m. damadzadeh

In order to identify the plant-parasitic nematodes of important cereals (wheat, barley, and corn) in Isfahan Province, 120 soil and root samples were collected from the rhizosphere of these crops in various locations in the region during 1999 and 2000. Nematodes were extracted from soil by sieving and centrifugal sugar-flotation method. The specimens were killed and fixed in FGA (formaldehyde, glycerin and acetic acid 4:1:1) hot solution. The extracted nematodes were mounted in glycerin, permanent slides prepared, and studied by light microscope. The results revealed the presence of three species belonging to two genera of family criconematidae as follows: Criconemella antipolitana , C. xenoplax, Hemicycliophora poranga. H. poranga was extracted from rhizosphere of corn and reported for the first time from Iran. The most frequently occurring and dominant species was C. antipolitana that was isolated from soil around the roots of wheat and barley in several areas. C. xenoplax was extracted from a wheat field with the history of peach cultivation. These species are new records for Isfahan Province.

In this study 58 isolates of Fusarium moniliforme which causes rice foot rot disease were collected from infected rice seeds. The morphological characteristics and pathogenicity of these isolates were determined in laboratory and greenhouse in the International Rice Research Institute (IRRI). Besides, by RAPD(Random Amplified Polymorphic DNA) technique using primer J-11 from operon kit by sequences of "5-ACTCCTGCGA-3" the randomized portion of the DNA of each isolate was amplified. Using cluster analysis at 25% similarities, the isolates were classified as follows: from point of the growth rate of fungi after 4 days in Petri dishes into 8 groups from point of the number of days that fungi reached to the 90 mm diameter in one group from point of the effect of isolates on the length of seedlings into 5 groups from point of the genetical pattern into 13 groups. The characteristics measured in the laboratory or greehouse for each isolate did not significantly differ with the mean of each group using t-test analysis. Therefore, it could be concluded that molecular markers by RAPD technique can be used in differentiation of morpological and pathogenicity of Fusarium moniliforme isolates. The positive significant correlation coefficient (r=0.54) was observed between the growth rate of fungi in petri dishes and its effect on the length of seedling.