James Hunt1, Bonnie Flohr2, Neil Fettell3, Mike Stear1, Tony Swan2, Brad Rheinheimer2, Barry Haskins4, John Kirkegaard2
1Department of Animal, Plant and Soil Sciences, AgriBio Centre for AgriBiosciences, 5 Ring Rd, La Trobe University, Bundoora VIC 3086, Australia; 2 CSIRO Agriculture and Food, PO Box 1700 Canberra ACT 2601 Australia; 3Central West Farming Systems and University of New England, PO Box 171 Condobolin NSW 2877, 4Ag Grow Agronomy and Research, 7 Francine Ct, Yoogali NSW 2680
Yield increases achieved through wheat breeding are essential in order to increase global supply to meet future demand, and keep Australian wheat growers competitive with growers in other countries. Breeders are unable to select for yield alone, but must also maintain grain quality and disease resistance in their released cultivars. Since the late 1970s, cultivars favoured by growers in southern NSW (SNSW) have tended to be of very high grain quality, and derived from northern Australian breeding programs where quality and disease resistance are emphasised. In order to quantify the genetic gain in yield potential of cultivars favoured by growers in SNSW, we planted experiments in 15 environments across SNSW containing a set of 15 cultivars (11 from southern and 4 from northern breeding programs) widely grown in the region between 1901 and the present day. Yield potential progressed at a rate of 25 kg/ha or 0.5% per year relative to the most recent release in the southern cultivars, but no yield increase was found in the northern cultivars (P=0.571) when grown in the SNSW environment. We hypothesise that this is primarily due to emphasis on grain quality and disease resistance of northern breeding programs at the expense of yield gain.