Incidence and Geographical Distribution of Loose Smut in Iran Barley Seed Loads

147 seed samples collected from harvested seed loads of irrigated barley fields in foundation and certified categories from major cultivated sites in Iran was used for this study. Isolation and identification of seed-borne fungi were conducted according to standard tests described by the Interinternational Seed Testing Association (ISTA). Embryo test was used for loose smut. Sample seeds were soaked separately NaOH for 22-24 hours, then washed through a set of sieves. Then the seeds for separation and clearing the embryos transferred to lactic acid-glycerol mixture and consequently stained mycelium observed through stereomicroscope. The infection rate indicated the significant differences between evaluated provinces. In the foundation barley seed loads contaminated with U.nuda, the highest infection rate belonged to Qom (1.1%) , in the same group with Isfahan ( 0.6%). West Azarbayejan was free from loose smut. The other provinces were between 0.1 -0.2 %. The level of infection of U. nuda in certified seed categories had recognized 3 different significantly meaning groups among provinces. In Yazd no loose smut disease was observed. Gom, Isfahan and Mazandaran by 1.25, 1.48 and 0.35 % had the highest infection level of U. nuda; and after that hamedan, Golestan and Semnan had more than 0.1 % infection. Less than 0.1% infection is acceptable barley. According to Iran national standard of barley seed the minimum acceptable level for U.nuda is 0.1 and 0.3 % for foundation and certified respectively. For the first time, the incidence and infection level of seed-borne fungi in different barley categories seeds have been determined.