yield componentsmajor yield components

ArgentinaAustraliaIndiaItalyMexicoUK

Relationship between grain yield and grain numberRelationship between grain yield and grain number

Calderini et al. (1999)

Variability of grain number, grain weight and grain yieldVariability of grain number, grain weight and grain yield(comparison between years)(comparison between years)

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

Spring

barley

Springoat

Spring

wheat

Winter

wheat

Winterrye

Grain Number

Grain Weight

Yield

Sta

ndar

d de

viat

ion/

mea

n

Adapted from Peltonen-Sainio et al. (2007)

Grain yield

Grain weightGrains m-2

Sowing

EmergenceAnthesis Physiological

MaturityBooting HarvestTillering

Adapted from Slafer and Rawson (1994)

Major yield components and crop cycleMajor yield components and crop cycle

Emergence Anthesis PhysiologicalMaturity

Booting HarvestTillering

Adapted from Slafer and Rawson (1994)

Gra

in n

um

ber

un

der

str

ess

Grain numberGrain number Growth of reproductive

organs

Gro

wth

of

rep

rod

uct

ive

org

ans

How to improve the growth of reproductive organsaimed at increasing grain number?

1.Higher partitioning of crop biomass to reproductive organs at pre-heading

2. Higher biomass production

3. Longer duration of the period when reproductive organs are growing

Grain numberGrain number

1.Higher partitioning of crop biomass to reproductive

organs at pre-heading

Gonzalez et al. (2005)

Grain numberGrain number

Year of release Grain yield Stem weight (g m-2) (g m-2)

1920 319.9 839.11990 649.1 496.4

Difference 329.3 -342.7

Calderini et al. (1995)

1. Higher partitioning of crop biomass

Grain numberGrain number

Muurinen & Peltonen-Sainio (2006)

Radiation interception

Radiation use efficiency

RUE at pre-heading

ab abbc

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Jama Aslak Suomi

Cultivar

Rad

iatio

n us

e ef

ficie

ncy

(g M

J-1 m

-2)

2. Higher biomass production

Grain numberGrain number

WheatRUE at pre-anthesis

Amador & Calderini (unpublished)

Rad

iatio

n us

e ef

ficie

ncy

(g M

J-1 m

-2)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Otto Quijote

b

a

Cultivar

Grain numberGrain number

0

100

200

300

400

500

600

700

Otto Quijote

a b

0.00.51.01.52.02.53.03.54.0

ba

Wheat

Cultivar

RU

ER

I

Amador & Calderini (unpublished)

Grain numberGrain number

(Slafer et al., 1996)

Emergence Anthesis PhysiologicalMaturity

Booting HarvestTillering

Adapted from Slafer and Rawson (1994)

Gro

wth

of

rep

rod

uct

ive

org

ans

3. Longer duration of the period when reproductive organs are growing

Grain numberGrain number

Whitechurch et al., (2007)

In wheat and barley, clear differences between In wheat and barley, clear differences between duration of pheno-phases have been found duration of pheno-phases have been found

Grain numberGrain number

Relative duration of pheno-phases in oat(14 cultivars and 6 lines from Finland)

Vegetative / whole crop cycle

Generative / whole crop cycle

Range of relative duration(%)

14.3 – 17.4

32.0 – 36.5

Phenological phases

Peltonen-Sainio & Rajala (2007)

Grain numberGrain number

Major yield components: Grain WeightMajor yield components: Grain Weight

Although more conservative than GN, GW could be aAlthough more conservative than GN, GW could be auseful trait for continuing increasing yield potential ofuseful trait for continuing increasing yield potential oftemperate cereals, especially if future plant breedingtemperate cereals, especially if future plant breedingprograms set more grains with lower GW potentialprograms set more grains with lower GW potential

Due to higher stability of GW, the knowledge of Due to higher stability of GW, the knowledge of physiological bases of GW determination canphysiological bases of GW determination canhelp breeding programs to increase grain yieldhelp breeding programs to increase grain yieldby improving GWby improving GW

