DAQ472 - Testing of Synthetic and Queensland Wheat Lines for Frost Tolerance after Heading
The minimisation of frost damage is of paramount importance to growers and, as a consequence, GRDC has made it a major objective. The direct yield loss, due to spasmodic frosting of winter cereals in Queensland (QLD) and northern New South Wales (NSW), runs into millions of dollars annually. Growers minimise the risk of frost by planting later and by using longer season varieties. Unfortunately, these strategies, although currently essential, result in even greater losses as flowering departs from the optimal period for maximum yield potential. If frost tolerance after head emergence could be increased just 2°C, to approx. -6°C, the annual yield increase due to earlier flowering, would exceed 0.8t/ha throughout the northern region. An 0.8t/ha yield increase is common when earlier flowering crops escape damaging frosts. Estimates suggest yield increases of this level across QLD would result in increases in the order of approx. 50% in gross wheat production.
The putative post-head emergence frost tolerance in the tested International Maize and Wheat Improvement Center (CIMMYT) synthetic wheat has either:
- Not been expressed at significant levels under QLD conditions, and/or
- Does not exist as tolerance per se, but rather as frost escape due to the long season nature of these types.
Hence, it is unlikely that useful levels (from a plant breeding perspective, >0.8°C) of frost tolerance will be available from this material.
Tested lines including CIMMYT synthetics are currently not suitable for use in a frost tolerance (post-head emergence) breeding program.
Work performed by D. Woodruff and T. Frederiks outside the scope of DAQ472 has identified high levels of frost tolerance after head emergence in another grass species. This provides a unique opportunity to study mechanisms of frost tolerance. A project proposal DAQ00002 'Novel Approaches to In-Head Frost Tolerance' has been submitted to GRDC to explore this exciting new mechanism.
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