Kenton Porker1, James Hunt2*, Felicity Harris3, Sarah Noack4, Michael Moodie5, Kelly Angel6, Michael Straight7, Genevieve Clarke6, Dylan Bruce8, Ashley Wallace9, Neil Fettell10, Greg Brooke11, Helen McMillan10, Barry Haskins12, Mick Brady5, Todd McDonald5, Brenton Spriggs13, Sue Buderick13, Darcy Warren7.
1 South Australian Research and Development Institute, Hartley Grove, Urrbrae SA 5064
2 Department of Plant, Animal and Soil Sciences, La Trobe University, 5 Ring Rd, Bundoora VIC 3086
3 NSW Department of Primary Industries, Wagga Wagga Agricultural Institute, Wagga Wagga NSW 2650
4 Hart Field-Site Group, 155 Main North Rd, Clare SA 5453
5 Frontier Farming Systems, 7B Byrne Ct, Mildura VIC 3500
6 BCG, 73 Cumming Ave, Birchip VIC 3483
7 FAR Australia, 4/97-103 Melbourne St, Mulwala NSW 2647
8 South Australian Research and Development Institute, 70 Farrell Flat Rd, Clare SA 5453
9 Agriculture Victoria, 110 Natimuk Rd, Horsham VIC 3400
10 CWFS, 1 Fifield Rd, Condobolin NSW 2877
11 NSW Department of Primary Industries, Trangie Agricultural Research Centre, PMB 19, Trangie NSW 2823
12 AgGrow Agronomy & Research, 7 Francine Ct, Yoogali NSW 2680
13 South Australian Research and Development Institute, McKenzie Rd, Minnipa SA 5654
*Presenting author; firstname.lastname@example.org
Australian wheat breeding programs have responded to the need for cultivars better suited to early sowing and have begun releasing a new generation of winter wheats. However, it is not known which of the new cultivars are best adapted to different environments across the wheat belt, or over what period they can be established and still achieve yields competitive with spring wheats sown in their optimal window. We grew four new winter cultivars and four elite spring checks in experiments with four times of sowing (mid-March, early-April, mid-April, early-May) in 11 different environments across SE Australia during 2017 and 2018. We found that yield of the best winter wheats was comparable with spring wheats sown in their optimal window. Due to the stable flowering time of winter cultivars, adaptation was driven by cultivar flowering time and coincidence with optimal flowering periods in the different environments. The fast winter cultivar Longsword tended to yield best in low yielding (<2.5 t/ha) environments with an early flowering window. The mid-slow winter cultivar DS Bennett yielded most in higher yielding environments (>2.5 t/ha) with a later flowering window, apart from the Mid North of SA where the mid-fast cultivar Illabo was superior. Highest yields of winter wheats were achieved when sown during April and declined when sown in either mid-March or early May.