Key Points
- Five wheat cultivars were sown over 5 months from June to October at 2 Canterbury sites.
- Delaying the sowing of spring or alternate wheat cultivars from June/July until October can result in large yield losses. Average yields fell from 9.7 t/ha to 6.6 t/ha with the largest drop in yield between September and October sowings.
- Test weight and grain size decreased with sowing time at both sites. Protein levels did not change much but were highest from the lowest yielding / October sowing.
- Reduced yields from the later sowings were likely to be the result of a combination of smaller grains and fewer grains per ear as ear development occurred during warmer weather.
- Yield response to time of sowing will vary with seasonal weather conditions. The information presented is one year’s data from two sites. Early growing conditions were favourable and grain fill for the late sowings was dry and warm. These conditions will generally result in larger yield depressions in late sown crops.