Wheat cultivars vary widely in their responses of grain yield and quality to short periods of post-anthesis heat stress. [Workshop paper]
1994
Stone, P.J. | Nicolas, M.E. (Melbourne Univ., Parkville (Australia). Dept. of Agriculture)
Short periods of high temperature (greater than 35 deg. C) are common during the post-anthesis period in Australian wheat crops and have recently been shown to significantly reduce grain yield and quality. In view of this, 75 cultivars of wheat were screened for tolerance to 3 days of high temperature (max. 40 deg. C). Detailed results for grain yield and quality are presented for 5 wheat cultivars in order to illustrate the wide range of responses to short periods of high temperature. Individual kernel mass decreased by up to 23 percent, depending on variety, and the gliadin: glutenin ratio altered in the range minus 9 to plus 18 percent in response to high temperature treatment, also depending on variety. Noodle swelling power was significantly affected by heat in 2 cultivars, but there was no significant change due to heat in the apparent amylose content in any variety. The marked response of several yield and quality components to a heat treatment lasting only ca 5 percent of the grain-filling period suggested that starch and protein synthesis do not immediately and-or fully recover from short, severe heat stress. In addition, it is concluded that wheat shows considerable genetic variability in tolerance to short periods of high temperature for both grain yield and quality.
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