Effect of VRN1 and PPD1 genes on anthesis date and wheat growth

Phasic development of wheat is largely determined by the interaction of the VRN1 and PPD1 genes with vernalising temperature and photoperiod.VRN1 andPPD1 are regulatory genes, known to influence freezing tolerance, plant
morphology and grain yield as well as phasic development. Forty-seven doubled-haploid lines were characterised for PpdB1, Ppd-D1, Vrn-A1, Vrn-B1 and Vrn-D1 to determine the effect of allelic combinations of these genes on timing of anthesis and crop growth rate. The lines were grown in replicated field experiments at two locations in Australia. The VRN1 andPPD1 genes accounted for 75% of the genetic variation for time from sowing to anthesis. Vrn-A1 andVrn-B1 similarly affected time to anthesis, but onlyVrn-B1 affected crop growth rate, with the springVrn-B1a allele resulting in faster crop growth rates than the winterVrn-B1v allele. This suggests thatthe effect ofVrn-B1 on crop growth rate is not a direct consequence of its effect on development per se, but rather due to its influence on other physiological processes.
The faster growth associated with Vrn-B1a may explain the high grain yield of cultivars with this allele in some environments, as shown in a previous study.