Abstract
Optimizing the timing of heading is crucial for achieving stable production in bread wheat ( Triticum aestivum L.). We analyzed a breeding line, ‘B1-0393’, that headed 5 days earlier than the Japanese elite cultivar ‘Kitahonami’. To identify quantitative trait loci (QTLs) responsible for this difference, we conducted QTL-seq using F 3 progeny of a cross between ‘Kitahonami’ and ‘B1-0393’. We detected QTLs on chromosomes 2D ( QDth.kupg-2D ), 3D ( QDth.kupg-3D ), and 4A ( QDth.kupg-4A ), explaining 10.25%, 2.00%, and 8.24%, respectively, of phenotypic variance. The QDth.kupg-2D locus corresponded to the major photoperiod-regulating gene Photoperiod-D1 ( Ppd-D1 ). ‘Kitahonami’ had the photoperiod-sensitive Ppd-D1b allele and ‘B1-0393’ had the insensitive Ppd-D1a allele. QDth.kupg-4A overlapped with previously reported QTLs, while QDth.kupg-3D was a novel QTL. Segregation analysis using F 2 and F 3 plants confirmed that alleles from ‘B1-0393’ at all three loci accelerated heading and that the three QTLs had additive effects on days to heading. Our findings could be valuable for regulating the timing of heading to optimize wheat yield.