In order to identify thylenchs species (Superfamily Tylenchoidea and suborder Aphelenchina) in Kerman province, 150 soil and root samples were collected from Kerman province during 2004 and 2005. The samples were washed and the NEMATODES extracted by centrifugal floatation technique. They were then fixed and transfered to glycerin according to the De Grisse method (1969). The permanent microscopic slides were prepared from the extracted NEMATODES. Morphological and morphometrical characters of the species were studied by light microscopy. As a resalt, 21 species belonging to several genera Tylenchoidea, three species of Aphelenchides and one species of Stictylus were identified. Among them, Cephalenchus lobus Dhanachand & Jairajpuri, 1980, Coslenchus areolatus (Egunjobi, 1967) Siddiqi, 1978 and Rotylenchus eximius Siddiqi, 1964 are new records for Iran.

Plant parasitic NEMATODES are amongst the most economically important groups of pathogens. The use of resistant cultivar, crop rotation, chemical control, antagonistic organisms and biocontrol agents are the principal methods for management of the NEMATODES. Natural nematode resistance genes present in gene pools of crop species and their relatives have been used with the aim of transferring such traits into economically important plants where effective resistance is lacking. Biotechnology contributes to this process via marker-assisted selection to identify the best nematode resistance genes, and increasingly in providing new knowledge of target genes, and the potential to exploit this knowledge using transgenic technology. Thus recent advances make it possible to exploit specific aspects of nematode-host plant interactions to design control strategies that include enabling plants to prevent nematode invasion, migration through tissues and reducing feeding ability or nematode fecundity. Application of RNAi, new biotechnology-based chemical nematicides and some other methods are amongst the modern strategies of control. New traits would be added to existing crop genotypes with the best conventional or natural nematode resistance to increase the effectiveness and durability of the nematode resistance trait. Biotech trait expression could also be limited to roots to minimize expression in harvested parts.

The abundance ofNEMATODES in different ecosystems makes thema most desirable agentfor monitoringenvironmental pollution. They are, indeed, considered as the most promising candidates for bioindication of soil disturbances such as heavy metals pollution in the soil. Studies ofthe effects of such heavy metals as lead, cadmium, chromium, copper, nickel, zinc, and selenium on different nematode generain different trophic groups usingdiversityanalysis and nematode assemblage indices have shownconsiderable changes in the populations of certain genera of NEMATODESwith increasing concentration of each specificmetal. Despite theunique characteristics of NEMATODESinmonitoring soil pollution, it is difficult to generalize the effects of toxic metal pollutants on nematode assemblages in soil asthe outcome of such analyseslargely vary with ecosystem, spatial scale, andsuchlocal characteristics as pH, vegetative cover, and the composition of indigenous nematode fauna present in the soil. In the evaluation of nematode community indices, it is, therefore, preferable toremove the genera that lead to ambiguity in predictions and to restrictthe indices only to those belonging to known genera with already establishedsensitivity or response to specific types of disturbance. Thus, population index analyses will not only yield better predictions but will also be more cost-effective. Examples of practical and commercial applications ofnematode assemblage analysis in other countries formonitoring chemical pollution in aquatic habitats are available that can be usefully exploited toward applied researchto overcome the present limitations in using NEMATODES formonitoring soil heavy metal pollution in Iran.

During 2000-2002 a study on NEMATODES of 665 fish specimens from Khouzestan province were carried out by set net and electro fishing. Fishes were collected from 3 stations in Hoor- Al- Azim, Hoor- shadegan and Karoon river.There were Aspius vorax (44 specimens), Barbus grypus (75 specimens), B. luteus (175 specimens), B. sharpeyi (94 specimens), B. pectoralis (8 specimens), B. esocinus (9 specimens), Liza abu (130 specimens), Cyprinion macrostomum (14 specimens), Cyprinus carpio (44 specimens) and Silurus triostegus (22 specimens). From 665 fishes 21% were infected by different parasitic worms collected parasites: Rhabdochona denudata, Rh. fortunatowi, Rhabdochona sp., Proleptinae gen. Cucullanus sp., Pseudocapillaria tomentosa, Philometra karunensis, Philometra sp., Anisakis sp.,Contracaecum sp. Rhabdochona fortunatowi is the first report in, B. pectoralis, B. luteus, B. grypus, S. triostegus and Cyprinion macrostomum of Khouzestan province area.

