Diapositiva 1

1
International Oat Conference Minneapolis, 2008
Physiological determination of oats yield
thoughts on promissory traits for further genetic
gains
Daniel Calderini Universidad Austral de Chile
2

• This presentation has the objective of
• Review few aspects of the effect of plant
  breeding
• on oat grain yield and associated traits
• Analyze major grain yield components (i.e., grain
• number and grain weight)
• 3. Propose traits that could be useful to
  continue
• increasing yield potential
• 4. Propose a model of GW determination for
  temperate
• cereals

3
Introduction
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

4
Introduction
2.8
In addition, some evidences are showing that
grain yield of temperate cereals are leveling off
2.6
2.4
2.2
Grain yield (Mg ha-1)
2
1.8
1.6
1.4
80
90
2000
85
95
Slafer and Peltonen-Sainio (2001)
Years
5
Plant breeding is the most cost effective, and
environmentally safe, way of increasing grain
yield
The knowledge of physiological bases of
grain yield determination could provide useful
tools to plant breeding programs aimed at
increasing yield potential
6
Breeding
Oat breeding effect on grain yield
Minnesota
Finland
Italy
Grain yield (Mg ha-1)
y 0.036x 67.4 (r 0.71 plt0.01)
y 0.099x 15.7 (r 0.66 plt0.05)
y 0.018x 31.9 (r 0.96 plt0.001)
Year of release
Adapted from Wych and Stuthman (1983) Peltonen-Sa
inio (1990) Redaelli et al. (2008)
7
Breeding
Relationship between grain yield and harvest index
Minnesota
Finland
Grain yield (Mg ha-1)
y 0.099x 0.36 (r 0.90 plt0.001)
y 0.114x 2.2 (r 0.54 plt0.05)
Harvest index ()
Adapted from Wych and Stuthman (1983) Peltonen-Sa
inio (1990)
8
Breeding
Relationship between grain yield and harvest
index in wheat and oat
9
Breeding
Plant height optimum
Grain yield
70
100
SH
DD
SD
Richards (1992) Miralles and Slafer (1995)
Plant height (cm)
10
Grain yield will be increased by improving major
yield components
Grain Weight
Grains m-2

x
11
Relationship between grain yield and grain number
Calderini et al. (1999)
12
Variability of grain number, grain weight and
grain yield (comparison between years)
0.18
0.16
0.14
0.12
0.10
Standard deviation/mean
0.08
0.06
0.04
0.02
0.00
Spring
Spring oat
Spring
Winter
Winter rye
barley
wheat
wheat
Adapted from Peltonen-Sainio et al. (2007)
13
Major yield components and crop cycle
Sowing
Harvest
Physiological Maturity
Anthesis
Booting
Tillering
Emergence
Grains m-2
Grain weight
Grain yield
Adapted from Slafer and Rawson (1994)
14
Grain number
Harvest
Physiological Maturity
Anthesis
Booting
Tillering
Emergence
Adapted from Slafer and Rawson (1994)
15
Grain number
How to improve the growth of reproductive
organs aimed at increasing grain number?

