Soybean sowing date × genotype × plant population – Narrabri and the Liverpool Plains 2013/14 and 2014/15

Abstract

Key findings •• Sowing date had mixed effects on yields. •• Seasonal conditions had the biggest effect on crop responses. •• RichmondA yields were consistently higher than Moonbi[PBR] on the Liverpool Plains for all sowing dates. Moonbi[PBR] yields were equal to or higher than Richmond[PBR] at Narrabri when sown after early December. •• Richmond[PBR] demonstrated significant improvements in the key seed traits of seed size and protein content compared with Moonbi[PBR], Soya 791 and the advanced breeding line PR443. •• Sowing date had no effect on the protein content or seed size of Richmond[PBR] and Moonbi[PBR] in three of the four experiments. •• Soybeans were able to compensate for low plant populations across a wide range of sowing dates, growing region and seasonal conditions. Yield losses were incurred when populations fell below 20 plants/m2 with an upper threshold of 40–50 plants/m2.