Effects of wheat cultivar mixtures on stripe rust: A meta-analysis on field trials

Using cultivar mixture with different resistance backgrounds is increasingly used to control wheat stripe rust. The effect size of cultivar mixtures on stripe rust from published results was analyzed using meta-analysis. One hundred sixty-one cultivar mixtures in eleven reference studies were analyzed using the random effect model and the fixed effect model. Furthermore, information on cultivar mixtures and wheat growing conditions were used as independent variables to analyze the influence of these variables on mixing effect on wheat stripe rust in a series of meta-regressions. Results showed that the effect size of cultivar mixtures on wheat stripe rust ranged from 22.5% to 33.4% with an average of 28.0%. The effect of cultivar mixtures was significantly affected by mixture components' disease diversity, wheat sowing rate and disease pressure (P < 0.05). Higher component disease diversity had a lower estimate of effect size. Cultivar mixtures on disease reduction showed a better effect when disease occurred intensively and with moderate sowing rate of wheat.