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.

We report a procedure for direct shoot regeneration via leaf segments of Lilium Oriental hybrid ‘Casa Blanca’. The segments were cultured with the abaxial side in contact with a Murashige and Skoog medium containing 0.1 mg • L-1 BA and 0.1 mg • L-1 NAA, 3% sucrose, and 0.8% agar for shoot regeneration. The cultures were incubated for 4 weeks under a 16 hrs photoperiod at 23 ± 2oC for adventitious shoot regeneration. With this procedure, a mean shoot regeneration frequency of 88-90% and a mean number of shoots of 2.5-3.6 per segment were obtained. Ploidy analysis of the regenerated plants using flow cytometer revealed the same ploidy level (diploid) with mother plant. This study will be used for large-scale multiplication and genetic transformation system in lily.

26 wild accessions and 2 cultivars of whip grass (Hemarthria compress a (L. f.) R. Br.), which collected in the fields of Sichuan Agricultural University (SAU), were used to study on their ploidy level and reproductive characteristics. The results showed that there were 4 tetraploids (14.3%), H028, H029, H052, H053, chromosome numbers were 2n=4x=36, and 24 hexaploids (85.7%), 2n=6x=54. There was no significant correlation between geographical distribution and ploidy level in this research. From 2006 to 2008, hexaploids set few seeds, but all of the tetraploids set some seeds more or less. H052 had the highest seed set (11.22%). The tetraploids had potential for seed production, especially H052, it should be possible to obtain hybrids by cross-pollination in the future.

The significance of cell ploidy and repair ability for the radioprotective efficiency of cysteamine was studied in DNA repair - proficient and repair - deficient yeast cells irradiated 60C0 γ-rays. Results have been obtained for the cell surviv

The purpose of this study is to examine fluctuating asymmetry of eye diameter, maxilla length, operculum length, and the number of pectoral fin ray and pelvic fin ray between ploidy and sex in diploid and triploid marine medaka, Oryzias dancena. In all experimental groups, eye diameter and maxilla length showed no significant difference between left side and right side (p>0.05). Results of operculum length in triploid male group and pectoral fin ray's number in diploid male group showed similarity ones with results of operculum length in triploid female group and pectoral fin ray’s number in diploid female group (p<0.05). However, the operculum length in diploid male group and pectoral fin ray's number in triploid male group showed consinderable difference with those of operculum length in diploid female group and pectoral fin in triploid female group. Findings of pelvic fin ray's number in all groups were similar to those of pectoral fin ray’s number in all groups (p<0.01).

The present study aimed to compare and investigate the morphological characteristics and yield components according to ploidy level of diploid and tetraploid Platycodon grandiflorum under vinyl-greenhouse and open field conditions. Plant height of diploid and tetraploid P. grandiflorum was 51.3 ㎝, 54.0 ㎝, respectively. The results revealed that the plants grown in the vinyl-greenhouse showed significantly higher growth compared to those grown in the open field. Regardless of the growing place, diploid and tetraploid of P. grandiflorum showed the rapid elongation of internodes after 4 and 3 internodes respectively and elongation tends to be decreased as entering the flower-bud differentiation period. The starting day of flowering in vinyl-greenhouse cultivation was found to be faster than that of the open field cultivation by 2∼ 3 days and tended to be delayed by about 5∼6 days in tetraploid P. grandiflorum compared to diploid. Fresh weight of roots from the vinyl-greenhouse cultivation showed a high quantity as 34.2g and 49.4g in diploid and tetraploid P. grandiflorum, respectively and especially tetraploid P. grandiflorum was found to be increased by approximately 44.4% compared to other plots.

밀 약배양에 있어서 Callus 유기, 식물체분화 및 분화식물체의 염색체 변이에 미치는 돌연변이 유기제의 처리 효과를 검토코자 감수 분열기 1 핵기 이삭에 X-ray는 4수준( 100, 200, 500, 1,000 rad) Ethyle Methane Sulphonate 는 3수준 ( 0.1, 0.2, 0.3M)으로 각각 처리하여 Cl7배지에서 callus를 유기시키고 1/2 MS 배지에서 식물체를 분화시켰다. 그 결과 callus 유기는 억제되었으나 식물체분화는 다소 높았으며 특히 약치상 후 61～80일째 장기치상된 약의 callus에서 식물체분화율이 높았다. 분화식물체의 염색체 변이는 반수체(n=3 x=21) 발생율이 증가되었고 n=20, n=21개의 염색체를 갖는 이수체가 발생되어 염색체 변이가 컸다.다.

벼 약배양을 통하여 분화된 식물체의 배수성분포와 반수체식물의 효과적인 염색체배가시험을 실시하여 얻어진 결과를 요약하면 다음과 같다. 1. 15조합의 F1 을 재료로 하여 약배양한 결과 얻어진 574 식물체의 배수성분포는 반수체가 49.7%, 2배체는 48.6%, 다배체는 1.7%로 나타났다. 2. 통일형조합(Japonica/Indica)에서는 반수체(60.6%)가 많은 경향이었고, 일본형조합(Japonica/Japonica)에서는 2배체(54.8%)가 많은 경향이었다. 3. 2,4 -D, NAA가 첨가된 배지에서는 반수체가, Kinetin이 첨가된 배지에서는 2배체가 많은 경향이었다. 4. 반수체의 분얼경 분주에 의한 염색체자연배가율은 개체에 따라 0~25%로 나타났고 평균 8.2%였다. 5. Colchicine 0.1% 용액의 잎집주사접종법에 의한 염색체배가율은 0~33.3%의 변이를 보였으며 평균 18.8%로 나타났다. 6. 약배양에서 유래된 식물체의 배수성에 따른 형태적인 차이는 반수체가 2배체에 비하여 간장이 64.6%, 수장이 63.4%, 지엽장은 68%, 지엽폭은74.4%로 뚜렷한 차이를 나타내었다.