1. Hari D Upadhyaya
Variability for Post-flowering
Drought Tolerance in
Sorghum Reference Set
Related GCP project–G4008.02: Phenotyping sorghum reference set for drought tolerance
Assistant Research Program Director-Grain Legumes
and Principal Scientist and Head Gene Bank
ICRISAT

2. • Sorghum [Sorghum bicolor (L.)
Moench] is fifth most important
cereal in the world
• Grown in 98 countries mainly
in the semi-arid areas of
tropics and subtropics
• Annual global production 56.1
million t from 40.0 million ha
Sorghum

3. • Landraces - 32,572
• Breeding material - 4,814
• Advanced cultivars -105
• Wild - 458 (13 species)
Sorghum germplasm
assembly at ICRISAT

4. Drought, especially post-flowering drought stress
can result in significant yield losses due to
• Reduced grain size
• Premature plant death
• Increased susceptibility to diseases
and insect-pests
Post-flowering Drought

5. • Sorghum reference set (384 accessions) representing
– 5 races (222 accessions)
– 10 intermediate races (106 accessions)
– Wilds (23 accessions)
• Stay-green QTL (Stg3, Stg4 or StgB) introgression
lines (QTL-IL)
Assessed for post-flowering drought tolerance.
Material

6. Collaborations
Asia
• ICRISAT, Patancheru, India
• UAS Dharwad, India (NARS), other locations
Africa
• ICRISAT, Bamako, Mali
• ICRISAT, Nairobi, Kenya
• KARI Machakos, Kenya (NARS)
• NPGRC Arusha, Tanzania (NARS)
• IER Mali (NARS)
• ISRA/CERAAS, Thies, Senegal (NARS)

7. Reference set- Allelic
richness and diversity
• Entire collection (33,100 accessions) is too large
for evaluation
• A composite collection (3,372 accessions)
developed from entire collection (core)
• Composite collection genotyped using 41 SSR
markers and a reference set (384 accessions)
developed (http://www.generationcp.org)
• 78% (615 of the 789 alleles) of the SSR marker
allelic diversity of the composite collection
represented by reference set

8. Legend:
Durra-bicolor (DB)
Durra-caudatum (DC)
Guinea-caudatum (GC)
Kafir-caudatum (KC)
Guinea-bicolor (GB)
Guinea-durra (GD)
Guinea-kafir (GK)
Kafir-bicolor (KB)
kafir-durra (KB)
Bicolor (B)
Caudatum (C)
Durra (D)
Guinea (G)
Guinea margaritiferum (Gma)
Kafir (k)
Wild
Caudatum-bicolor (CB)
Tree diagram of sorghum
composite and reference set
41 SSR markers
789 alleles
615 alleles

9. Reference set accessions classified into seven groups based
on the 2007-08 flowering data from Patancheru, India
Group Range of
days to 50%
flowering
Number of
accessions
Group I 54-68 36
Group II 69-82 114
Group III 83-96 124
Group IV 97-110 51
Group V 111-124 38
Group VI 125-138 13
Group VII 139-149 8
Total 384
Phenology-based classification

10. • Post flowering drought stress was imposed by withholding
irrigation in different groups after specific number of days
after sowing (DAS), which were calculated as:
(Mid point of the range for days to 50% flowering for a
group – 30 days)
Groups DAS after
which irrigation
was withheld
Group I 31 DAS
Group II 46 DAS
Group III 60 DAS
Group IV 74 DAS
Group V 88 DAS
Group VI 102 DAS
Group VII 115 DAS
Post-flowering drought stress

11. • Evaluated each group with controls (IS 2205, IS
18758, IS 33844) in a split-plot design with three
replications during 2008/09 and 2009/10
postrainy seasons at Patancheru.
Main plots: Water-stressed (WS) and non-
stressed (well-watered, WW)
moisture regimes
Sub-plots: Accessions within moisture regimes
Evaluation for drought stress

