Plant Pathology Science

Introduction: The Hoplolaimidae family is one of the largest and economically most important families of the order/ infraorder Tylenchida / Tylenchomorpha. The members of this family spread all over the world and can be found under different climatic conditions. Some species in this family are serious plant parasites and significantly reduce crop yields. Materials and Methods: In the forests of Khorramabad city in western Iran 70 samples were collected from the soil around the roots of hawthorn trees in the period of 2017-2019. After recording the properties of each sample, they were transferred to a laboratory and cooled at 4 °C. The nematodes were extracted from the soil using the tray method, then fixed and transferred to pure glycerin, and permanent slides were made. The morphological and morphometric properties of the nematodes were examined using a light microscope equipped with a Dino Capture camera. The nematode species were identified using scientific identification keys. Results: Five species of plant parasitic nematodes belonging to two genera of Hoplolaimidae were identified in this study, including Rotylenchus goodeyi, Helicotylenchus canadensis, H. digonicus, H. vulgaris and H. tunisiensis. Conclusion: R. goodeyi is reporting as a new record for the nematode fauna of Iran. Morphometrical and morphological characteristics of these nemadodes are described here.

Introduction: Chickpea blight, caused by Didymella rabiei, is the most limiting factor in chickpea production areas in the world, including the western provinces of Iran. The aim of this study was to investigate the pathogenic diversity of the isolates collected from western provinces of Iran (Ilam, Lorestan and Kermanshah) on differential lines of chickpea, as well as the relationship between pathogenic diversity of the isolates and their geographical origins. Materials and Methods: During the 2017-18 chickpea growing season, samples of infected plants were collected from fields in western provinces and transferred to the laboratory. Then 100 pure isolates of D. rabiei were obtained. Based on the location of collection, the isolates were divided into 20 groups. Based on the morphological characteristics, one isolate from each group was selected as a representative for greenhouse experiments. The pathogenic diversity of theses 20 isolates was assessed on eight differential lines of chickpea. The factorial experiments were performed in a completely randomized block design under greenhouse conditions. Results: The results of analysis of variance showed that there was a significant difference between differential lines and isolates at a probability level of p<0.01. Based on the response of the differential lines, the pathogenic isolates were grouped into three pathogenic groups, including pathogenic group 1 (weakly aggressive), group 2 (aggressive or moderately aggressive), and group 3 (highly aggressive). The isolates from Kermanshah and Lorestan Province were classified into Group 1 and the Ilam isolates into Groups 1, 2 and 3. The greatest severity of the disease was found in three isolates of Ilam province. The variety ILC3996 showed the highest resistance to all isolates. Conclusion: D. rabiei isolates from three western provinces of Iran are divided into three pathogenic groups: 1 (low aggressive), 2 (moderately aggressive), and 3 (highly aggressive). Highly aggressive isolates identified in Ilam province can be used in chickpea breeding programs to produce resistant cultivars to the disease.. The wild variety ILC3996 has resistant genes against these pathogenic groups and showed resistance to all of these isolates.

Introduction: Canola is one of the most important oilseeds in the world. Fusarium species can causes of canola root and crown rot. Material and Methods: In order to identify Fusarium species associated with rapeseed, some samples of the roots and crown of infected and suspicious plants were taken from rapeseed fields in the counties of Lorestan Province during the 2018 growing season. The samples were transferred to the laboratory and pathogenic fungi isolated and purified using specific and public media and then identified with valid keys. Results: A total of 88 isolates were obtained from the collected samples, which due to the morphological characteristics as F. acuminatum, F. culmorum, F. diversisporum, F. oxysporum, F. sambucinum, and F. solani. F. culmorum with 21 isolates (23.86%) and F. solani with 7 isolates (7.95%) had the highest and lowest frequency percentage, respectively. Conclusion: Canola is reported for the first time as a new host for F. diversisporum and F. sambucinum in Iran.

Introduction: Two soil-borne fungi, Fusarium oxysporum and F. solani, are the causes of important diseases of beans wilting and root rot. The best way to manage these diseases is to identify and cultivate resistant cultivars. This study was conducted to identify the reaction of nine Iranian beans cultivars to these two pathogenic fungi. Materials and Methods: Bean-diseased plants were collected from farms in Aligudarz city in Lorestan province, in western Iran, and F. oxysporum and F. solani were isolated from them in the laboratory. At first the pathogenesis of these fungi was investigated on a local cultivar. Then, the reaction of nine bean cultivars to them was determined in a completely randomized design experiment in the greenhouse. Results: Reaction of cultivars to F. oxysporum and F. solani respectively were, Dadfar red-bean with disease severity of 28.8 and 26.6%, Sayad red-bean  with 33.3 and 28.8%, Koosha pinto-bean  with 35.5 and 33.3%, White 247 with 40 and 37.8%, Pak white-bean with 46.6 and 46.7% and pinto-bean 492 with 48.8 and 46.7% respectively, were grouped as semi-sensitive. Saleh pinto-bean with a disease severity of 64.4 and 62.2%, Yaghot red-bean  with 77.7 and 80% and Almas white with 82.2 and 86.7% respectively, were determined as sensitive. Pearson correlation analysis also showed that there was a significant negative correlation between root length, fresh and dry weight of root with diseases severity. Conclusion: Six cultivars of Iranian beans vs Dadfar, Sayad, Koosha, White247, Pak and 492 are semi-sensitive to these diseases.