Occurrence and expansion of wheat stripe rust under mixed-cultivar planting

Six mono-cultivar planting treatments and nine mixed-cultivar planting treatments were designed to study the occurrence and expansion of wheat stripe rust (Puccinia striiformis f. sp. tritici) and control effect of mixed-cultivar planting. The results indicate that the number of foci at seedling stage obviously reduces under mixed-cultivar planting compared with mono-cultivar planting. Over-wintering rate of foci is 77.78% and a few single diseased leaves survive after winter. The spreading distance of stripe rust is shorten on mixed-cultivar plots. Stripe rust shows a trait of central distribution in different plots. Relative efficacy of mixed-cultivar planting at booting stage ranges from 16.25% to 58.89%, with a mean value of 35.31%. “Shaan 138” and “Xinong 979” mixed-planting, and “Shaan 138”, “Xiaoyan 22” and “Xinong 889” mixed-planting show the highest relative efficacy, which is 58.89% and 52.19% respectively. Mixed-cultivar planting has a higher control effect on wheat stripe rust than mono-cultivar planting. Mixed-cultivar planting can thus be used as a good ecological measure in disease prevention and control.