Abstract: The relationships among grain yield, root size and root: shoot ratio were studied for spring wheat in semi-arid area. Our results demonstrate that the old landrace has higher root biomass and root: shoot ratios than modern varieties at the flowering stage. In the severe drought year of 1995, there was no significant difference in grain yield between the landrace and modern varieties(p>0.05). In 1996, with more normal rainfall, the landrace was the lowest productive variety, irrespective of whether it was irrigated or not. Negative correlations between root weight and yield, and between root weight and above-ground biomass were observed. Root redundancy is suggested since the landrace produced lower yield under conditions of favorable rainfall. Reduction of root system to a reasonable size may be an effective way to improve the yield of spring wheat in semi-arid areas.