Effect of limited irrigation on growth and yield of a semi-dwarf wheat in southern New South Wales

Abstract

The semi-dwarf wheat cv. Egret, was subjected to moisture stress at specific growth stages in a field experiment in the Murmmbidgee Irrigation Area of New South Wales. The 6 treatments ranged from natural rainfall (129 mm of effective rainfall) to flood irrigations in the spring. Moisture stress during spike emergence and anthesis reduced yield from 7.0 to 3.3 t/ha through reductions in spikesJm2 (37%), individual grain weight (15%) and grain number per spike (13%). Stress during grain filling reduced yield by 20% mainly through a 16% reduction in individual grain weight. Irrigation treatment also significantly influenced dry matter production, plant height, leaf area, duration of grain filling and grain protein. Where irrigation water supply is limited, the best strategy would be avoidance of moisture stress during tillering through to spike emergence. An effective rooting depth of 70-80 cm was extended to >110 cm under severe moisture stress during grain filling, but at the expense of considerable yield.