Abstract
The frequency of heat shocks during grain filling of wheat crops across the Australian wheatbelt has significantly increased over the last 30 years. These post-flowering heat events significantly reduce wheat yields with a relatively greater impact on grain size than grain number. A controlled environment study was conducted to assess the impact of post-flowering heat shocks on wheat recombinant inbred lines SB062 and SB003. Plants were submitted to 7-day heat shocks (33/21 °C day/night temperature) at different periods during grain filling. Heat shocks significantly accelerated leaf senescence, with a greater impact on older leaves and for mid post-flowering stresses. Overall, the tolerant line (SB062) could maintain leaf greenness longer than the sensitive line (SB003), especially when submitted to heat stress. Further, heat shocks during early-to-mid grain filling reduced the grain size and weight. While the impact on developing grains was significant in SB003, no significant effect of post-flowering heat was observed on leaf senescence nor on grain size in the tolerant line SB062. Delayed leaf senescence appeared to play a role in maintaining grain size under heat stress. The research findings will assist improving crop models for post-flowering heat effects and developing techniques for screening heat tolerant wheat lines. Increased post-flowering assimilate production through sustained leaf greenness could improve the performance of wheat crops in increasingly warmer environments.
Highlights
Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland, Toowoomba, QLD 4350, Australia; b.ababaei@uq.edu.au (B.A.); karine.chenu@uq.edu.au (K.C.) * Correspondence: n.ullah@uq.edu.au † Presented at the third International Tropical Agriculture Conference (TROPAG 2019), Brisbane, Australia, 11–13 November 2019
A controlled environment study was conducted to assess the impact of post-flowering heat shocks on wheat recombinant inbred lines SB062 and SB003
Plants were submitted to 7-day heat shocks (33/21 °C day/night temperature) at different periods during grain filling
Summary
Increasing Heat Tolerance in Wheat to Counteract Recent and Projected Increases in Heat Stress † Najeeb Ullah*, Behnam Ababaei and Karine Chenu Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland, Toowoomba, QLD 4350, Australia; b.ababaei@uq.edu.au (B.A.); karine.chenu@uq.edu.au (K.C.) * Correspondence: n.ullah@uq.edu.au † Presented at the third International Tropical Agriculture Conference (TROPAG 2019), Brisbane, Australia, 11–13 November 2019.
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