بررسي تنوع ژنتيكي در جمعيت قارچ Gibberella intermedia عامل غالب بيماري پوسيدگي طوقه برنج در استان مازندران با استفاده از گروه‌هاي سازگاري رويشي

A Study of the Genetic Diversity of Gibberella intermedia, the Common Causal Agent of Rice Bakanae Disease in Mazandaran Province, Based on Vegetative Compatibility Groups

Thirty-five isolates of Gibberella intermedia (anamorph: Fusarium proliferatum) as the common causal agent of rice bakanae disease were collected from infected rice plant samples in different regions of Mazandaran province during 2004. Genetic diversity of F. proliferatum as the major causal agent of rice bakanae disease in Mazandaran province was investigated. Nitrate non-utilizing (nit) mutants were generated from 35 isolates to study the vegetative compatibility among these isolates. Nit mutants were not obtained from 3 isolates using MMC culture media containing 1, 3 and 5% potassium chlorate. These were discarded as crn isolates. Nit mutants were divided into three phenotypic classes (nit 1, nit 3, and Nit M) based on their growth on the medium containing different nitrogen sources. Nit mutants obtained from three isolates were nit 1, only. These isolates were discarded. Nit mutants were used to force heterokaryon to determine distribution of Vegetative Compatibility Groups (VCGs). The remaining 29 isolates were placed into 26 vegetative compatibility groups (VCGs). Of the 26 VCGs identified, 23 were represented each by a single isolate and the remaining 3 belonged to three multimembers, each containing two isolates, VCGs. It is worth mentioning that all multimember VCGs were placed in a special limited area indicating more similarity of this areaʹs population than those of the other areas. These data suggest that the population of F. proliferatum is genetically diverse which is so expected because of abundant occurrence of sexual reproduction.