Interplot Interference Disorts Yield Estimates in Spring Wheat

Abstract

Research in Europe and the USA indicated that interference between plots in cultivar trials can distort yield and result in misleading conclusions from yield comparisons. Field trials were conducted at Swift Current and Saskatoon in 1993 and 1994 to determine if interplot interference is a concern in the wheat growing region of Saskatchewan. Four spring wheat (Triticum aestivum L.) cultivars, Biggar, Oslo, Genesis, and Glenlea, were grown in four‐row plots in a diallel competition treatment design, with the competition treatments applied randomly to each of the eight replications. Generally, yield was distorted from pure stand yield when flanking plots differed for height. On average, yield was reduced 0.34% per centimeter increase in height of the flanking plots, and the reverse occurred when height of the flanking plots was less. Plots of the short cultivars Biggar or Oslo flanked by the tall cultivars Genesis or Glenlea yielded less than when flanked by themselves, and the reverse occurred when the tall cultivars were flanked by the short cultivars. Interplot interference affected spike density in the same fashion, did not significantly affect height, and was inconsistent with regards to kernel weight. It was concluded that when plots differ for height, yield distortion can occur in the Saskatchewan wheat growing region.