Populations of Thielaviopsis basicola (Berk.et Br.) Ferr. were determined in six tobacco fields in a large 'Virginia Bright' growing area of Umbria (central Italy). The fields, having similar physical-chemical characteristic, had supported tobacco monoculture for many years. The concentration of propagules of T.basicola was quantified at 110 propagules/g soil in fields with only two years, while lower populations were found in fields in which monoculture had been practiced for many years. Moreover, pathogen populations were negatively correlated (r=-0,728, P=0,01) with the number of years in tobacco. Marked differences in susceptibility to T.basicola were observed in ten tobacco cultivars tested by 'chlamydospore test' and in greenhouse trials. Cultivars Bright VB 44, Bright F.B. and Coker 48 were more tolerant to the pathogen in both assays. However differences in the results obtained using the two techniques to evaluated resistance were noted.
Effect of monoculture on soil populations of Thielaviopsis basicola and screening tobacco cultivars for resistance
TOSI, Laura;ZAZZERINI, Antonio
1991
Abstract
Populations of Thielaviopsis basicola (Berk.et Br.) Ferr. were determined in six tobacco fields in a large 'Virginia Bright' growing area of Umbria (central Italy). The fields, having similar physical-chemical characteristic, had supported tobacco monoculture for many years. The concentration of propagules of T.basicola was quantified at 110 propagules/g soil in fields with only two years, while lower populations were found in fields in which monoculture had been practiced for many years. Moreover, pathogen populations were negatively correlated (r=-0,728, P=0,01) with the number of years in tobacco. Marked differences in susceptibility to T.basicola were observed in ten tobacco cultivars tested by 'chlamydospore test' and in greenhouse trials. Cultivars Bright VB 44, Bright F.B. and Coker 48 were more tolerant to the pathogen in both assays. However differences in the results obtained using the two techniques to evaluated resistance were noted.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
