Impact of post-flowering heat stress on stay-green and grain development in wheat

Najeeb Ullah1, Karine Chenu1

1 The University of Queensland, Queensland Alliance for Agriculture and Food Innovation (QAAFI), Toowoomba, QLD, Australia Email: n.ullah@uq.edu.au;  karine.chenu@uq.edu.au

Abstract:

With recent and projected changes in climate, wheat crops are increasingly likely to experience post-flowering heat stress. An experiment was conducted to assess the impact of post-flowering heat on wheat crop. Recombinant inbred lines SB062 and SB003 were exposed to a 7-day heat shock (32.7/21.6°C day/night temperature) at different periods during the grain filling. These post-flowering heat shocks accelerated leaf senescence, with a greater impact on older leaves and for mid post-flowering stresses. Substantial genotypic differences were observed, with SB062 maintaining leaf greenness longer than SB003 especially when submitted to a heat stress. High temperature also reduced grain dimension and weight, especially for stresses applied during early-to-mid grain filling. SB062 was found as heat tolerant, as neither senescence of its two top leaves nor its grain size were significantly affected by heat in the tested conditions. Delayed leaf senescence appeared to play a role in maintaining grain size in SB062 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.

Host

The Australian Society of Agronomy is the professional body for agronomists in Australia. It has approximately 500 active members drawn from government, universities, research organisations and the private sector.

Photo Credits

David Marland Photography david_marland@hotmail.com Graham Centre for Agricultural Innovation, Charles Sturt University

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