Cryopreservation has been known as an efficient method for long-term preservation of clonally propagated plants, and several cryopreservation methods have been developed. Among them, a droplet-vitrification method for potato using axillary shoot tips in vitro has been established previously. In this study, we have optimized the procedure in which explants were submitted to a step-wise pre-culture in liquid sucrose-enriched medium (0.3 and 0.7 M for 7 and 17 h, respectively). The pre-cultured explants were dehydrated with PVS3 (w/v, 50% glycerol + 50% sucrose) for 90 min or modified PVS2 vitrification solution (w/v, 37.5% glycerol + 15% DMSO + 15.0% ethylene glycol + 22.5% sucrose) for 30 min. This two dehydration solutions produced post-cryopreservation regeneration percentages of 57.2% and 80.9%, respectively. We also compared a new post-culture medium (0.1 mg L ･ -1 GA3, 0.1 mg L ･ -1 kinetin) with the conventional one (0.15 mg L ･ -1 IAA, 0.2 mg L ･ -1 zeatin, 0.05 mg L ･ -1 GA3); the shooting initiation rates were 80.9% and 43.5%, respectively. The results suggest that the modified droplet-vitrification protocol described in this study is more effective, easier to implement, and more economical than the droplet-vitrification protocols currently used for potato.

"Chuyoung" as a new double cropping potato variety was bred in 2005 for table use through a cross between "Dejima" with short tuber dormancy and HRB-31 which is a tetraploid derived from an interspecific cross between "Russet Burbank" and Solanum phureja line. It was evaluated for short dormancy, growth and tuber characteristics every twice a year from 1997 to 2001. Regional yield trials were performed from 2002 to 2004 at three locations, Jeju, Namhae and Gangneung of Korea, respectively. Its tuber shape is oblong with yellow skin and flesh colors. Its dormant periods is 60~70days. It showed less incidence of physiological disorders such as cracking or knobs on tubers, and higher resistance to common scab by Streptomyces scabies compared to "Dejima". It has tall plant height and erect growth type with green-broad leaflets and white large inflorescence. Its average yields are 29.5 and 22.6 ton/ha at 90 days after planting in spring and autumn cropping, respectively. It also showed higher marketable yield due to the lower incidence of common scab and physiological disorders compared to "Dejima".

본 연구는 방과후 스포츠 활동에 참가하고 있는 대전광역시의 중학생들을 대상으로 성별, 운동회수, 그리고 운동시간에 따른 운동정서 프로파일을 분석하는데 목적을 두었다. 총 886명의 남녀 중학생(남=392, 여=494)을 대상으로 운동정서를 검사하였다. 자료 분석은 탐색적 요인분석, 신뢰성 분석, 기술통계, 다변량분석 등을 통해 이루어졌다. 운동정서의 하위요인을 종속변수로 하여 다변량분석을 실시한 결과 성별, 운동회수 및 운동시간에서 주효과가 나타났지만 상호작용효과는 유의하지 않았다. 남학생은 모든 하위요인에서 여학생보다 높은 정서 수준을 보였으며, 주 4회 이상 및 1시간 이상 운동하는 학생이 모든 하위요인에서 긍정적인 정서를 경험하는 것으로 나타났다. 이 결과는 청소년의 신체활동에 따른 심리적 이점과 관련된 선행연구의 결과들과 비교하면서 논의되었다.