• Proceedings of the Korean Society of Grassland Science Conference
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• 2002.09a
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• pp.37.1-37
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• 2002

• Proceedings of the Korean Society of Crop Science Conference
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• 1988.02a
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• pp.52-53
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• 1988

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.4
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• pp.323-334
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• 2004

Silage yield Potential and some agronomic characteristics of Korean improved and introduced corn hybrids from the United States were tested for five year in Gyeongsan, Gyeongsangbug-do and for one year in Hongcheon, Gangwon-do. 1. At 20 days after emergence, plant height and dry matter of hybrids were different, while the early growth of the hybrids was not correlated to the culm length and silage yield. 2. In Cyeongsan, silage yield potential of Suwon19 was relatively high, while most susceptible to rice black-streaked dwarf virus (RBSDV) disease and leaf senescence at harvest time. In contrast, silage yield potential and resistance to RBSDV of Cwanganok were moderate, while susceptible to leaf senescence at harvest. Generally, Suwon19 showed similar or higher yield than most introduced hybrids, while some introduced hybrids showed lower silage yield than Korean improved hybrids. Most introduced hybrids were more resistant to RBSDV and leaf senescence at harvest time compared to Korean improved hybrids. 3. In Hongcheon, silage yield of three Korean improved hybrids were lower than that of NC+5514 and DK729, while similar or higher than other introduced hybrids. af senescence of all Korean hybrids was severer compared to introduced hybrids.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.24 no.4
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• pp.45-52
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• 1979

This study was conducted to determine the proper time of corn marketing by cultivating time movement and cultural practice system establish. The rate of development of corn from planting to anther is a function of temperature rather than of photosynthesis. The major yield components of sweet corn for yield increase are more ear heavier grain weight, greater of kernels and heavier 100 grain weight. Early sowing has show yield decrease because yield capacity decreased with the shorting of vegetative growth and it was relatively susceptible to maize black streaked dwarf virus.

• Proceedings of the Korean Society of Crop Science Conference
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• 1988.02a
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• pp.74-75
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• 1988

• Applied Biological Chemistry
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• v.38 no.6
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• pp.522-527
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• 1995

To develop an antiviral agent for the rice black-streaked dwarf virus (RBSDV), a hammerhead type ribozyme, which has a potential target site on the genome segment 3, was designed. Oligonucleotides for the ribozyme and its substrate were synthesized, annealed, and cloned into a plasmid pBluescript II KS(+). Ribozyme and substrate RNAs were then synthesized by in vitro transcription with $T_3$ RNA polymerase, obtaining RNAs in expected size, 193 and 182 nucleotides, respectively. The substrate RNA was efficiently cleaved into two fragments when incubated with the ribozyme at $55^{\circ}C$, while the cleavage was not detected at $37^{\circ}C$. In addition, the segment 3 RNA of RBSDV was also cleaved into two fragments by the same ribozyme at $55^{\circ}C$. Taken together, our results demonstrated that the hammerhead ribozyme has an in vitro endonucleolytic activity and may be used as an antiviral agent in transgenic plants.

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.2
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• pp.129-136
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• 1991

Dry matter productivity at silage stage of two corn hybrids varying resistance to rice blackstreaked dwarf virus(RBSDV) and two sorghum hybrids varying growth duration was evaluated at six planting dates (Apr. 1, Apr. 15, Apr. 29, May 13, May 27, and June 10) in Kyongsan where RBSDV is prevalent.Corn was harvested 38-40 days after silking. For sorghum 1st-cut was made 19-22 days after heading and some regrowth (2nd-cut) on October 13. 1. Percent stand of both corn hybrids was over 91% at all planting dates, but that of sorghum ranged 37.2-80.3% depending on hybrids and planting dates. 2. The number of days from planting to emergence decreased as planting date delayed in both crops. The number of days from emergence to silking of both corn hybrids and a sorghum hybrid(P 956) decreased as planting date delayed, but that of the other sorghum hybrid(P 931) increased significantly after May 13 planting. 3. RBSDV infection rate of corn hybrids was highest at April 1 planting (Kwanganok 24.896, Jinjuok 63.0%) and decreased up to April 29 planting and then increased as planting date delayed. Sorghum was not infected by RBSDV at all. 4. EarfTotal dry matter ratio of corn ranged 30.6-47.9% and that of sorghum 3.1-30.7% depending on hybrids and planting dates. All the hybrids developed grain normally at all planting dates except a sorghum hybrid (P 931) which developed few grains after May 13 planting. 5. Crude (C) protein and C. fat contents were similar among all treatments. C. fiber content of P 931 was higher than that of both corn hybrids and P 956, but nitrogen free extract (NFE) was lower. C. fiber and NFE of both corn hybrids and 1st-cut sorghum were similar among the planting dates, but C. fiber and NFE of 2nd-cut of sorghum decreased and C. protein increased as planting date delayed due to plants were younger. 6. Dry matter (DM) yield of all hybrids decreased as planting date delayed except Jinjuok of which yield was highest at April 29 planting. DM yield of corn was similar to 1st-cut sorghum, but lower than total DM yield of sorghum at April 1 and 15 plantings where regrowth yield was high.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.3
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• pp.249-255
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• 1987

