Conidial germination and infection byDiplocarpon rosaeon susceptible and resistant rose species

Identification of five physiological races of blackspot, Diplocarpon rosae, Wolf on roses

“…However, the final proof for the existence of a 'gene for gene' relationship requires genetic analysis of avirulence genes on the pathogen side, which is beyond the scope of the present work. Our data supported previous results which demonstrated varying degrees of resistance among rose cultivars and species (Palmer et al 1966, Knight and Wheeler 1978a, Reddy et al 1992, Wiggers et al 1997. In tests with our fungal isolates, the plant genotypes 'Pariser Charme', Rosa indica and R. wichuraiana (b) were generally susceptible and, 91/100-5 and R. wichuraiana (a) were generally resistant, even when inoculated with conidial mixtures from several European countries.…”

“…In addition to field investigations (Wolf 1912, Aronescu 1934 several methods have been developed for the artificial inoculation of rose genotypes, most of them based on detached leaf (Palmer et al 1966) or leaf disc (Knight and Wheeler 1978a) assays. It was found that the fungus varies in pathogenicity between different polysporous isolates (Jenkins 1955, Palmer et al 1966) and on different host genotypes (Palmer et al 1966, Knight and Wheeler 1978a, Wiggers et al 1997. Most ofthe varieties proved to be susceptible to some of the isolates while only a few species were resistant to all isolates tested.…”

Promising genetic resources for resistance to powdery mildew in chestnut rose(Rosa roxburghii)and its relatives in China

“…It was introduced into Europe in 1815 via India for ornamental planting, and named chestnut rose in 1904 because of the prickles on the hip (Fangan 1988). Chestnut rose is free from rose blackspot disease (Wiggers et al 1997) and thus shows great potential for the exploitation of its fruits and for ornamental breeding. Powdery mildew is among the most common and widespread of the fungal plant diseases, affecting an extremely wide range of plants, from grasses to tree species (Agrios 1997).…”

Micropropagation of chestnut rose (Rosa roxburghiiTratt) and assessment of genetic stability inin vitroplants using RAPD and AFLP markers

“…Chestnut rose is one of three promising new fruit crops in China (Fan et al, 1997), and is also grown as an ornamental plant for its colorful, prolific, multi-corollate flowers (Xiang et al, 1987;Fagan, 1988;Ji and Li, 1998). Chestnut rose is also highly resistant to rose blackspot disease (Reddy et al, 1992;Wiggers et al, 1997).…”