• The Korean Journal of Pesticide Science
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• v.10 no.2
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• pp.124-130
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• 2006

Rice plant extracts of brown planthopper (BPH) resistant rice varieties, Jangseongbyeo (JSB) and Hwacheongbyeo (HCB) at different growth stages (seedling, tillering, heading and ripening) were sequentially fractioned using hexane, ethyl ether, ethyl acetate, butanol, and distilled water. The extracts were applied to BPH susceptible rice variety, Dongjjnbyeo (DJB), to investigate the insecticidal and repellent effects against BPH. BPH insecticidal effects were not clearly observed with almost all of the extract fractions obtained from both JSB and HCB varieties for 12 h, whereas the ethyl ether and hexane extract fractions showed about 10 to 30% of BPH mortality in 24 to 48 h of application periods. An effective BPH repellent activity was found with the applications of ethyl ether extract fractions obtained from JSB variety. The extract fractions obtained from HCB variety did not show any different repellence among the various fractions. The BPH repellent effects of the extract fractions obtained at different growth stages of either JSB or HCB varieties did not show any correlations. The effect of ethyl ether fraction on BPH repellent was continually increased by 30 h after treatment and thereafter decreased. In addition, the first sub-fraction separated by a flash column chromatography eluted with chloroform:methanol (9:1, v/v) from the BPH effective ethyl ether faction in JSB variety might be meaningful to repel BPH from BPH susceptible target rice plants. The results indicated that the ethyl ether fraction obtained from JSB was higher in repellent activity than in insecticidal activity, and suggesting that there might be specific substance(s) in the first sub-fraction (sF1) of the ethyl ether fraction in JSB that could provide repellent activity against BPH.

• Research in Plant Disease
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• v.24 no.4
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• pp.313-320
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• 2018

Fusarium infection rate of the paddy rice grain after harvest seemed to be influenced by the average temperature from late July (before heading) to the end of September (during ripening). In case of 2010 and 2013 in which average temperature of the same period was similar, Fusarium infection was related to cumulative precipitation, cumulative precipitation days, and precipitation durations over two days. The distribution ratio of Fusarium species complex isolated from paddy rice grains after harvest was 57% in 2010 and 45% in 2013 for Fusarium graminearum species complex (FGSC), 35% and 50% for Fusarium incarnatum-equiseti species complex, and 8% and 5% for Fusarium fujikuroi species complex (FFSC). The distribution ratios of FGSC and FFSC were higher in 2010 than 2013. Among the total 26 promoted rice varieties, the 'Mihyang' showed resistant response against the natural infection with Fusarium species belonging to FGSC and the varieties of 'Nampyeong', 'Hi-ami'and 'Younghojinmi' showed resistant response against the natural infection with overall Fusarium pathogens. Majority of the promoted rice varieties could not be classified for resistance or susceptibility. These results are valuable as basic data to determine the resistance and susceptibility of rice variety against Fusarium spp. infection in the field.

• Korean Journal of Breeding Science
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• v.40 no.4
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• pp.443-446
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• 2008

'Gangbaek' is a japonica rice variety developed and registered by the rice breeding team of Department of Rice and Winter Cereal Crop, NICS, RDA in 2006. 'Gangbaek' was derived from a cross between 'Suweon345' with good grain quality and 'DV85' resistant to bacterial blight, $K_{3a}$. $F_1$ plants were grown in the greenhouse in winter of 1992/1993 and backcrossed with 'Suweon345' as the recurrent parent. Plants resistant to $K_{3a}$ race of bacterial blight (BB) were selected from $BC_1F_1$ to $BC_4F_1$ and used as parents in the backcrossing processes. This variety has about 120 days growth duration from transplanting to harvesting in west-southern coast and Honam plain of Korea. It is about 69 cm in culm length and tolerance to lodging. In reaction to biotic and abiotic stresses, it shows moderately resistance to blast, and resistance to bacterial blight pathogen, $K_1$, $K_2$, $K_3$ and $K_{3a}$, but susceptible to other major diseases and insect pests. The milled rice of 'Gangbaek' exhibits translucent, relatively clear non-glutinous endosperm and midium short grain. It has lower amylose content of 18.6% and protein content of 6.4% compared with 'Nampyeongbyeo'. The milled rice yield performance of this variety is about 5.28 MT/ha in local adaptability test for three years. This cultivar would be adaptable to the bacterial blight-prone area in the south-western coastal and Honam plain of Korea.

