The barley ortholog of FLOWERING LOCUS T, HvFT1, also called VrnH3, is the main integrator of the photoperiod and vernalization signals leading to the transition from the vegetative to the reproductive stage. Results gathered by us and other groups for the last years have repeatedly identified variation in this gene related with flowering time QTL in mapping populations and also in genome wide association studies. Differences in the promoter, SNPs in the first intron and also copy number variation have all being associated with phenotypic and expression differences, resulting in earlier or later heading. The first reports found that mutations in the HvFT1 first intron differentiated plants with dominant and recessive alleles, with large phenotypic effect on time to flowering. The catalog of polymorphisms at this gene with potential phenotypic effect has been enlarged with copy number variation and sequence variation at the promoter. There is variation in the number of copies of the HvFT1 gene, apparently related to growth habit. A large set of winter genotypes, with a functional VrnH2 allele, has one copy of VrnH3, whereas variable number (1-5), was found in also a large set of spring or facultative barleys (without VrnH2). The dominant VrnH3 allele, which overrides the vernalization requirement of winter VrnH1 and VrnH2 alleles, is found only in Nordic barleys and carries a particular structure of the gene, with one promoter and variable number of transcribed regions. Using two indels from the promoter region and allele-specific markers for two SNPs in the first intron, we were able to classify four VrnH3 haplotypes, which showed differences in heading time among Spanish landraces. We will present results from several mapping populations and association analyses to contribute to describe the different polymorphisms that should be taken into consideration when analyzing this gene and its phenotypic effects.

1 .pdf copy (A3) of the original poster presented by the Authors.

Peer reviewed