• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.s02
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• pp.34-44
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• 1989

The stability of rice cultivation in Korea is largely depended on climatic conditions, especially, low temperature at the period of early growth stage and after heading. The improvement of cold tolerant varieties and appropriate cultural practices in rice are very effective to minimize the cold damage. This paper is summarized the mechanism and counterplans of cold injury of rice plants. The paddy area having commonly cold injury in Korea is approximately 15, 522ha in 1,709 sites on the national scale. The cold damage at seedling stage in nursery bed appeared to poor germination, leaf discoloration, dead seedlings and seedling rot ect.. At the vegetative stage, the decreased tiller number due to poor rooting and the delayed heading caused by slow growth and panicle differentiation are commonly showed. The cold injury at early reproductive stage appeared to the degeneration of spikelets and rachis - branches, while that at meiosis stage showed to increased sterility due to poor development of pollen and shortened panicle length with delaying heading, therefore the grain yield is largely decreased. The cold damage at heading and ripening stages showed to poor pollination and fertilization, low panicle exsertion, poor grain filling and finally grain quality became low. To minimize the cold injury to rice plants by low temperature, following counterplans would be recommonded ; Improvement of the cold toelrant rice varieties for the regions of midmountains and alpines. Raising healthy seedlings at upland nursery beds and by using of growth regulators such as ABA, Fuchiwang and Tachiace. Soil improvement and organic matter application to reduce cold damage by increasing water and fertilizer holding capacities in the paddy field having commonly cold water and in the place where cold damage is regularly occurred. Appropriate fertilization for raising healthy rice plants to tolerate under low temperature condition. Water management to increase water temperature in the paddy such as depth watering, round channels and polyethylene tubes around the field. Establishment of the optimum cultivation time of rice based on minimum, mean and maximum temperatures at different regions with appropriate rice varieties.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.3
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• pp.163-166
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• 2000

Cassia mimosoides var. nomame was grown at five phosphate rates (0, 5, 15, 25 and 35 kg/10a) at Cheju in 1998 to determine the influence of phosphate rate on growth, forage yield and quality. As phosphate rate increased from 0 to 35kg/10a, the plant growth was increased such as days to flowering, plant height, the number of branches and green leaves per plant, stem diameter and SPAD (Soil Plant Analysis Development) reading values of leaves but the number of withering leaves per plant decreased. Fresh forage yield was 3, 291kg/10a at 0 kg/10a of phosphate rate and increased 5, 200 and 5, 230 kg/10a at 25 and 35 kg/10a of phosphate level, respectively. Dry matter, crude protein and total digestible nutrients (TDN) showed the same tendency of changes as the fresh forage yield. Crude protein, crude fat, nitrogen free extract and TDN content increased but crude ash and crude fiber content decreased as the increasing of phosphate rate increased.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.3
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• pp.334-339
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• 1995

Removal of apical ear after silking is a method to increase seed production in corn inbreds. Due to the phenomenon of apical dominance, the subapical ear would develope and produce seeds following the removal of the apical ear. This experiment was conducted to investigate the varietal difference in subapical ear development and seed production. Days to silking of subapical ears were delayed by about 4 days compared to normal apical ears. Cob length and filled ear length of subapical ears across seven inbreds tested were reduced by 21% and 36%, respectively. Those of inbred INV302 decreased less and subapical ear of inbred NC246 were barren, which incicated the varietal defferences. Number of kernel rows, kernels per row, and total kernels per ear also decreased. The mean reduction rates for those characters were 28%, 37%, and 47%, respectively. Weights of ears and kernels were reduced and showed different response among inbred lines. Coefficients of variations for cob and filled ear lengths, number of kernel rows and kernels were greater in subapical ears than in apical ears. Seed production of subapical ears was 40 ~ 80% of apical ears, depending on inbred lines when the apical ear is removed immediately after silking.

