Influence of Virus Concentration on Expression of Cucumber Mosaic Virus Resistance in Pepper

Abstract

ABSTRACTPepper lines L57 andL113 and cv. Pico are inoculated by 1, 5, 10, 25, 75 μg/ml cucumber mosaic virus (CMV) in inoculum. Both lines are resistant to the virus and cv.Pico is used as a susceptible control. The lines respond with the development of chlorotic (L57) and necrotic (L113) spots on the inoculated leaf. The virus is established only in the inoculated leaves and their petioles of the resistant lines but cv.Pico is inoculated systemically. The virus existence on the rubbed leaves is an indicator for the effectiveness of inoculation. Inoculum with virus concentration 1 μg/ml does not inoculate the leaves, with CMV concentration of 5 μg/ml inoculates 66,7% of the rubbed Pico and L57 leaves and 50% of the L113 ones. The higher concentrations (25 and 75 μg/ml) inoculate all the rubbed leaves. The mosaic symptoms on inoculated Pico plants are developed up to 14 days post inoculation. All L57 plants which are inoculated by 75 μg/ml virus in inoculum and 50% of these which are inoculated by 50 μg/ml are infected systemically. The resistance is overcome at 66,7% of L113 plants which are rubbed by 75 μg/ml CMV. The data suggest that the expression of CMV resistance in pepper depends on virus concentration in inoculum and it is different for the both lines.