Conference Proceeding

Study of cultural, morphological characteristics and effect of various culture media on growth and sporulation of Alternaria spp, infecting carrot crop

Mr. V. Prasanna Krishna

A. dauci causes leaf blight disease in carrot. The pathogen exhibited profuse growth (90.00mm) on PDA plate. The colony colour was olivaceous green black, irregular to circular shaped colony with smooth margins, flat elevation, thick texture, poor zonation and good to excellent sporulation. Morphological characteristics of A. dauci revealed dark brown muriform conidia of the size 45-70 x 10-22 μm. and the beak measured of 30-120 μm. The conidia possessed about 3-7 horizontal and 1-2 vertical septa and the conidiophores measured about 28-85μm in length and 5.0μm in breadth and a total of 11 solid culture media were tested to assess their effect on cultural characters and sporulation of A. dauci Mean colony diameter recorded on test culture media was ranged from 39.33 mm (V8 juice agar) to 90.00 (PDA) mm. However, it was significantly highest on PDA (90.00 mm), followed by Potato carrot agar (75.67 mm), Oat meal agar (70.67 mm),carrot root agar (62.41 mm), Carrot leaf extract agar (54.00 mm), Richard’s agar (51.67mm) and Czapek’s dox agar (50.67), later two were on par. However, comparatively minimum growth was obtained on Radish root extract agar (45.50mm), Ashby’s agar (44.67mm) which were also at par and V8 juice agar (39.33mm). The colony growth produced on test culture media was mostly circular and with cottony or cushiony to carpet like mycelial mat. Colony colour varied from white, grayish-white, and olivaceous green to black. The test culture media exhibited a wide range of sporulation. However, Oat meal agar and Potato dextrose agar exhibited excellent (++++) sporulation. It was good (+++) on V8 juice agar, Potato carrot agar and Carrot root extract agar; fair (++) on Czapek’s dox agar, Ashby’s agar and Radish root extract agar; whereas, it was poor (+) on Radish leaf extract agar and Richard’s agar.

Published: 08 November 2017


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