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Flowering Time Pathways Underlying Quantitative variation in heading date of wheat

Final Report Summary - FTPUQ (Flowering Time Pathways Underlying Quantitative variation in heading date of wheat)

The EU funded research project was focused on the analysis of the eps gene located on chromosome 3AS combining molecular and phenotypical strategies to determine the gene’s effect on plant development, adaptation and performance in wheat.
The 3A heading QTL was validated using NILs and recombinants segregating for the QTL region which were grown under controlled environments (under different vernalization and photoperiod treatments). The results obtained confirmed that the 3A heading QTL is an eps effect. In addition, the pair of NILs that were used to develop the recombinants was used to determine that the 3AS eps QTL affects the duration of early developmental phases.
In order to refine the 3A QTL map location, recombinants were genotyped using new markers developed based on the Illumina iSelect custom 90K wheat chip and SNP markers available in cerealsdb (http://www.cerealsdb.uk.net) and phenotyped in two field experiments (one spring-sown and one autumn-sown). A bimodal distribution of flowering time within the populations was obtained indicating the trait resolves to a single Mendelian factor, and therefore converted the eps gene from a quantitative to a qualitative trait. The genotypic and phenotypic information was used to perform a QTL analysis which allowed us to detect a significant QTL on the short arm of chromosome 3A confirming that the early flowering time is associated with the Avalon allele. This information was also used to explore for candidate genes. Genes involved with flowering and development were isolated from Avalon and Cadenza genomic DNA and sequenced to determine any significant polymorphisms between them.
The precise mapping of the eps locus provides a better understanding of the contributions of individual eps genes and the interaction with different environmental factos which is essential to manipulate wheat heading time and maximize yield potential in different environments. Therefore, they could be very useful for wheat-breeding programmes where selection is based on selection of specific eps traits and genes rather than indirect selection, because they could be exploited independently of vernalization and day-length responses. In addition, the results obtained provides a basis for the future positional cloning of the 3A eps gene.