Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2007
Publication Date: 5/1/2008
Citation: Fleisher, D.H., Timlin, D.J., Reddy, V. 2008. Interactive effects of CO2 and water stress on potato canopy growth and development. Agronomy Journal. 100(3):711-719. Interpretive Summary: The United States is the fifth largest potato producing country in the world. Limited water availability for irrigation is a major limitation to potato production because potato yield decreases at mild levels of water stress. Potato yield is known to increase under elevated carbon dioxide concentration (CO2) conditions, and the interaction of CO2 and water stress on potato productivity may be important under projected climate change scenarios. Different levels of water stress were imposed on potato plants growing in outdoor growth chambers maintained at ambient or elevated CO2. Potato yield increased with irrigation under both CO2 levels, but was consistently higher for elevated CO2 plants. Plants grown under elevated CO2 were also shorter and produced approximately the same amount of vegetation as ambient CO2 plants. This result indicated that plants grown with elevated CO2 can sustain higher yields at the same quantity of irrigation as ambient CO2 plants, if nutrient levels are not limiting to growth. The results can benefit scientists and policy planners who are evaluating changes in water management for potato in response to global warming scenarios.
Technical Abstract: Canopy growth and development over the growing season plays a significant role in potato productivity. Potato is drought sensitive and reductions in leaf expansion and canopy growth are observed at mild levels of water stress. Potato productivity is enhanced by elevated atmospheric carbon dioxide concentration ([CO2]), but the interaction of [CO2] and water stress on the dynamics of canopy formation and carbohydrate partitioning have not been documented. Two soil-plant-atmosphere research (SPAR) chamber experiments were conducted at 370 or 740 umol per mol [CO2] and six different levels of irrigation ranging from 10 to 100% of the daily water uptake of the control chamber. Increases in plant length from 23 to 111 cm at 60 days after emergence (DAE), leaf appearance duration from 38 to 71 days, leaf appearance rates from 0.5 to 0.93 leaves per day, individual leaf area from 50 to 175 cm2, and lateral branch elongation and development were observed as seasonal irrigation increased. These values were generally smaller for elevated [CO2] plants. Total biomass was linearly correlated with seasonal irrigation and increased from 877 to 4151 g per square meter. The percentage of biomass allocated to the canopy increased from 50% to 80% with irrigation in ambient [CO2] and 30 to 80% in elevated [CO2]. Despite decreased canopy growth and development, elevated [CO2] plants produced more biomass and yield at most irrigation levels. Reduced canopy mass in elevated [CO2] plants was attributed to suppressed lateral branch development apparently due to an interactive effect of [CO2] enrichment and water stress on tuber sink strength. Data can improve studies evaluating change in management and production strategies for potato production in response to global warming.