Because of their attractive and colorful flowers, many species from the genus Aster serve as garden plants. Chrysanthemum owes its popularity to its ornamental and medicinal herb value. It can be used as a cut flower, potted plant, vegetable, and herbal tea. Plant breeders have attempted to identify the available species and produce new cultivars to improve the quality of chrysanthemum for commercial purposes. The use of cytogenetic studies has paved the way for identifying compatibility, ancestry, and other useful information for this undertaking. Thus, an investigation was conducted into the chromosome numbers of 23 wild Asteraceae species in Republic of Korea to determine their genetic characteristics and variations. The somatic chromosome spread has been used for chromosome counting. The results revealed that Asteraceae species have a chromosome range from 18 (diploid) to 54 (hexaploid). These findings provide primary and important information on the chromosome numbers in chrysanthemum plants that can be used to select the right variety for cultivation.

Chrysanthemum is a valuable ornamental plant worldwide, and several of its species are used as herbal tea, medicinal plants, and dietary supplements, among others. Commercial cultivars have been developed through interspecific hybridization and artificial selection to improve the characteristics, production quality, and environmental adaptation for enhancing ornamental value. To better understand the recent research in cytogenetic studies of chrysanthemum, we examined studies concerning polyploidy, karyotyping, banding, fluorescence in situ hybridization (FISH) technique, and inter/intraspecific hybridization. Ploidy level is important in genomic characteristics and has a significant value to horticulturists and plant breeders. Studies have reported that flow cytometry analysis and single-dose molecular markers can be used to determine the chrysanthemum ploidy level. As for karyotyping, a better understanding of karyomorphological relationships and evolution of chrysanthemum and its closely related genera has already been gained. Moreover, karyotype parameters in chrysanthemum studies play a critical role in cultivar identification, classification, and genetic analysis. The FISH technique in chrysanthemum research provides more information on chromosome identification, sequences distribution, and evolution for expediting the development and improvement of plant species. The genomic in situ hybridization (GISH) technique can also be used to test hybridization in chrysanthemum breeding. Hence, this review of molecular cytogenetic studies of chrysanthemum will help us to have a better understanding and knowledge of the taxa breeding and the development and improvement of new cultivars.

We present 3 rare subtypes of the FFSs observed with high temporal resolution at 4-frequency (1.42, 2.13, 2.84 and 4.2G GHz). The various FFSs occurred during the main and post-flare phase can demonstrate that coronal nonthermal electron acceleration/injection may go through the whole development process of flares, and deduce that there may exist the re-forming of loop-like structures in the post-flare phase, and the complex multi-type magnetic structures in corona.