PP-15: Töpfer, Weisshaar, Weigel
Determination of the relationship between allelic constitution and the flowering time phenotype in grapevine
Within phase 1 of the SPP1530 programme, several QTL regions have been identified for control of flowering in grapevine.First results indicate additive effects of these loci that result in very early resp. late flowering. To limit and analyze these genomic regions, a greatly extended mapping population will be used for quantitative trait locus (QTL) fine mapping and to test the hypothesis that specific QTL alleles and haplotypes lead to either very early or late flowering. The project will (1) make use of the complete genome sequence of the parents of the mapping population as a basis for determination of haplotype specific expression, (2) identify candidate genes by genotyping-by-sequencing (GBS) of pre-selected offspring individuals and SNP analysis, (3) characterize selected candidate genes within QTL regions by allele-specific RNAseq experiments and (4) integrate these results with phenotypic data from the offspring and selected additional cultivars to identify flowering time determinants. By co-operation with further research groups within the SPP community, additional insights will be generated, e.g. from the phylotranscriptomic analysis of floral transition (I. Grosse). By being able to accurately predict flowering time, new favorable hybrids that are adapted to a changed climate can be generated.
Fechter I, Hausmann L, Zyprian E, Daum M, Holtgräwe D, Weisshaar B, Töpfer R (2014). QTL analysis of flowering time and ripening traits suggest an impact of a genomic region on linkage group 1 in Vitis. Theoretical and Applied Genetics, Theor Appl Genet. 2014; 127(9): 1857–1872, doi: 10.1007/s00122-014-2310-2