1. Challenges to sustainable potato production in a changing climate: A research perspective R. Quiroz, A. Posadas, C. Yarlequé, H. Heidinger, C. Barreda, R. Raymundo, C.Gavilán, M. Carbajal, H. Loayza, H. Tonnang, J. Kroschel, G. Forbes, and S. De Haan. Centro Internacional de la Papa August 15th 2011 Conference presented at the 95th Annual Meeting of the Potato Association of America. Wilmington NC Symposium - Breeding for Sustainable Production in a Changing Climate Understanding the Physiological Basis of Genetic and Environmental Interactions

2. Contents • Potato in variable environments • CC-Potato - Literature findings • Summary of perceived research gaps • Addressing research gaps at CIP • Farmers adaptation strategies in theAndes and tradeoffs

4. Temperature

5. Water & Nutrients

6. Light & CO2

7. Where is potatoProduced?

8. Potato acreage

10. It is about climate change w/oforgetting climate variability

11. The concentration of GHGs is rising Long-term implications for the climate and for crop suitability

12. Areas where maximum temperature during the primary growing seasonis currently < 30°C but will flip to > 30°C by 2050 Areas where rainfall per day decreases by 10 % or more between 2000 and 2050.

13. DIRECT EFFECTS: elevated levels of Carbon dioxide on potato crops Leaf Processes Increased CO2 •When exposed for a short period -substantial increment Photosynthetic rate •Down regulation when grown continuouslyin elevated CO2 •Decreases at elevated CO2 Stomatalconductance •Expected to increase WUE •Contradictory responses, probablyassociated to cultivar differences Leaf Protein, Chlorophyll contentStarch / CHO content •Increases with long-term exposure toelevated CO2

14. Effect of elevated levels of Carbon dioxide on potato crops Process Increased CO2 Changes in plant growthand development •Stimulates both above-and below-groundbiomass (early growing season) •Period of active plant growth endsprematurely •Senescence begins earlier •Limited growth rates towards the end ofgrowing season •Tuber yield stimulated and magnitudevaries with cultivar and growing conditions Effects on crop yield •Increase number of tubers Effects on tuber quality •Increased tuber DM & starch content •Reduced tuber N and glycoalkaloidcontent

15. Effect of elevated Temperature on potato crops •Elevated temperatures seems to reduce tuber initiation •Temperature above the desired ones reduce the photosynthetic efficiency, thusreducing potato growth •High temperature may also reduce the ability of the plant to translocate photosynthates to the tuber •Elevated temperature increases DM partitioning to stems but reduces root, stolon, tuber and total DM and total tuber number •Offset the CO2 fertilization effect

16. INDIRECT EFFECT: potato pests and diseases Baseline w/o crop protection 75 % of potato production today would be lost to pests Major factors likely toinfluence plant diseaseseverity and spread •increased CO2, •heavy and unseasonal rains, •increased humidity, droughtsand hurricanes, •warmer winter temperatures

17. •alterations in the geographical distribution ofspecies, Changes in the climate are expectedto produce •increase overwintering, •changes in population growth rates, •increase the number of generations perseason, •extension of the development season, •changes in crop-pest synchrony, •increase risk of invasion by migration pests, •may cause the appearance of newthermophilicspecies, •changes in the physiology ofpathogens/insects and host plants, •changes in host plants resistance toinfection/infestation, •critical temperature/infection threshold, •modification of pathogen aggressivenessand/or host susceptibility

18. Knowledge gaps and research priorities: Experimental analyses and model simulation to quantify: - Effect of increasing CO2 on crops other than cereals, includingthose of importance to the rural poor (e.g. local potato cultivars) - Interaction between crop yields and other factors of production(pests, diseases, weeds, etc.) under climate change conditions - Impact of climate extreme events on crop yields Reduce and quantify uncertainties of future prediction: - Generate reliable data to test GCMs through hindcasting - Improve the spatial resolution of climate predictions Develop tools to evaluate adaptation strategies at differentspatial levels (cropping, farm, region) - Link climate-pathogens-hosts interactions across scales Evaluate actual applicability of adaptation strategies: - Quality of seeds - Cost and benefits (economic, social, environmental) - Role of new technology (e.g. biotechnologies, fertilizers, etc.) - Tradeoffs analyses

