Key Points
- Ten field experiments over five seasons examined the effects of February, March and April sowing dates on the yield of irrigated feed wheat crops (six of the trials also had sowing rate treatments) at four trial sites in Canterbury. The cultivar Wakanui was used in all of the trials and Inferno in four trials.
- As an average of the ten trials, the highest grain yields (13.9 t/ha) were obtained from April sowings. There were differences between sites e.g. at the Leeston site, late March sowings had the highest yields.
- For the late March and April sow dates, target plant populations of 150-200 plants/ m2 were generally optimal for highest grain yield.
- For later sown crops there was a greater yield response from higher sowing rates compared to earlier sown crops.
- Grain yield increased as head population increased to about 600 heads/m2.
- Defoliating a March sown wheat crop in May and August reduced lodging susceptibility while maintaining grain yield.
- On-going trials are focused on selecting cultivars with good disease and lodging resistance and slow development for early sowing.