Effect of timing of heat stress during grain filling in two wheat varieties under moderate and very high temperature

W. F. Song; L. J. Zhao; X. M. Zhang; Y. M. Zhang; J. L. Li; L. L. Zhang; Q. J. Song; H. B. Zhao; Y. B. Zhang; C. L. Zhang; W. L. Xin; L. F. Sun; Z. M. Xiao

W. F. Song PostDoctoral Programme, Heilongjiang Academy of Agricultural Sciences, Harbin 150086, China;
L. J. Zhao Crop Breeding Institute, Heilongjiang Academy of Agricultural Sciences, Harbin 150086, China;
X. M. Zhang College of Life Science and Technology, Harbin Normal University, Harbin 150025, China;
Y. M. Zhang College of Life Science and Technology, Harbin Normal University, Harbin 150025, China;
J. L. Li College of Life Science and Technology, Harbin Normal University, Harbin 150025, China;
L. L. Zhang College of Life Science and Technology, Harbin Normal University, Harbin 150025, China;
Q. J. Song Crop Breeding Institute, Heilongjiang Academy of Agricultural Sciences, Harbin 150086, China;
H. B. Zhao Crop Breeding Institute, Heilongjiang Academy of Agricultural Sciences, Harbin 150086, China;
Y. B. Zhang Crop Breeding Institute, Heilongjiang Academy of Agricultural Sciences, Harbin 150086, China;
C. L. Zhang Crop Breeding Institute, Heilongjiang Academy of Agricultural Sciences, Harbin 150086, China;
W. L. Xin Crop Breeding Institute, Heilongjiang Academy of Agricultural Sciences, Harbin 150086, China;
L. F. Sun Crop Breeding Institute, Heilongjiang Academy of Agricultural Sciences, Harbin 150086, China;
Z. M. Xiao Crop Breeding Institute, Heilongjiang Academy of Agricultural Sciences, Harbin 150086, China;

Keywords: Wheat; post-anthesis heat stress; grain weight; rate of grain filling; duration of grain filling

Abstract

In order to examine the effect of short periods heat stress on grain growth, two cultivars (Longmai26 and Longmai30) were grown in pots at two different diurnal temperatures (32/22°C; 25/15°C) in climate-controlled growth cabinets and exposed to a 5-day heat stress (38/22°C) at 5-day intervals throughout grain filling after anthesis.The results indicated that long periods of moderate high temperature (>30°C) have higher effect than short periods of heat stress (5 days with maximum 38°C for 6h each day). However, plants grown at the moderate temperature (25/15°C) showed a greater response to a short period of heat stress than plants grown at the high temperature (32/22°C). At elevated temperatures, the change in the rate of grain filling is smaller than duration of grain filling.The high grain-filling rate and high potential grain weight should be used as a criterion in selecting for high temperature tolerance in wheat.