S05 - Session O5 - Genome wide association study and marker development for adventitious root formation in rose

Authors: David Wamhoff *, Thi Hong Nhung Nguyen, Dietmar Schulz, Jasmin Rudeck, Thomas Debener, Traud Winkelmann

Propagation of roses on own roots via cuttings or micropropagation is desirable. However, while pot roses are already mainly propagated by cuttings, cut and garden roses are still propagated by elaborate and costly grafting amongst others due to deficient ability to form adventitious roots. Genotypic differences in wound-induced adventitious root formation (ARF) are challenging in breeding and propagation of these rose groups. The process of ARF is complex and regulated by phytohormone-induced signal transductions as well as metabolic processes. Nevertheless, ARF in general is not fully understood and reasons for differences in rooting ability are not identified for rose. A garden rose population and a cut rose population of 96 genotypes each were phenotyped for different ARF related traits in hydroponic rooting experiments. Based on genotypic data generated via the rose Axiom® SNP array, genome wide association studies (GWAS) were conducted for the different ARF traits. So far, interesting SNPs could be identified within or close to the genes SAC9 (predicted, SUPRESSOR OF ACTIN 9 ), ARF6 ( AUXIN RESPONSE FACTOR 6 ), SCR ( SCAREROW ), CYCA and CYCD ( CYCLINE genes) and several other genes involved in different traits, which are connected to ARF in literature. Especially SNPs located in the gene SAC9 showed in different experiments significant associations between allele dosage and values for the specific ARF related trait. A "Kompetitive Allele Specific PCR" (KASP) marker was established for the SNP located in the SAC9 gene. In upcoming experiments, the KASP marker will be tested and validated for further independent rose genotypes which are homozygous (nulliplex or quadruplex) for this SNP. In case of a verification of the association between ARF and the allele dosage for the KASP, this marker holds the potential to be used in breeding programs in order to improve the rooting ability in rose.