• Korean Journal of Environmental Biology
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• v.34 no.4
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• pp.223-232
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• 2016

Drought is one of important environmental stress for plant. Drought has deleterious effect to plant growth including maize (Zea mays L.) such as vegetative and/or reproductive growth, root extension, photosynthesis efficiency, flowering, anthesis-silking interval (ASI), fertilization, and grain filling. In this study, we screened drought tolerant maize in 21 cultivars from different sources, sixteen NAM parent lines (B73, CML103, CML228, CML247, CML277, CML322, CML333, CML69, Ki11, Ki3, Ky21, M37W, Mo18w, NC350, Oh43 and Tx303), four Korean hybrids (Cheongdaok, Gangdaok, Kwangpyeongok and Pyeonganok) and one Southeast Asian genotype (DK9955). Drought stress (DS) index was evaluated with leaf rolling score at seedling stage and ASI at silking date. The leaf rolling scoring of CML228, DK9955 and Ki11 were determined 1.28, 1.85, 1.86, respectively. However, M37W, Kwangpyeongok, B73 and NC350 were determined over the 3. ASI analysis revealed that CML228, CML103, Cheongdaok, NC350, B73, CML322, Kwangpyeongok and Ki11 are represented less than 5 days under DS and less than 3 days of difference between DS and well-watered (WW), but CML69, Ki3, Pyeonganok, M37W, Mo18w and Gangdaok were represented more than 10 days under DS and more than 8 days of difference between DS and WW. Multi-Dimensional Scaling (MDS) analysis determined CML228, Ki11, and CML322 were regarded as drought tolerance cultivars. Eventually, Ki11 showed genetic similarity with Korean cultivars by QTL analysis and MDS analysis. Ki11 has a potential for development of drought tolerance maize with Korean cultivars.

• Journal of Bio-Environment Control
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• v.26 no.3
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• pp.188-193
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• 2017

The purpose of this study was to investigate the changes of environmental conditions and the quality and yield of melon fruit by heat fan operation in greenhouses at winter season. The average daily temperature inside the tunnels during January 1 to 31, 2017 was $0.9^{\circ}C$ higher than that of the control $17.8^{\circ}C$. The air flow rate of heater fan treatment was 4.8 times higher than the control (untreated $0.05m{\cdot}s^{-1}$) at 20cm above the ground where the korean melon grew. The temperature of the heater pan was $5.6^{\circ}C$ higher than that of the untreated at $35.3^{\circ}C$ and the relative humidity was 8.1% lower than that of the untreated at 39.1%. The flowering rate of the heater fan treatment was 96%, 5% higher than the control. The number of first harvest days of heater fan treatment was shortened by 4 days than that of untreated treatment. Fruit quality and marketable fruit yield increased by 3.4% and 38% compared to untreated respectively, the heater fan treatment increased the temperature inside the greenhouse and air flow rete, which were beneficial for growing the korean melon in greenhouses at winter season.

• Journal of Korean Society of Forest Science
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• v.87 no.2
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• pp.201-210
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• 1998

Sex ratios, and patterns of tree size and growth variation, resource allocation, spatial and age class distribution between the sexes were investigated in natural populations of the sexual trees, R. trichocarpa and R. sylvestris, and the mainly asexual, clonal tree, R. javanica of the dioecious Rhus (Anacardiaceae) distributed in Korea. Sex ratios for three species exhibited a significant degree of female bias, but among the populations, sex ratios were seen to vary quite widely. The measurement of tree size and annual increment of male trees in R. trichocarpa and R. sylvestris were significantly higher than those of female trees, but not significantly different in R. javanica. In all of the species, flowering branch number per individual and inflorescence number per branch of males outnumbered those of females. Branch number per individual, rachis(leaf) number per branch and rachis(leaf) number per inflorescence were more in females than in males. These results were considered as reproductive efforts to increase the pollen supply in males and the fruit production in females. Spatial distribution analysis in two different populations of R. trichocarpa indicated that males and females were randomly distributed in space, but seedlings were clumped around parental trees. Analysis of age class distributions between the sexual reproduction trees, R. triclaocarpa and R. sylvestris, and the asexual, clonal tree, R. javanica showed a different distribution in frequencies of males and females in each age class. These results showed that sexual and asexual reproduction tree species had almost different preference of habitats, and different sex ratio and annual growth.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.14
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• pp.173-189
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• 1973

