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United States Department of Agriculture

Agricultural Research Service

Title: Impact of Nighttime Temperature on Physiology and Growth of Spring Wheat

Authors
item Prasad, Vara - KANSAS STATE UNIVERSITY
item Pisipati, S.R. - KANSAS STATE UNIVERSITY
item Ristic, Zoran
item Bukovnik, Urska - KANSAS STATE UNIVERSITY
item Fritz, Allan - KANSAS STATE UNIVERSITY

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 25, 2007
Publication Date: November 17, 2008
Citation: Prasad, V., Pisipati, S., Ristic, Z., Bukovnik, U., Fritz, A.K. 2008. Impact of Nighttime Temperature on Physiology and Growth of Spring Wheat. Crop Science. 48:2372-2380.

Interpretive Summary: Climate models predict greater increases in nighttime temperature in future climates. The effects of high nighttime temperature on wheat (Triticum aestivum L.) are not well understood and are needed to better understand impacts of climate change. Two spring wheat cultivars (Pavon-76 and Seri-82) were grown in controlled environments chambers at optimum temperatures (day/night, 24/14°C; day/night photoperiod, 16/8 h) from sowing to booting and thereafter plants were exposed to four different nighttime temperatures (14ºC, 17ºC, 20ºC, 23ºC) until maturity. The daytime temperature was similar at 24ºC across all treatments. High night temperature (>14ºC) decreased photosynthesis after 14 d of stress. Grain yields linearly decreased with increasing nighttime temperatures. High nighttime temperature (=20ºC) decreased spikelet fertility and grains per spike, and grain-size. When compared to control (14ºC) grain filling duration was decreased by 3 and 7 d, respectively, at night temperatures of 20°C and 23ºC. High nighttime temperatures increased the expression of chloroplast protein EF-Tu in both cultivars suggesting possible involvement of this protein in wheat response to nighttime temperature stress. This study highlights the importance of high nighttime temperatures in determining the responses of wheat and possibly other crops to climate change.

Technical Abstract: Climate models predict greater increases in nighttime temperature in future climates. The effects of high nighttime temperature on wheat (Triticum aestivum L.) are not well understood and are needed to better understand impacts of climate change. The objectives of this study were to investigate the effects of high nighttime temperatures during reproductive development on phenology, physiological, vegetative, and yield traits of wheat. In addition, we also investigated the expression of a chloroplast protein synthesis elongation factor, EF-Tu. Two spring wheat cultivars (Pavon-76 and Seri-82) were grown in controlled environments chambers at optimum temperatures (day/night, 24/14°C; 16/8 h photo/dark period) from sowing to booting and thereafter plants were exposed to four different nighttime temperatures (14°C, 17°C, 20°C, 23ºC) until maturity. The daytime temperature was similar at 24ºC across all treatments. Data on phenology (time to panicle emergence, flowering and maturity), physiological traits (photosynthesis, stomatal conductance, transpiration, chlorophyll fluorescence and leaf chlorophyll content) were collected at frequent intervals. At maturity, numbers of tillers and ears, shoot dry weight, spikelet fertility (proportion of filled to total grains per ear), grain-size and grain yield were determined. There were significant influences of high nighttime temperatures on growth and yield traits, but not cultivar by temperature interactions. High night temperature (>14ºC) decreased photosynthesis after 14 d of stress. Grain yields linearly decreased with increasing nighttime temperatures, leading to lower harvest indices at 20 and 23ºC. High nighttime temperature (=20ºC) decreased spikelet fertility, grains per spike, and grain-size. When compared to control (14ºC) grain filling duration was decreased by 3 and 7 d, respectively, at night temperatures of 20°C and 23ºC. High nighttime temperature increased the expression of EF-Tu protein in both cultivars suggesting possible involvement of this protein in wheat response to nighttime temperature stress. This study highlights the importance of high nighttime temperatures in determining the responses of wheat and possibly other crops to climate change.

Last Modified: 10/23/2014
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