Progress on breeding for drought and heat tolerance in maize. CIMMYTFontagro_Presenta… ·...
Transcript of Progress on breeding for drought and heat tolerance in maize. CIMMYTFontagro_Presenta… ·...
Progress on breeding for
drought and heat tolerance in
maize
J Cairns, JL Araus, C Sanchez, S Trachsel, R Babu, J Crossa, S
Hearne, D Makumbi, S Taitad, C Magorokosho, A Menkir,
M Banziger, C Bedoya, PH Zaidi
Overview
● Progress in breeding for heat and drought tolerance
● Genetic analysis of grain yield under drought and
heat stress
● Effects of 1-MCP on stay green and grain yield under
drought
● Outlook on CIMMYTs current activities for heat
screening
Susceptibility to heat stress
Lobell et al. 2011
Increase in maximum temperatures (2050)
Thornton et al. 2009
Kai Sonder/Cairns et al. 2012
Anthesis-silking interval (d)
Gra
in y
ield
(t
ha
-1)
Combined drought and heat stress
Anthesis-silking interval (d)
Gra
in y
ield
(t
ha
-1)
Drought stress
Drought ≠ Drought + heat
Sensitivity of maize to high temperatures
Reduced
pollen shed
Reduced pollen
viability
Sensitivity of maize to high temperatures
Anthesis-silking interval (d)
Gra
in y
ield
(t
ha
-1)
Fonseca and Westgate, 2005
Pollen shed duration
Pollen quality
(shed & duration)
Zimbabwe,
2011
Chiredzi, Zimbabwe 2011
Sensitivity of maize to high temperatures
Fre
qu
en
cy
SPAD (2 weeks after anthesis)
Heat + drought
Drought
Relationship between combined drought
and heat stress
Drought
Drought + Heat Heat
Well-watered
Drought -
Drought + heat
0.08 -
Heat 0.49 -0.07 -
Well-watered 0.63 0.24 0.27 -Cairns et al. 2012 submitted
Phenotyping GermplasmManagement
options
Future opportunities
Semi-
controlled
(FATE)
Field
Tools
Current
breeding
pipeline
Heat
breeding
Germplasm
movement
Conservation
agriculture
Seed
production
options
Growth
regulators
Identification of heat tolerant donors
Phenotyping of the Drought Tolerant Maize for Africa
(DTMA) association mapping set
Phenotyping in 5 countries across 3 years
Drought, heat, combined drought and heat stress, well-watered
Evaluation of DTMA germplasm under
abiotic stress
Test environment
No. of trials Grain yield
(t ha-1) VG VGE VE H
Optimal 7 6.88 0.35 0.24 0.48 0.84
Managed drought 7 2.58 0.12 0.36 0.39 0.64
Managed drought + heat 3 1.13 0.07 0.12 0.18 0.50
Effect of heat stress on grain yield
Year 2010 2011
TemperatureOptimal T High T Optimal T High T
Supra-High
T
GY, WW (t ha-1)* 7.39 6.45 7.38 6.27 1.50
GY, DS (t ha-1) * 3.29 0.24 2.67 2.25 -
LPSC7F64-2-6-2-2/CML312SR* 3.70 1.24 2.72 3.12 1.85
CML444/CML312* 3.88 0.19 2.50 2.38 -
ASI (DS) 2.1 12.0 2.9 2.6
-
LSD (5%) 0.90 0.51 1.36 1.12 1.23
H 0.69 0.32 0.80 0.72 0.64
*Adjusted means (BLUPS)
- 12% - 15% - 80%
Effect of heat stress on grain yield
Year 2010 2011
TemperatureOptimal T High T Optimal T High T
Supra-High
T
GY, WW (t ha-1)* 7.39 6.45 7.38 6.27 1.50
GY, DS (t ha-1) * 3.29 0.24 2.67 2.25 -
LPSC7F64-2-6-2-2/CML312SR* 3.70 1.24 2.72 3.12 1.85
CML444/CML312* 3.88 0.19 2.50 2.38 -
ASI (DS) 2.1 12.0 2.9 2.6
-
LSD (5%) 0.90 0.51 1.36 1.12 1.23
H 0.69 0.32 0.80 0.72 0.64
*Adjusted means (BLUPS)-
55%
-63%
Effect of heat stress on grain yield
Year 2010 2011
TemperatureOptimal T High T Optimal T High T
Supra-High
T
GY, WW (t ha-1)* 7.39 6.45 7.38 6.27 1.50
GY, DS (t ha-1) * 3.29 0.24 2.67 2.25 -
LPSC7F64-2-6-2-2/CML312SR* 3.70 1.24 2.72 3.12 1.85
CML444/CML312* 3.88 0.19 2.50 2.38 -
ASI (DS) 2.1 12.0 2.9 2.6
-
LSD (5%) 0.90 0.51 1.36 1.12 1.23
H 0.69 0.32 0.80 0.72 0.64
*Adjusted means (BLUPS)
Effect of heat stress on grain yield
Year 2010 2011