• Korean Journal of Breeding Science
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• v.41 no.3
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• pp.288-291
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• 2009

A new commercial rice variety "Donghaejinmi" is a japonica rice (Oryza sativa L.) with lodging resistance and high grain quality. It has been developed by the rice breeding team of Yeongdeog Substation, National Institute of Crop Science (NICS), RDA. This variety was derived from a cross between "Milyang 64" as a resistance source of brown planthopper (Bph) and "Milyang 165" as grain quality source. The donor parent, "Milyang64" has been backcrossed three times with recurrent parent, "Milyang165" and selected by the pedigree breeding method. The pedigree of "Donghaejinmi", designated as "Yeongdeog 41" in 2003, was YR21259-B-B-68-1. It has a short culm length with 69 cm and medium-late growth time. This variety is resistant to stripe virus and moderately resistant to leaf blast disease with durable resistance. It also has tolerance to unfavorable environment such as cold, dried wind and storm. Milled rice kernel of "Donghaejinmi" is translucent, clear in chalkness and good at eating quality in panel test. The merit of this variety is high head rice ratio, which is essential element to produce an article of superior quality rice brand. The yield potential of "Donhaejinmi" in milled rice is about 6.05 MT/ha at ordinary fertilizer level of local adaptability test. This cultivar would be adaptable to Yeongnam inland plains and eastern costal area of Yeongnam province.

• Korean journal of applied entomology
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• v.13 no.2 s.19
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• pp.77-82
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• 1974

The variety Tong-il from the IR667 lines have been reported as a variety resistant to the smaller brown planthopper, Laodelphax striatellus Fallen, in Korea. The resistance of Tong-il to the insect, however, have been mainly evaluated from a viewpoint of plant reaction of rice at the seedling stage. In this study, the nature of resistance of Tong-il to the insect was furthermore evaluated from the standpoints of feeding preference, antibiosis and plant tolerance in comparison with the resistant varieties Karsamba Red ASD-7 and Vellailangalayan. and the susceptible variety Jinheung which have been reported to the insect. The smaller brown planthopper much more prefered Tong-il for feeding than the resistant varieties ASD-7 and Vellailangalayan. The degree of antibiosis of Tong-il to the smaller brown planthopper was significantly lower than ASD-7 and Vellailangalayan. The results showed significantly lower nymphal mortality and higher adult emergence in Tong-il and Jinheung than other two resistant varieties. The degree o( tolerance of Tong-il to the insect was also lower than ASD-T and Vellailangalayan. Only. Tong-il seemed to be relatively more tolerable than Jinheung. The reason of showing resistant reaction of Tong-il in the mass screening test might be related with relatively lower feeding preference and more tolerance than Jinheung and other susceptible varieties.

• Korean journal of applied entomology
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• v.15 no.2 s.27
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• pp.53-56
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• 1976

A laboratory experiment was conducted to investigate varietal differences in feeding preference of striped rice borer larvae (Chilo suppressalis W.) to the stem pieces of the eight rice varieties. The preference of the larvae for feeding was significantly differed with the varieties, and in some varieties they were changed with the stages of the plants after transplanting. The larvae much more preferred the susceptible variety Rexoro than the resistant variety TKM-6. The varieties Tongil (Suweon 213-1), Yushin, Jinheung and IR-26 showed comparatively lower feeding preference than TKM-6. Some varieties exhibited a rather interesting phenomenon; strong preference in feeding was observed during the vegetative phase for Tetep and Tongil (Suweon 213-1) and during the maturing phase for Suweon 240 and Yushin. When the varieties TKM-6, Tongil and Rexore were given in several combinations, Rexore was strongly preferred by the larvae than others, and Tongil was still comparatively low in feeding preference of the larvae. The non-feeding preference of the larvae were considered to be in coincidence with the resistance of rice varieties to the striped rice borer.

