• Korean Journal of Plant Resources
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• v.27 no.1
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• pp.80-88
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• 2014

This study was carried out to understand the effect of sowing date on growth characteristics, flower duration of a total of 6 domestic rapeseed cultivars, "Sunmang", "Tammiyuchae", "Tamlayuchae", "Naehanyuchae", "Yongsanyuchae" and "Hallayuchae" with different sowing dates (25 Sept., 5 Oct., 15 Oct., 25 Oct., 5 Nov.) in Muan, Jeollanamdo, Republic of Korea. The results obtained were summarized as the follows: The number of seedling stand after overwintering was decreased in all 6 cultivars. It changed little until 5 Oct., and then showed continuously largely decrease as the sowing date being delayed. As the sowing date was being delayed, plant height was decreased while Silique length and thousand seed weight were increased. Seed yield in all 6 cultivars decreased almost linearly with late sowing date. In correlation analysis between the delaying sowing date and growth characteristics, it was inversely correlated with plant height ($r=-0.769^{**}$), No. of branches/plant ($r=-0.760^{**}$), No. of siliqua/panicle ($r=-0.631^{**}$) and seed yield ($r=-0.946^{**}$), while showed a positive correlation with silique length (r=0.635), seed diameter ($r=0.629^{**}$) and thousand grain weight ($r=0.422^*$). No. of seeds/silique and seed set percentage were not significantly correlated with the delaying sowing date. The flower duration was long in order of Sunmang, Tammiyuchae, Yongsanyuchae, Naehanyuchae, Hallayuchae and Tamlayuchae. Varietal variation of flowering date was larger with early sowing date than with delaying sowing date. The range of flower duration across all cultivars was from 1 day of Tamlayuchae to 14 days of Sunmang according to the sowing date, and the end flowering date was able to be extended from 2 to 9 days, compared to normal date of end flowering.

• Korean Journal of Plant Resources
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• v.17 no.2
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• pp.139-146
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• 2004

Kenaf (Hibiscus cannabinus L.), an annual plant of the family Malvaceae, is considered to be the most promising for alternative plants with potential use as a non-wood fiber source. The objectives of this study were to select the optimum seeding date and adaptable cultivar among newly introduced kenaf cultivars (Everglades-41, Tainung-2 and Chingpi-3) in Jeju island, and to clarify the photosynthetic characteristics of those cultivars. Among the three cultivars, the fresh shoot weight per unit area of Chingpi-3 at harvest season showed highest through all seeding dates, that of while Everglades-41 was the lowest. The difference of shoot yield at harvest mainly due to seedling stand rate and plant number per unit area among the cultivars. The Chingpi-3 showed the highest shoot fresh weight in the seeding date of May 11 and decreased trend in the late seeding dates. Net photosynthesis rate was higher on Everglades-41 with entire type leaf than other two cultivars with palmate type leaf. The activity of ribulose-1,5-bisphosphate carboxylase/foxygenase (rubisco) estimated from the A-Ci curve showed highest in Chingpi-3 among three cultivars. These results suggest that Chingpi-3 might be adaptable cultivar with seeding date of around May 10 for kenaf production in Jeiu island.

• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.2
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• pp.73-79
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• 2020

This study was conducted to develop a technique for the stable production of Italian ryegrass(IRG) seeds in reclamation sites. Harvesting 35 days after heading in Autumn resulted in the highest production, an average of 2,232kg/ha. The production yield decreased due to seed loss as harvesting was delayed to 45 and 55 days post-heading. For the harvested 35 days post-heading, under growing rice sowing resulted in 80% seed yield of after rice sowing's; spring sowing resulted in 40%. After rice sowing using the domestic IRG seeds of 30kg/ha produced the highest seed yield of 2,507kg/ha. The highest straw yield has resulted when using the imported IRG seeds of 20kg/ha for after rice sowing 35 days post-heading fresh weight 36,667kg/ha, dry weight 14,500kg/ha, and TDN weight 7,895kg/ha.

