Rose is one of the most economically important ornamental crops worldwide. Although rose products are widely used, limited genetic and genomic data from this species is available. Fundamental genetic knowledge can accelerate the development of superior rose germplasms. In the present study, we explored the genetic data (e.g., chromosome numbers, total chromosome length, and ploidy level) of 39 rose cultivars using conventional cytogenetic methods. Of the 39 rose cultivars tested, 36 (92.3%) were tetraploid (2n = 4x = 28). ‘Rosada,’ ‘Rosemarin,’ and ‘Hanmaum’ were diploid (2n = 2x = 14), triploid (2n = 3x =21), and tetraploid-based aneuploid (2n = 4x = 28 + 2), respectively. The total chromosome length ranged from 46.03 ± 0.55 μm in ‘Rosada’ (2x) to 138.51 ± 0.92 μm in ‘Christoper’ (4x). The chromosome information obtained in this study will be useful for rose breeding and germplasm evaluation.

Freshwater green algae are one of the important sources of bioenergy in the future. Spirogyra is a conjugating filamentous zygnematacean green algal genus that is widely distributed worldwide with more than 400 species. Despite its widespread occurrence throughout the world, cytological studies of the genus have been limited. We investigated karyological features and chromosome numbers for seven Korean Spirogyra species. Most of the species examined in the present study showed significant karyological features, inner organization of nucleolus, heavily stainable nucleolar substance and the diffuse-centric nature of chromosomes, typical of the Conjugales. Chromosome number ranged from n=12 in S. varians to n=38 in S. africana. Aberrant cytokinesis resulted in binucleate and tetranucleate cells, which sometimes provide cytological explanation for different morphology and ploidal changes in clonal culture of Spirogyra or even different cells within the same filament. The present chromosome data also substantiates the earlier held assumption that aneuploidy must have been the chief driving force for speciation and evolution of the genus Spirogyra.

Aneuploidy breeding was utilized as a method to develop a new type ofdiploid Brassica crop. Novel combinations oftheA genome of Chinese cabbage and C genome of cabbage were established by crossing to produce a sesquidiploid and successivebackcrossing with