19. CIP advances on potato modeling y S. Tuberosum - tuberosum - andigena y S. Ajanhuiri y S. juzepczukii Light Light Interception ) DM LUE (PAR— Photosynthetic Apparatus Kg DM.ha¨¹.d ¨¹ T GC LAI Light Reflectance Tubers Roots Stems Leaves

20. Improving model inputs G B R NIR

21. RS data for helping select tolerant potato cultivars NDVI 0-0.1 0.1-0.2 0.2-0.3 0.3-0.4 0.4-0.5 0.5-0.6 Fresh yield (t/ha) <16 >24 60 60 50 50 40 40 30 30 20 20 10 10 0 0 1 2 3 4 5 6 7 8 9 10 1112 1 2 3 4 5 6 7 8 9 101112 Plot Plot Normal irrigation Deficit irrigation Terminal drought

22. MRI- Potato tuber scanning

23. MRI -potato root scanning

24. Coping with limited spatial-temporal coverage of climate data

25. From RS data to rainfall (ppm) HUANCANE 50 40302010 0 1-Jan-99 20-Jul-99 5-Feb-00 23-Aug-00 11-Mar-01 27-Sep-01 15-Apr-02 1-Nov-02 Días Source: Yarlequé et al., 2007

26. Andean Farmers: Adaptation strategies and potential tradeoffs

27. 20th Century Climate Change in Tropical Andes Variable Assessment Temperature Average warming of 0.09-0.15 ◦C decade−1; western slopes>highlands>eastern slopes Relative humidity (near Increased 0 - 2.5 % decade−1; surface levels) Precipitation Little change in the latter half of 20th Century. Some increments inEcuador, NW Argentina andBolivian lowlands Source: Vuille et al., 2003

28. Projected Climate: Andes

29. Late Blight (LB) ‰ Warmer temperatures with some humidity in higher grounds will increase the presence of potato late blight. ‰ High incidence of LB in the future (2050) above 3000 masl (highlighted in the map) where it is virtually absent today

30. Potato tuber moth (PTM) ‰ PTM is actually present in interandean valleys and thecoastal areas of the Andes ‰ PTM is expected to climb as well due to climate change

31. 60 45 Potato species 30 Solanum juzepczukii (juz) Solanum tuberosum ssp. Andigena (and) 15 Solanum tuberosum ssp. Tuberosum (tub) 0 Solanum phureja (phu) 50 A B C Solanum acaule (acl) 40 30 Cultivar and progenitors 20 (A) Luki 10 juz 100% 0 (B) Gendarme A B C 50 and 100% 40 (C) Sajama Hybrid 30 and: 25% 20 tub: 50% 10 phu: 12.5% 50 acl 12.5% 0 40 A B C 30 Period 20 50 10 40 1965-19751976-19851986-19951996-2005 0 30 A B C 20 10 0 A B C

32. As temperature and presence of pest increase in the Andes Potatoes are planted in higher grounds 1975: (4000-4150msnm) 2005: (4150-4300msnm) S. De Haan & H. Juarez, CIP (2008)

33. Putting pieces together for a hypothetical example: Changes in potential potato (improved and native) in Peru: 2000-2050

34. Sampling-transect to assess carbon contents and stocks in Southern Peru. Source: Segnini et al., 2010

35. Carbon stocks in diverse Andean soils

36. Peatlands and other land uses in theAndean highplateau

37. Potential loss of soil carbon stocks due to cropping peatlands and grasslands in Peru & Bolivia Peatlands to potato 350 300250200150100 50 0 2000 2050 Scenarios Bolivia Peru Grasslands to potato 12000 1000080006000 40002000 0 2000 2050 Scenarios Bolivia Peru

38. The challenge (Climate smart agriculture) Potato agriculture that sustainably increases productivity, resilience(adaptation), reduces/removes greenhouse gases (mitigation), andenhances achievement of national food security and developmentgoals.