BM Flohr1, 3, JR Hunt2, JA Kirkegaard1, JR Evans3
1 CSIRO Agriculture and Food, PO Box 1700 Canberra ACT 2601 Australia, 2Department of Animal, Plant and Soil Sciences, AgriBio Centre for AgriBiosciences, 5 Ring Rd, La Trobe University, Bundoora 3086, Australia, 3 The Australian National University, Research School of Biology, Canberra, ACT 0200
Australian wheat (Triticum aestivum) producers facing reduced autumn rainfall, more extreme spring weather and increasing farm size, have moved to earlier sowing to adapt to these trends. Analysis of sowing date records indicate a shift of around 1.5 days/year over a 10-year period. Field experiments comparing a pre-release fast winter line (RAC2341 – derived from the high yielding spring cultivar Mace) with elite spring cultivars were conducted across a broad range of environments (SA, NSW, VIC and WA) and sowing times. We found that in the years 2013-2015, 42% of wheat crops in the Yield Prophet® database were sown prior to 10 May. In the cool environment of Temora NSW, RAC2341 could flower at an optimal time from a broader range of sowing dates (mid-April to early May) than either mid- or fast-developing spring wheats, thus minimising the combined damage from frost, heat and water stress and maximising yield. In warmer Mediterranean environments (Minnipa SA, Cunderdin WA and Berriwillock Vic), RAC2341 was only able to flower during the optimal period from sowing dates in early to mid-April. However, when sown at this time, yields of RAC2341 were comparable to those of elite mid- and fast-developing spring cultivars sown later and flowering concurrently. Given the change in grower sowing times, new wheat cultivars with altered development patterns are required to ensure flowering during optimal periods with earlier and extended sowing periods.