12. Evaluation for post-flowering
drought stress
• Evaluated at three ICRISAT locations:
- ICRISAT Patancheru, India
- ICRISAT Bamako, Mali
- ICRISAT Nairobi, Kenya
for post-flowering drought tolerant traits
(stay-green, chlorophyll content, and yield)

13. Evaluation for water extraction
& Transpiration efficiency
• 152 reference set accessions and
58 QTL introgression lines (QTL-
IL) evaluated for water extraction
(WE) and transpiration efficiency
(TE) under terminal WS and WW
in large and long PVC cylinders
(2.0 m long and 25 cm diameter
tubes) during 2008-09 and 2009-
10 postrainy seasons under
rainout shelter
• Reference set evaluated for TE in
potted trials under WW conditions
Lysimetric study of sorghum
variation for water extraction (WE)
and transpiration efficiency (TE)
under post-flowering drought stress

14. Criteria used:
• Accessions with least reduction in grain
yield under WS compared to WW
• Accessions with good performance under
WS identified as drought tolerant
Identification of post-flowering
drought stress tolerant lines

15. • Accessions which yielded at par or less affected
(<10% yield reduction) under WS compared to WW
Group Number of
accessions
GP I 7
GPII 42
GP III 66
GP IV 33
GP V 32
GP VI 6
GP VII 4
Drought tolerant accessions

16. • Least affected under WS: Arundinaceum and
cultivated Guinea race
• Most affected (29%): kafir-caudatum race
reduction in grain yield)
• SPAD Chlorophyll meter reading (SCMR)
Five accessions: IS 2398, IS 3963, IS 13989, IS
24009, IS 393(411)659 had high SCMR both at
flowering and 30 DAF under both WS and WW
conditions
Drought tolerant accessions

17. • Significant variation (-0.074 to -0.225 leaf d-1) for
stay-green trait (measured by leaf senescence)
• 22 accessions green at grain maturity due to a low
leaf senescence before flowering
• 34 green due to low leaf senescence after flowering
• 7 accessions had both qualities
ICRISAT Samanko, Mali

18. • Short duration plants (group 1)
- Shorter in height
- More basal and nodal tillers than longer duration
genotypes (group 7)
• Initial chlorophyll content of 2nd leaf from the flag
leaf (N-2) differed significantly among lines at all
stages of evaluation
• Chlorophyll content was higher at flag leaf initiation
and earlier weeks after irrigation compared to later
weeks
ICRISAT Nairobi, Kenya

19. • A large range variation observed for grain Fe and
Zn, with higher range under WS (ICRISAT, India)
Groups Range
Fe Zn
WW WS WW WS
Group 1 24.0-42.3 27.5-74.1 13.2-32.2 14.4-41.6
Group 2 17.9-53.9 26.5-128.0 13.7-32.1 15.3-35.7
Group 3 21.3-45.5 23.0-50.8 11.4-30.7 13.0-38.5
Group 4 20.8-39.9 22.5-101.1 10.1-26.7 11.6-27.9
Group 5 21.1-45.4 25.0-61.2 13.1-29.2 13.2-31.0
Group 6 27.7-44.6 28.8-93.7 16.1-34.8 18.7-31.2
Group 7 33.5-48.1 30.3-62.2 20.0-39.0 20.2-39.1
Entire set 17.9-53.9 22.5-128.0 10.1-39.0 11.6-41.6
Variability for grain Fe and Zn
under WW and WS conditions

