Morphological classification of Chinese old roses using numerical taxonomy

Chinese old roses, which possess desirable features such as continuous flowering, dark-red petals, strong adaptability and fragrance, have been cultivated for over 2000 years. They were instrumental in the development and breeding of modern roses. An investigation of relationships among extant Chinese traditional roses was carried out using numerical taxonomy. Twenty-three Chinese old rose cultivars and Rosa odorata were studied based on 27 morphological characters (15 qualitative and 12 quantitative). Cluster analysis using the unweighted pair group method with arithmetic average (UPGMA) and principal component analysis were performed with NTSYS software. The first three axes in the principal component analysis explained 53.3% of the total variation and revealed that 19 characters, most of which are related to branchlet type and floral traits, were important discriminators. The old roses were clustered into four groups on the basis of differences in growth habit and floral traits in a Q cluster analysis. The cultivars with a climbing habit were distinct from those with an erect shrubby habit. The erect shrubby group was divided into three subgroups; semi-double, double, and highly double flower producers.