Cathrine H Ingvordsen1, David J Smith2, Tina Rathjen1, Gurjet Gill3, Leslie A. Weston4, Washy Gapare1, Greg J Rebetzke1
1 CSIRO, Black Mountain Science and Innovation Park, Canberra, ACT, 2601, http://www.csiro.au/en/Research/AF/Areas/Plant-Science, firstname.lastname@example.org
2 CSIRO, Agriculture and Food, Private Mail Bag, Yanco, NSW, 2703
3 The University of Adelaide, Waite Campus PMB 1, Glen Osmond, SA, 5064
4 Charles Sturt University, Locked Bag 588, Wagga Wagga, NSW, 2678
Weeds are an ongoing challenge and herbicide-resistant weeds are on the rise. Incorporating weed-competitive varieties in the non-herbicide integrated weed management toolbox, make up a low cost and low risk approach to decrease the $4.3 billion weed costs Australian growers every year. We have assessed the competitive ability of a diverse set of 100 entries. The 100 entries vary from historic and modern wheat varieties to wheat lines developed to have wide leaves and greater biomass at stem elongation. Among the entries were also durum wheat, triticale and barley. The 100 entries were grown under field conditions in seven environments over three seasons with and without competition from oat or barley used as a weed-surrogate. Through in season measurements and separation of wheat grains and weed-surrogate grains after harvest we identified that wheats with wide leaves and greater biomass at early stem elongation only experienced yield decreases of 4-10% when grown in competition with weed-surrogate, whereas the best varieties decreased yield by 14% and worst decreased yield by 35%. Weed suppression was greatest in the high vigour lines.