The vernalization sensitive (Vrn-A1) and photoperiod sensitive (Ppd-D1) alleles delayed floral initiation 8–20 days depending on sowing date in the two sib lines studied.

Anthesis date was delayed 6–17 days and maturity 4–9 days.

Rate of crop dry matter accumulation was little affected.

Total dry matter was therefore greater at anthesis and maturity with the longer vegetative period.

Grain yield was unaffected or slightly less with the longer vegetative period, even comparing lines at the same anthesis date.