Major yield components: Grain WeightMajor yield components: Grain Weight

In oat, there are clear evidences that this trait has beenIn oat, there are clear evidences that this trait has beenincreased by plant breedingincreased by plant breeding (e.g., Wych and Stuthmann, 1983;(e.g., Wych and Stuthmann, 1983;Peltonene-Sainio, 1994)Peltonene-Sainio, 1994)

Grain yield

Grain weightGrains m-2

Sowing

EmergenceAnthesis Physiological

MaturityBooting HarvestTillering

Adapted from Slafer and Rawson (1994)

Assumptions on GN and GW determinationAssumptions on GN and GW determination

Temperature was increased (5.5°C) at differentTemperature was increased (5.5°C) at differentdevelopmental phases in wheat, barley and triticaledevelopmental phases in wheat, barley and triticale

S Em Anthesis PM Heading Harvest

Time DR TS Booting

B-AH-A

SE-B

Ugarte et al. (2007)

Effect of temperature on major yield componentsEffect of temperature on major yield components

Grain weightGrain weight

Effect of increased temperature on GN and GWEffect of increased temperature on GN and GWAveraged across crops and experiments (3 years)Averaged across crops and experiments (3 years)

H-A -7%

B-A -15% -15%

SE-B -7%

GNGN GWGW

-8%

-42%

Grain yield

S Em Anthesis PM Head Harvest Time DR FI TE

Grain weightGrains m-2

Booting

This has important consequences for the study of This has important consequences for the study of grain weight determination grain weight determination

All these evidences are showing that flowers,All these evidences are showing that flowers,which grow at the pre-anthesis period, are which grow at the pre-anthesis period, are

involved in GW determinationinvolved in GW determination

Grain weightGrain weight

New evidences of the involvement of the pre-anthesis period in GW determination gives support to promising molecular traits for increasing GW in temperate cereals

spikelet

Different traits associatedwith GW were measuredat central spikelets of thewheat spike

G1G2

G3G4

rachis

Grain weightGrain weight

36.351.055.552.7Huayun  

45.357.557.956.3Pandora2

41.751.658.455.9Huanil

42.752.657.953.5Pandora12

42.565.172.167.8Kambara

35.350.356.952.5Bacanora3

36.357.866.261.5Kambara

37.451.656.351.6Bacanora2

41.860.365.262.3Kambara

31.643.949.844.9Bacanora11

G4G3G2G1

Grain weight (mg)CultivarSeasonExperiment

Grain weight in two experimentsGrain weight in two experiments

Grain weightGrain weight

y = 86.18x + 3.97

R2 = 0.790

1020

30

40

5060

70

80

0,0 0,2 0,4 0,6 0,8 1,0

y = 126.93x – 5.93

R2 = 0.860

10

20

3040

50

60

70

80

0,0 0,2 0,4 0,6 0,8 1,0

Carpel weight at pollination, W10 (mg)Carpel weight at pollination, W10 (mg)

Gra

in w

eigh

t (m

g)G

rain

wei

ght

(mg) year 2006year 2006 year 2007year 2007

Relationship between grain weight and carpel weightRelationship between grain weight and carpel weight

Grain weightGrain weight

Dynamic of grain dimensionsDynamic of grain dimensionsPM

0

2

4

6

8

10

0 10 20 30 40 50

days after anthesisdays after anthesis

Gra

in d

imen

sion

s (m

m)

Gra

in d

imen

sion

s (m

m)

Length

WidthHeight

Grain weightGrain weight

y = 1.12x + 4.06

R2 = 0.870

20

40

60

80

100

0 20 40 60 80 100

Grain volume (mmGrain volume (mm 33))

Gra

in w

eigh

t (m

g)G

rain

wei

ght

(mg)

y = 17.89x - 81.53

R2 = 0.860

20

40

60

80

5 6 7 8 9 10

Grain length (mm)Grain length (mm)G

rain

vol

ume

(mm

Gra

in v

olum

e (m

m33))

Relationship between grain weight, grain volume andRelationship between grain weight, grain volume andgrain lengthgrain length

Grain weightGrain weight

0

10

20

30

40

50

60

70

0 10 20 30 40 50

days after anthesisdays after anthesis

Gra

in d

ry m

atte

r an

d w

ater

G

rain

dry

mat

ter

and

wat

er

cont

ent

(mg)

cont

ent

(mg)

