Latitude and epistatic effects uncover novel stable regulators of
flowering time on chromosomes 5A and 3A in winter wheat
Abstract
Modern bread wheat has a huge genetic potential to adjust its heading
date with favorable conditions that has remained largely unexplored so
far. In this study, we used an association panel of in Germany adapted
cultivars that was tested in multi-location field trials across Germany
over three years. The genotypic response to climatic parameters
variation depending on location and year uncovered the implication of
photoperiod in promoting transition to flowering in higher latitudes,
while spring temperature accelerates flowering in lower ones. Spring
temperature overdominates other factors in decreasing the days to
heading whereas the higher amount of solar radiation is delaying it.
Genome wide scan detected a so far unknown stable locus TaHd14 on
chromosome 5A. Including non-adapted cultivars, the exotic allele
TaHd119 on chromosome 3A could be identified. The later explains up to
33% of the genetic variance and accelerates heading date by 5.63 days.
The response to the competition of latitude dependent climatic variables
detected fine tuning QTL responding to temperature and photoperiod in
lower and higher latitudes, respectively. A novel locus TaHd12 on
chromosome 5A showed significant epistatic interactions with 15 known
operators of HD regulation when exotic cultivars were included in the
analysis