In a spring wheat breeding nursery at the University of Manitoba in 1967, the wheat protein content of systematic control plots of Triticum aestivum cv. Manitou varied from 10.3% to 16.5% (at 13.5% moisture basis). The correlation between grain yield and protein content of these plots was 0.88 and significant at the 99% confidence level. Correlations calculated for control plots at specified distances apart indicate that for all breadmaking quality test characteristics except bushel weight and flour yield, contiguous plots are significantly more similar in quality than those further apart. The correlation between control plots 2.7 m (9 ft) apart is 0.84 (P = 0.05) for wheat protein percent and of similar order for those quality characteristics which are dependent on total protein. Areas of high and low quality "potential" can be identified in a wheat nursery by using quality data from controls at frequent intervals, and this information should be used by the breeder when assessing the single quality test of a breeding line from a given area of the nursery.