The study was conducted in the Department of Plant pathology, Faculty of Agricultural Sciences and Technology, Bahauddin Zakariya University, Multan, Pakistan during the year 2012-2015. Stepwise regression model was developed for the devastating pathosystem; bacterial leaf blight of rice caused by Xanthomonas oryzae pv. Oryzae. Three highly susceptible rice cultivars (Basmati Super, IRRI-24 and TN-1) were tested based on the seasonal dataset of disease severity and environmental variables. As the climatic conditions greatly influence the disease developments so datasets for the environmental parameters i.e. maximum and minimum daily temperature of air, relative humidity of morning and evening, rainfall, wind speed and daily sunshine hours were collected and analyzed by correlation for stepwise linear regression model. Stepwise regression analysis was performed to indicate potentially useful predictor variables and to rule out the incompetent parameters. Step wise regression analysis proved that the wind speed and relative humidity in the morning was the most significant (P >0.0001) influential environmental variable for the development of disease. The performance of this model was calculated based on the coefficient of determination (r2) and showed 97 percent variability in disease development.

Oryza sativa L., Epidemiology, Regression, Correlation, Environmental variables, BLB, Pakistan