TemperatureOptimal T High T Optimal T High T
Supra-High
T
GY, WW (t ha-1)* 7.39 6.45 7.38 6.27 1.50
GY, DS (t ha-1) * 3.29 0.24 2.67 2.25 -
LPSC7F64-2-6-2-2/CML312SR* 3.70 1.24 2.72 3.12 1.85
CML444/CML312* 3.88 0.19 2.50 2.38 -
ASI (DS) 2.1 12.0 2.9 2.6
-
LSD (5%) 0.90 0.51 1.36 1.12 1.23
H 0.69 0.32 0.80 0.72 0.64
*Adjusted means (BLUPS)
Grain yield (t h-1)* Grain yield (rank)#
Rank Pedigree Drought
Well-
watered
Drought +
heat Heat
1 DTPYC9-F46-1-2-1-2 2.66 7.35 2 130
2 La Posta Seq C7-F86-3-1-1-1 2.53 7.46 155 142
3 CL-G1628=G16BNSeqC0F118-1-1-4-2 2.53 7.08 16 111
4 La Posta Seq C7-F64-2-6-2-2 2.51 7.88 3 13
5 La Posta Seq C7-F78-2-1-1-1 2.51 7.79 184 270
6 DTPWC9-F24-4-3-1 2.49 7.27 15 62
7 La Posta Seq C7-F180-3-1-1-1 2.48 7.76 113 229
8 DTPYC9-F46-1-2-1-1 2.48 7.14 17 114
9 La Posta Seq C7-F103-2-2-2-1 2.45 7.76 179 10
10 [CML-384 X CML-176]F3-135-2-2-1 2.45 7.98 283 272
*Adjusted means (BLUPS)#300 entries within trial
Ensuring drought tolerant germplasm
for future environments
Identification of heat tolerant donors
Pedigree GY (t ha-1)
CML311/MBR C3 Bc F12-2-2-2 0.63
DTPYC9-F46-1-2-1-2 0.59
La Posta Seq C7-F64-2-6-2-2 0.55
CLA44 0.49
DTPYC9-F143-5-4-1-2 0.46
CML412 (check) 0.19
Trial mean 0.24
Combined heat and
drought tolerance
Heat stress tolerance
Pedigree GY (t ha-1)
DTPWC9-F67-2-2-1 2.60
CML497=[CL-00331*v]-3-B-3-2-1 2.59
La Posta Seq C7-F10-3-3-1-1 2.57
DTPYC9-F114-2-4-1-2 2.45
1368 2.42
Trial mean 1.50
Drought donors (with heat tolerance)
http://dtma.cimmyt.org/index.php/varieties/dt-donors
Cluster AnalysisD
ista
nce
Well-wateredDroughtDrought+heatHeat
PC
2 (2
1.4
%)
PC1 (34.9 %)
Well-wateredDroughtDrought+heatHeat
PCA for genetic correlations matrix
Structure in DTMA-AM panel
PC Eigenvalue
1 9.52
2 8.96
3 6.62
4 4.74
5 3.61
6 3.22
7 3.05
8 2.90
9 2.76
10 2.64
� PCA analysis based on 55K SNPs
� No pronounced structure in the DTMA-AM panel – first 10 PCs explain ~ 50% of the variation
DTMA-AM panel and 55K SNPs can identify large effect genes – 1. Grain Color
Psy2R² = 14%
Psy1R² = 37%
SNP with largest significant association with grain color located within one of the exons of Phytoene Synthase1 (psy1) on chr.6
92 – Yellow lines (1)186 – white lines (0)
DTMA-AM panel and 55K SNPs can identify large effect genes – 2. QPM
Opaque2 at 7.01R² = 16%
Ask2?R² = 8%
Besides opaque-2 and ask-2, several minor QTL regio ns influencing kernel modification and tryptophan cont ent identified that overlap with previously reported re gions…
10 – QPM lines (1)268 – Normal lines (0)
Haplotype based association analysis for GY under stress (drought)
7.3%6.2%5.7%
7.0%
5.7%5.5%
5.1%
5.8%
4.9%
5.1%
• 50K SNPs were reduced to 10K haplotype blocks and association test was performed correcting for population structure using principal components and results validated with mixed linear model analysis (kinship + structure)
• Only 47 SNPs (~15 genomic regions) out of 10,000 had R2 values more than 5%Raman Babu
Haplotype based association analysis for GY under combined drought + heat
• Noise levels are relatively higher under very severe stress condition• Significant regions such as those on chr.10, chr.9, chr.4 and chr.7 also
got identified in the severe stress condition… Raman Babu
Plant growth regulators -2010 (recap)
Drought stress (DS)Well-watered (WW)
Summary of experimentGenotypes: 1 (DTPYC9-F74-1-1-1-1)Water treatments: well-watered and drought stressChemical Treatments: control (water), 1-MCP (single dose of 10 g ai ha-1 and double dose 20 g ai ha-1), ethephon (single dose of 1.5 l ha-1 and double dose of 3 l ha-1)Application time: 1 week before anthesis or 10 days after anthesis