To find out the optimum planting date of silage corn in the rice black-streaked dwarf virus (RBSDV) pre-valent area, a resistant hybrid of Jinjuok and a susceptible hybrid of Suweon 19 were planted at the 8 planting dates from April 1 to June 10 at the la-day intervals. Considering escape of RBSDV and silage yield, the optimum planting date seems to be during the April in both hybrids. At the April plantings silage yield of two hybrids ranged from 17 to 23 tons/ha on the dry matter base due to a lower infection rate and higher tolerance to RBSDV and there was no difference in silage yield between two hybrids. At the May plantings yield of ear, stover, and silage, culm length, and digestible dry matter decreased significantly as planting date delayed due to an increase in RBSDV infection rate in both hybrids although performance of a resistant hybrid of Jinjuok was better than a susceptible hybrid of Suweon 19. At the June 10 planting RBSDV infection rate was low and performance of corn was better than that at the May plantings but poorer than that at the April plantings. The peak of small brown planthopper population occurred in late March or early April, middle June, middle July, and early September although it fluctuated a little yearly. Very low small brown planthopper population during the May may attribute to a lower RBSDV infection and high silage yields at the April plantings because the plants grow enough to be tolerant when infected by RBSDV in middle June. However, at the May plantings plants are too young to be tolerant when infected by RBSDV in middle June.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.1
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• pp.30-39
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• 1989

Forage productivity of cropping systems of rye - silage corn, silage corn - oats, silage corn - rape was studied in the south-eastern part of Korea where rice black-streaked dwarf virus(RBSDV) infection of corn are severe. Rye(cv. Paldanghomil) was planted on Oct. 20 of 1986 and harvested 10 times from April 5 to May 5 at the 5-day intervals in 1987, corn (cv. Suweon 19 and Jinjuok) was planted 5 times from April 5 to May 15 at the 10-day intervals in 1987, and oats(cv. Megwiri) and rape (cv. Velox) were planted 4 times from Sept: 4 to 25 at the 7-day intervals and harvested 4 times from Nov. 10 to Dec. 10 at the 10-day intervals in 1987. Considering yield, nutrition value, and in vitro dry matter digestibility (IVDMD), forage productivity of the cropping systems was compared. As harvesting time of rye delayed, plant height, dry matter(DM) yield, percent DM, crude fiber, and digestible DM yield increased, but crude protein, crude fat, and IVDMD decreased. However, nitrogen free extract was not different among the harvesting dates. As planting date of corn delayed, RBSDV infection rate increased. but DM yield of silage decreased. However, silage yield of Jinjuok was higher, but RBSDV infection rate was lower compared with Suweon 19 at all planting dates. DM yield of oats and rape decreased as planting date delayed. However, at Sept. 4 and 11 plantings yield of oats on Nov. 10 was much lower than that of rape, but the differences in yield between two crops decreased with delayed harvesting, and yield was similar on Dec. 10. A cropping system harvesting rye around April 20 and followed by planting corn in late April was best among the rye-corn systems considering yield and nutrition value of both crops. However, among the corn-oats or corn-rape cropping systems early April planting of corn and followed by early Sept. planting of oats or rape showed best results with similar yield potential of the best rye-corn cropping system.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.3
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• pp.379-385
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• 1983

Forage productivity of Job's tears (Coix lachryma-jobi L.) and adlay (C. lachryma-jobi var. mayuen (ROMAN.) STAPF) and a hybrid corn (Kwangog) and sorghum-sudangrass hybrid (Pioneer 988) was compared in the southern part of Korea where black streaked dwarf virus' (BSDV) is prevalent. Emergence of Job's tears and adlay was more delayed compared to a corn or sorghum-sudangrass hybrid under the drought field conditions. Early growth and regrowth of Job's tears and adlay were less than those of sorghum-sudangrass hybrid. Fresh weight, dry weight, and digestible dry matter of Job's tears and adlay cut once approximately 40 days after flowering were much higher than those of two cuts at every flowering stage. Dry weight of one-cut Job's tears and ad lay harvested 40 days after flowering was similar to the total dry weight of three-cut sorghum-sudangrass hybrid but higher than that of silage corn. Digestible dry matter production was greater in the order of sorghum-sudangrass, corn, one-cut and two-cut Job's tears and adlay. Corn was severely infected with BSDV, but digestible dry matter was relatively high due to its higher in vitro dry matter digestibility. Among the Job's tears and adlay varieties, a variety of Job's tears with globular fruit shape was best for forage production due to its taller plant height, thick stem, wider leaf blades, higher leaf blade/total dry weight ratio, and higher forage yield. However, hulled grain yield of ad lay varieties was higher than that of Job's tears due to a higher hulled/rough grain ratio although they had similar rough grain yields.