Dynamic of dry matter and water content of grainsDynamic of dry matter and water content of grains

Dry matter

Water

Maximum water contentMaximum water content

Grain weightGrain weight

Relationship between grain weight and maximumRelationship between grain weight and maximumwater content of grainswater content of grains

Gra

in w

eigh

t (m

g)G

rain

wei

ght (

mg)

Maximum water content (mg)Maximum water content (mg)

Experiment 1Experiment 1 Experiment 2Experiment 2

y = 1,39x - 2,45

R2 = 0,950

20

40

60

80

20 30 40 50 60

y = 0,93x + 15,89

R2 = 0,92

0

20

40

60

80

20 30 40 50 60

Grain weightGrain weight

010203040506070

0 20 40 60 0 20 40 60 80 0 20 40 60 800

2

4

6

8

10

Days after flowering

Gra

in w

ater

co

nte

nt

(mg

)G

rain len

gth

(mm

)

Pandora Bacanora Kambara

Dynamics of water content and enlargement of grainsDynamics of water content and enlargement of grains

Grain weightGrain weight

0

20

40

60

80

5 6 7 8 9 10

Grain length (mm)Grain length (mm)

Gra

in w

eig

ht o

r M

axim

um

Gra

in w

eig

ht o

r M

axim

um

W

ate

r C

ont

en

t (m

g)W

ate

r C

ont

en

t (m

g)

Relationship between grain weight or maximum waterRelationship between grain weight or maximum watercontent and grain lengthcontent and grain length

GW

MWC

(r= 0.91; p<0.001)

(r= 0.95; p<0.001)

Grain weightGrain weight

Grain length is associated with carpel weightGrain length is associated with carpel weight

4

5

6

7

8

9

10

0.20 0.30 0.40 0.50 0.60 0.70

r = 0.75; p<0.01

Carpel weight at pollination (mg)Carpel weight at pollination (mg)

Gra

in le

ngth

(m

g)G

rain

leng

th (

mg) year 2007year 2007

year 2006year 2006

Grain weightGrain weight

Recurrent selection for grain yield in oat increased GW, grain area, grain length and grain width (De Koeyer et al., 1993)

In the poster session of this conference, Hu et al. (2008) show data of GW and grain dimensions

Relationship between GW and grain length:

r2= 0.74; p<0.05

Grain weightGrain weight

As a consequence of the relationship between final grain weight and carpel weight at anthesis, is proposed that the pericarp of grains is involved in grain weight determination. In other words, the final size of the pericarp is setting the potential weight of grainsPericarp growth is the result of the number of pericarp cellsand the enlargement of these cells. Plant cell enlargementis controlled by proteins called expansins, which are involved in cell wall loosening (McQueen-Mason et al., 1992)

Recently, expansin expression has been found in growing grains of wheat (Calderini et al., 2006; Liu et al, 2007)

Grain weightGrain weight

Preliminarily, we found the expression of 6 expansins in pericarp of grains at 10 days after anthesis from the experiment 2

- ExpA 2- ExpA 4- ExpA 6- ExpA 8- Exp novel 1 (similar to Festuca

pratensis)- Exp novel 2 (similar to Oriza sativa)

After this first step, ExpA 6 has been separated in 3 different goups: ExpA 6 a, ExpA 6 b and ExpA 6 c

ExpansinsExpansinsGrain weightGrain weight

0

2

4

6

8

0 5 10 15 20 25

Days after anthesis

Gra

in le

nght

(m

m)

1,0

1,2

1,4

1,6

1,8

2,0

Expression of E

XP

A 6c (ID

)

Lenght

Expansin

Dynamics of grain length and ExpA 6c expresion in Dynamics of grain length and ExpA 6c expresion in cultivar Bacanoracultivar Bacanora

Grain weightGrain weight

Antisense Sense Negative control

Hybridization of Expansin A 6c in grains at Hybridization of Expansin A 6c in grains at 5 days5 days after anthesisafter anthesis

