Response of current and potential wheat varieties to four sowing dates – Narrabri 2014

Abstract

Key findings • Grain yield (GY) results highlight the importance of sowing varieties in their recommended sowing window. • Early sowing of short season varieties resulted in significant GY penalties, with Dart [PBR] for example experiencing a 2.4 t/ha (42%) yield penalty from a TOS 1 (April 23) versus a main season TOS 2 (May 15) sowing date, due principally to frost induced sterility. • Delayed sowing of longer season varieties such as EGA Eaglehawk [PBR] TOS 1 to TOS 2, resulted in a 1.2 t/ha (22%) GY loss. • Lancer [PBR] and Suntop [PBR] performed well in both TOS 1 and TOS 2 and would appear good varietal choices for this sowing window and environment. • Mitch [PBR] and Spitfire [PBR] maintained yield and ranking with a main season (TOS 2) and a delayed TOS 3 (June 12) sowing date. Sunmate [PBR] was able to maintain yield ranking from delayed sowings in TOS 3 and TOS 4 (July 4). • Averaged across varieties there was a negative effect of delays in sowing on yield with a reduction of 1.27 t/ha from TOS 2 to TOS 3, with a further reduction of 1.23 t/ha at TOS 4, associated with increased temperature and moisture stress during the critical grain fill period.