Abstract

This experiment was conducted to improve the germination rate of the seed treated by temperature, light, media, watering frequency, and covering depth on sowing or gibberellic acid ($GA_3$) in Rhododendron brachycarpum native to Korea. The rate of the seed germination in the temperature at $20^{\circ}C$ was excellent as 69.1% compared to control 52.9% at 20 days after sowing. The germination under unshaded or LED supplement light condition showed 60.5% or 61.1% respectively, however the germination of 30% or 60% shade condition was 40.6% or 38.9%. As increasing covering depth of vermiculite on sowing, ranged from uncovered to 6 mm, the rate of germination was decreased. The proper depth of covering on sowing was under 2 mm showed above 60% germination compared to the 6 mm covered with 3.5%. And watering frequency of 1 or 2 times spray in a day was the best for the germination 58.1% or 62.9%, respectively. The rate of the seed germination was similar in the mixed media with vermiculite or peat moss based on commercial media. As increasing concentration of $GA_3$, ranged from 25 ppm to 100 ppm, the rate of germination was also increased. The ger-mination of seed dipping in 100 ppm $GA_3$ before sowing was the highest with 98.6% compared to the control with 64.0%.

만병초의 종자는 $20^{\circ}C$에서 발아율이 69.1%로 가장 높았고, $25^{\circ}C$는 63.0%이고, 상온에서는 발아율이 52.9%로 낮았다. 광 조건에 따른 발아특성은 LED 보광 및 자연광에서 60% 이상 발아되었으나 차광 시에는 발아율이 40% 이하로 현저하게 낮았다. 만병초 종자를 인공배양토에 vermiculite 또는 peatmoss를 50% 혼합하여 파종한 결과, 발아율은 큰 차이 없이 51.6 ~ 58.2%로 나타났다. 복토 깊이에 따른 발아율은 무 복토가 62.3%, 2mm 복토는 60.2%에 비하여 6mm복토는 3.5%로서 복토의 깊이가 깊어질수록 발아율이 현저하게 낮아졌다. 관수 방법에 따른 발아율은 1일 2회 관수와 1일 1회 관수하였을 때 58 ~ 63%로 발아율이 양호하였으며, 3일 1회 관수 시 발아율이 10.6%로 현저하게 떨어졌다. $GA_3$ 25ppm에서 $GA_3$ 100ppm까지 $20^{\circ}C$와 $25^{\circ}C$에서 처리 농도가 증가할수록 발아율이 증가하는 경향이었다. $GA_3$ 100과 200ppm을 처리한 종자의 발아율은 농도간 차이 없이 97.3 ~ 98.6%로 높았고, 50ppm 처리에서는 80%이상의 발아율을 보였으나 25ppm 처리는 73.0%를, 무처리는 64.0%이였다.

Keywords

• seed;
• sowing;
• condition;
• media;
• increase

• 종자;
• 파종;
• 조건;
• 배양토;
• 증가;