Modeling Wheat Yield Based on Brown Rust, Cultivar Resistance, Weather Conditions, Maturity, and Planting Date

Background and Objective: Estimation of wheat yield based on specific brown rust descriptors is little understood. This four-growing-season study attempted to predict yield in brown-rust-affected cultivars of wheat differing in maturity and planting date, and resistance index. Materials and Methods: Experimental plots were prepared to assess specific descriptors of brown rust progress across wheat cultivars and planting dates considered as treatments. A significance level of 5% was considered in the H-test and correlations to examine associations of treatments with disease, maturity, cultivar resistance, and yield. Weather data was also considered in the data analyses. Results: Highest ranking of yield was detected for early plantings in October, with yield being increased by 185% compared to late plantings in early January. Factor analysis accounting for 76% of data variance demonstrated significant associations of brown rust progress variables (first principal factor), wheat yield with environment, maturity and planting date (second principal factor), brown rust progress with resistance index (third principal factor), and environment with brown rust progress (fourth principal factor). Yield model describing 94% data variability revealed that a greater productivity of wheat corresponded with an earlier planting date, a greater resistance index, fewer moist and temperate days in spring, and a longer maturity period. Conclusion: This is the first report on the joint analysis of wheat yield, cultivar resistance, maturity duration, planting date, and weather. This new information helps with predicting future brown rust epidemics and estimating wheat yield in conjunction with breeding efforts for more resistant cultivars.