20. • Fe content increased from 10.6% to 31.3% in different
groups (21.0% in the entire set ); Zn content increased
from 0.8% to 16.4% (average 13.3%) under WS
Groups Mean
Fe Zn
WW WS t- test
probability
WW WS t- test
probability
Group 1 32.9 ± 1.00 42.5 ± 2.16 <0.001 21.9 ± 0.78 25.5 ± 1.22 0.015
Group 2 29.4 ± 0.49 38.6 ± 1.04 <0.001 20.3 ± 0.33 23.9 ± 0.40 <0.001
Group 3 31.0 ± 0.45 36.4 ± 0.63 <0.001 20.1 ± 0.36 22.4 ± 0.42 <0.001
Group 4 29.9 ± 0.68 34.8 ± 1.52 0.005 19.0 ± 0.47 20.9 ± 0.49 0.005
Group 5 32.3 ± 0.78 36.5 ± 1.23 0.006 19.5 ± 0.63 22.1 ± 0.78 0.010
Group 6 35.0 ± 1.37 38.8 ± 4.66 0.439 22.5 ± 1.51 23.6 ± 1.19 0.559
Group 7 38.7 ± 1.91 42.8 ± 4.57 0.433 26.0 ± 2.20 26.2 ± 2.38 0.967
Entire set 31.0 ± 0.28 37.5 ± 0.52 <0.001 20.3 ± 0.21 23.0 ± 0.25 <0.001
Variability for grain Fe and Zn
under WW and WS conditions

21. • Wild type accessions had higher Fe & Zn contents than cultivated types
Race/subrace
classification
Fe Zn
WW WS WW WS
Races 30.53 36.28 20.14 22.90
Intermediate races 30.36 35.81 20.05 22.48
Wilds 38.27 58.81 22.74 26.16
Cultivated
Bicolor 30.51 40.69 21.59 25.11
Caudatum 29.57 34.47 17.99 20.57
Caudatum-bicolor 32.48 38.96 21.95 24.81
Durra 27.48 32.58 19.63 22.26
Durra-bicolor 31.29 34.96 21.24 23.97
Durra-caudatum 31.66 36.86 20.75 22.85
Guinea 34.28 38.66 22.45 24.88
Guinea-bicolor 35.81 35.03 22.92 20.75
Guinea-caudatum 28.88 33.93 18.44 20.85
Guinea-durra 27.30 29.16 18.98 20.63
Guinea-kafir 25.09 40.44 19.81 24.08
Kafir 28.80 35.03 19.42 22.55
Kafir-bicolor 24.50 35.95 17.54 23.21
Kafir-caudatum 23.65 31.09 17.36 18.42
Kafir-durra 28.84 41.45 22.19 23.81
Wild relative
Verticilliflorum 40.95 68.91 23.70 28.07
Virgatum 40.70 40.79 20.14 24.66
Aethiopicuum 38.48 50.34 23.78 28.01
Arundinaceum 40.12 72.78 24.83 28.46
Drummondii 35.63 50.66 21.38 23.87
Variability for grain Fe and Zn
under WW and WS conditions

22. • Four accessions
IS 18879
IS 18821
IS14259
IS 3957
having high contents of Fe and Zn
both under WW and WS conditions
Variability for grain Fe and Zn
under WW and WS conditions

23. • A large range variation in WE (10.2 kg plant-1 to 15.3 kg
plant-1) and TE (2.44 g kg-1 to 6.09 g kg-1 water transpired)
among reference set accessions under WS, with a number
of accessions showing higher WE and/or TE than stay-
green QTL recurrent parent lines, R 16 and S 35
Variation for WE and TE under post-
flowering drought stress conditions

24. Variation in TE among stay-green
QTL-IL in R16 background
A number of stay-green QTL-IL in R 16 background
had higher TE under WS than under WW conditions

25. • Yield related to HI, however at any level of HI,
substantial yield difference were closely
related to TE (R2 = 0.60)
• Substantial yield variations not explained by
HI or TE were closely related to the total WE
under WS (R2 = 0.35)
Lysimetric studies for WE and TE

26. • Race durra had highest WE, whereas durra-caudatum
had the lowest followed by caudatum-bicolor
Vadez et al., 2011; Crop & Pasture Science 62: 645-655
Lysimetric studies for WE and TE

27. • Races durra, caudatum and guinea-caudatum had
highest TE, and Guinea had the lowest
Vadez et al., 2011; Crop & Pasture Science 62: 645-655
Lysimetric studies for WE and TE

28. • A wide range of variation (between about 6 and
10 g biomass kg-1 water transpired) observed for
TE based on pooled analysis of two years data
• No relationship between TE and SCMR
0.0
2.0
4.0
6.0
8.0
10.0
12.0
387 entries tested
TE(gbiomasskg-1water
transpired)
Testing for TE in potted trials

