To compare identical plant population x cultivar trials under overhead and surface irrigation (lateral overhead trial)

• The highest yield of 5.20 t/ha under overhead irrigation was achieved when 45Y28 RR hybrid was sown at 80 seeds/m² and established a plant population of 51 plants/m².
• There was no interaction between variety and plant population with both varieties achieving increased yields as the plant population was increased.
• The oilseed yield of 45Y28 RR hybrid (4.77 t/ha) averaged across 4 plant populations, was significantly higher than HyTTec® Trophy (4.05 t/ha).
• Seed yield of HyTTec® Trophy showed little difference (0.21t/ha) when grown at populations between 37-58 plants/m² with 0.7t/ha drop associated with populations of approximately 20 plants/m².
• With 45Y28 RR hybrid the drop in seed yield associated with a population of 13 plant/m² was relatively small but there was a trend for a seed yield increase up to 50 plants/m².
• HyTTec® Trophy had a higher plant establishment (82%) than 45y28 RR hybrid (64%), averaged across 4 seed rates.
• There was no significant difference in seed oil content across plant population or variety and oil content ranged from 44.5% to 46.2% (data not shown).
• HyTTec® Trophy had a low seed test weight (60.3kg/hL) and was well below the minimum receival standard of 62kg/hL, 45Y28 RR hybrid achieved an average test weight of 63.3kg/hL.