Presentation during IITA R4D week 2015 (23 - 27 Nov. 2015). By: S. Meseka, A. Menkir, B. Badu-Apraku, S. Ajala, W. Mengesha, O. Bossey, A. Adepoju, & O. Azeez

1. A member of CGIAR consortium www.iita.org
S. Meseka, A. Menkir, B. Badu-Apraku, S. Ajala, W.
Mengesha, O. Bossey, A. Adepoju, & O. Azeez
Recent advances in phenotyping advanced drought
tolerant and Striga resistant maize genotypes for
tolerance to combined drought & heat stress
R4D Week, 22 – 27 November 2015

2. A member of CGIAR consortium www.iita.org
Outline of presentation
Introduction
Objectives
Screening of advanced DT TWC hybrids
Screening advanced DT & DTSTR Testcrosses
New hybrids & inbred lines
Challenges
Lessons learned
Way forward

3. A member of CGIAR consortium www.iita.org
 51% population in sub-Saharan Africa
(SSA) depend on maize as major staple
food
 Drought & high temperatures are limiting
maize productivity in SSA – causing
extensive economic yield losses
 Increase in temperature above 30oC
reduces yield by 1% under optimal rain-
fed & by 2.1% under drought conditions
Introduction

4. A member of CGIAR consortium www.iita.org
Introduction
Source: Cairn et al., 2012a.
 Average optimum temp for lowland
tropical maize 30 – 34oC
 Increase in temp by 2oC reduce
maize yield by 13%, while 20%
reduction in rainfall reduces maize
yield by 4.2%
 By 2030, drought & heat will
reduce 40% of currently maize
mega environments unsuitable for
varieties available today

5. A member of CGIAR consortium www.iita.org
Introduction
 Drought stress at
 vegetative stage yield loss – 15 to 20%
 reproductive stage yield loss - 20 to 50%
 High temperature at
 grain filling stage 42% yield loss (Badu-
Apraku et al., 1983)

6. A member of CGIAR consortium www.iita.org
Introduction
Drought stress
 leaf rolling
 delay in silk emergence -long ASI
 abortion & poor seed set
 leaf senescence
 reduced kernel number & weight
Heat stress
 leaf firing
 tassel blast
 drying of pollen grains
 unreceptive silk
 barren plants

7. A member of CGIAR consortium www.iita.org
Introduction
 Climate change exacerbate drought & heat
 erratic rainfall pattern - Drought
 increase in temperature - Heat
 Combined drought & heat stress has greater effect on maize than the
individual stress; yield losses depend on:
 Time
 Severity
 Duration
 at reproductive stages >40% to 100% yield loss (Lobell et al, 2011)
Variability for tolerance to drought & heat stress may exist in
advanced DT & DTSTR maize genotypes developed at IITA

8. A member of CGIAR consortium www.iita.org
Objectives
 Screen advanced DT & DTSTR maize genotypes for tolerance to
combined drought & heat stress
 Identify genotypes combining tolerance to drought & heat stress
with high yield as donors for developing resilient hybrids &
varieties
 Develop new resilient maize hybrids & synthetics for sharing
with partners in SSA

9. A member of CGIAR consortium www.iita.org
Materials & Methods
 Site: Kadawa, Kano State
 Genetic materials
 48 Advanced DT three-way cross hybrids
 650 Advanced DT & DTSTR inbred lines
 Planting & field management
 Planting: mid-February
 Furrow irrigation
 Approach of evaluation
 Irrigation withdrawn for 21 days
 Irrigation resumes once/week
 Data – weather & maize crop

10. A member of CGIAR consortium www.iita.org
Daily temperature during the growing season
0
5
10
15
20
25
30
35
40
45
50
1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106 113 120
Number of growing days
Temperature(o
C)
Day 2013 Day 2014 Night 2013 Night 2014
Drought

11. A member of CGIAR consortium www.iita.org
Effect of high temperature on grain yield of DT hybrids
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
30 32 34 36 38 40 42 44
Temperature (o
C)
Grainyield(t/ha)
Adv. DT hybrid Comm. hybrid Local checkTolerance to drought
confer tolerance to
combined Drought &
Heat stress!

12. A member of CGIAR consortium www.iita.org
Relationship between grain yield & tassel blast
y = -0.704x + 2.953
R
2
= 0.24
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
Tassel blast (1 - 5)
Grainyield(t/ha)
Adv. Hybrid Comm. hybrid Local check

13. A member of CGIAR consortium www.iita.org
Grain yield and other traits of eight selected DT hybrids, five commercial hybrids and a local check
evaluated for two years under combined drought and heat stress
Hybrid Grain yield Ear/plant Leaf senesc.1 Tassel blast Barren plant
(t/ha) (no.) (1 - 10) (1 - 5) (1 - 5)
M1124-23 3.24 0.7 4 1.7 1.6
M1227-18 3.11 0.8 4 1.7 1.5
M1227-15 3.09 0.8 5 2.2 1.5
M0826-3 3.08 0.7 4 1.0 1.3
M1124-27 2.96 0.6 5 2.0 1.7
M1227-17 2.65 0.6 5 2.3 1.9
M1227-4 2.42 0.7 4 1.7 1.3
M1124-22 2.33 0.7 5 1.7 1.6
Oba Super 2 2.04 0.6 5 2.7 1.8
Oba Super 1 1.01 0.4 5 2.5 1.9
SC637 0.87 0.4 5 3.0 2.3
Oba Super7 0.60 0.3 6 4.2 2.7
Oba Super9 0.49 0.3 6 2.8 1.8
Local check 0.99 0.3 7 2.7 2.1
Mean 2.06 0.56 5.00 2.30 1.79
LSD 1.03 0.22 0.79 0.74 0.45
CV 57 41 14 19 23

14. A member of CGIAR consortium www.iita.org
Grain yield of under drought & drought + heat stress
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0.5 1.0 1.5 2.0 2.5 3.0 3.5
Grain yield (t/ha) under drought stress
Grainyield(t/ha)underdrought&heatstress
DTSTR Testcross Yellow DTSTR Testcross White

15. A member of CGIAR consortium www.iita.org
New hybrids & inbred lines
New three-way cross & single-cross hybrids being generated
from promising testcrosses for further evaluation
Advanced inbred lines with low levels of leaf firing and tassel
blast scores identified for bi-parental crosses - genotyping
using molecular tools
14 advanced DT varieties identified as potential donors to
extract new DTHST inbred lines

16. A member of CGIAR consortium www.iita.org
Challenges
 LAND for conducting field trials
 Genetic bases of tolerance to combined drought &
heat stress in maize not well understood
 Plant Root System – more relevant to water &
canopy temperature
 Throughput phenotypic tools & facilities for
screening large populationsChlorophyll meter
Maize root system

17. A member of CGIAR consortium www.iita.org
Lessons learned
 Variability exists among DT & DTSTR maize developed at IITA
 Not all DT & DTSTR maize confer tolerance to combined drought & heat
stress
 Some DT & DTSTR maize were found to be tolerant to combined drought &
heat stress – ready for release
 Leaf firing & tassel blast are good indicators of tolerance to
drought & heat stress – can be used for indirect selection in
combination with Grain yield
 Screening for tolerance to combined Drought & Heat stress and
Drought stress should be done be done independently

18. A member of CGIAR consortium www.iita.org
Looking Forward
High throughput
genotyping
Environmental data Field evaluation
Greenhouse evaluationMaker trait association
Maker Assisted Breeding
Physiology
GIS & Modeling