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By Kulvinder S. Gill, In this presentation, wheat resiliency and genes are discussed in terms of crop yields.
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Feed the Future Innovation lab: Improved Wheat for Heat
Tolerance and Climate Resilience
Kulvinder S. Gill
Washington State University
Project partners • Washington State CCSU, Meerut
• DWR, Karnal GBPU, Pantnagar
• Kansas State JK Seeds
• Metahelix NBPGR
• Dupont-Pioneer PAU, Ludhiana
• RAU, Pusa IARI, Delhi & Wellington
Project Goal Develop high-yielding, heat-tolerant wheat cultivars for the Indo-Gangatic Plains
Specific Objectives 1. Develop heat tolerant varieties using marker assisted background
selection and forward breeding approaches: Acurate phenotyping, QTLs, enzymatic markers, fast breeding methods
2. User-friendly markers for heat tolerance: QTLs, physiological markers, biochemical markers
3. Pyramid genes with complementary mechanisms of heat tolerance: Doubled-haploid approach, Objective 4 critical for this objective
4. Understand physiological mechanisms of heat tolerance: Study genetic, physiological, biochemical, and epigenetic mechanisms controlling heat tolerance
5. Scientist training and exchange: Exchange and collaboration (senior scientists), training (younger scientists), and PhD student training.. Younger scientists are a major focus of the project.
Genetics Genomics physiology molecular biology Scaling up
Fast breeding
Adoption
Discovery
Products
Products
SCALING UP AND LINKAGES WITH OTHER INNOVATION LABS
• Heat Screening Methods • Heat tolerant germplasm • Heat tolerant varieties • Markers/Enzymatic assays/other screening tools • Relationship between heat and drought tolerance • Effect of terminal heat on grain quality • Novel breeding and genotyping approaches • Heat tolerance vs disease severity • Others?
Breeding strategy to develop heat tolerant varieties
1. Evaluate cultivated wheat germplasm to select 10 donor lines
2. Select a recurrent parent with highest yield potential and wide adaptation
3. Simultaneous detection and utilization of QTL
4. Forward breeding to increase yield over the recurrent parent
5. Gene pyramiding to combine genes with complementary gene action
Donor Selection • Select known heat tolerant material from
around the world: Selected 75 lines
• Evaluate by multi-location field, as well as controlled condition screening for heat tolerance
• Enzyme thermal stability tests on the donor and recurrent parents
• Select 10 most heat tolerant lines with complementary heat tolerance mechanisms
MABS&MAFB: Simultaneous detection and use of QTLs
Recurrent parent X Donor F1 BC1 and BC2 DH mapping population MABS QTL analysis
A B D A B D
Marker-Assisted Background Selection
BC2F3 Field Selection based Backcross Breeding
BC4F7
Graphical Genotypes
97% RPG 80.5% RPG
Recurrent Parent Donor Parent Randhawa et al. 2009, PLoS ONE 4 (6): 5752
Commonly used physiological Traits
• Canopy Temperature Depression (CTD) • Stomatal conductance • Grain filling duration (GFD) • Membrane thermo-stability (MT) • Chlorophyll content and fluorescence • Stem reserve mobilization
Reliability and reproducibility issues
Heat tolerance mechanisms in wheat
Photosynthesis
Sugar Starch
Sugar transport
Proposed Approach for Physiological studies Hypothesis: At least three different mechanisms for
heat tolerance:
1. Maintaining photosynthesis at higher a temperature
2. Maintain transport of sugars to the developing grains
3. Maintain conversion of sugars into starch
These mechanisms are expected to be controlled be different sets of genes thus should be
complementary.
Variation for Root length in the AM population
Coleoptiles length vs. seedling emergence
Effect of temperature on germination
PBW343
Indian
KSG33
KSG63
KSG89
KSG126
KSG233
Germ
inat
ion
Perc
ent
age
Effect of temperature on coleoptiles length
PBW343
Indian
KSG33
KSG63
KSG89
KSG126
KSG233
Col
eopt
iles
leng
th
Results summary of initial screening of heat tolerance donors
BLUE – HIGHLY Susceptible, no seed set RED - Susceptible, 0.1 to 0.49 GREEN – Tolerant, 0.67 to 0.88
Results summary of initial screening of heat tolerance donors
DARD BLUE – HIGHLY Susceptible, no seed set ORANGE- Susceptible, 0.1 to 0.49 LIGHT BLUE– Tolerant, 0.67 to 0.88
Spike Weight
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
16.00
18.00
20.00
GEMIZA10 GIZA 168 RED FIFE Seri 82 SONORA 64
cont mean
Treat mean
CONTROL
TREATMENT
KSG121 KSG168 KSG311 KSG82 KSG64
Our approach • Check thermal stability of various enzymes in
involved in photosynthesis, sugar transport and grain filling
• Screen for RO and others correlating with heat tolerance at flowering
• Screen the donors to identify enzymes or other physiological parameters corresponding to each donor line
• Develop high-throughput assay and use as marker for MABS and forward breeding
Genetics Genomics physiology molecular biology Scaling up
Fast breeding
Adoption
Discovery
Products
Products
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