• Korean journal of applied entomology
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• v.14 no.4 s.25
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• pp.214-214
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• 1975

This study was conducted to evaluated the nature of the variety Tongil(Suweon 213-1) in resistance to the striped rice borer, Chilo suppressalis Walker, comparing with those of Rexoro(susceptible check) and TKM-6(resistant check) selected at IRRI. 1. The striped rice borer moths much more preferred the variety Tongil for oviposition than the varieties Rexoro and TKM-6. The variety Tongil and more egg masses and number of eggs than the varieties Rexoro and TKM-6, while TKM-6 having more egg masses and more number of eggs than Rexoro. This reaction was consistent throughout the test regardless of the number of tillers per hill. 2. In laboratory, preference of larvae for feeding was studied with 5cm of stem pieces of the varieties. The results showed, in contrast to the case of ovipositional preference, that the striped rice borer larvae least preferred the stems of Tongil among the test varieties, while larvae much more preferred the stems of Rexoro than those of TKM-6. 3. The larval weights at 20 days later infested on the 40 day-old plants were the lowest on Tongil among the test varieties. On the variety Rexoro the larvae had heavier body weights(43.0mg), higher pupation(64.9%) and higher adult emergence(83.3%) than those on Tongil(larval weights 30.3mg, pupation 60%, adult emergence 60.7%) and TKM-6(larval weights 35.7mg, pupation 56.3%, adult emergence 51.9%). The pupal weights, however, were not consistent among the test varieties and/or sexes in comparison with the larval weights, pupation and adult emergence above mentioned. 4. Field experiments indicated that the incidence of dead hearts at 70 days after transplanting was relatively higher on the variety Tongil(11.1%) than those on Rexoro(8.9%) and TKM-6(8.4%), and the incidence of white heads at harvest was, in contrast to the dead hearts, lower on Tongil(9.8%) than those on Rexoro(27.4%) and TKM-6(13.9%). At harvest lower larval survival observed on Tongil (49 larvae/40 hills) than those on the susceptible variety Rexoro(104 larvae/40 hills) and on the resistant variety TKM-6(70 larvae/40 hills). The average larval weights collected from three test varieties at harvest were 80.5mg from Tongil, 83.7mg from TKM-6 and 99.6mg from Rexoro. 5. Increased nitrogen fertilizer application to the variety Tongil, the striped rice borer damage was increased. Also, preference of larvae for feeding significantly increased with the increase of nitrogen fertilizer application. 6. Any specific association between the plant characters and striped rice borer resistance could not be found. The variety Tongil even having large number of tillers, short plant height, large stem, broad leaf, etc, had still high preference of moths for oviposition, low preference of larvae for feeding, low damage, and relatively high antibiosis. 7. Resistance of the variety Tongil to the striped rice borers seemed to be associated with the low feeding preference and the relatively high antibiosis, not associated directly with the ovipositional preference.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.31-31
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• 2022

Rice contains a wealth of genetic diversity, both within Oryza sativa and in related A-genome species. Decades of genetic research into this diversity have identified dozens of major genes contributing to a wide variety of important traits, including disease resistance, abiotic stress tolerance (drought, salinity, submergence, heat, cold etc.), grain quality, flowering date and maturity and plant architecture. Yet despite these opportunities, very few of the major genes and QTLs known have been successfully applied through rice breeding programs to produce sustained changes in farmer's fields. This presentation will briefly examine some of the factors limiting application of major genes in the mainstream breeding programs, and steps that have been taken to alleviate those limitations. As a result of these interventions, dozens of major genes that were previously unavailable to breeders are now being used confidently in the variety development process. Case studies will be discussed of genes critical for blast resistance worldwide, rice yellow mottle virus for Africa, and new validated QTLs for salinity tolerance.

