A novel source of food – garden rose petals

Even though rose is the most widely grown ornamental, the garden rose market in western Europe has been declining for over 30 years. In the past roses were valued based on aesthetic characteristics, while petals and hips were considered waste. At the same time, a need for added value in garden roses production has arisen and trends for healthy nutrition and a need for new food sources became imperative. The rose petal compounds suddenly turned out to be a source for new product market combinations. In this study, two aspects of rose petals were considered: biochemical composition (amount of vitamin C, antioxidants, sugar and organic acids) and consumers’ perception (taste and texture). Biochemical analysis revealed that rose petals contain a high amount of vitamin C and antioxidants, which indicates the potential value of roses as food. Additionally, the ratio between organic acids and sugars was positively correlated with taste perception and could be used as a marker for the selection of edible roses. The aim of the study was to test the effectiveness of a genome-wide association study (GWAS) for mapping QTLs related to biochemical compounds and morphological traits related to petal production. A set of 192 tetraploid cultivars/accessions was genotyped using the WagRhSNP Axiom SNP Array. PCA and Ward’s clustering of genetic similarities indicated the presence of two main groups of cultivars/accessions. GWAS was performed by a linear mixed model approach, taking into consideration different corrections for population structure. All models detected QTLs for citric acid, antioxidant capacity and yield.