Studies on pathogenicity and phytotoxicity assays for Bipolaris Sorokiniana on wheat seedlings
Banu, S.P.
Studies on pathogenicity and phytotoxicity assays for Bipolaris Sorokiniana on wheat seedlings - Sydney (Australia) : University of Sydney, 1996 - xvi, 191 pages
Thesis (M. Sc.)
Primary leaves of wheat seedlings from twelve cultivars/lines at two-leaf-stages were treated by inoculation with and by infiltration of toxin from two isolates of Bipolaris sorokiniana. Inoculation was done on primary leaves by conidial suspensions of 105/ml and in roots by pathogen-permeated chaff of the fungus. Phytotoxicity was assessed by infiltration of primary leaves of with serial dilutions of culture filtrates of the fungus. Inoculation of the primary leaf with the fungus caused spot blotch and inoculation of the root caused common root rot of wheat seedlings. Infiltration of the primary leaf caused a toxicological symptom typical of spot blotch of wheat. There was variation in susceptibility to inoculation and sensitivity to infiltration within twelve wheat cultivars/lines, within isolates of the fungus and within cultivars/lines X isolates. This study was done in a growth room. Results presented in this thesis are discussed in relation to the current literature on pathogenicity and phytotoxicity of B. sorokiniana on wheat seedlings. The techniques used for phytotoxicity and pathogenicity in this study would be beneficial for initial screening of germplasm before its incorporation in breeding programs. All cultivars/lines were susceptible to the fungus and were sensitive to toxin. Significant differences among cultivars/lines were obtained. Timgalen was the most susceptible cultivar for common root rot and spot blotch of wheat, and Hartog was found to be a more resistant cultivar than the other cultivars/lines. There was a significant difference between cultivars/lines for sub-crown internode production, which is the main criterion for common root rot assessment. Variation in sensitivity to toxin was found with serial dilutions of culture filtrates in respect of number of seedlings affected and severity of differential symptoms obtained after infiltration. Cultivars Vasco, Kite, ISWYN-32 and Timgalen were more sensitive; and Batavia was less sensitive to toxin than the other cultivars/lines. The isolates were pathogenic and differed in pathogenicity and phytotoxicity. The relationship between common root rot and spot blotch susceptibility was positive. No distinct relationship was detected for sensitivity to toxin and susceptibility to the fungus, but the association between susceptibility and sensitivity seemed to be positive for isolates. Further assessment will require studies with more isolates and using a suitable disease rating scale for seedling stages.
English
Wheat
Bipolaris sorokiniana
Pathogenicity
Phytotoxicity
Seedlings
Studies on pathogenicity and phytotoxicity assays for Bipolaris Sorokiniana on wheat seedlings - Sydney (Australia) : University of Sydney, 1996 - xvi, 191 pages
Thesis (M. Sc.)
Primary leaves of wheat seedlings from twelve cultivars/lines at two-leaf-stages were treated by inoculation with and by infiltration of toxin from two isolates of Bipolaris sorokiniana. Inoculation was done on primary leaves by conidial suspensions of 105/ml and in roots by pathogen-permeated chaff of the fungus. Phytotoxicity was assessed by infiltration of primary leaves of with serial dilutions of culture filtrates of the fungus. Inoculation of the primary leaf with the fungus caused spot blotch and inoculation of the root caused common root rot of wheat seedlings. Infiltration of the primary leaf caused a toxicological symptom typical of spot blotch of wheat. There was variation in susceptibility to inoculation and sensitivity to infiltration within twelve wheat cultivars/lines, within isolates of the fungus and within cultivars/lines X isolates. This study was done in a growth room. Results presented in this thesis are discussed in relation to the current literature on pathogenicity and phytotoxicity of B. sorokiniana on wheat seedlings. The techniques used for phytotoxicity and pathogenicity in this study would be beneficial for initial screening of germplasm before its incorporation in breeding programs. All cultivars/lines were susceptible to the fungus and were sensitive to toxin. Significant differences among cultivars/lines were obtained. Timgalen was the most susceptible cultivar for common root rot and spot blotch of wheat, and Hartog was found to be a more resistant cultivar than the other cultivars/lines. There was a significant difference between cultivars/lines for sub-crown internode production, which is the main criterion for common root rot assessment. Variation in sensitivity to toxin was found with serial dilutions of culture filtrates in respect of number of seedlings affected and severity of differential symptoms obtained after infiltration. Cultivars Vasco, Kite, ISWYN-32 and Timgalen were more sensitive; and Batavia was less sensitive to toxin than the other cultivars/lines. The isolates were pathogenic and differed in pathogenicity and phytotoxicity. The relationship between common root rot and spot blotch susceptibility was positive. No distinct relationship was detected for sensitivity to toxin and susceptibility to the fungus, but the association between susceptibility and sensitivity seemed to be positive for isolates. Further assessment will require studies with more isolates and using a suitable disease rating scale for seedling stages.
English
Wheat
Bipolaris sorokiniana
Pathogenicity
Phytotoxicity
Seedlings