• 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

16
Grain number

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

Gonzalez et al. (2005)
17
Grain number
1. Higher partitioning of crop biomass
Calderini et al. (1995)
18
Grain number
2. Higher biomass production
Muurinen Peltonen-Sainio (2006)
19
Grain number
Wheat RUE at pre-anthesis
4.0
a
3.5
b
3.0
2.5
Radiation use efficiency (g MJ-1 m-2)
2.0
1.5
1.0
0.5
0.0
Otto
Quijote
Cultivar
Amador Calderini (unpublished)
20
Wheat
Grain number
a
4.0
3.5
b
3.0
2.5
RUE
2.0
1.5
1.0
0.5
0.0
700
a
b
600
500
RI
400
300
200
100
0
Otto
Quijote
Cultivar
Amador Calderini (unpublished)
21
Grain number
3. Longer duration of the period when
reproductive organs are growing
(Slafer et al., 1996)
Adapted from Slafer and Rawson (1994)
22
Grain number
In wheat and barley, clear differences between
duration of pheno-phases have been found
Whitechurch et al., (2007)
23
Grain number
Relative duration of pheno-phases in oat (14
cultivars and 6 lines from Finland)
Peltonen-Sainio Rajala (2007)
24
Major yield components Grain Weight
Although more conservative than GN, GW could be
a useful trait for continuing increasing yield
potential of temperate cereals, especially if
future plant breeding programs set more grains
with lower GW potential
Due to higher stability of GW, the knowledge of
physiological bases of GW determination can help
breeding programs to increase grain yield by
improving GW
25
Major yield components Grain Weight
In oat, there are clear evidences that this trait
has been increased by plant breeding (e.g., Wych
and Stuthmann, 1983 Peltonene-Sainio, 1994)
26
Assumptions on GN and GW determination
Sowing
Harvest
Physiological Maturity
Anthesis
Booting
Tillering
Emergence
Grains m-2
Grain weight
Grain yield
Adapted from Slafer and Rawson (1994)
27
Grain weight
Effect of temperature on major yield components
Temperature was increased (5.5C) at
different developmental phases in wheat, barley
and triticale
S
Harvest
PM
Booting
Anthesis
Heading
Em
DR
TS
Time
SE-B
B-A
Ugarte et al. (2007)
H-A
28
Effect of increased temperature on GN and
GW Averaged across crops and experiments (3 years)
GN GW
-42
-15
-15
B-A
-7
-8
H-A
29
This has important consequences for the study of
grain weight determination
S
Time
Harvest
PM
Anthesis
Head
FI
TE
Booting
Em
DR
Grains m-2
Grain weight
Grain yield
30
Grain weight
All these evidences are showing that
flowers, which grow at the pre-anthesis period,
are involved in GW determination
31
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
32
Grain weight
Different traits associated with GW were
measured at central spikelets of the wheat spike
spikelet
33
Grain weight
Grain weight in two experiments
Grain weight (mg)
Cultivar
Season
Experiment
G4
G3
G2
G1
31.6
43.9
49.8
44.9
Bacanora
1
1
41.8
60.3
65.2
62.3
Kambara
37.4
51.6
56.3
51.6
Bacanora
2
36.3
57.8
66.2
61.5
Kambara
35.3
50.3
56.9
52.5
Bacanora
3
42.5
65.1
72.1
67.8
Kambara
42.7
52.6
57.9
53.5
Pandora
1
2
41.7
51.6
58.4
55.9
Huanil
45.3
57.5
57.9
56.3
Pandora
2
36.3
51.0
55.5
52.7
Huayun
 
 
34
Grain weight
Relationship between grain weight and carpel
weight
35
Grain weight
Dynamic of grain dimensions
PM
10
8
6
Grain dimensions (mm)
4
2
0
0
10
20
30
40
50
days after anthesis
36
Grain weight
Relationship between grain weight, grain volume
and grain length
37
Grain weight
Dynamic of dry matter and water content of grains
38
Grain weight
Relationship between grain weight and
maximum water content of grains
39
Grain weight
Dynamics of water content and enlargement of
grains
40
Grain weight
Relationship between grain weight or maximum
water content and grain length
80
60
Grain weight or Maximum
Water Content (mg)
40
20
(r 0.91 plt0.001)
(r 0.95 plt0.001)
0
5
6
7
8
9
10
Grain length (mm)
41
Grain weight
Grain length is associated with carpel weight
10
year 2006
9
year 2007
8
Grain length (mg)
7
6
5
r 0.75 plt0.01
4
0.20
0.30
0.40
0.50
0.60
0.70
Carpel weight at pollination (mg)
42
Grain 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 plt0.05
43
Grain 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 grains
Pericarp growth is the result of the number of
pericarp cells and the enlargement of these
cells. Plant cell enlargement is 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)
44
Expansins
Grain 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
45
Grain weight
Dynamics of grain length and ExpA 6c expresion in
cultivar Bacanora
46
Grain weight
Hybridization of Expansin A 6c in grains at 5
days after anthesis
Antisense
Sense
Negative control
47
Grain weight
Hybridization of Expansin A 6c in grains at 10
days after anthesis
Antisense
Sense
Negative control
48
Proposed Model of Potential Grain Weight
Determination
Physiological Maturity
Pollination
Booting
Lag Phase
49
Conclusions

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

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

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

50
Conclusions

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

• The involvement of expansins in grain
• enlargement could be used for increasing
• GW in temperate cereals

51
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)
52
Thank you!
53
Grain weight
Usual approach for studying GW
54
Response of sunflower yield components to shading
Cantagallo et al. (2004)
55
Grain weight
Other evidences of the involvement of the
pre-anthesis period in grain weight determination
56
Grain weight
Relationship between GW and carpel weight at
anthesis in wheat (data from different
experiments)
Calderini Reynolds (2000)
57
Grain number reduction relative to the control
Exp. 1 Exp. 2
Ugarte et al. (2007)
58
Grain weight
Grain weight reduction relative to the control
Exp. 1 Exp. 2
Ugarte et al. (2007)
59
Grain weight
Relationship between grain weight and grain volume