Document Type : Research Paper
Authors
1 Sararood Deputy, Dryland Agricultural Research Institute, Agricultural Research Education and Extension Organization (AREEO), Kermanshah, Iran.
2 3- Agricultural and Natural Resource Research and Education Center, Golestan, Agriculture Research, Education and Extension Organization, Gorgan, Iran
3 2- Agricultural and Natural Resource Research and Education Center, Ilam, Agriculture Research, Education and Extension Organization, Ilam, Iran.
Abstract
Introduction: The chickpea (Cicer arietinum L.) is grown in more than 50 countries and the crop is the third most important food legume in the world after beans (Phaseolus vulgaris L.) and peas (Pisum sativum L.) in terms of both cultivated area and total production. Ascochyta blight caused by Ascochyta rabiei is one of the major disease of chickpea worldwide. This study was conducted to investigate the genetic variability and identify the existing pathotype(s)/race(s) of A. rabiei, which will be helpful in improving and breeding resistant varieties of chickpea.
Methodology: Three set of standard differential chickpea genotypes from ICARDA and ICRISAT were used to identify the pathotypes and physiological races of A. rabiei. Three chickpea genotypes were used to determine the pathotypes of A. rabiei and the rest to identify the physiological races according to their aggressiveness and virulence, respectively. Plant samples were cut into small pieces and sterilized with 5% sodium hypochlorite for 3 minutes, rinsed in sterile distilled water, and then placed on filter papers. After that, pieces were placed on each petri dish containing potato dextrose agar media (PDA). All the plates were incubated at 25° C for 5-10 days.The field results were confirmed by growth chamber trial. The mini-dome virulence assay was used to determine pathotypes in the growth chamber under optimum condition.
Research findings: All isolates were classified into three pathotypes based on pathogenicity studies on the differentia varieties. All three pathotypes were found in Kermanshah, pathotypes I and II in Ilam, and pathotype III in Golestan and Kermanshah. Five races of A. rabiei were determined in different parts (races 1, 3, 4, 5 and 6). Races 1, 2 and 3 were established in pathotype I, races 4 and 5 was represented by the pathotype II, and pathotype III included the race 6, which were highly virulent isolates. The genotype ILC 1929 showed susceptible reaction against all the isolates of the pathogen. Race 1 widely prevalent in Ilam and Kermanshah, races 3 and 4 in Ilam, race 4 and 5 in Kermanshah, and the most virulent is race 6 found in Kermanshah and Golestan. The information is entirely new in respect of differential genotypes and distribution pattern of pathotypes and races of A. rabiei in Iran.
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