Breeding Drought Tolerance for Rainfed Lowland Rice in the Mekong region

Presented by Boonrat Jongdee, BRRD, Thailand and Jaquie Mitchell, The University of Queensland, Australia. Other contributors: NAFRI, Laos: Phoumi Inthapanya, Phetmanyseng Xangsayasane, Thavone Inthavong, Sipaseuth CARDI, Cambodia: Ouk Makara, Veasna Touch The University of Queensland, Australia): Shu Fukai BRRD, KKU and DOA: Grienggrai Pantuwan, Tidarat Monkham and Grissana Linwattana

Area harvest Production Yield

(million ha) (million tons) (tons/ha)

Vietnam 7.3 35.6 4.9

Indonesia 12.2 57.0 4.7

Myanmar 8.2 32.6 4.0

Philippines 4.3 16.0 3.8

Laos 0.8 2.9 3.5

Malaysia 0.7 2.2 3.4

Thailand 10.4 27.9 2.7

Cambodia 2.5 6.0 2.4

Rice area, production and yield in 2007

Source: FAOSTAT(2007)

% Irrigated Rainfed lowland Upland Deepwater

Total F D DS S MD

Cambodia 16 75 7 22 43 0 3 1 8

Indonesia 54 35 20 4 0 3 8 11 0

Laos 14 65 21 22 22 0 0 21 0

Malaysia 66 21 15 0 0 5 1 12 1

Myanmar 30 59 24 6 0 15 14 4 7

Philippines 67 30 15 5 1 3 6 3 0

Thailand 20 74 6 38 18 9 3 2 4

Vietnam 53 39 15 8 0 12 4 5 3

Rainfed lowland rice production area

F: favorable, D: drought prone, DS: drought and submergence prone, S: submergence prone, MD: medium deep Source: Mackill et. al. 1996, IRRI(2005)

Large areas of rainfed lowland areas with drought-prone and drought- & submergence-prone environments in the Mekong region

65% of total rice land in Cambodia, 44% in Laos, 56% in Thailand

Our previous work on rice drought tolerance improvement in the region

• Supported by The Rockefeller Foundation and ACIAR

• A concept for improving drought tolerance

• Development of drought screening

• Identification of drought tolerant traits

• Selection of parental materials for drought tolerance

• Development of drought tolerance populations

•Evaluation the advanced lines for drought tolerance

A concept for improving drought tolerance

Nil SevereSeverity of drought

Droughtresistance

traits

Droughtescape

YIELDPotential yield

Unpredictable

Predictable

Timing of drought

(Fukai and cooper, 2001)

Water condition under rainfed lowland rice field

Rain Rain

Flood Dry Dry Wet Flood

Rain

Anaerobic Aerobic Anaerobic Aerobic

Developing effective selection strategies for drought tolerance and high yield potential (wide adaptation) To identify effective traits that are related to drought tolerance and general adaptation that can be used for selection in breeding program Selecting genotypes that are high yielding in drought prone areas and that can be released as varieties To characterize drought environment, ie frequency, magnitude and timing of the drought events for use in identifying target areas that can utilize the drought tolerance traits identified and the genotypes selected in the project

Objectives of current project

Two series of experiments in each country

• Water condition, on-station experiments for 3 years (2009-2011) – Fully flooded – Aerobic (Intermittent drought) – Prolonged drought (Terminal drought)

• Multi-location trials for 2 years (2010-2011) – Selected lines from water condition experiments – 6 locations in each country in each year – Top and low paddy positions

Major achievements

• New drought screening methods developed

• Drought tolerant characters determined

• High yielding, drought tolerant lines identified

for each country

• Drought maps developed

New screening method

On-station: Agriculture Research enter, Vientiane, Central Laos

Year and season: 2010 and 2011 wet and dry seasons

Grown conditions: flood, aerobic and drought

Genotypes: common 25 genotypes

Multilocation trial: Vientiane, Savannakhet, Champasack

Year: 2010 and 2011 wet season

Paddy positions: Top and bottom positions

Province Field position Yield

(g/m2) Water level

(cm) pH

(H2O) OM N-total

(%) (ppm) Vientiane Low 320** -3.1 3.86 0.9 1.42

Top 150ns -8.8 3.5 0.8 1.02

Savannakhet Low 176ns -5.6 4.2 0.5 0.26

Top 305** -9.5 4.6 1.1 0.98

Champasack Low 280ns -5.4 5.87 0.9 2.45

Top 215** -12.2 5.28 0.5 1.35

Yield, water level from soil surface, soil pH, organic matter, and soil nitrogen (N) available in top and low field positions

