Forty-eight carnation cultivars were tested in field trials for resistance to rust disease, Uromyces caryophyllinus, with artificial inoculations. After two trials, five cultivars were selected, two of which were highly susceptible and three which were resistant. These five cultivars were further tested for the following components of partial resistance to the disease: latent period (LP 50), infectious period (IP), infection frequency (IF), mean pustule area (AS) and leaf area injury (LAI). Stomatal density (DS) was also evaluated since fungal penetration seems to occur through the stomata. No differences in cultivar responses were found for LP 50 and IP, whereas remarkable differences were observed for all the other components of resistance with similar values in the two susceptible and in the three resistant cultivars. Linear correlations between components were never very high. Despite noticeable differences in cultivar response, any one parameter of all components may not suffice alone to explain plant behaviour towards the disease. However, IF and DS can be considered valuable indexes of partial resistance in an initial selection for resistant cultivars. These indexes could be used in association with adequate growing techniques, as part of an integrated control of the disease.
An analysis of components of resistance to Uromyces caryophyllinus in carnation
LORENZINI, GIACOMO;PANATTONI, ALESSANDRA
1999-01-01
Abstract
Forty-eight carnation cultivars were tested in field trials for resistance to rust disease, Uromyces caryophyllinus, with artificial inoculations. After two trials, five cultivars were selected, two of which were highly susceptible and three which were resistant. These five cultivars were further tested for the following components of partial resistance to the disease: latent period (LP 50), infectious period (IP), infection frequency (IF), mean pustule area (AS) and leaf area injury (LAI). Stomatal density (DS) was also evaluated since fungal penetration seems to occur through the stomata. No differences in cultivar responses were found for LP 50 and IP, whereas remarkable differences were observed for all the other components of resistance with similar values in the two susceptible and in the three resistant cultivars. Linear correlations between components were never very high. Despite noticeable differences in cultivar response, any one parameter of all components may not suffice alone to explain plant behaviour towards the disease. However, IF and DS can be considered valuable indexes of partial resistance in an initial selection for resistant cultivars. These indexes could be used in association with adequate growing techniques, as part of an integrated control of the disease.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
