Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 24 Page 25 Page 26 Page 27 Page 28 Page 29 Page 30 Page 31 Page 32 Page 33 Page 34 Page 35 Page 36 Page 37 Page 38 Page 39 Page 40 Page 41 Page 42 Page 43 Page 4419 IREC Farmers' Newsletter No. 197 — Autumn 2017 Plant population had a significant effect on grain yield and lodging but no effect on protein content. The optimum plant population was between 80 and 160 plants/m2 for most varieties. Varietal response to plant populations also needs to be considered when targeting high yields. Mace, Corack, EGA Gregory, EGA Bellaroi, LongReach Trojan and LongReach Cobra achieved higher yields at 80–120 plants/m2, whilst LongReach Lancer and Suntop achieved higher yields at 160–200 plants/m2. Differing responses to plant population and variety may have been due to differences in crop architecture and plant structure. With an average grain size of 40 g/1000 seeds, a sowing rate of approximately 70 kg/ha is required to achieve a plant population of 160 plants/m2. Lodging was affected by variety and plant population. The lowest incidence of lodging occurred in the lowest plant populations and for every increase in plant population there was an increase in lodging. A plant population of 120 plants/m2 had a higher yield than 200 plants/ m2 whilst reducing the incidence of lodging. Previous irrigated wheat experiments conducted within this project showed similar results. LongReach Cobra was the highest yielding variety at both Murrumbidgee trial sites in 2015. In the plant population experiments at Leeton in 2014, yield decreased and lodging increased when plant population exceeded 210 plants/m2. Acknowledgements This research is part of the Southern irrigated cereal and canola varieties achieving target yields project (DAN00198), jointly funded by GRDC and NSW DPI. We would like to gratefully acknowledge David and Paul Bellato for allowing us to establish the experiment on their property. The support of Daniel Johnston, Glenn Morris, Gabby Napier and Michael Hately for assistance with trial management, field assessments and data collection is also gratefully acknowledged. Further information Tony Napier Research & Development Agronomist Yanco Agricultural Institute M: 0427 201 839 E: tony.napier@dpi.nsw.gov.au Wallup had the highest protein content of the bread wheat varieties with 13.05% and had significantly higher protein than all other bread wheat varieties. Mace had the second highest protein content of the bread wheats with 12.05% and was statistically similar in protein content to Corack with 12.29 %. LongReach Trojan had the lowest protein content with 11.43% and was statistically similar in protein content to Suntop with 11.62%. All varieties (except for LongReach Trojan) met the minimum standard for H2 grade with grain protein content above 11.5% (Figure 2). Lodging Lodging was assessed on 30 November using a score of 0 to 9, with 0 indicating no lodging and 9 indicating horizontal plants. EGA Gregory had the most severe lodging with an average score of 3.24 and had significantly more lodging than all other varieties. LongReach Trojan had the least lodging (1.47) but was statistically similar to line 280913, Corack, Kiora, Cobra and Suntop (Figure 3). Lodging for most varieties was not much more than a lean in one direction and most likely had no impact on yield. EGA Gregory was the only variety that lodged in a twisted manner that may have had a small impact on yield. Plant population response Plant population had a significant effect on yield when averaged across all varieties. The low plant population had the highest average yield (8.08 t/ha) but was statistically similar to the medium and very low plant populations. The high plant population had the lowest average yield (7.96 t/ha) but was statistically similar to the medium and very low plant population (Table 3). The varieties differed in their grain yield response to plant population with Mace, Corack, EGA Gregory, EGA Bellaroi, LongReach Trojan and LongReach Cobra achieving higher yields at lower plant populations, whilst LongReach Lancer and Suntop achieving higher yields at higher plant populations. Plant population also had a significant effect on lodging severity. The very low plant population had the lowest incidence of lodging (1.71) but was statistically similar to the low plant population. The high plant population had the highest incidence of lodging (2.62) but was statistically similar to the medium plant population (Table 3). Plant population had no effect on grain protein content with all treatments resulting in 12.24% to 12.36% protein (Table 3). Conclusion LongReach Cobra has the potential to produce high grain yields under irrigation, yielding 9.52 t/ha with an average protein content of 12.0%. LongReach Trojan also achieved a high yield (9.12 t/ha) but had the lowest protein content (below 11.5%) and failed to meet the minimum standard for H2 grade. Table 3. Grain yield, protein content and crop lodging response to plant population in the irrigated wheat experiment at Coleambally in 2016. Treatment Grain yield (t/ha) Protein content (%) Lodging score (0-9) Very low (80 plants/m2) 8.06 a b 12.24 a 1.71 a Low (120 plants/m2) 8.08 a 12.27 a 1.94 a Medium (160 plants/m2) 7.98 a b 12.36 a 2.50 b High (200 plants/m2) 7.96   b 12.31 a 2.62 b Trial mean 8.02 12.29 2.19 l.s.d.(P