• Journal of Korean Society of Forest Science
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• v.3 no.1
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• pp.1-4
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• 1963

Present experiment has been carried out in order to make clear the abnormalities of the female gametophyte formation and its relation to fertility, using the short-style of F. koreana, the results of which are summarized as follows : (1) Anatropous ovule has single integument with thick cell-layer and tiny nucellus consisting of nucella-epidermis and megaspore mother cell. (2) Meiotic division of megaspore mother cell takes place around middle or latter part of March, while that of microspore mother cell occurs from the end of September to the beginning of October. (3) Megaspore mother cell stage is long, and ranges from October to March next year. (4) Formation of mature embryo sac is not completed until the beginning of May, approximately one month after blooming. (5) Normal embryo sac is rare, most of the nucellus being devoid of embryo sac.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.2
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• pp.141-146
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• 1982

In the vine training methods, main vine training yield was 36% higher than the non-training. Main vine training date was studied for increasing cone yield in hops. Training was done four different dates from May 14 to May 29 including non-training as a check. Earlier training increased cone yield from 12 to 43% due to more beared branches per plant, longer branch length caused by accelerating the branch growth, and an increased of number of cone per beared branch and total cone number.

• Horticultural Science & Technology
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• v.18 no.1
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• pp.28-32
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• 2000

This study was carried out to investigate the effects of uniconazole treatment on the growth and flowering of potted Chrysanthemum indicum L. for high quality pot plant production. Uniconazole was drenched at 0.05, 0.01, or 0.15 mg a.i./pot at 14 days after planting (DAP) of rooted cuttings. Simultaneously the short-day treatment (SDT) and pinching were adapted. The same amount of uniconazole (0.05 mg a.i./pot) was spilt drenched at once, twice, and three times, respectively, at 1 week interval. Uniconazole markedly reduced plant height, branch length, and stem diameter. Plant height was reduced linearly with increasing uniconazole concentration at 0.05, 0.01, or 0.15 mg a.i./pot up-to 41.6%, 52.5%, and 58.5%, respectively. In 0.05 mg a.i./pot, the number of branches greatly increased and plant height of 22.6 cm was adequate for pot plant. However, higher concentrations (0.10, 0.15 mg a.i.) were not suitable for production of high quality pot plant (17.0, 14.8 cm, respectively). Pinching and SDT decreased the number of days to visible bud, while uniconazole treatments delayed days to visible bud by 5-9 days compared with pinching and SDT. Number of visible buds was highest at 0.05 mg a.i./pot uniconazole treatment. However, flower diameter was decreased by uniconazole treatment, resulting in compact form. Number of stomata was increased by uniconazole treatment. The length of vascular tissues of uniconazole-treated plants ($11.2{\mu}m$) was smaller than that of non-treated plants ($15.0{\mu}m$, and the size of xylem vessel was also decreased. Uniconazole treatment at 0.05 mg a.i./pot at 14 DAP with pinching and SDT were recommended for pot plant production of C. indicum L.

• Korean Journal of Medicinal Crop Science
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• v.8 no.1
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• pp.64-68
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• 2000

This study was conducted to determine effects of seeding date, method, and amount on the growth and yield in dill (Anethum graveolens L.). Dill was seeded at six different dates (from Feb. 15 to May 16 at 15 days interval) and two seeding methods (drilling and broadcasting). Required days to emergence, days to flowering and days to maturity were decreased as seeding date was late. In growth characteristics, plant height was significantly different at different seeding times, and lodging affect plant growth in the case of Feb. 15 and Mar. 2 seeding. Essential oil contents was not affected by different seeding times except Feb. 15. Seed yield was different at different seeding times. In seeding method tests, yield was increased by 14% in drill seeding compared with those in broadcast seeding. Regarding the amount of seeding, the yield from the plot of 3 l /10a was increased more 24% than 1 l/10a plot. As a result, this study suggest that dill have to be seeded before April 1 with drill seeding method and the optimum seeding amount appeared to be 3 l/10a.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.4
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• pp.470-476
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• 2014

