Nuclear ribosomal DNA (rDNA) was analyzed to identify inter-specific genetic relationships among 8 Cymbidium species (Cymbidium insigne, C. ensifolium, C. marginatum, C. faberi, C. gyokuchin, C. kanran, C. forrestii, and C. goeringii). Nuclear rDNA including 2 internal transcribed spacer (ITS) regions and 5.8S, was amplified using polymerase chain reaction and sequenced. The sequences were compared via pair-wise multiple alignment to determine the genetic relationships among the studied species. The lengths of the ITS1, ITS2, and 5.8S regions were 235 bp, from 255 bp to 257 bp, and from 153 bp to 165 bp, respectively. Sequence similarities in the ITS region ranged from 78.7% between C. gyokuchin and C. kanran to 96.8% between C. ensifolium and C. kanran. A phylogenetic tree was constructed from nuclear rDNA nucleotide sequence data of the 8 cymbidiums and 1 outgroup species to estimate genetic relationships. The tree revealed that cymbidiums could be classified by their ecological traits, such as their temperature preference or inflorescence pattern. The phylogenetic data is applicable for identification, classification, and breeding of cymbidiums.

Freesia is one of the most popular flowers over the world including Korea, due to the fragrance and beauty of the plant flower. The first domestic freesia cultivar ‘Shiny Gold’ was developed by NIHHS, RDA, in 2003, which has yellow double and large petals and strong fragrance. Ten years have passed since ‘Shiny Gold’ was cultivated at floral farms, and the deterioration of cut flower quality and yield are reported from the farms. Virus infection causes a reduction in the quantity and quality of the cut freesia flowers and is one of the most serious problems in Korea. Virus detection was carried by reverse transcription polymer chain reaction (RT-PCR) for FreMV, FreSV, BYMV, CMV, and TRV, as known to infect freesia. FreMV, FreSV, BYMV, and TRV were detected single or multiply, and CMV was not found in the freesia leaves collected from the farms. To produce virus-free freesia, meristem culture of ‘Shiny Gold’ was conducted in MS medium added ribavirin at different concentration. As the increased of ribavirin concentration, the growth of ‘Shiny Gold’ plantlets was inhibited in freesia’Shiny Gold’. The plantlets produced by meristem culture in ‘Shiny Gold’ were virus free at the enzyme-linked immunosorbent assay (ELISA) level.

The direct use of mutation is a valuable approach to generate variability in crops. The electron beam, one of the ionizing radiations, has been applied to evaluate its effect on seed germination and early seedling growth of creeping bentgrass (Agrostis palustris Huds., cv Penn-A1). The mature dry seeds were irradiated with various electron beam energies (0.3, 1.0, 1.3, and 2 MeV) and current levels (0.03 and 0.06 mA). Although large variability was existed within each dose, distinct difference of germiability and seedling vigor were not found at 0.3 MeV / 0.03 mA and 0.3 MeV / 0.06 mA beam condition. However, 1.0 MeV / 0.06 mA application most effectively inhibited and retarded seed germination and most severely restricted cotyledon and root growth in early seedling growth. The direct use of electron beam would be a valuable supplementary approach to generate mutants suitable for breeding purposes.