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Morphological and molecular variability of rice blast pathogen pyricularia grisea (cooke) sacc.

KrishiKosh

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Title Morphological and molecular variability of rice blast pathogen pyricularia grisea (cooke) sacc.
 
Creator B.S.Meena
 
Contributor S.K.Prashanthi
 
Subject Plant Pathology
 
Description Rice blast caused by Pyricularia grisea (Cooke) Sacc.) [Magnaportha grisea (Hebert)
Barr)] a filamentous ascomycetes fungus is a major threat to rice production. Twelve blast
infected rice samples were collected from different agro-climatic regions of Karnataka viz.,
Shirguppa, Bheemarayanagudi, Raichur, Sirsi, Mundagod, Shimoga, Mugad, Haveri and
Khanapur.
During survey, the highest per cent disease incidence was noticed in Mugad (66.00%)
and least disease incidence was observed in Khanapur (20.00%).
Cultural and morphological studies on host extract + 2% sucrose agar, oat meal agar,
potato dextrose agar + biotin + thiamine and Richards’s agar revealed considerable variation
among the isolates.
The isolates of Sirsi, Mundagod, Mugad, Khanapur and Neck blast Mugad showed
maximum growth on 10th day after inoculation whereas remaining isolates showed maximum
growth on 12th day after inoculation.
The isolates of Sirsi, Mundagod and Nodal blast Mugad preferred 25°C and
remaining isolates preferred 30°C. The pH 6.5 was found to be best for all the isolates.
The isolates of Neck blast Mugad and Neck blast Sirsi preferred both sucrose and
dextrose carbon sources equally. Dextrose alone was preferred by the isolates of Raichur,
Sirsi, Shimoga and Khanapur whereas remaining isolates preferred sucrose.
The Sirsi isolates preferred urea as nitrogen source whereas the isolates of Shimoga
and Khanapur preferred both asparagine and urea equally. The remaining isolates preferred
asparagine.
Disease reaction on international differentials revealed the prevalence of four groups
viz., IA, IB, IC and IH in rice growing regions of Northern Karnataka.
Isozyme analysis viz., peroxidase and polyphenol oxidase confirmed the existence of
variability in the collected blast isolates. RAPD data distinguished the isolates into two
major clusters A and B, whereas the isolates belonging to same geographical location has not
come in the same cluster, reflecting the fact that the variation was independent of
geographical locations.
 
Date 2016-10-24T18:57:40Z
2016-10-24T18:57:40Z
2006
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/81654
 
Format application/pdf
 
Publisher UAS, Dharwad