DETACHED LEAF ASSAY AND WHOLE PLANT INOCULATION FOR STUDYING RESISTANCE TO DIPLOCARPON ROSAE IN ROSA SPP.

Q. Dong , D.H. Byrne, K. Ong, Xinwang Wang
Black spot disease, caused by the fungus Diplocarpon rosae Wolf, is the most serious disease of landscape roses (Rosa spp.) worldwide. Dominant genes for complete resistance to specific races of the pathogen were identified in roses as Rdrs. From a breeding perspective, a rapid screening of potential hybrid materials by molecular markers is beneficial for identifying the resistant genotypes efficiently. Although partial resistance has also been documented, the responsible QTLs remain unidentified. In this study, responses to D. rosae of 16 rose genotypes that were used as parents in breeding populations created by cross pollination were characterized with two inoculation methods: the detached leaf assay (DLA) and the whole plant inoculation (WPI). The correlation between the two methods and their precision at measuring relative resistance among genotypes was analyzed. None of the roses assayed were completely resistant to black spot race 8, although in some genotypes not all the inoculated samples developed acervuli. DLA is more sensitive than WPI in measuring relative resistance. However, the correlation among the two methods is high (up to 0.87) which indicates that either can be utilized to characterize resistance against D. rosae. For hybrid populations generated from this germplasm, phenotyping data will be collected by DLA.
Dong , Q., Byrne, D.H., Ong, K. and Xinwang Wang, (2015). DETACHED LEAF ASSAY AND WHOLE PLANT INOCULATION FOR STUDYING RESISTANCE TO DIPLOCARPON ROSAE IN ROSA SPP.. Acta Hortic. 1064, 317-322
DOI: 10.17660/ActaHortic.2015.1064.39
https://doi.org/10.17660/ActaHortic.2015.1064.39
Rosa, black spot, fungus, resistance, partial resistance, horizontal resistance
English

Acta Horticulturae