The Winter-Type Allele of HvCEN Is Associated With Earliness Without Severe Yield Penalty in Icelandic Spring Barley (Hordeum vulgare L.)

Icelandic barley genotypes have shown extreme earliness both in flowering and maturity compared to other north European genotypes, and earliness is a key trait in adapting barley to northern latitudes. To better understand the mechanisms underlying this observed earliness, we partially re-sequenced four genes, Ppd-H1, HvCEN, HvELF3, and HvFT1, all known to play a part in the photoperiod response. The objective being to correlate allelic diversity with flowering time and yield data from Icelandic field trials. The resequencing identified two to three alleles at each locus, resulting in twelve haplotype combinations. One haplotype combination containing the winter type allele of Ppd-H1 correlated with extreme earliness, however with a severe yield penalty. In four genotypes, a winter type allele in HvCEN, correlated with earliness combined with high yield. Our results open the possibility of marker-assisted pyramiding as a rapid way to develop varieties with a shortened time from sowing to flowering under the extreme Icelandic growing conditions and possibly in other arctic or sub-arctic regions.