Mapping Low Temperature Tolerance in Barley.

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Low temperature tolerance (LTT) is an important climate change-related trait. Although the overall global trend is towards higher temperatures, greater LTT is needed for successful production of fall-sown barley, which in many areas of the world is higher yielding than spring-sown barley and is more water use efficient. Prior research has revealed QTLs for low temperature tolerance in a range of germplasm.  There are two biological phenomena underlying these reported QTLs: the timing of the vegetative to reproductive transition and regulation of cold-induced genes.  The principal mechanisms governing these phenomena are copy number variation and gene deletion. In order to expand the catalog of genes determining LTT we assembled a large GWAS panel (n = 941) of barley germplasm - from historic to contemporary  - and assessed the panel for field survival in the 2013/2014 season at 14 locations around the world. Differential survival was observed at 5 locations. In these data sets, we validate prior reports regarding the effects of FRH1 and FRH2 and we have identified significant associations in several genomic regions other than FRH1 and FRH2.  The experiment will be repeated in 2014/2015.  We anticipate that this experiment will contribute to a deeper understanding of LTT genetics and physiology and lead to the development of improved varieties.