The phenotypically quantitative nature of hypersensitivity of European plum (Prunus domestica L.) against the Plum pox virus and its description using the hypersensitivity index

Abstract

More than 1,300 seedlings of European plum originating from crossing combinations with at least one parent showing hypersensitivity resistance against PPV were analyzed for their reaction to artificial inoculation with PPV using the double grafting method with virus infected interstem. It was shown that the hypersensitivity resistance against the virus is a phenotypically quantitative trait. The different kinds of symptoms observed in the test system, which contribute to the hypersensitivity resistance, range from weak necrosis on the leaf blade and on the stem to the death of the whole young shoots. A hypersensitivity index was developed which helps to determine the degree of hypersensitivity resistance of an individual genotype. Its use is strongly recommended as selection tool in breeding for hypersensitivity resistance.

Prunus domestica 'Jojo' – Good Parent for Breeding of New Plum Cultivars Resistant to Plum pox Virus

“…However, the sharka virus in those shoots cannot be detected with ELISA (Neumüller, Hartman, & Stösser, 2007). Moreover, the wilting or abnormal growth of shoots can take a different course depending on the genotypes tested because there are different degrees of hypersensitivity (Neumüller, Hartman, & Stösser, 2005, Neumüller & Hartmann, 2008. The wilting of shoots was also observed in 14 genotypes in the first stage of tests, repeated in three or four different years.…”

“…The wilting of shoots was also observed in 14 genotypes in the first stage of tests, repeated in three or four different years. According to Neumüller and Hartmann (2008) and Neumüller (2011), testing of plum genotypes under greenhouse conditions in three replications (three plants) is sufficient to assess their sensitivity/resistance to PPV. In our tests, although the genotypes were grafted each year on a single infected interstem, the recurring wilting of their shoots in several different years indicated that those genotypes were hypersensitive to PPV-D.…”

“…Rapid death of the cells around the site of penetration by the virus into leaf tissue results in the localization of the infection and eventual destruction of the virus (Hartmann, 1998b). Genotypes showing this type of resistance remain free from the sharka virus under the natural conditions in which the pressure of the pathogen has been high for a number of years (Kegler, Grntzig, & Fuchs, 1994;Neumüller & Hartmann, 2008). One of the sources of this type of resistance in P. domestica is the variety 'Jojo' bred in Germany.…”

Plum pox virus as a stress factor in the vegetative growth, fruit growth and yield of plum (Prunus domestica) cv. ‘Cacanska Rodna’

“…As regards the sensitivity to the economically most important plum diseases, Ogašanović et al (1993) observed that 'Cacanska Rodna' was also susceptible to anthracnose, rust and to PPV, which caused only negligible economic damage. As reported by Prichodko (2006), 'Cacanska Rodna' exhibits susceptibility to PPV in Russia, as well as in Poland (Zawadzka et al 1994) and Germany (Neumüller et al 2007;Neumüller and Hartmann 2008). Zagrai et al (2005) determined that 'Cacanska Rodna' belongs to the group of cultivars that can be easily infected with the sharka virus.…”

Causal agents of stone fruit diseases in Slovenia and the potential for diminishing their economic impact - a review

“…Plum orchards can be saved via the use of sharka-tolerant cultivars, such as the wellknown Stanley variety. No completely sharka-resistant varieties of plums are known to exist, and while some hypersensitive tolerance has been observed, only a few related studies have been reported in literature (Neumüller & Hartmann 2008).…”