• Korean Journal of Plant Resources
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• v.36 no.2
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• pp.181-190
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• 2023

Domestic hop (Humulus lupulus L.) production has been suspended since the early 1990s due to foreign imports, but interest in local production is rising due to the recent craft beer boom in Korea. This study was conducted focusing on the development of growth characteristics and propagation technology for 6 introduced hop cultivars as a basic study for domestic hop production and breeding program. In the hop growth survey conducted in 2021 and 2022, the 5-year-old plants after planting generally showed a tendency to increase the height of strobile setting, strobile size, number and weight of strobile per hill compared to the 4-year-old plants. As a result of the experiment with hop vine cuttings, the average rooting rate of all cultivars was as high as 88% even in only water treatment that were not added with Atonik (Atonik, Arysta, Japan), a rooting agent. There were differences between cultivars in rooting length and rooting rate according to the Atonik treatment method. When checking the survival rate of the rooted cuttings seedlings after transplanting into the soil, it was confirmed that the survival rate of the cuttings in the tissue culture room was significantly lower than that of the cuttings in the greenhouse. However, in transplanting step, cutting plants from culture room condition was strongly inhibited plant growth because of changing environment conditions. As a results of tissue culture, the thidiazuron (TDZ) 1 ㎎/L treatment in the media generated 6 to 9 shoots/explant, while the 6-benzylaminopurine (BAP) 1 ㎎/L treatment generated only 1 to 2 shoots/explant. Therefore, it is more effective to culture by adding TDZ rather than BAP. These results indicated that the development of technology to manage stably after transplanting of cutting or micropropagating plants into potting soil is important for mass propagation of hops.

• The Korean Journal of Zoology
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• v.14 no.2
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• pp.57-74
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• 1971

The present investigation has been done to observe the ecological habits of field mice to protect the rice from damages during the growing season in paddy-field and during the storge period. The results obtained are summarized as follows: 1. Of 155 mice captured in the period of April-November 1970, which belong to four genera (Apodemus, Cricetulus, Rattus, and Micromys), 148 mice(95%) were found as striped field mice (Apodemus agrarius coreae). The population density of striped field mouse was revealed by the present study as 55/ha, which is quite a low level compared with that in Japan of 900/ha. 2. The age distribution of the mice as judged by their body weight was found mainly composed of adult and the sex ratio was found to be 1.8 as determined with 147 individuals. The nest was found to be occupied by an adult and was composed of at least three openings and more than one food storage tunnels. The mice usually keep hulled rice rather than unhulled one in storage tunnel. The weight of food found in a nest was about 50 grams on an average. 3. The mice show a most active behaviour 1-2 hours after the sunset, around midnight, and an hour before the sunrise, but they are active even in daytime in order for searching for food and for breeding. 4. The ratio (%) of damage appeared in high stem of sweet corn in August was 30 ~ 40 percent, whereas that in low stem was 80 ~ 90 percent. The weight of spoiled grains in paddy-field was 11, 400gm/0.4ha and this gives an estimate of 349, 695 for whole country. 5. The female striped field mouse weighs average of about 30 grams and gives birth to average of 4.8 younglings which wean away from female mouse three weeks after delivery. 6. The natural enemies to the mice are found to be carnivores (weasel, cat, mountain cat, fox, raccoon, and otter), raptatores(eagle, owl, kete, buzzard), and snakes. Two kinds of field rats(Rattus norvegicus, Cricetulus tritor) are also the predator to the mice. 7. The feeding preference of striped field mice follows in decreasing order of sweet corn, soybean, sweet potatoes, chestnut, and wheat. The mice do not have a preference for barley, millet, rough millet, red bean, and green bean. 8. The starvation experiment, in which water alone was supplied, revealed that the mice in good physical and nutritional conditions survived for 71 ~ 79 hours, whereas those in worse conditions survived for only 32 ~ 39 hours.