The followings are the results obtained in a series of experiments concerning of the varieties, the short-day-treatment, the fertilizer application, and the planting space of soybean, which were carried out to investigate the methods best suited for cultivating green soybean as the preceding crop of the rice. in the paddy-field in the middle parts of Korea at the practice farm attached to Agriculture College of Kon Kuk University in 1972. 1. Though the varieties of soybean was planted on the hot-bed on March 15 and then set in the main plot, none of them did flower within May 15, which is the limit time of flowering in growing soybean as the preceding crop of the rice in the paddy-field without the short-day-treatment being applied during raising seedlings. 2. The earliest-maturing variety groups such as HOKKAl#l, WASEMIDORI, YAEHUSANARI, MIT AKARAHAKUCHO, and VERDE flowered within May 15 by the short-day-treatment during raising seedlings. 3. The optimum hours of the day length was known to be 7 to 9 in the medium-maturing and late-maturing variety groups and 7 to 11 in the early-maturing and the earliest-maturing variety groups in the case of appling the short-day-treatment for 10 days from the beginning of the primary regular compound leaf development. 4 The optimum days in appling the short-day-treatment for 11 hours a day was recognized to be about 10 days regardless of the maturity of varieties. 5. Reduction of days required to flower by the short-clay-treatment, that is, light-sensitivity was remarkably higher in the medium-maturing and the late-maturing variety groups than in the earliest-maturing and the early-maturing variety groups. 6. The yield showed an increase of about 17 per cent in the case of appling the standard amount of nitrogen(4.0 kg/10 a), but it tended to reduce on the contrary in appling the increased amount of nitrogen. 7. The application of increased amount of phosphate had less significant effect on the yield increase than in the case of application of its standard amount( 4.0 kg/l0 a). 8. When the number of transplantation plant was changed from 54 to 130 per 3.3 $m^2$, the yield in 130 plant plot was about two times so higher than in 54 plant plot that the effect of close planting cultivation on the yield was proved to be remarkable. 9. Conditions possible for cultivating green soybean as the preceding crop of the rice in the paddy-field in the middle parts of Korea are turned to be as follows: (a) to plant the earliest-maturing-variety groups on the hot-bed on March 15. (b) to apply the short-day-treatment by 11 hours a day for 16 days from April 16, which is about the time when the primary regular leaf begin to develop. And it was, found to be a most remarkable in the increased yield that apply nitrogen 4.0 kg, phosphate 4.0 kg, and potassium 6.0 kg per 10 a as basic manuring totally and apply the close planting by 130 plants per $3.3{m^2}$(50 cm $\times$ 5 cm).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.2
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• pp.151-159
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• 2012

Direct seeding of rice is a time- and laborsaving method, compared to machine transplanting. However, the area planted to direct-seeded rice is decreasing because of instability of seedling establishment, lodging, occurrence of weedy rice, and deterioration of grain quality. A newly developed wet-hill-seeding of rice, a type of direct seeding method, has shown features of growth similar to machine transplanted rice. This study was carried out to compare tillering pattern, heading characteristics and grain filling traits between transplanting and wet-hill-seeding in rice. Tillering of wet-hill-seeded rice was more vigorous than that of transplanted rice showing maximum tiller number 30~100% higher than transplanted rice. Wet-hill seeded rice showed later heading and shorter heading duration than transplanted rice. To find out the relationship between heading characteristics and grain filling traits, every panicle was tagged for flowering date, and the panicles on each heading date were inspected for grain filling traits. Wet-hill seeded rice and transplanted rice exhibited no significant difference in culm length, panicle length, the percentage of grain filling and perfect brown rice on each heading date during total heading period. Therefore, we conclude that wet-hill-seeding method is not inferior to machine transplanting in terms of seedling establishment, growth, grain filling and head rice yield.

