مطالعه تاكسونومي و جنبه هايي از اكولوژي PUCCINIA GRAMINIS عامل زنگ سياه روي گندميان در ايران

ON THE TAXONOMY OF PUCCINIA GRAMIMS PERS. AND SOME REMARKS ON THE ECOLOGY OF THE RUST IN IRAN

Puccinia graminis is a macrocyclic heteroecious species with aerial hosts in the Berberidaceae and telial hosts in the Poaceae. As a plant pathogen stern rust, P. graminis, has been known in Iran from 1939. In all scientific papers in Iran stem rust is usually presented in a broad taxonomic sense (P. gmminis s.l.). The main attention in this study was paid to the taxonomy and ecology of P. graminis in Iran. The study was based on dried specimens mostly collected from different parts of Iran during 1991-1999 and specimens preserved in the following herbaria: Herbarium Ministerii Iranici Agriculturae (MAN), Agricultural college of Tehran University (KAR) and Arthur Herbarium, Purdue University (PUR). Spores from dried specimens were mounted mostly in lactophenol and examined with an Olympus BH2 microscope equipped with Nomarski Differential Interference Contrast (DIC) at a magnification of x 400 or x 1000. Specimens were photographed using a PM-10 AD photomicrograph system. Seventy spores per specimen were randomly selected and measured. Specimens were deposited in the Herbarium Ministerii Iranici Agriculturae (IRAN) in Tehran and duplicates were sent to the Arthur Herbarium, Purdue University (PUR). For Scanning Electron Microscopy (SEM) urediniospores were mounted on a specimen stub and coated with gold (3-3.5 minutes at 29 mA). The specimens were observed and photographed using a Leitz AMR/1000 Scanning Electron Microscope. Cluster analysis was done with NTSYS software using SAI-IN clustering. The clustering method used was UPGrMA (unweighted, pair-group method with arithmetic average).Morphological features of 44 specimens of P. graminis were evaluated. As a result three infra-specific taxa were recognized for stem rust of wheat and grasses in Iran. The resulting phenogram confirmed these infra-specific taxa. These taxa are as follows: -P. graminis subsp. graminis var. graminis, on Triticum aestivum and other closely related genera belong to Triticeae. Urediniospores (25)27-43(50) x (12)14-21(24) gm, urediniospore echinulae are finest on pore belt and coarsest near ends, germ pores 4-5(6) rarely 7, equatorial. P. graminis subsp. graminis var. stakmanii, on grasses belong to Triticeae, Bromeae, Poeae and Avenae. Ihediniospores (20)24-35(39) x (13)15-20(22) gm, the echinulae are about half the diameter on the spore equator than they are at the ends, germ pores (3)4-5 equatorial. -P. graminis subsp. graminicola, on Poa spp. Urediniospores 19-29(31) x 13-16 pm, germ pores 2-4 equatorial. All above rust taxa are new to the Iranian rust flora. The results of this study confirmed the validity and value of Urbanʹs infra-specific taxonomy for P. graminis. In this study moreover, life cycle of P. graminis was clarified from field observation. The geographic distribution and host range of this species were also determined. Aegilops rauschii, Avena ludoviciana, Boissiera squarrosa, Bromus sterilis, B. tom entosus, Elymus elongatiformis, E. libanoticus, Eremopyrum distans, Hordeum bulbosum, H. glaucum, Leucopoa sclerophylla, Poa pratensis, P. trivialis and Taeniatherum crinitum are reported as new hosts for P. graminis in Iran.