Characterization of Ascochyta rabiei and Evaluation of Chickpea Germplasm Against Ascochyta Blight

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Date
2021-12
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Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu
Abstract
The present investigation entitled “Characterization of Ascochyta rabieiand evaluation of chickpea germplasm against Ascochyta blight” was undertaken to study the status, epidemiology, cultural and morphological characterization of pathogen and evaluation of chickpea germplasms against blight disease. Extensive survey of chickpea fields conducted during 2020-21 Rabi season, revealed that disease was prevalent in all the surveyed locations of Samba district of Jammu province. The disease severity was ranged from 19.86 to 43.89 per cent with overall mean of 31.49 per cent. The maximum disease severity (38.88%) was recorded in Samba tehsil and minimum disease severity (25.53%) in Ramgarh tehsil. Epidemiological studies of disease revealed that weather factors played a vital role in disease development as maximum and minimum temperature showed significant positive correlation whereasmorning and evening relative humidity showed significant but negative correlation and rainfall showed positive but non-significant correlation with Ascochyta blight disease severity. The microscopic study of pathogen showed that the mycelium of pathogen was septate, branched, brown in colour and hyphae width was measured 3.2-4.5 µm. The conidia of pathogen were hyaline, unicellular, oval to cylindrical, single celled and measured 9.45-13.65 × 3.15-5 µm. The pycnidium was brown, globose to sub-globose with an ostiole. The diameter of pycnidium measured about 183.3 µm with the ostiole width of 37.06 µm. Among six different mediums studied, Chickpea dextrose agar media supported maximum mycelial growth (57.83 mm)whereas, the minimum mycelial growth was recorded on V8 juice agar (23.50 mm). The suitable temperature range for pathogen was 15-25oC with optimal temperature of 20oC at which maximum mycelial growth of pathogen was recorded. Thirtygenotypes of chickpea were screened and none of genotypes werefound free from Ascochyta blight infection under epiphytotic conditions. Among 30 genotypes, 10, 9, 9, and 2 were found resistant, moderately resistant, susceptible and highly susceptible, respectively.
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Preferred for your work Panwar, S.S. 2021. Characterization of Ascochyta rabiei and Evaluation of Chickpea Germplasm Against Ascochyta Blight. M.Sc. thesis, Skuast-Jammu
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