• Korean journal of applied entomology
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• v.13 no.1 s.18
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• pp.33-39
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• 1974

For the investigations on the mechanism of blast disease resistance in the rice variety 'Toilg-il', Ihe chemical contents such as silicate, nitrogen and flavonoid in the leaf blades of tile variety were determined as compared to moderately susceptible variety 'Pung-kwang' A correlation between disease severity of rice blast and the chemical contents in the variety 'Pung-kwang' were also studied. The results showed that silicate and flavonoid contents were decreased inversely with application of nitrogen fertilizer, and negative correlation between silicate and flavonoid contents and disease severity in the field were observed. In the resistant variety 'Tong-il', these chemical contents and silicified cells were significantly higher than in the variety 'Pung-kwang' From these results, it seemed that the high contents of silicate and flavonoid in the leaf blades were related closely to the resistance of the variety 'Tong-il'.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.112-112
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• 2017

Rice blast caused by Magnaporthe oryzae is one of the most serious diseases that affect the quantity and quality of rice production. The use of resistant rice varieties would be the most effective way to control the rice blast. However R gene incorporation into the rice variety takes time and pathogen could overcome the R gene effects after for a while. For monitoring the rice blast resistance gene distribution in Korean varieties, the four major blast resistance genes against M. oryzae were screened in a number of Korean rice varieties using molecular markers. Of the 120 rice varieties tested, 40 were found to contain the Pi-5 gene, 25 for the Pi-9 gene, 79 for Pi-b and 40 for the Pi-ta gene. None of these rice varieties includes tested 4 R genes. 3 R genes combination, Pi-5/Pi-9/Pi-b, Pi-5, Pi-9.Pi-ta, or Pi-9/Pi-b/Pi-ta were found in 12 varieties, the rice blast disease severity were showed as resistant in the rice verities containing Pi-9/Pi-b/Pi-ta R genes combination, respectively. Also pathogenic diversity of M. oryzae isolates collected in the rice field from 2004 to 2015 in rice field in Korea were analyzed using rice blast monogenic lines, each harboring a single blast resistance gene. Compatibility of blast isolates against rice blast monogenic lines carrying the resistance genes Pi5, Pi9, Pib, and Piz showed dynamic changes by year. It indicates that pathogen has high evolutionary potential adapted host resistances to increase fitness and would lead to rice blast resistance bred into the cultivar becoming ineffective eventually.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.92-92
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• 2017

Bakanae disease is one of the most serious and oldest problems of rice production, which was first described in 1828 in Japan. This disease has also been identified in Asia, Africa, North America, and Italy. Germinating rice seeds in seed boxes for mechanical transplantation has caused many problems associated with diseases, including bakanae disease. Bakanae disease has become a serious problem in the breeding of hybrid rice, which involves the increased use of raising plants in seed beds. The indica rice variety Shingwang was selected as resistant donor to bakanae disease. One hundred sixty nine NILs, YR28297 ($BC_6F_4$) generated by five backcrosses of Shingwang with the genetic background of susceptible japonica variety, Ilpum were used for QTL analysis. Rice bakanae disease pathogen, CF283, was mainly used in this study and inoculation and evaluation of bakanae disease was performed with the method of the large-scale screening method developed by Kim et al. (2014). SSR markers evenly distributed in the entire rice chromosomes were selected from the Gramene database (http://www.gramene.org), and the polymorphic markers were used for frame mapping of a $BC_5F_5$ resistant line. Here, we developed 168 near-isogenic rice lines (NILs, $BC_6F_4$) to locate a QTL for resistance against bakanae disease. The lines were derived from a cross between Shingwang, a highly resistant variety (indica), and Ilpum, a highly susceptible variety (japonica). The 24 markers representing the Shingwang allele in a bakanae disease-resistant NIL, YR24982-9-1 (parental line of the $BC_6F_4$ NILs), were located on chromosome 1, 2, 7, 8, 10, 11, and 12. Single marker analysis using an SSR marker, RM9, showed that a major QTL was located on chromosome 1. The QTL explained 65 % of the total phenotype variation in $BC_6F_4$ NILs. The major QTL designated qBK1 was mapped in 91 kb region between InDel15 and InDel21. The identification of qBK1 and the closely linked SSR marker, InDel18, could be useful for improving rice bakanae disease resistance in marker-assisted breeding.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.310-310
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• 2017

'Gawaji 1', an early maturing and low amylose content rice variety adaptable to double cropping system with barley as later winter crop., was developed by the crop breeding team of Crop Research Division, GARES, Hwaseong, Korea in 2016. 'Gawaji 1' was derived from a cross between 'Baegjinju' and 'Sangmibyeo' in 2004. This variety had heading date of August 4 in Gyeonggi Province. It had a semi-elect plant type and resistance to lodging with strong culm. Its culm length was 67 cm. This variety had 15 tillers per hill and 104 spikelets per panicle. It was medium grain variety showing 1,000 grain weight of brown rice of 19.3g. Its protein contents of milled rice was 8.2% which was lower than 'Baegjinju'. Its milling ratio was 75.5% which was higher than 'Baegjinju'. The yield of milled rice was 5.0 MT/ha under the ordinary culture of the local adaptability test in 3 areas of Gyeonggi Province for three years. 'Gawaji1' is highly adaptable to Gyeonggi Province, especially to northern region of Han River.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.645-648
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• 2009