• Journal of Plant Biotechnology
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• v.5 no.3
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• pp.173-179
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• 2003

The combination of a radiation technique with an in vitro culture system was appiled to develop submergence tolerant rice. The 3,000 $M_3$ lines with an average 80 percent of fertile grain were utilized for the selection of submergence tolerance. Salt tolerant lines were selected based on high plant height, root length and root number after submergence in plastic pots. Of the lines tested, the tolerant line (403-6) showed a dramatic difference in morphological traits under submergence compared to its original variety (Dongjinbyeo). It was suggested that genetic variations between the original variety and $M_3$-403-6 did exist. The levels of $\alpha$-amylase and alcohol dehydrogenase activities were significantly increased in the mutant line compared to its original variety. The mutant with greater tolerance showed less electrolyte leakage indicating a greater membrane integrity and better survival. Also, this line was much more resistant to a salt stress of $1.25\%$ than the original variety. The proline level of the line was significantly (p<0.01> higher than that of the original variety. The relationships between the inhibition of growth caused by stress and the physiological changes in the plant cell were discussed.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.520-524
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• 2009

A newly developed rice variety "Pungmi 1" is a japonica rice(Oryza sativa L.) with high grain quality and multi-resistant to diseases. It was developed by the rice breeding team of Yeongnam Agricultural Research Institute (YARI), RDA. in 2004. This variety derived from a cross between "YR13616Acp 1", having short culm and multi-resistance to biotic stresses and "Milyang 122" with good grain quality. It has short stature of 73cm in culm length and mid-early flowering date of Aug. 13. This variety is moderately resistant to leaf blast showing durable resistance of lower 10% diseased leaf araea in sequential planting meothod. Milled rice kernel of "Pungmi 1" is translucent, clear in chalkness and good at eating quality in panel test. Milling recovery and head rice ratios were comparable to Milyang 122, while it has low protein content. The milled rice yield potential of "Pungmi 1" is about 5.59 MT/ha at ordinary fertilizer level of local adaptability test. This cultivar would be adaptable to Yeongnam inland plains and southern coastal areas of Yeongnam province at ordinary transplanting as well as after barly cultivation.

• Korean journal of applied entomology
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• v.20 no.4 s.49
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• pp.207-211
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• 1981

It has been documented that the resistance to planthoppers is attributed to the feeding preference of the insects. This might be related to difference in the amount of feeding plant sap between resistant and susceptible hosts. In this aspect, this study was conducted to verify it and to develop an effective screening method for resistance to planthoppers by tracer technique. An effective P-32 labelling of rice seedlings at $2\~3$ leaf stage was dipping the roots in concentration of $0.1{\mu}Ci/ml$ solution for 48 hours. Radioactivity was significantly higher in planthopers fed on susceptible variety for 48 hours as compared to those fed on resistant variety. Radioactivity of adults was higher than that of nymphs and also higher in female than male. The results were highly correlated to that indicated by the feeding preference of the insects and therefore, considered to be valid for a screening technique.

• Korean journal of applied entomology
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• v.11 no.2
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• pp.61-68
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• 1972

This study has been carried out to investigate the varietal resistance of Tong-il rice variety (IR-667) at the seedling stage to the brown planthopper. Nilaparvata lugens STAL, and further to know the biological effects of the varieties to the insects. The results obtained were as followings; 1. Tong-il variety tested in this experiment was susceptible to the brown planthopper but it seemed to be a little more tolerable than the Japonica varieties which had been recommended in Korea. 2. Tong-il variety (Suwon 213, Suwon 213-1, Suwon 214, and Suwon 215) was highly prefered by brown planthopper for feeding to the Korean recommended varieties Paltal, Jinheung, Akibare, and Shin #2. 3, The resistant varieties Mudgo, Kayama MGL-2, and Karsamba ASD-7 which showed low feeding preference exhibited higher ovipositional preference than the susceptible varieties. Relatively greater number of eggs was recorded on the Tong-il variety (Suwon 213, Suwon 213-1, and Suwon 215) in comparison with the Korean recommended varieties, 4, When the female brown planthopper adults were caged on Tong-il variety (Suwon 214) and the resistant variety Karsamba ASD-7 separately, greater number of eggs were observed on Suwon 214 and less on Karsamba ASD-7, while when two varieties Suwon 214 and Karsamba ASD-7 were given together in the same cage, Karsamba ASD-7 was much more prefered for oviposition to Suwon 214. 5. There was no difference in e99 Periods and their hatchal\bility between the resistant and susceptible varieties, but nymphal periods, rate of adult emergence, longevity of the adult, and its fecundity were significantly different according to the varieties.