• 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.

• Research in Plant Disease
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• v.12 no.1
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• pp.62-64
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• 2006

July in 2005, we collected infected maize plant that showing stripe dwarf disease on maize leaf in Jeonbuk provinces including Gochang-gun and conducted genomic dsRNA extraction and RT-PCR. Genomic dsRNA was extracted directly in infected maize plant and electrophoresis in agarose gel. We confirmed 10 segments of genomic dsRNA. We conducted RT-PCR by genomic dsRNA and specific primer of S7, S8 and S10. As a result, specific band of expected size was confirmed respectively. In the results of dsRNA and RT-PCR analysis, we confirmed Rice black-streaked dwarf fijivirus (RBSDV) from naturally infected maize plant. Occurrence of RBSDV of maize plant was dealt 22 ha's damage in maize field. The occurrence rate was 80% in a lot of places of disease.

• Proceedings of the Korean Society of Grassland Science Conference
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• 1999.06a
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• pp.78-79
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• 1999

미국으로부터 도입된 18종의 옥수수 품종과 국내품종 1종을 가지고 1997년에 경기 수원, 경북 경산 및 충남 천안에서 사일리지 생산성 비교 시험을 수행하였고, 특히 흑조위축병(RBSDV) 이병률이 옥수수의 가소화 영양소 총량(TDN)에 어느 정도 영향을 미치는가를 알아보기 위하여 일련의 조사를 수행하였다.(중략)

• The Plant Pathology Journal
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• v.28 no.4
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• pp.428-432
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• 2012

We determined the complete genome sequence of a Vietnamese isolate of Southern rice black-streaked dwarf virus (SRBSDV). Whole genome comparisons and phylogenetic analysis showed that the genome of the Vietnamese isolate shared high nucleotide sequence identities of over 97.5% with those of the reported Chinese isolates, confirming a common origin of them. Moreover, the greatest divergence between different SRBSDV isolates was found in the segments S1, S3, S4 and S6, which differs from the sequence alignment results between SRBSDV and Rice black streaked dwarf virus (RBSDV), implying that SRBSDV evolved in a unique way independent of RBSDV. This is the first report of a complete nucleotide sequence of SRBSDV from Vietnam and our data provides new clues for further understanding of molecular variation and epidemiology of SRBSDV in Southeast Asia.

• Journal of The Korean Society of Grassland and Forage Science
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• v.10 no.1
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• pp.42-47
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• 1990

Silage productivity of 7 corn and 3 sorghum hybrids was determined at two planting dates differing in rice black-streaked dwarf virus (RBSDV) infection rates in the southern part of Korea where RBSDV is prevalent. 1. Percent stand was similar between two planting dates, but that of corn hybrids (85.0-99.5 %) was higher compared with sorghum (59.8-82.3 %). Culm length of corn hybrids at April 23 planting was longer compared with May 20 planting, but that of sorghum hybrids was similar between two planting dates. 2. RBSDV infection rate of corn hybrids at April 23 planting was lower compared with May 20 planting, but sorghum was not infected at both planting dates. Among corn hybrids Suweon 19 was most severely infected, but Suweon 99 was least infected at both planting dates. 3. Percent ear bearing plants and earltotal dry matter (TDM) ratio of corn hybrids at April 23 planting was higher than those of May 20 planting. Among the corn hygrids percent ear beraring plants, ear/TDM ratio of Suweon 19 was lowest at both planting dates due to severe RBSDV infection. Ear/TDM ratio of sorghum hybrids was below 17.8 % due to sterility and partially bud damages. 4. Silage yield at April 23 planting was higher than that at May 20 planting and sorghum hybrids outyielded corn hybrids. Silage yield of Suweon 19 and Jinjuok was lowest due to severe RBSDV infection. 5. Crude protein was similar regardless planting dates, species, and varieties except the lowest P 931. Ether extract at April 23 planting was lower then that at May 20 and corn was lower compared with sorghum hybrids. Crude fiber and nitrogen free extracts(NFE) was similar between planting dates. Crude fiber of corn was lower, but NEF was higher compared with sorghum, but similar among hybrids in a species. 6. In vitro dry matter digestibility (IVDMD) at May 20 planting was higher than that of April 23 planting and corn was higher than sorghum hybrids. Digestible dry matter (DDM) of both corn and sorghum at April 23 planting was higher than that of May 20 planting. At April 23 planting DDM of all corn and sorghum hybrids was similar, but DDM of Suweon 19 and Jinjuok was lower than other corn and sorghum hybrids.

• Korean Journal Plant Pathology
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• v.1 no.2
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• pp.109-114
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• 1985

The experiments were conducted to clarify the influence of transplanting date on the occurrence of rice virus in field condition of 1984. The rate of RBSDV (rice black-slreaked dwarf virus) viruliferous vector, smaller brown planthopper (Laodelphax striatellus Fallen), was shown to be $13.6\%$ at the 2nd adult and that of rice stripe virus (RSV) viruliferous was $6.7\%$ at the 2nd adult. The vector in the field was begun to come from May 29, the maximum densities were 19.6 insects per hill on June 13 in cultivar Chucheongbyeo, 19.3 in Nagdongbyeo, 7.4 in Cheongcheongbyeo and 4.9 in Samgangoyes. The number of vectors per hill was inclined to increase by early transplanting. Although the infection of rice virus in nursery bed was not recognized until May 30 transplanting, the nursery infection could be seen from June 10 transplanting. The highest rate of nursery infection with RSV was $4.1\%$ at June 10 transplanting plot, and that of RBSDV was $14.2\%$at June 20 trans planting plot. The infection of rice virus in paddy field was the highest at May 20 transplanting plot, the lowest at July 10 plot. The earlier transplanting, the more severe occurrence of rice viruses. Occurrence of infected plants with RBSDV was shown to increase more rapidly at May 20 and May 30 planting plot than May 10 plots. However, the occurrence of infected plant with RSV was more rapid at May 10 transplanting plot than May 20 and 30.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.3
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• pp.229-235
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• 1988

Several agronomic characters, feed value, and mineral uptake of two corn hybrids infected by different degrees of rice black-streaked dwarf virus (RBSDV) were studied at the south-eastern part of RBSDV prevalent areas in Korea. Although both hybrids were infected with RBSDV by 100%. culm length of Suweon 19 was more severely reduced than that of Jinjuok and there were positive correlations between culm length and top dry weight of individual plants. The reduced culm length was largely due to the shortened length of upper five internodes in both hybrids and also due to the reduced number of internodes in Jinjuok. As culm length reduced, percent ear-bearing plants, average ear weight, and number of kernels per ear reduced significantly in both hybrids. The kernel weight of Suweon 19 decreased with reduced culm length, but that of Jinjuok was similar among the different culm lengths. However, as culm length decreased, crude protein and fiber in whole plants and N, P, K, Mg in culm ＋ leaf sheath increased, but nitrogen free extract in whole plant decreased. And crude fat in whole plant and N, P, K, Mg concentrations in leaf blades and ear were similar among the culm lengths.

• 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.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.10a
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• pp.24-24
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• 2017

• 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.