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Macrophomina phaseolina (Tassi) Goid is economically important fungal pathogen with wide host range. In this study we found morphological and phenotypical variation among isolates of the fungus infecting sunflower crop in Sindh province of Pakistan. Thirty two M. phaseolina isolates were obtained from infected plant samples of sunflower collected from different ten districts viz., Badin, Thatta, Hyderabad, Tando Muhammad Khan, Shaheed Benazirabad, Mirpurkhas, Sanghar, Dadu, Sukkur and Khairpur. Significant variation in characteristics was noticed among collected isolates. They were usually black, blackish-gray, grayish-black and gray in colony color. Generally three growths pattern; dense, feathery and restricted were seem. Among them dense was most common (50.0%) followed by feathery (34.36%) and restricted (15.64%). Maximum colony growth (90.0%) and minimum (65.0%) was recorded after 7 days of inoculation on medium. Feathery growth was generally fast and restricted growth was slow. Maximum average linear colony growth (13 mm) and minimum (9 mm) growth was noted. Isolates showed significantly varied sizes of microsclerotia. Maximum sclerotia size (124.0 µm) was obtained from fields of Badin while, minimum size of microsclerotia (83.0 µm) from sunflower fields of Sukkur. Microsclerotia from dense growth pattern were black and big in size and small microsclerotia from gray growth pattern.
Keywords: Charcoal rot; Isolates and Characterization; Macrophomina phaseolina; Sunflower