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Received: 05/07/2018 Revised: 24/08/2018 Accepted: 02/09/2018 Online First: 07/09/2018
Abstract
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 pm) was obtained from fields of Badin while, minimum size of microsclerotia (83.0 pm) 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
Introduction
Macrophomina phaseolina (Tassi) Goid. which is dominant fungal pathogen of sunflower and is polyphagous causing disease to many other crop species. Importance ofM. phaseolina rot is increasing with time because of attack on root, stem and fruit of more than 500 plant species worldwide, especially in regions where temperature is high [1, 2]. Up to 90% losses due to this fungus are reported in sunflower under favorable conditions for infection [3]. The fungus belongs to Phylum: Ascomycota, class: Botryosphaeriales, order: Botryosphaeriales and family: Botryosphaeriaceae. M. phaseolina isolates are differing in various morphological and other aspects like mycelium colour, microsclerotia distribution, pycnidia formation and chlorate phenotypes [4]. Iqbal and Mukhtar [5] reported 65 isolates of M. phaseolina from Punjab and Khyber Pakhtunkhwa (KPK) provinces of Pakistan which are varying in morphological characteristics and pathogenic nature to infect mungbeen crop. Ashraf et al. [6] conducted such study in Punjab province to differentiate morphologically and virulent potential...