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Climate Impacts and Resilience in Caribbean Agriculture: Climate Proof Screen
Aidan Farrell UWI St. Augustine, Trinidad
Motamayor et al. (2008) PLoS ONE 3(10): Different colours show different genetic groups
Harnessing genetic differences to increase cocoa resilience?
Aims of workpackage 1 : Climate Proof Screen
Assess available methods for identifying differences in resilience to drought and heat stress
Establish protocols for testing resilience and use these to compare three genetic groups
Assess the potential impact of climate resilience on current and future cocoa crops (via workpackage 2 & 3)
Motamayor et al. (2008) PLoS ONE 3(10):
Three groups: testing three accessions from each
Hybrid: Trinitario
Upper Amazon: Guiana
lower Amazon: Nanay
Control Bench Dry Bench
Assessing ‘performance’ in the field and greenhouse
Leaf temperature:Infrared camera (FLUKE 410)
Photosynthesis:Chlorophyll fluorescence (Walz MINI PAM)
Transpiration:Porometer (SC-1 Decagon Devices)
Control Bench Dry Bench
Visual assessment of stress symptoms
0 % 10% 50% 70%
Membrane stability test: to assess tolerance to ‘damage’ using leaves from field and greenhouse
Leaf segments immersed in deionised water
High conductivity = low membrane stability
Leaf segments exposed to:
30; 35; 40; 45; 55 Celsiusor
0; -1.0; 2.0; -3.0 Megapascals
Then incubated overnight
Control Bench Dry Bench
Best method for assessing differences in heat stress
In the greenhouse
Max air temperatures were approx. 5 C higher
Transpiration was consistently elevated
Photosynthesis unaffected
Visual assessment unaffected
Membrane stability test was consistent…
Impact of temperature on photosynthetic performance The impact of temperature on membrane integrity
0
20
40
60
80
100
30 35 40 45 50 55 60
Co
co
a p
erf
orm
an
ce
(%
of
op
tim
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Maximum temperature (oC)
'best' group
current group
'worst' group
Control Bench Dry Bench
Best method for assessing differences in water stress
In the greenhouse
Stomatal conductance reduced
Leaf temperature elevated
Membrane stability test- inconsistent
Visual index was reduced
Photosynthesis was reduced…
Control Bench Dry Bench
Impact of soil moisture on photosynthetic performance The impact of moisture content on photosythesis
0
20
40
60
80
100
020406080100
Co
co
a p
erf
orm
an
ce
(%
of
op
tim
um
)
Soil moisture (% of optimum)
'best' group
current group
'worst' group
Selection for resilience to drought stress has great potentialSeveral methods available, including low-tech methods that could be implemented through participatory selection
Conclusions of workpackage 1 : Climate Proof Screen
At UWI St Augustine:Ariel CoolmanAnupa GobinChrista BobanDevan InderalSalina Mohammed
At the Cocoa Research Centre:Prof. UmaharanAnnelle HolderStaff at the Cocoa Genebank
Acknowledgements
Figure 1. Localization of the origin of individuals analyzed; colors indicate the inferred genetic cluster to which they belong.
Motamayor JC, Lachenaud P, da Silva e Mota JW, Loor R, Kuhn DN, et al. (2008) Geographic and Genetic Population Differentiation of the Amazonian Chocolate Tree (Theobroma cacao L). PLoS ONE 3(10): e3311. doi:10.1371/journal.pone.0003311http://127.0.0.1:8081/plosone/article?id=info:doi/10.1371/journal.pone.0003311
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