This research made efforts to predict yield in wheat cultivars differing in maturity and planting date, and resistance to stem rust over four seasons. The highest yield ranking was detected for the earliest planting date (October) with yield improved by 184.55% compared to the latest date (January). Planting wheat cultivars at the optimum date (November) increased yield ranking by 153.09% when compared with very late plantings. Early onset of stem rust in wheat cultivars planted at different dates increased maximum disease severity by 62%. Early disease onset improved yield ranking by 27% in comparison with late-onset. The first principal factor was defined as stem rust progress associated with weather. The second principal factor defined stem rust, planting date, and yield. The third principal factor defined resistance to stem rust. The fourth factor contributed to exponential parameters b and r. Factor analysis outcomes simplified the selection of predictors for the model according to predictive values of the crop, stem rust, and weather descriptors tested at field plot scale during four seasons. The model justified 96% of variations in wheat yield. Higher yield corresponded with earlier planting date and stem rust onset, fewer rainy days in spring months, warmer spring, and greater wheat resistance index when interacting with a greater area under the stem rust progress curve.
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