29. • NARS partners identified promising
lines for multilocation (2-3 locations)
evaluation in Asia and Africa and for
use in breeding programs
Multilocation evaluation of promising
drought-tolerant accessions

30. Region Country Locations Number of
lines selected
Controls
Asia India (5) ICRISAT, Patancheru 100 ISs 2205, 18758, and 33844
Dharwad 30 ISs 2205, 18748, and 33844
Bijapur 30 ISs 2205, 18748, and 33844
Indi 30 ISs 2205, 18748, and 33844
Bailhongal 30 ISs 2205, 18748, and 33844
Africa Senegal
(3)
Bambey 14 CE 151-262, CE 180-33
Nioro 14 CE 151-262, CE 180-33
Darou 14 CE 151-262, CE 180-33
Mali (2) Cinzana Agricultural
Research Station
12 B 35, Séguifa, and Jakumbè
Bema Agricultural
Research Sub-Station
12 B 35, Séguifa, and Jakumbè
Kenya (4) Kampi ya 22 KARI Mtama-1, Gadam, ZSV-3
Mawe 22 KARI Mtama-1, Gadam, ZSV-3
Masongaleni 22 KARI Mtama-1, Gadam, ZSV-3
Kiboko 22 KARI Mtama-1, Gadam, ZSV-3
Sites for multilocation evaluation

31. • Promising drought tolerant lines (12-30) identified for
different location in Asia and Africa based on least
reduction in grain yield or good performance under
WS, stay-green, SCMR, TE and rate of water loss per
unit of leaf area under terminal drought conditions
• Large variation observed for TE and WE capacity, and
each contributes to a substantial yield differences
under terminal drought
• The lysimetric system useful to precisely assess yield-
traits and assess their respective influence on yield
• Races as a group, responded differentially to drought
stress
Conclusions

32. • ICRISAT, Patancheru, India: V Vadez, Shivali
Sharma, CT Hash, SL Dwivedi, LKrishnamurthy
• ICRISAT, Bamako, Mali: E Weltzein-Rattunde
• ICRISAT, Nairobi, Kenya: MA Mgonja
• UAS Dharwad, India: PM Salimath and others
• KARI Machakos, Kenya: CK Karari
• NPGRC Arusha, Tanzania: LND Mapunda (yet
to be confirmed) in place of W Ntundu
• IER Mali: M Diourte
• ISRA/CERAAS, Thies, Senegal: N Cisse
Collaborators

33. Thank you

34. 3 years work plan
Objective 1 Seed increase and complete characterization of reference set for morpho-agronomic
traits
Activity 1 Seed increase of reference set entries using plants from which DNA was extracted
Activity 2 Complete characterization of reference set for morpho-agronomic traits
Objective 2 Evaluate reference set for variation in seed micronutrients density (Fe and Zn) under
varying moisture regimes (rainfed and irrigated)
Activity 3 Evaluate sorghum reference set for seed Fe and Zn contents under varying moisture (irrigated and
rainfed) conditions
Objective 3 Evaluate reference set and stay-green QTL introgressions lines for stay-green,
chlorophyll content, transpiration efficiency, and rate of water loss per unit of leaf area
under terminal drought conditions
Activity 4 Evaluation of the full reference set for stay-green and chlorophyll content under terminal drought
conditions
Activity 5 Evaluation of the full reference set for transpiration efficiency (TE) under well-watered and water-
stressed conditions, and for rate of water loss per unit of leaf area
Activity 6 Evaluation of a portion of reference set (with relatively similar flowering time during rabi) and selected
stay-green QTL introgression lines for water uptake under stressed conditions in lysimeters (2.0 m
long and 25 cm diameter tubes) for the proportion of water used prior anthesis/ after anthesis
Objective 4 Multilocation evaluation of promising reference set accessions and selected stay-green
QTL introgressions lines
Activity 7 Multilocation evaluation of promising reference set and stay-green QTL introgression lines for
stover/grain yield and component traits