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RAPD based genetic diversity among different isolates of Fusarium oxysporum f. sp. lycopersici and their comparative biocontrol

Mishra, K. K., Kumar, Ashish, Pandey, K. K.
World journal of microbiology & biotechnology 2010 v.26 no.6 pp. 1079-1085
Aspergillus, Fusarium oxysporum f. sp. lycopersici, Fusarium wilt, Solanum lycopersicum, Trichoderma, antagonists, biological control, biological control agents, chemical control, culture filtrates, disease control, genetic variation, in vitro studies, niches, pathogens, random amplified polymorphic DNA technique, tomatoes, India
Fusarium wilt of tomato (Solanum lycopersicum Mill.) caused by Fusarium oxysporum f. sp. lycopersici (Sacc.) W. C. Snyder and H. N. Hans (Fol.), is most serious and versatile pathogen. Chemical control of disease is not satisfactory and biological control is an attractive and potential alternative to the use of chemicals to control fusarium wilt of tomato. No any bioagent is universally effective everywhere therefore, search for potential biocontrol agent is continuous process and mandatory for several and individual ecological niches. In this experiment biocontrol efficacy of five species of Aspergillus and five species of Trichoderma were evaluated in vitro against Fusarium oxysporum f. sp. lycopersici. In both the experiments (dual culture and culture filtrates) T. harzianum was found to be highly effective against the isolates of Fol. followed by A. niger biocontrol potential of A. terreus is least among all the isolates tested. Culture filtrates obtained from A. luchuensis exerted least inhibition of Fol. The most sensitive isolate of Fol. against all the antagonists tested was identified as IIVR-2 (Fol. 9). Inherent diversity among Fol. isolates, from different tomato growing regions in India, was determined using RAPD primers. The genetic similarity coefficients ranged from 0.20 to 0.96, indicating that no any two or more isolates were 100% similar. RAPD profiles revealed up to 20% genetic diversity among ten isolates of Fusarium oxysporum f. sp. lycopersici.