Mean grain yield (g/m2) in flood

150 200 250 300 350 400 450

Mea

n gr

ain

in m

ultil

ocat

ion

(g/m

2 )

150

200

250

300

350

400

450

Mean grain yield (g/m2)in terminal drought

150 200 250 300 350 400 45

r=0.49 ** (a)

Mean grain yield (g/m2) in intermittent drought

150 200 250 300 350 400 450

r=0.50 ** (b) (c)

Relationships between mean grain yield on-station screening and MLTs in Laos

Intermittent drought screening can select varieties that produce high yield in farmers field.

DRI

-2.0 -1.5 -1.0 -.5 0.0 .5 1.0 1.5 2.0 2.5

r=0.42 *

Mean potential GY (g/m2)

150 200 250 300 350 400 450

Mea

n G

Y in

mul

tiloc

atio

n (g

/m2 )

150

200

250

300

350

400

450r=0.79 ** (a) (b)

Relationships between mean GY in MLT and mean PGY (a) and GY in MLT and DRI

Genotypes with high potential yield and drought tolerance produced high yield in MLT

GY estimated from DRI and potential GY (g/m2)

150 200 250 300 350 400

GY

in o

n fa

rm (g

/m2 )

150

200

250

300

350

400

450

(f)r=0.86**

Relationship between grain yield in MLT and yield estimated from DRI and potential yield

DRI-intermittent drought

-1.5 -1.0 -.5 0.0 .5 1.0 1.5

DR

I-ter

min

al

-1.5

-1.0

-.5

0.0

.5

1.0

1.5

r=0.46 **

Some drought tolerant genotypes identified in intermittent drought conditions can be also tolerant against prolonged terminal stress

2. Drought tolerance traits

• Short delay in flowering under drought – Tolerant varieties may minimize the delay

• Photoperiod sensitivity – Common in Thailand and Cambodia – Useful trait for maturing before severe terminal

drought develops – Its usefulness to tolerate drought is not well known

Estimating flowering duration and delay due to drought at Ubon, Thailand

Day after sowing (days)

60 70 80 90 100 110

Flow

erin

g (%

)

0

20

40

60

80

100

Population 1population 4

TTC

TF50

X0

TTC: Time to commencement flowering from sowing time X0: From TTC to 50% flowering TF50: Time from sowing to 50% flowering

TTC X0 TF50

Flood Drought Flood Drought Flood Drought pop.1 86 88 6.7 5.9 93 99 pop.2 90 91 6.8 6.3 96 99 pop.4 80 80 9.5 8.5 89 88 pop.5 78 79 7.1 6.5 85 86 Mean 83 84 7.5 6.8 91 93 p-value Genotypes <0.001 0.071 <0.001 Water 0.844 0.043 0.445 W x G 0.125 0.623 0.019

Correlation coefficient among delay in flowering, yield reduction and flowering

duration in drought conditions

Flowering at 84-88 DAS Delay Yield reduction Yield reduction (%) 0.58** --

Flowering duration 0.69** 0.65**

Flowering at 94-98 DAS

Yield reduction 0.18ns -- Flowering duration 0.32ns 0.18ns

Similar correlation matrix were also found at Chum Phae, Thailand

CPA-Drought

Num

ber p

er 4

hill

s

10

20

30

40

r=0.1641ns

r=0.3806**

CPA-Flood

TF50

75 80 85 90 95 100 105

Num

ber p

er 4

hill

s

10

20

30

40

panicletiller

r=0.4033**

r=0.4816**

UBN-Drought

Num

ber p

er 4

hill

s

0

10

20

30

40

r= -0.3788**

r=0.4500**

UBN-Flood

TF50

70 80 90 100 110 120

Num

ber p

er 4

hill

s

0

10

20

30

40

panicletiller

r=0.2794*

r=0.2740*

Relationships between TF50 and tiller and panicle numbers

Time to flowering (DAS) Grain yield (g/m2) 2009 2010 2011 Mean 2009 2010 2011 Mean

