Greg Rebetzke1, Kathryn Bechaz2, David Smith3, Tina Rathjen1, Neil Fettell4, Andrew Fletcher5, Cathrine Ingvordsen1
1 CSIRO Agriculture and Food, Black Mountain Science and Innovation Park, Canberra, ACT, 2601, firstname.lastname@example.org,
2 NSWDPI, Yanco Agricultural Institute, Yanco NSW 2703,
3 CSIRO Agriculture and Food, Yanco Agricultural Institute, Yanco, NSW 2703,
4 Central West Farming Systems, 1 Fifield Rd Condobolin, NSW 2877,
5 CSIRO Agriculture and Food, Centre for Environment and Life Sciences, PMB 5, Wembley, WA 6913
Optimising row spacing is a key target to better manage limited soil water, weeds and optimise radiation interception to increase biomass and yield in rainfed systems. Studies to date indicate little opportunity with current wheat varieties to exploit genetic improvement when targeting variable wheat populations and genotype × row spacing interaction. The exploiting of novel genetics offers potential to develop synergies with specific farming systems not routinely selected for in commercial breeding programs. Early vigour genes bred into wheat through novel recurrent selection methods show promise of more rapid leaf area development, a trait by which crop water-use and water productivity may be improved in wide row situations. Narrower row spacings were associated with significantly greater light interception, grain yield (3.6 vs 2.9 t/ha) and total biomass (10 vs 7.7 t/ha). Commercial bread and durum wheats, and triticales intercepted significantly less radiation than high vigour-selected wheats under wide row spacing. Comparisons between low- and high vigour selected lines indicated a small increase in yield with greater vigour in wider rows. Identification of high-yielding lines with greater early vigour indicate potential to select wheats with adaptation to wider row spacing.