Breeding for resistance: breeding for Plum pox virus resistant plums (Prunus domestica L.) in Germany

Abstract

In German plum breeding programmes new varieties tolerant to Plum pox virus (PPV) were initially obtained by selecting hybrids originating from crossings between tolerant old varieties while, later on, sharka tolerant varieties bred in f a ç ak, Serbia were used as crossing partners. Varieties released from these programmes replaced the sensitive ones in all sharka infected regions in Germany. While all the new tolerant varieties can be infected by the virus, PPV symptoms on the fruits are acceptable. However, environmental factors can weaken the plant, causing them to suffer more from PPV infections and to display worse symptoms on fruits, as did occur during some recent very dry and warm years. A breeding programme at the University of Hohenheim is tackling this problem with genotypes that show a hypersensitive response after infection. These genotypes are completely field resistant to PPV, remaining virus free in the field since they cannot be infected via aphid transmission. They are able to isolate the virus after infection. The first hypersensitive variety was 'Jojo'. Many seedlings originating from crossings with at least one hypersensitive parent are under evaluation. Since the inheritance of the trait 'hypersensitivity against PPV' is very good, combining hypersensitivity with excellent fruit quality and good cropping capacity will be possible soon. In 2005, a breeding programme for hypersensitive Prunus genotypes began at the Technical University of Munich.

Plum pox virus (sharka) sensitivity in Prunus salicina and Prunus cerasifera cultivars against a Dideron‐type isolate

“…These results agree with the quantitative response towards PPV described by Hartmann and Neumüller (2006) and Blažek and Karešová (2007). Kegler et al.…”

“…1994, Kegler et al. 1996, Hartmann and Neumüller 2006). In European plum, a large body of information exists about the behaviour of the cultivars against PPV, but in other plum species, data are very scarce (Dragoiski et al.…”

Genomic analysis reveals MATH gene(s) as candidate(s) for Plum pox virus (PPV) resistance in apricot (Prunus armeniaca L.)

“…These have subsequently been used as PPV resistance donors, even though they are not well adapted to the various growth conditions of different European regions (Martínez-Gómez et al, 2000). With regard to other Prunus species, some genotypes showing tolerance or a hypersensitive response to PPV infection have been found in plum (Hartmann and Neumüller, 2006), but no resistance sources have yet been found in peach (Prunus persica L. Batsch) (Escalettes et al, 1998). In apricot, the introgression of PPV resistance into commercial cultivars has been accomplished, but breeding progress is still hampered by difficulties inherent to both fruit tree management and PPV resistance phenotyping (Egea et al, 2009;Martínez-Calvo et al, 2010).…”

Narrowing down the apricot Plum pox virus resistance locus and comparative analysis with the peach genome syntenic region

“…Epidemiological studies (Cambra et al ., 2006; Labonne and Dallot, 2006) and improved detection methods at early infection stages (Olmos et al ., 2006) have contributed to a better management of the disease, but the best long‐term solution is to grow new PPV‐resistant varieties. Unfortunately, only a few resistance sources have been reported in apricot ( Prunus armeniaca L.) (Martínez‐Gómez et al ., 2000) and plum ( Prunus domestica L.) (Hartmann and Neumüller, 2006), and no peach ( Prunus persica L. Batsch) cultivar resistant to PPV has been found (Escalettes et al , 1998).…”