Results1) No significant differences between control and chemical treatments under WW conditions2) Drought stress reduced grain yield by ~76 % relative to WW control3) Yields under DS were significantly higher with a single dose of 1-MCP applied prior to and
after anthesis, and a double dose Ethephon applied after anthesis
Plant growth regulators -2011
Summary of experimentGenotypes: 6; Water treatments: 2 (well-watered and drought stress); Chemical treatments: 9Sowing date: 14th Feb 2011
Entry
Genotype
1 DTPYC9-F74-1-1-1-1/CML-451
2 LPSC7-64-2-6-2-2/CML-495
3 2A120 (Dow)
4 (CML-269/CML-264)//CML-494
5 CML-442/CML-444
6 DTPYC9-F66-2-1-1-2/ CML-539
Treatment Chemical Dose Timing
1 Control - Before anthesis
2 Control - After anthesis
3 1-MCP Singlea Before anthesis
4 1-MCP Doubleb Before anthesis
5 1-MCP Single After anthesis
6 1-MCP Double After anthesis
7 Ethephon Singlec Before anthesis
8 Ethephon Doubled Before anthesis
9 Ethephon Single After anthesis
Genotypes Chemical treatments
a10 g ai ha-1
b20 g ai ha-1
Plant growth regulators - 2011
DTPYC9-F74-1-1-1-1/CML-451 LPSC7-64-2-6-2-2/CML-495
2A120 (Dow) (CML-269/CML-264)//CML-494
Treatments1: Control (before anthesis); 2: control (after anthesis); 3: 1-MCP (single app, before anthesis); 4: 1-MCP (double app, before anthesis); 5: 1-MCP (single app, after anthesis); 6: 1-MCP (double app, after anthesis_; 7: Ethephon (single app, before anthesis); 8: Ethephon (double app, before anthesis); 9: Ethephon (single app, after anthesis)
TreatmentTreatment
Gra
in y
ield
(t h
a-1 )
Gra
in y
ield
(t h
a-1 )
WW
DS
Plant growth regulators - 2011
WW
DS
CML-442/CML-444 DTPYC9-F66-2-1-1-2/ CML-539
Treatment
Gra
in y
ield
(t h
a-1 )
Treatment
Results1) Drought stress reduced grain yield by 60% relative to the WW control2) No significant differences in grain yield between chemical treatments under WW and DS
conditions3) No significant difference in the % reduction in GY relative to the WW control between
chemical treatments
Plant growth regulators - 2011
Treatment Treatment
ND
VI
18 days after anthesis 25 days after anthesis
Results1) Under drought stress 1-MCP delayed senescence (estimated through NDVI) 18 and 25
days relative to the control (p<0.01)2) There was no significant genotype*treatment interaction3) No significant difference in NDVI was identified 32 days after anthesis
Treatments1: Control (before anthesis); 2: control (after anthesis); 3: 1-MCP (single app, before anthesis); 4: 1-MCP (double app, before anthesis); 5: 1-MCP (single app, after anthesis); 6: 1-MCP (double app, after anthesis_; 7: Ethephon (single app, before anthesis); 8: Ethephon (double app, before anthesis); 9: Ethephon (single app, after anthesis)
Can landraces help improved tolerance to
drought and high temperatures?
Evaluation of landraces under WW and DS
Status
Cluster analysis for 38 Mexican
populations
Use of accesions in breeding
Summary- Different Mechanisms allow plants to cope with
drought, high temperatures - Accordingly there is only little overlap between
germplasm tolerant to the three stresses- In several years of screening under drought, high
temperatures CIMMYT has identified hybrids and crosses that are tolerant to these stresses
- Tolerant lines are available for partners to be used in their breeding pipeline.
- CIMMYT keeps screening germplasm for tolerance to heat in Ciudad Obregon and potentially in Arizona
- Attempts are underway to identify alleles conveying tolerance to abiotic stress in landraces