|Rahman, Lutfor - TEXAS A&M UNIV|
|Quebedeaux, Bruno - UNIV OF MD|
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 26, 2006
Publication Date: August 3, 2006
Citation: Timlin, D.J., Rahman, L., Baker, J.T., Reddy, V., Fleisher, D.H., Quebedeaux, B. 2006. Whole Plant Photosynthesis, Development and Carbon Partioning in Potato (Solanum tuberosum L.) as a Function of Temperature. Agronomy Journal. 98:1195-1203. Interpretive Summary: Potato is adapted to cool temperatures and grows well where daytime temperatures are in the range of 15 ' 20 degrees C. Often daytime temperatures exceed these values and this may reduce tuber yield. High temperatures also accelerate senescence and result in excess vegetative growth. Computer simulation models can help growers manage their crop better by forecasting temperature effects on crop growth and yield. There are few canopy level data on photosynthesis and its effect on growth in potato, however, to use to develop or test a simulation model. Our goal was to collect comprehensive data on temperature effects on canopy photosynthesis and plant development that are needed to develop these kinds of models. We found that the optimum temperature for photosynthesis was 24 degrees C early in the season. This optimum shifted to cooler temperatures as the season progressed. The optimum temperature for tuber production was 20 degrees C. As temperature increased, the relative proportion of tuber to total plant dry matter decreased. These data will enable us to develop more accurate equations to quantify plant growth and development as a function of temperature. As a result we will be able to develop more accurate and robust crop models.
Technical Abstract: An understanding of temperature effects on whole canopy photosynthesis, growth, and development of potato (Solanum tuberosum L.) is important for crop model development and evaluation. The objective of this study was to quantify the effect of temperature on canopy photosynthesis, development, growth and partitioning of potato cv. Atlantic under elevated atmospheric carbon dioxide concentration (700 uL L-1 CO2). Potato plants were grown in day-lit plant growth chambers at five constant day/night temperatures, 12, 16, 20, 24, 28 and 32 degrees C during the 52-d experimental period. Plant height, main stem node number, leaf number were obtained nondestructively at four day intervals and leaf area index, dry matter partitioning and yield were obtained by destructive harvesting at biweekly time intervals. The optimum temperature for canopy photosynthesis was 24 degrees early in the growth period. The optimum moved to lower temperatures as the plants aged. The highest dry matters were obtained from the 20 degree treatment. Tuber weight and the ratio of tuber to total dry matter decreased with increasing temperature above 24 degrees. The accumulation of dry matter as a function of carbon assimilation was constant over temperature treatments but the proportion allocated to tubers increased with decreasing temperatures. Temperature effects on canopy level photosynthesis were mainly due to carbon partitioning, and differences in leaf area and canopy architecture that resulted from the different development rates. When simulating photosynthesis and carbon assimilation in crop models, source/sink relationships with temperature and photosynthesis need to be accounted for. Implications for simulation model development are discussed.