Introduction: NEMATODES are an abundant and very diverse group among the living organisms of soils. They are few information about them as animals which can live in all habitats including fresh waters, marines, soil of farms, gardens, forests and pastures. In addition to plant parasitic NEMATODES, which have parasitic relationship with different plants in agricultural soils, NEMATODES belonging to other trophic groups also have indirect impacts on the growth of plants in the agroecosystems and nature. They are used as biological indicators of soil health. The knowledge on their abundance, presence or absence of different groups of NEMATODES in the soils are considered important in various biological sciences. Materials and Methods: In order to study the diversity of dorylaimid NEMATODES in Arasbaran forests, 65 soil samples were collected during 2015-2016 from different plant rhizosphere. The soil samples were transferred to the Nematology laboratory-University of Tabriz and kept at four degree centigrade until extraction time. They processed and the NEMATODES extracted, killed, fixed and transferred to anhydrous glycerin using common nematology methods. After preparing permanent microscopic slides, their morphometric and morphological characteristics were studied under optical microscope and identification was done using related valid literature. The morphometric data of nematode and microscopic images prepared using Motik optical microscope connected to scaled lens and future wine camera, respectively. All figures were prepared by Corel draw® 12 software. Results and Discussion: As a result 20 dorylaim species (Crassolabium saccatum, C. himalum, C. ettersbargense, Syncheilaxonchium nairi, Paravulvus hartingii, Eudorylaimus spaulli, Epidorylaimus lugdunensis, Nygolaimus brachyuris, Paraxonchium carmenae, Metaxonchium persicum, Aulolaimus oxycephalus, A. nanocephalus, Discolaimus mariae, Longidorella soadi, Sectonema demani, Xiphinema macroacanthum, X. vuittenezi, X. uthahense, Longidorus africanus, Tylencholaimus constricus, T. tahatikus, Xiphinemella globilabiata, Enchodelus macrodorus which are belonging to 16 genera and ten different families. The family Qudsianematidae had more number of genera (five) and two genera, Crassolabium (three species) and Xiphinema (three species) were found having the most number of species compared to the other genera. Six species namely Discolaimus mariae, Crassolabium saccatum, C. himalum, C. ettersbargense, Xiphinema uthahense and Tylencholaimus tahatikus that are new records for Iran nematode fauna described here in. D. mariae has been reported for the first time around the roots of olive trees in Spain by Pen-santiago. In this study, the nematode was collected and identified in Arasbaran forests-Shirin Bolagh. Comparing the present population of D. mariae with its main description there were not much differences. The only difference was in the c index (80-95 vs. 88-73). The closest species to C. saccatum is C. circuliferum which distinguished from that by non-sclerotized vulval region in C. saccatum. C. diversum as another related species to C. saccatum is characterized by a complete offset head (vs. relatively offset head) and posterior position of vulva (V= 52. 9-57 vs. V = 49-50). This population of C. ettersbargense can be compared to the morphometric characteristics of previous reports that has shorter body length (0. 5-0. 6 mm vs. 0. 6-1 mm). In members of Crassolabium having equal to less than one millimeter body length is characteristic of C. ettersbergense, C. medianum, C. pumilum, C. goaens and C. pumilum. C. medianum species has bubble-like organs in the tail (vs. absence of them in C. ettersbergense). C. pumilum has no pars refringense, and the expanded part of the esophagus is one third of length of the esophagus (vs. absencs pars refringense in C. ettersbergense, and the above ratio is 50-60% of the esophagus). C. goaens distinguished from C. ettersbergense with longer Odontostyle (15-17 vs. 11-12 μ m). The head in C. parvulum, is different in comparing C. ettersbergense (continues vs. offset). Crassolabium himalum comparing the main description has slightly longer tail (25-27 vs. 21-24 μ m. C. himalum is comparable for morphological traits with C. neohimalum and C. porosum. The C. neohimalum is characterized by a shorter body length (1. 07-1. 35 mm vs. 1. 32 to 1. 47 mm) and the asymmetrical lips (vs. symmetrical). The C. himalum is also distinguished from C. porosum by having offset head-(vs. countinouse) and a relatively tall tail (25-27 μ m vs. 21). Xiphinema uthahense is member of Xiphinema americanum-group and compared to the main description and previous reports, there was no significant difference between the morphological traits and the morphology. The species X. taylori, due to the lower coefficient b (5. 6-7. 5 vs. 8-8. 5), has a lower coefficient (39. 3-51 vs. 61-66. 5) and the coefficient c 'less (0. 75-1 vs. 1. 2-1. 7) can be distinguished from X. utahense species. X. pacificum is relatively longer (5. 8-7. 8 vs. 8-8. 5). Tylencholaimus tahatikus in morphological characteristics has similarity to T. mongolicus and T. innebus. Compared to T. mongolicus it has a longer odontostyle (10. 6-15 μ m vs. 7-6 μ m), longer tail (19-22 μ m vs. 8-14 μ m), greater c (44-50 vs. 24-30) and c 'is less (0. 7-0. 9 vs 1-1. 2). In T. innebus, V is greater (V =62-64 vs. V= 53-57) and shorter body length (0. 54-0. 68 mm vs. 0. 90-0. 95 mm).

In order to identify the biodiversity of plant parasitic NEMATODES in vegetable fields of Tabriz, during 2004-2005, 88 soil and a few root samples were collected from rhizosphere of 25 dominantly cultivated vegetable crops. NEMATODES were extracted by combined sieving and centrifugal–flotation method and processed to be transferred to glycerin. After preparing microscopic slides, the morphological and morphometrical features of the NEMATODES were studied using the light microscope equipped with a drawing tube. The morphological features and measerments of the extracted NEMATODES were compared with those ones given in literature and similarities and differences with original descriptions and closest species were discussed. As a result, 25 species belonging to 16 genera including Amplimerlinius globigerus, Aphelenchus avenae, Aphelenchoides bicaudatus, A. haguei, A. richardsoni, Boleodorus thylactus, Criconema mutabile, Criconemoides informis, C. mongolensis, Ditylenchus medicaginis, Filenchus vulgaris, Geocenamus brevidens, G. rugosus, Helicotylenchus digonicus, H. exallus, H. pseudorobustus, H. vulgaris, Heterodera cruciferae, Mesocriconema antipolitanum, M. curvatum, Paratylenchus mexicanus, Pratylenchus alleni, P. neglectus, Psilenchus hilarulus and Zygotylenchus guevarai were identified. Most of the NEMATODES are already recoded from Iran and herein, three species namely, Aphelenchoides haguei, Aphelenchoides richardsoni and Pratylenchus alleni and one newly reported species (Helicotylenchus exallus) are described.