"Deuraechan" is a new japonica rice variety developed and registered by the rice breeding team of Department of Rice and Winter Cereal Crop, NICS, RDA in 2008. This variety was derived from a three way cross Iksan438, YR19105Acp222 and Milyang165. This variety has about 122 days of growth duration from transplanting to harvesting in Honam and Youngnam plain of Korea. It is about 76 cm in culm length and tolerance to lodging. In reaction to biotic stresses, it shows moderately resistance to blast, resistance to bacterial blight pathogen races from $K_1$ to $K_3$, and Rice stripe virus, but susceptible to other major diseases and insect pests. The milled rice of "Deuraechan" has high Quality, midium short grain. The milled rice yield of this variety is about 6.52 MT/ha in local adaptability test for three years. "Deuraechan" would be adaptable to Middle plain, Honam plain and Youngnam plain area of Korea.

• Korean Journal of Breeding Science
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• v.42 no.3
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• pp.302-306
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• 2010

'Migwang' is a new japonica rice variety developed from a cross between SR15926-10-2-3-3-3 having a good canopy architecture and multiple disease resistance, and Iksan431 having a translucent milled rice and good eating-quality with a view of developing a new variety having multiple disease resistance by the rice breeding team at NICS, RDA in 2009. The heading date of this variety is August 15 and later than check variety, Hwaseongbyeo, by four days. 'Migwang' has 75 cm of culm length and 98 spikelets per panicle. This variety showed longer heading delay and higher spikelet sterility than those of Hwaseongbyeo while exposed to cold stress. This variety showed resistance to blast disease and bacterial leaf blight, but susceptible to rice stripe virus and planthoppers. The milled rice of this variety exhibits translucent, clear non-glutinous endosperm and short grain shape. 'Migwang' has better palatability index of cooked rice than that of Hwaseongbyeo. The whole grain rate of milled rice and milled rice recovery of 'Migwang' are higher than those of Hwaseongbyeo as 96.8% and 73.1%, respectively. 'Migwang' has 5.5 MT/ha in milled rice. 'Migwang' could be adaptable to the middle plain area, mid-western and southeastern costal areas and mid-mountainous areas in Korea.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.265-265
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• 2017

This study was carried out to develop rice variety integrated with rice bacterial blight resistance gene and to know the information of major agronomic traits of developed variety. Advanced backcross Lines 21 having Xa3 and Xa21 gene cross from japonica cultivar Hwanggeumnuri and indica variety IRBB21. Days after seeding and culm length of ABLs21 were 108 days (Aug. 16) and 76 cm, respectively. Ripened grain rates was 87.4 %, which was similar to the parents. 1000 grain weight of brown rice of ABLs21 was 21.4g, which was lower than the donor parent. Milled rice yield of ABLs21 was 532 kg/10a, which was smaller than recurrent parent and higher than the donor parent. Grain length/width ratio of brown rice was form of japonica with short-ellipse and glossiness of cooked rice has japonica trait. Head rice rate showed a large difference compare to the donor parent and similar to the recurrent parent. ABLs21 would be useful genetic resources for resistance breeding program against bacterial blight.

• Korean Journal of Breeding Science
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• v.40 no.4
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• pp.452-455
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• 2008

"Baegseolchal" is a new Japonica type waxi rice variety developed and registered by the rice breeding team of Department of Rice and Winter Cereal Crop, NICS, RDA in 2007. This variety was derived from a across between Iksan435 which is highly tolerant to lodging and high yield potential, and Iksan425 which is resistance to multiple diseases. This variety has about 120 days of growth duration from transplanting to harvesting in middle, Honam and Youngnam plain of Korea. It is about 80 cm in culm length and tolerant to lodging. It is moderately resistant to blast, and resistance to bacterial blight pathogen races from $K_1$ to $K_3$, but susceptible to other major diseases and insect pests. "Baegseolchal" is midium-short grain and the milled rice exhibits high whiteness. The milled rice yield was about 5.37 MT/ha in local adaptability test for three years. "Baegseolchal" would be adaptable to plain areas south of the Chungnam Province of Korea.