Canopy Temperature: A potential trait in selection for drought tolerance in grain sorghum

Raymond N. Mutava, Prasad P.V. Vara, Zhanguo Xin

SICNA Meeting, Lubbock Texas August 28 – 30, 2013

Sorghum genetic resource and current utilization

http://www.icrisat.org/crop-sorghum-genebank.htm

The genetic pool used in sorghum breeding is very small

Breeding for drought tolerance

Some important traits in sorghum breeding Goal: Increased yield Improved tolerance to environmental

stresses – drought and heatKey trait in drought tolerance: Staygreen - post-flowering drought

stressBUT not tolerance to:

Pre-flowering drought stress Heat stress

There is need to screen germplasm for other traits for improved drought tolerance

The sorghum diversity panel

300 lines with diverse background representative of sorghum genotypes from all over the world

Identify physiological traits associated with pre- and post flowering drought tolerance

Grown in multi-locations in multiple years in Kansas Data was collected in several traits (phenology, growth,

Physiological, yield

Leaf/canopy temperature

Mutava et al., 2011 (Field Crops Research)

There were genotypes that recorded: High leaf/canopy temperature with high and also low yields Low leaf /canopy temperature with high and also low yields

Thermal camera

IR sensors

Drought coping mechanisms in sorghum

High transpirational

cooling

Cooler canopies

Drought escape

mechanism

Low transpirational

cooling

Warmer canopies

Drought tolerance

mechanism

These two mechanisms seemed to exist among sorghum genotypes Drought tolerance through conservative water use (slow wilting trait)

Modified from Mutava et al., 2011

Leaf area and regression results for 17 genotypes that were found to fit the two-segment regression model

  Genotype Leaf Area Breakpoint Slope1 Slope2 R2

With a breakpoint SC982 295[20.6] 1.62(0.23) 50.0(12.6) 6.3(4.8) 0.79  SC1074 280[17.7] 1.99(0.17) 45.8(9.5) 1.0(4.1) 0.84  BTX623 265[10.0] 2.05(0.18) 56.3(10.7) 10.4(5.2) 0.90  SC979 290[14.4] 2.06(0.18) 47.7(7.8) 0.0(6.5) 0.84  BTX2752 288[13.0] 2.08(0.20) 52.0(9.0) 11(6.7) 0.89  SC1019 261[13.7] 2.08(0.25) 43.8(8.1) 1.3(10.1) 0.81  SC630 277[15.2] 2.16(0.31) 40.1(9.7) -1.5(8.2) 0.74  SC599 286[15.1] 2.23(0.27) 35.5(7.0) 3.4(8.4) 0.80  SC1047 258[14.8] 2.24(0.23) 32.2(5.6) 1.1(6.5) 0.84  SC803 267[12.8] 2.29(0.19) 39.8(6.5) -6.1(6.8) 0.84  BTX3197 280[13.2] 2.29(0.29) 38.8(6.5) 3.2(9.2) 0.85  SN149 294[17.4] 2.30(0.19) 38.2(5.2) -1.8(8.8) 0.87  Macia 270[12.6] 2.51(0.27) 35.7(3.8) 4.0(12.4) 0.91  BTX378 268[16.0] 2.55(0.39) 30.2(3.3) 11.3(11.0) 0.91  B35 265[22.2] 2.61(0.18) 40.3(6.8) 2.4(7.7) 0.88  TX3042 278[13.8] 2.69(0.23) 33.5(4.6) -0.5(11.4) 0.89  TX7078 300[17.4] 2.72(0.23) 37.7(6.0) 1.4(10.2) 0.88With no breakpoint DK28 311(14.7)   28.6(2.5)   0.89  BTXARG-1 277(22.4)   27.5(2.4)   0.90  SC1345 308(14.3)   27.5(3.0)   0.84  Hegari 280(14.9)   26.3(2.8)   0.84  DK54 300(20.4)   25.4(2.9)   0.83  RTX430 289(19.7)   25.4(2.8)   0.87  SC489 298(15.6)   24.8(2.8)   0.83  SC532 283(13.9)   23.9(2.8)   0.81  SC299 283(14.1)   23.1(2.3)   0.86

Gholipoor et al., 2010 (Field Crops Research)

Transpiration rate response to Vapor pressure deficit

No BP and low rate of increase in TR with VPD (Red line)• Consistently dry environmental conditions. • Restricted carbon assimilation • Slow growing and probably low yielding even under

well-watered conditions.

Sorghum genotypes could be selected to pursue soil water conservation as a way to improve yields under water-deficit conditions.

BP selection could therefore be matched with the likelihood of water-deficit conditions

• A low BP = greatest water conservation when soil water is still available

• High BP = less-restrictive water conservation.

High initial slope and a low BP, e.g. SC982• Offer a better approach to developing drought

tolerance.• Maximize gas exchange under low VPD and then

shift to water conservation at high VPD.

Gholipoor et al. 2010 (Field crops Research

Canopy temperature monitoring using IR

Time of Day

12 a

m

1 am

2 am

3 am

4 am

5 am

6 am

7 am

8 am

9 am

10 a

m

11 a

m

12 p

m

1 pm

2 pm

3 pm

4 pm

5 pm

6 pm

7 pm

8 pm

9 pm

10 p

m

11 p

m

Tem

pera

ture

(°C

)

0

16

18

20

22

24

26

28

30

32

34

36

AirTemp 84G62 B.Tx2752 B.Tx399 B.Tx615 DK28E DK54-00 Hegari Liang PI584085 R.Tx436 SA5330 SC1019 SC1124 SC224 SC60 SC663 SC701 SC720 TX7078

IR sensors detected variation in canopy temperature among genotypes between 2:00 and 6:00 PM

Genotypes SC1019, SA5330, and SC701 recorded high canopy temperature while Hegari, pioneer hybrid 84G62, SC663 and SC1124 had low canopy temperature consistently between 2:00 and 6:00 PM

Canopy temperature and yield

CTD was positively correlated to yield, harvest index and CWSI while canopy temperature was positively correlated to CWSI

Variation in biomass and TE

There was significant genotypic variation in biomass produced and TE

Genotype ranking based on TETotal

Genotypes SC1019, SC720, SC1047, SC1074 and SC979 had high TE

Collaborators

J. YuIowa State University

Sorghum Genetics

T. TessoKansas State University

Sorghum Breeder

T.R. SinclairNorth Carolina State University

Crop Physiologist

Kansas Grain Sorghum Commission

Zhanguo XinPlant Stress and Germplasm Development Unit USDA-ARS, Lubbock, TX

NCSUManoochehr Gholipoor

Sunita Choudhary

Kansas State UniversityCrop physiology Lab members

Maduraimuthu DjanaguiramanGeorge Mahama

George PaulSruthi Narayanan

Subramanian Satheesh Kumar