Hyper Yielding Crop Wheat Disease Management x Variety - SA

• There was a significant interaction between cultivar and fungicide management with cultivars responding differently to the number of fungicide units applied. Yields ranged from 7.34t/ha in untreated RGT Cesario, to 10.16t/ha in the newly released AGF cultivar Longford with full fungicide protection.
• Stockade (white wheat – APW) was the only cultivar to give no significant response in yield to fungicide application, although there was a trend for higher yield under full protection.
• Red wheats Longford, RGT Cesario and AGTW005 gave significantly higher yields with full protection based on 4 units of fungicide, but only RGT Cesario gave a significant response when a single fungicide was applied at GS39 (8.21t/ha vs. untreated 7.34t/ha).
• The yield response to full protection over untreated was Stockade (0.29t/ha), Longford (0.63t/ha), RGT Cesario (2.12t/ha) and AGTW005 (0.64t/ha).
• The dominant diseases were stripe rust in RGT Cesario and Septoria tritici blotch (STB) in Stockade, although drier spring conditions reduced upper canopy infection with STB.
• There was no obvious disease in Longford and only traces of Wirrega blotch and stripe rust in AGTW005 during grain fill, so it is difficult to suggest where the additional yield came from in these two varieties.
• Longford and AGTW005 retained their green leaf the longest, however four fungicide units were necessary to retain green leaf in RGT Cesario which is now very stripe rust susceptible.
• Higher senescence in Stockade was primarily related to a shorter growing season rather than the effect of more STB, which although less evident under four fungicides did not remove the senescence in the lower canopy.
• In terms of economics the most profitable approach in a dry spring with Stockade was based on four units of fungicide (despite lower yield response there was an improvement in bin grade through improved test weights), the same was the case with RGT Cesario where it was imperative to provide full protection against stripe rust. The net margin advantage of four fungicide units over one being almost over $300/ha.
• Grain quality parameters varied slightly with the different combinations of fungicide and cultivar, but all treatments had protein at least 11% or over with slightly, but significantly higher test weights under more intensive fungicide management.

Trial design: Factorial (Variety x Foliar)

Rotation position: 2022 Canola
Soil type: Organosol over grey clay
Nitrogen 0-30cm: 253kg N/ha
Colwell P (ppm) 0-10cm: 59 ppm
pH (CaCl2) 0-10cm: 7.5
Organic Carbon (%) 0-10cm: 8.0%