Flooded 91 93 113 99 220 408 333 320 Intermittent 95 95 114 101 114 301 253 223 Prolonged drought 110 97 116 107 84 291 209 195 Mean 98 95 114 102 140 333 265 246 Delay in flowering (day) Reduction in grain yield (%) Intermittent 4 2 1 2 48 26 24 30

Prolonged drought 19 4 3 9 62 29 37 39

Days to flowering, grain yield, delay in flowering and reduction in grain yield in 2009 (very late planting), 2010

(late planting) and 2011 (early planting) in Cambodia

0.0 0.2 0.4 0.6 0.8 1.0

Del

ay in

flow

erin

g in

200

9

-10

0

10

20

30

40

0.0 0.2 0.4 0.6 0.8 1.0

Del

ay in

flow

erin

g in

201

0

-2

0

2

4

6

8

Drought condition; R2=0.58**

Aerobic condition; R2=0.11**

Drought condition; R2=ns

Aerobic condition; R2=ns

Photoperiod sensitivity index

0.0 0.2 0.4 0.6 0.8 1.0

Del

ay in

flow

erin

g in

201

1

-6

-4

-2

0

2

4

6

8

Drought condition; R2=0.60**

Aerobic condition; R2=ns

Relationships between

photoperiod sensitivity and delay

in flowering under intermittent

and prolonged drought

in 2009, 2010 and 2011 in

Cambodia

Shorter delay in flowering in photoperiod sensitive genotypes

Strongly photoperiod sensitive lines produced higher yield with better drought tolerance and shorter delay when flowered at the

same time (late planting) Insensitive

(PSI<-0.3)

Mildly

sensitive

(0.3<PSI<0.5)

Moderately

sensitive

(0.5<PSI<0.7)

Strongly

sensitive

(0.7<PSI)

Number of genotypes 5 2 10 5

Days to Flowering (flood) 85 89 86 87

Flowering Delay -intermittent 2.9 4.0 2.2 2.1

- prolonged drought (days) 6.1 6.0 3.3 3.1

Yield Flooded 372 435 454 417

Intermittent drought 263 (70 %) 260 (59 %) 310 (68 %) 324 (77 %)

Prolonged drought 290 (78 %) 352 (80 %) 324 (71 %) 313 (75 %)

Mean drought response index -0.07 0.04 -0.07 0.33

Correlation with PSI – Yield -flood (0.47*), intermittent (0.54**), -- Delay –intermittent (-0.47*), prolonged (-0.90**)

Drought tolerance traits

• Delay in flowering – Requires observation in drought as well as flooded

conditions – This can be used as selection trait in prolonged

drought with adjustment to flowering time under flooded conditions

• Photoperiod sensitivity – Potential trait; requires further evaluation

3. High yielding, drought tolerant lines are identified

• Phka Rumduol x Neang Tai Dun - F6 -3 appears most promising in Cambodia-- strongly tolerant to drought, strongly photoperiod sensitive and moderately high potential yield.

• IRUBN050035-B-7-B, IRUBN040041-B-B-5, Y329-UBN-13 and IRUBN050032-B-1-B are high yielding from 10 multi-location trials in Thailand across 2 years.

High yielding lines in Lao multi-location trials, and their characteristics found in water experiments

High yielding lines had high potential yield or drought tolerance (high drought response index DRI) or both. Drought tolerant lines had shorter delay in flowering

4. Environmental characterization - Drought mapping

• Lowland water balance model with deep percolation rate estimated from clay content (Inthavong et al. 2011).

• Start, end & length of growing period estimated, LGP is closely associated with drought occurrence.

• Extended from province to whole country Cambodia and Thailand.

Annual (median rainfall) and length of growing period across Thailand, Laos and

Cambodia Annual median rainfall (mm) Length of growing period

Laos drought prone environments

identified by start, end and length of growing season

Conclusions • New drought screening methods developed

– Intermittent stress – Top paddy positions as drought screening

• High yielding lines identified for each country – 6 Laos; 1 Cambodia; 4 Thailand

• Drought tolerant characters determined – Yield potential, photoperiod sensitivity, delay in

flowering and DRI • Drought maps developed for length of growing

period – Laos, Cambodia, NE Thailand.

Products

Simple drought screening technique that breeder can be used

promising lines for high potential grain yield and

drought tolerance for each country

Maps for drought prone areas in Laos, Cambodia and

NE Thailand

Paper: 5 papers, 1 has been submitted

Capacity building: there are 2 PhD students at KKU

Thank you