Grain weightGrain weight

Antisense Sense Negative control

Hybridization of Expansin A 6c in grains at Hybridization of Expansin A 6c in grains at 10 days10 days after anthesisafter anthesis

Grain weightGrain weight

Proposed Model of Potential Grain Weight DeterminationProposed Model of Potential Grain Weight Determination

Carpelsgrowth

Lag Phase

Carpel weightat pollination

Endosperm

Endospermcell number

PhysiologicalMaturityPollinationBooting

Pericarpcells

Water ingrain

Maximum watercontent

Pericarp elongation

Expansin expression

ConclusionsConclusions

- The overlapping of both GN and GW The overlapping of both GN and GW determination in temperate cereals is determination in temperate cereals is longer than generally assumed longer than generally assumed

- The sensitivity of major yield components The sensitivity of major yield components to environmental constraints during this to environmental constraints during this overlapping has been similaroverlapping has been similar

- There is not evidences of trade-off betweenThere is not evidences of trade-off between GN and GW as a consequence of theGN and GW as a consequence of the overlapping between booting and anthesisoverlapping between booting and anthesis

ConclusionsConclusions

- There are opportunities for increasing GNThere are opportunities for increasing GN of temperate cereals. Differences between of temperate cereals. Differences between pheno-phases found in oats is a starting pointpheno-phases found in oats is a starting point for using this trait in plant breeding programsfor using this trait in plant breeding programs

- The involvement of expansins in grain The involvement of expansins in grain enlargement could be used for increasingenlargement could be used for increasing GW in temperate cerealsGW in temperate cereals

Mrs. Carolina Lizana Ph.D. Student (U. Austral de Chile)

Dr.Ricardo Riegel Adjunt Professor (U. Austral de Chile)

Dr. Simon McQueen-Mason Professor (U. of York)

Thank youThank you!!

Time (days after anthesis)

G

rain

we

igh

t (m

g)

0

10

20

30

40

50

60

0 10 20 30 40 50

Grain growth rate

Grain filling duration

Usual approach for studying GW Usual approach for studying GW

Grain weightGrain weight

Response of sunflower Response of sunflower yield components to yield components to shadingshading

Cantagallo et al. (2004)

0

20

40

60

80

15.5 24.5Pre-anthesis temperature (°C)

K

ern

el w

eig

ht

(mg

)

Wardlaw (1994)

Wheat

Other evidences of Other evidences of the involvement of the involvement of the pre-anthesis the pre-anthesis period in grain weight period in grain weight determinationdetermination

Grain weightGrain weight

Carpel weight at anthesis (mg)

Gra

in w

eig

ht

(mg

)

0

20

40

60

80

0 1 2 3 4 0 1 2 3 4 0 1 2 3 4

G1 G2 G3

Control

De-graining

Buenos Aires

Relationship between GW and Relationship between GW and carpel weight at anthesis in carpel weight at anthesis in

wheatwheat

(data from different experiments)

Calderini & Reynolds (2000)

Grain weightGrain weight

Grain number reduction relative to the controlGrain number reduction relative to the control

H-A +1%

B-A -13% -13%

WheaWheatt

SE-B -40%

Exp. 1 Exp. 2

H-A +3%

B-A +4% -18%

BarleyBarley SE-B -36%

H-A -2%

B-A -15% -16%

TriticaleTriticale SE-B -48%

Ugarte et al. (2007)

Grain weight reduction relative to the controlGrain weight reduction relative to the control

H-A -9%

B-A -14% -19%

WheaWheatt

SE-B -7%

Exp. 1 Exp. 2

H-A -8%

B-A -13% -21%

BarleyBarley SE-B -8%

H-A -9%

B-A -15% -23%

TriticaleTriticale SE-B -6%

Ugarte et al. (2007)

Grain weightGrain weight

y = 1.12x + 4.06

R2 = 0.870

20

40

60

80

100

0 20 40 60 80 100

Grain volume (mmGrain volume (mm 33))

Gra

in w

eigh

t (m

g)G

rain

wei

ght

(mg)

Relationship between grain weight and grain volumeRelationship between grain weight and grain volume

Grain weightGrain weight