• Journal of The Korean Society of Grassland and Forage Science
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• v.32 no.2
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• pp.157-164
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• 2012

This experiment was conducted to investigate an optimum harvest time for hairy vetch (HV) seed production. The seeds were harvested at 5 times, 35, 42, 48, 54, and 58 days after flowering (DAF) in 2009 and 2010. In 2011, 3 times of harvest, 39, 49, and 53 DAF were done at Suwon, middle part of Korea. HV plants were harvested and threshed by manually at each time. Seed yield, yield components, germination rate, hard seed rate, and viviparous germination rate were investigated. The highest seed yield represented 54 DAF in 2009, 42 DAF in 2010, and 49 DAF in 2011. When the triticale, HV support plant, comes to early lodging, the time of highest yield was delayed. 1,000-seed weight linearly increased from 35 DAF to 54 DAF. The later harvested seed showed a trend of increasing germination and hard seed ratio. However, viviparous germination had occurred because of in rainy season. In conclusion, it was presumed that an optimum harvest time for safe seed production in HV should be during 42 DAF ~ 54 DAF before the rainy season considering seed yield, 1,000-seed weight and germination.

• Korean Journal of Ecology and Environment
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• v.48 no.4
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• pp.253-262
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• 2015

The sustainability of Cypripedium japonicum, a rare plant designated by the Korea Forest Service, is threatened due to artificial factors such as habitat loss and climate change etc. and internal factors such as changes in biological properties of the habitat etc. but conservation research has not been performed in South Korea. The objective of this study is to establish the species conservation strategies by analyzing the characteristics of their habitats, including: 1) Population characteristics, and 2) habitat analysis of the vegetation and abiotic environments. From April to September, 2014, population characteristics [density (stems $m^{-2}$), flowering rate (%), and leaf area ($cm^2$)] in Cypripedium japonicum habitats such as Chuncheon (CC), Hwacheon (HC), Muju (MJ), and Gwangyang (GY) and vegetation characteristics (plant sociological research and ordination analysis), and abiotic environments [temperature ($^{\circ}C$), relative humidity (%), transmitted light ($mol{\cdot}m^{-2}{\cdot}d^{-1}$) and canopy openness (%)] were measured. Cypripedium japonicum was mainly distributed at elevation 450 to 990 m and 5 to $30^{\circ}$ slope. Slope direction was shown as 0 to $110^{\circ}$. Habitats temperature (mean $18.94^{\circ}C$) was well matched to seasonal changes. Differences among sites showed greater level according to latitude difference. It showed the highest in habitat, GY located in the South. On the other hand, relative humidity (77.38%) didn't show much difference among sites. The average degree of canopy openness was 18.17%. It showed the highest at HC (22.1%) and the lowest at MJ (16.1%). The average degree of transmitted light was $9.1mol{\cdot}m^{-2}{\cdot}d^{-1}$. It showed the highest at CC ($10.6mol{\cdot}m^{-2}{\cdot}d^{-1}$) and the lowest at GY ($6.87mol{\cdot}m^{-2}{\cdot}d^{-1}$). Chlorophyll content showed average 26.12 SPAD. It showed the highest at MJ (30.64 SPAD value) and the lowest at HC (23.69 SPAD value). Leaf area was average $253.35cm^2$. It showed the highest at CC ($281.51cm^2$) and the lowest at HC ($238.23cm^2$).

