National Symposium on Strategic Issues in Plant Pathological Research held at Department of Plant Pathology, CSK HP Krishi Vishvavidayalaya, Palampur on November 24–25, 2011
Bipolaris sorokiniana (Sacc.) Sheom. is an important pathogen of wheat and causes economic losses particularly under rice-wheat rotation cropping system. The pathogen has been found to show variable disease response to different wheat varieties. Thirteen isolates (BS-1 to BS-13) of the fungus were collected from different agroclimatic zones of India (NWPZ-Pant Nagar, Karnal, Hisar and Ludhiana; NEPZ-Faizabad, Dharwad, Coochbehar and Samastipur; CZ-Pune and Vijapur and NHZ-Almora) and pathological variability among them was studied on five wheat genotypes viz. Sonalika, GW322, HD2733, PBW-34 (d) and HPW184 used as differential under polyhouse conditions. Four different parameters viz. infection response, number of lesions on flag-2 leaf, necrotic area development and terminal disease severity (0–9 scale on flag and flag-1 leaf) were used to assess the pathological variability of isolates. Differential infection response was varied on wheat genotypes. Sonalika showed moderately susceptible to susceptible reaction for all isolates and per leaf lesion number ranged 2–9. HPW184 showed resistant to moderately resistant reaction to all isolates, whereas, varieties GW322, HD2733 and PBW-34 (d) showed mixed response. The isolate BS-2 produced maximum number of lesions which ranged between 2.6 to 9.0 per leaf. The maximum average necrotic area of 3.9 mm2 was observed in BS-2 and BS-4. The isolate BS-2 was found to be more virulent as compared to the other isolates and exhibited highest terminal disease severity score in the range of 14 to 68 on five different wheat genotypes.