The purpose of this study was to investigate the effects of sowing time on ecological responses, growth, and yields of cowpeas grown in plastic greenhouses in a southern region of South Korea. Experiments were carried out in Naju, Jeonnam Province (Latitude $35^{\circ}$ 04' N, Longitude $126^{\circ}$ 54' E) during 2012 and 2013. The intermediate-erect type strains used in this study were Jeonnam1 and Jeonnam2. Sowing was performed between mid-March and mid-August at intervals of one month. The days from sowing to emergence was significantly higher for the mid-March sowing (12 days) but no significant differences were observed among the other sowing dates (3 to 4 days). The days from sowing to first flowering were shorter for sowing dates between mid-March and mid-July because sowing time was delayed and then were lengthened again at mid-August sowing; the days were longest at mid-March sowing (around 75 days) and were shortest at mid-July sowing (30 days). The days from first flowering to harvesting were short for the sowing dates between mid-March and mid-May (24 to 28 days) but were relatively long for subsequent sowing dates (35 to 38 days). Stem and peduncle lengths were relatively long for the mid-April and mid-August sowing dates. Main-stem node number was highest for the mid-June sowing. Branch number per plant was highest for the mid-March sowing. The mid-March sowing displayed the highest number of pods per plant as well as the heaviest seed weight. Yield per 10 ares was highest for the mid-March sown Jeonnam1 and the Jeonnam2 strains (340 and 367 kg respectively), and then tended to decrease due to subsequent delays in sowing.

• Korean Journal of Weed Science
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• v.3 no.1
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• pp.14-22
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• 1983

To study ecological characteristics of Cyperus serotinus occuring in Korea its propagules were collected from 6 locations from the northern part to the southern part of Korea (Chuncheon, Suweon, Iri, Jeonju, Gwangju, Milyang) in 1981, cultured and replanted 4 times (May 20, June 5, June 20, July 5) in 1982. They flowered from August 10 to August 29 in the plants planted on May 20 and from August 22 to September 4 in the plants planted on July 5. Plant height, number of tillers and top fresh weight were 85-100cm, 375-1,500 tillers/$m^2$ and 500-1,750g/$m^2$, respectively, when they were planted on May 20, and 58-67cm, 300-625 tillers/ $m^2$ and 125-250g/$m^2$, respectively, when they were planted on July S. Weight of seeds and number of rhizomes per plant were 20-50g/$m^2$ and 20.75-61, respectively, whey, they were planted on May 20, and 5-17.5g/$m^2$ and 51.5-80.25 when they were planted on July 5. Local collections showed. the same morphological characteristics at the level of species identification, but there existed variations among the local collections. Cyperus serotinus from Chuncheon and Suweon were longer in the length of inflorescence, than those from Gwangju and Milyang and rhizomes from Chuncheon and Suweon were thicker than the others. Each of local collections may be regarded as different ecotype based on the above mentioned differences in morphology, growth and flowering response to the planting date. The results appear to imply that Cyperus serotinus weeds occuring in various locations of Korea are different one another in competitive ability with rice crop.

• Korean Journal of Agricultural Science
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• v.3 no.1
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• pp.39-51
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• 1976

As an accempt to increase thc efficiency of land use and the food production to achieve the national goal in the food self-sufficiency, nine cropping systems on the upper-land were examined in pure-stand and in mixtures of soybean, corn, potato and radish. The important conclusions of this study were summarized as follows; 1. The flowering date of soybean was two or three days earlier in pure-stand than in the mixture with corn. The maturing date two days earlier in the pure-stand than in the mixture with corn. The flowering and maturing dates were not different among various cropping systems in corn. 2. The stem length of soybean was significantly different among various cropping systems. Soybean in pure-stand was shorter in stem length than with corn. 3. The number of pods per soybean plant did not give any significant differences among various cultivation methods. 4. The length of internode and the number of nodes per soybean plant in the mixture with corn were greater than in the pure-stand. In the number of branches per plant this was reversed. 5. The average stem dry weight of soybean per 10a was not significantly different among various cultivation methods. 6. The soybean yield per 10a in the pure-stand was obviously greater than the mixture and there were significant differences among cultivation method within the mixture with corn in soybean yield. 7. The 1,000-grain weight of soybean was significantly different and those in the pure-stand was heavier than those in the mixture with corn. 8. Grain weight per soybean plant and the stem diameter in the pure-stand were significantly lesser than those in the mixture with corn. 9. In the comparisons of corn in the pure-stand and in the mixture with soybean, plant height, number of ear per 10a, mean ear weight and remember of grain per plant, 100-grain weight, ear length, ear girth and number of ear pel plant were not significantly different among various cultivation methods except for the grain yield per 10a. 10. In the economic analysis, the mixture with soybean and corn gave the greatest gross income. The combination 7 was the best which was 47.6% increase income comparing with the soybean pure-stand. 11. As it can be assumed, soybean plant was influenced greatly than corn by various cropping system. It is necessary to study more complex cropping system finding and giving more desirable multiple cropping system for the farmer.