Wheat phenology development predicted by Ppd and Vrn allelic combinations

The optimum combination of Vrn and Ppd alleles to target developmental events such as flowering for a given sowing date in a given region is important in breeding to maximise grain yield and adaptation. A study was conducted at seventeen experimental sites in the High Rainfall Zone of southern Australia in 2014 and 2015 to investigate the effects of photoperiod and temperature on 205 experimental wheat lines and to use this information to develop a wheat phenological model based solely on allelic information. The sites had an 11° difference in latitude (1200 km) and germplasm included near-isogenic lines that varied in the vernalisation and photoperiod alleles, a set of highly diverse lines from the Multiparent Advanced Generation Inter Cross (MAGIC) population and commercial cultivars. The different site x genotype x sowing time combinations gave a wide range in flowering times. Phenological models developed from the allelic data provided root mean square error of 4.6 days for timing of terminal spike and anthesis. This study demonstrated the ability of different combinations of Ppd and Vrn alleles to predict the duration from sowing to terminal spikelet and flowering using photo-corrected thermal time sums based solely on crop allelic combinations. This information can now be used to develop cultivars for different production environments and changing climates. It could also be useful for farmers to identify the most suitable cultivars for a given date of sowing. Our work allows the integration of different allelic combinations with sowing times to target optimum flowering dates at individual locations across the entire wheat growing region of Australia.