iarjalsIARJALSIARJALS2708-5104https://doi.org/10.47310/iarjals.2020.v01i02.018Evaluation of Pathogenic Variability of Bipolaris Sorokiniana at Different Growth Stages Causing Leaf Blight of WheatA. Z. M.SalehuddinF. H.TumpaA.SultanaS.ChakrabortyM. A. R.KhokonMS Student, Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh-2202Assistant Professor, Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh-2202, BangladeshPhD Student, Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh-2202Research Assistant, Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh-2202Professor, Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh-2202, BangladeshInvestigation was conducted to examine the pathogenic variability of the isolates of Bipolaris sorokiniana at three growth stages viz. seedling stage, tillering stage and heading stage of two wheat varieties (BARI Gom 26 and Kanchan). Based on the morphological variation of seven isolates of B. sorokiniana, BdBSLtan 6 was the most potent considering the maximum mycelial growth (5.40 cm), and the highest conidia production capacity (13.3×106 conidia/mL). At each growth stage, three selected isolates (BdBSL_tan, BdBSL_mym and BdBSL_jam) were inoculated and BdBSL_tan 6 showed the most potential to cause higher infection (100%) in both varieties followed by BdBSL_mym 2. Tillering stage was most vulnerable showing the highest incidence and severity which was followed by heading stage. It canconclusively suggest that both the Bangladeshi isolates (BdBSL_tan and BdBSL_mym) are morphologically distinct and can be aggressive to cause infection in wheat plant at tillering stage and heading stage.