• Korean Journal of Weed Science
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• v.3 no.2
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• pp.129-136
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• 1983

To study ecological characteristics of Sagitiaria pygmaea and Sagittaria trifolia occurring in Korea their propagules were collected from 3 locations (Sagittaria pygmaea: Chuncheon, Suweon, Milyang; Sagittaria trifolia: Suweon, Iri, Jeonju) in 1981, cultured and replanted 4 times (May 20, June 5, June 20, July 5) in 1982. Sagitraria pygmaea from Suweon flowered earlier than those from Chuncheon and Milyang in the plants planted on May 20, but this was reversed in another planting dates. Three storied inflorescence was observed newly in Sagittaria pygmaea. Sagittaria pygmaea from Iri and Jeonju had more number of tillers, but less number of tubers per tiller than those from Suweon. Sagittaria rrifolia from Chuncheon flowered earlier than those from Suweon and Milyang. Sagirtaria trifolia from Milyang was narrower in the upper leaf width and less in the number of tubers per plant than those from Chuncheon and Suweon. Each of local collections may be regarded as different ecotype based on the above differences.

• Korean Journal of Organic Agriculture
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• v.16 no.4
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• pp.409-420
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• 2008

The highland area remained bare for the winter and spring seasons and this condition has resulted in soil erosion. In this areas, crop rotation by legume has not been commonly practiced. Thus, this study was carried out to evaluate the effects of the growth characteristics and nitrogen yield as a green manure crop according to sowing seasons of hairy vetch and woolly pod vetch. In this experiment, we was investigated the growth characteristics, winter tolerance, soil coverage and productivities of hairy vetch and woolly pod vetch. We cultivated two hairy vetch(Madison, H1) and two woolly pod vetch(Naomi, Haymaker) varieties in the highland area from 2006 to 2007. The result are summarized as follows; The plant height of hairy vetch increased with the progress of growth stage until flowering stage. The wintering rate of hairy vetch was $79{\sim}83%$ in highland area. But, the wintering rate of woolly pod vetch was $29.5{\sim}39.2%$. The 100% soil coverage of hairy vetch was reached between end of May and beginning of June under autumn sowing, and between end of June and beginning of July under spring sowing. The weeds density of hairy vetch field under autumn sowing was lower than that under spring sowing. Dry matter yield of hairy vetch was significantly higher than that of woolly pod vetch under autumn sowing. The dry matter yield of hairy vetch and woolly pod vetch were $5,255{\sim}5,405kg/ha$ and $3,520{\sim}3,640kg/ha$, respectively. But, hairy vetch in spring sowing was not significantly higher fresh matter yield than that of woolly pod vetch. The nitrogen content in hairy vetch and woolly pod vetch was $2.98{\sim}3.08$ and $2.74{\sim}3.21%$, respectively. There were no significant difference in nitrogen content of the hairy vetch and woolly pod vetch under the spring sowing. N-uptake of hairy vetch was significantly higher than that of woolly pod vetch in autumn sowing. The N uptake was $156{\sim}164\;kg/ha$ in hairy vetch and $96{\sim}101\;kg/ha$ in woolly pod vetch under autumn sowing. It was thought that hairy vetch was better than woolly pod vetch as a green manure crop in autumn sowing considering wintering rate and yield of dry matter in highland area. And woolly pod vetch could use as a green manure crop under spring sowing in highland area.

• Korean Journal of Medicinal Crop Science
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• v.5 no.1
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• pp.56-61
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• 1997

This research was conducted to investigate morpological and growth characteristics of 358 Coix lacryma-jopbi mayuen STAF collected in Korea. The test collections contained 76% medium wide-type leaf, 59% medium size-type seed, 34% large size-type seed, 70% elliptical-type shell, 50% brown shell color, 92% low stem color and hardness of seed coat averaged $3.4kg/cm^2$ with the range of $1.1{\sim}18.7kg/cm^2$. 24% adaptable plant height ranged from 156cm to 170cm, days to heading after seeding averaged 83.2% with the range of $74{\sim}94$ days, early maturating varietes was 24.9% below 80 days. Rate to leaf blight 48.5% with the range of $9{\sim}92%$ and rate to stem borer averaged 8% with the range of $0{\sim}17%$. The weight of 1000 seeds showed positive correlation with days to flowering and plant height and number of seeds per plant showed positive corrleation with percentage of ripness, but weight of 1000 seeds showed negative correlation with occurrence of leaf blight and stem borer plant. Therefore we are expecting useful germplasm and selectable index for effective breeding.