Trends in Biosciences

Indian mustard (B. juncea) is a crop of tropical as well as temperate zone, which is grown during rabi. Alternaria blight disease caused by A. brassicae (Berk.) Sacc. is one of the most important diseases of Indian mustard. Eight isolates of A. brassicae were collected from different locations of Uttar Pradesh for studied the cultural and morphological variation. All the isolates showed high level of variability in vitro in respect of radial growth, conidial length, width and number of septa. Radial growth varied from 76.60 to 90.00 mm and 62.37–88.57 mm at 25°C and 100% RH respectively. The average conidial length ranged from 104.48 to 139.25 μm and width from 10.58 to 14.83 μm. Number of transverse and longitudinal septa ranged from 6.25 to 9.75 and 1.00 to 2.50 respectively. Colony colour, appearance, margin and zonation were also noted on PDA medium.