Genetic gains in yield have increased by 0.9 per cent per year over the last 30 years. Yield progress has been associated with improved harvest index and grain number, and in very recent cultivars higher biomass too. However, global demand for wheat is predicted to increase by 1.6 per cent per year over the next 20 years hence physiological strategies such as improving radiation use efficiency (RUE), manipulating source-sink balance, and application of rapid early generation selection tools are being considered to accelerate the rate of breeding progress. In the area of RUE, several studies have indicated good associations between yield and leaf photosynthetic rate (An). While An was not always associated with higher RUE, An and related traits such as stomatal conductance (gs) and canopy temperature depression (CTD) have potential application in breeding to screen for physiologically superior genotypes.