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

• 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

• Landraces - 32,572

• Breeding material - 4,814

• Advanced cultivars -105

• Wild - 458 (13 species)

Sorghum germplasm

assembly at ICRISAT

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

• 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

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)

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

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

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

• 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

• 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

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)

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

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

• 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

• 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

• 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

• 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

• 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

• 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

• 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

• 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

• 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

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

• 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

• 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

• 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

• 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

(g

bio

mass k

g-1

wate

r

tran

sp

ired

)

Testing for TE in potted trials

• 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

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

• 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

• 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

Thank you

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