ASCOCHYTA بررسي ارتباط ميان فعاليت آنزيم پلي گالاكتوروناز و شدت بيماري زايي جدايه هاي ايراني قارچ

A total of forty-three isolates of Ascochyta rabiei obtained from infected seeds and plants of chickpea from different areas of Kermanshah, Lorestan, Hamadan, Kordestan, and East and West Azarbaijan provinces were studied during the period 1996-1999. A rapid and simple method was developed for pathogenicity test in CDA (chickpea seed meal dextrose agar) medium. CDA medium was inoculated with different isolates and incubated at 21±1 °C for 9 days. The disease severity was scored as 0- 100% at 24-hour intervals up to five days. Virulence forms were designated according to spectrum of disease reactions of each isolate. Thirteen isolates (IK04, IK08, IK10, IK13, IK14, IK17, IK19, IK21, IL01, IL10, IO00, IE04, IE06) were distinguished as highly virulent (HV) and 7 isolates (IK03, IK06, IK 15, IE01, IE08, IL04, IL06) as weakly virulent (WV). Polygalacturonase activity of these isolates from 6 days old inoculated PZ (pectin zymogram) medium were assayed. Comparison of the results of pathogenicity test and PG activity of 43 isolates demonstrated that HV isolates show predominant enzyme activity while the WV isolates show enzyme activity.