• Korean Journal of Environment and Ecology
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• v.31 no.6
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• pp.485-491
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• 2017

This study examined the germination characteristics by collecting fruits and pretreatment of the diaspore from April 2014 to June 2015 to investigate the diaspore characteristics, seed dispersion, and seed germination characteristics of two myrmecochorous spring ephemerals (MCSE): -Jeffersonia dubia (Jb) and Corydalis remota (Cr)-. The diaspore of Jb was about 5mm-long yellow-dark brown, oblong seeds with the attached amorphous white elaiosome. The mean weights of diaspore, seed, and elaiosome were 15.86mg, 13.46mg, and 2.40mg, respectively, and the elaiosome ratio was 15.13%. The diaspore of Cr was about 1.2mm diameter and glossy black ovoid seeds with the attached white spatula-shaped elaiosome. The mean weights of diaspore, seed, and elaisome were 2.58mg, 2.05mg, and 0.53mg, respectively, and the elaiosome ratio was 20.54%. Camponotus niponensis and Formica japonica transported the diaspore of Jb while Formica japonica and Lasius japonicus transported the diaspore of Cr. The germination percentage of Jb seeds was statistically significant and had the significance level of 1% with the pretreatment and date of sowing. However, it was independent of attachment of elaiosome. The mean germination percentages of Jb seeds was 65.0% during sowing on June 20, 17.5% during sowing on August 19, and 0% during sowing on October 20. The germination percentage of Cr was statistically significant and had the significance level of 5% and 1% with the attachment of elaisome and date of sowing, respectively. The mean germination rates were 54.17% and 35.0% in the non-treatment section and the treatment section with elaisome detached, respectively. The mean germination percentages of Cr seeds was 75.0% during sowing on June 20, 53.75% during sowing on August 19, and 5.0% during sowing on October 20. Considering the fact that the ants transported the diaspores to the ant house when the fruits of MCSE were ripened and dropped the seeds, the direct seeding right after collecting may be most suitable to the characteristics of the evolution of these plant species and may be the best method to obtain the highest germination percentages. Since the ants distribute their seeds, the MCSE produces and attaches the elaiosome to the seed to maintain the symbiotic relationship with ants. The ants then transport the seed to the ant house where the environment is controlled for suitable temperature and humidity, and then the MCSE succeeds in germination after the embryo grows sufficiently in the next spring.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.4
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• pp.308-314
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• 2011

Seed germination and dormancy of three green manure seeds such as hairy vetch, crimson clover and narrow-leaved vetch (Vicia angustifolia L.) produced in Milyang, southern part of Korea were investigated to provide a basic information on the stability of seedling establishment in green manure seeds. In addition, the effect of seed storage duration on the germinability of imported hairy vetch and crimson seeds was also investigated. To determine the seed maturity time of three green manure seeds, the seeds were harvested manually at May 25, May 30, and June 4, and the 100-seed weight, germinability and percentage of hard seed were evaluated. Freshly harvested seeds of three green manure crops were strongly dormant because of hard seed coat. Germination percentage of the three green manure crops varied depending on the seed harvest time ranging from 30 - 52% in hairy vetch, 16 - 35% in crimson clover and 2 - 61% in V. angustifolia, respectively. Of the three crops, crimson clover and V. angustifolia matured early on May 30 to June 4 (around 35 to 40 days after flower) but hairy vetch seed did not mature until June 4 based on the seed germinability. The matured seed of crimson clover and V. angustifolia germinated less than 20% while scarification on seed coat significantly overcome the innate dormancy. On the other hand, the seed germination of hairy vetch and crimson clover was lower under dark than in the presence of light. The germination percentage of the imported hairy vetch and crimson clover seeds showed high with 77 - 79%, 94 - 95%, respectively, but the seed germination significantly declined by 21 - 32%, 30 - 40% after one-year of storage under natural conditions. The seeds germinated only 8 - 13% for hairy vetch but crimson clover did not germinate at all after two years storage. These results indicate V. angustifolia and crimson clover mature at May 30 to June 4 but hairy vetch did not. The imported hairy vetch and crimson clover seeds should be used within one-year after import for stable seedling establishment in green manure-rice cultivation cropping system.

• The Korean Journal of Ecology
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• v.25 no.3 s.107
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• pp.163-170
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• 2002

In order to analyze the life cycle of A. artemisiifolia var. elatior dormancy and some environmental factors inducing germination of the seeds were examined. The results were as follows : Dormancy of fertile seeds was broken in part within a month after seed collection in case of adequate moisture and alternating temperature was also effective in breaking dormancy. The temperature range, which allow germination was $12^{\circ}C{\sim}32^{\circ}C$. Optimum temperature for germination was $24^{\circ}C$. The seed of A. artemisiifolia var. elatior was light-independent. The difference of storage period appeared to have no particular effect on the viability of seeds at any time during the 9-month storage period. In the increasing temperature(IT) regime, A. artemisiifolia var. elatior seeds started to germinate at $16^{\circ}C$, showing the higher temperature the greater germination rate : the final germination percentage was 99.34%. On the other hand, in the decresing temperature(DT) regime, seeds began to germinate at $20^{\circ}C$ with the 1.34% germination. An induced dormancy occurred at $12^{\circ}C$ making the 5.34% final germination in the DT regime. Low temperature was more effective to break dormancy than higher temperature. Seeds of A. artemisiifolia var. elatior seems to be germinated in mid to late autumn or germination delayed until following spring. The above results suggest these variation of germination response in diverse environmental factors seems to be a physiological strategy to maintain their existence and to reproduce in the extreme thermal variation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.5
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• pp.425-431
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• 2006

