Vol. 11, Issue 1 (2022)

Author(s):
Sunaina Varma, Data Ram Kumhar and Priyanka

Abstract:
Blight of cumin caused by Alternaria burnsii (Uppal, Patel and Kamat) is one of the more severe yield destabilizing factors causing serious yield losses each year. In recent years, blight of cumin is becoming more prevalent in agricultural areas where growing crop is predisposed to cloudy weather and severe rain due to changing climate. An experiment was conducted in which, a series of fungal isolation, purification, identification and pathogenicity test from the infected plant parts were done. Infected plant parts with typical disease symptoms were collected from ARS and Institutional Farm, Collage of Agriculture, SKRAU, Bikaner. These infected plant samples were brought to the laboratory for microscopic examinations and for further investigations. For the identification of fungus, koch’s postulates were proven. Isolation was made from infected plant parts. The culture of A. burnsii was purified by hyphal tip culture method. The identification of the test pathogen was confirmed by cultural characteristics as well as shape of conidia and conidiophores. The pathogen Alternaria burnsii causing cumin blight was isolated from the diseased plant, purified on PDA and pathogenicity was proven under screen house condition. Disease appeared after the flowering stage of the plant when leaf tip became necrotic and purple or brownish in colour and ultimately black. All the above ground plant parts were severely affected as there was no seed formation and if formed they were shrivelled and non- viable. On re-isolation it was found that the fungus was identical to the original isolate. It was observed that the infection was much higher in inoculated plants as compared to control.