In order to investigate the effects of ethylene on the seed development of three corn types (dent, sweet, and super sweet corns), aminoethoxyvinyl glycine (AVG) and silver thiosulfate (STS) and ethephon (2-chloroethylphosphonic acid, CEPA) were applied either on whole plants or shanks of ears at 9 and 21 days after silking. Ethylene production of developing super sweet corn seeds was much higher than those of sweet and dent corns. The cavity in the endosperm tissues of the super sweet corn started earlier and endosperm was collapsed more severely compared to those of sweet and dent corns. Ethylene production seemed to be related to the death of endosperm cells to form a cavity. Application of AVG and STS reduced ethylene production and delayed cavity formation in endosperm of super sweet corn seeds, while CEPA increased ethylene production and enhanced the time of cavity formation. AVG and STS increased 100-seed weight, while CEPA decreased.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.20
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• pp.107-114
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• 1975

To develop the technics of generation shortening for the breeding of rape oil composition. effect of the ethrel and hydroperoxide treatment for the increasing of germination ability during maturing period was investigated. It was the most effect ire for a generation shortening that the seeds after, 10 days treated with $H_2O$$_2$-0.5% and 2, 000ppm of ethrel and after 15 days treated with $H_2O$$_2$-0.5% and 500ppm of ethrel on 15 day after flowering were germinated 76% and 90% respectively. It suggested that effect of ethrel and hydroperoxide was multiple and 4-5 generations could pass in a year because one generation needed only 66-71 days.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.246-250
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• 2010

This study was conducted to find out the propagation method of a rare variety Daphne kiusiana Miq. in Korea through softwood cuttings. Daphne kiusiana Miq are the evergreen broad leaf tree which have lived in the southern part of Korea. The flowering time of Daphne kiusiana Miq is early spring and the flower has an attractive fragrance. Generally, plants are dioecious and only the male plants are found in Korea. Propagation by seed is very difficult in this tree. Softwood cuttings were taken to establish an efficient propagation method in Daphne kiusiana Miq Cuttings were grown in perlite:vermiculite (1 : 1), perlite, vermiculite, sand rooting media under shaded greenhouses during summer in 2007. The rooting rates of cuttings were 86.7%, 95%, 75% and 95% in perlite:vermiculite (1 : 1), perlite, vermiculite and sand media, respectively. Softwood cuttings taken on July and rooting at $27^{\circ}C$ were significantly improved the growth and rooting rates. Softwood cutting can be an effective means of propagation in Daphne kiusiana Miq.

• Parasites, Hosts and Diseases
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• v.35 no.4
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• pp.239-244
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• 1997

Genus Metasonimus has been a subject of taxonomic debates for several years. In morphological aspects, M. vokogawci has been thought to have three subtypes, namely Yokogawa type (M. yokogawai in strict sense) , Miyata type and Koga type. But dif- ferences in the intestinal pathology induced by these subtypes have not been studied yet. In this study we compared the pathological reactions inducted by M. yokoBnwai and Metcgonimus Miyata type using proliferating cell nuclear antigen (PCNA) index. Metacercariae (Mc) of M. yokogcuani were collected by artificial digestion of Plecoslossw oLtiveLis and Mc of Metngonimus Miyata type were collected from Zacco pEntvpus. Three hundreds Mc of each species were infected orally to ICR mice. The mice were sacrificed at 3, 6. 10. 16 and 23 days after infection and the small intestines were resected into three portions (proximal. middle, and distal) . Immunohistochemical staining for PCNA was done using PC-10 (DAKO-PCNA, CA, USA) The PCNA indices in M. Wokosnwci infected group on the 6th and 23rd day after infection were lower than in the control and Miyata type infect ed groups (p < 0.05) from all of the three intestinal regions. On the other hand, the control group and Ifetngonimus Miyata type infected group did not make any differences in PCNA indices. The villus/crypt WIC) ratio was also decreased significantly in M. Wokogcwni infected mice but not in Metagonimus Miyata type infected ones. It is suggested that M. wokogawci induce villous atrophy through a decrease in the cell proliferation at the crypt. The results of this study suggested that M. WokoBnwai induce more serious intestinal pathology than Metcsonimuf Miyata type.