• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.4
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• pp.235-241
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• 2016

Three different transplanting dates for two rice cultivars grown in Daegu, Republic of Korea, were examined to identify the changes in growth, rice quality, and characteristics of amylopectin. An early transplanting date caused a reduction in the number of panicles in both rice cultivars compared to that in the optimal and late transplanting dates. The 1000-grain weight in the two rice cultivars was significantly increased in the late transplanting date. The rice cultivar tolerant to high temperatures, Donganbyeo, exhibited the lowest milky grain rate in the late transplanting date. The highest rate of head grain was observed in the late transplanting date in both rice cultivars. Regarding the pattern of pasting properties, peak viscosity increased with delayed transplanting dates. With respect to changes in the amylopectin branch-chain length distribution, the amylopectin structure of the translucent Dongan rice cultivar transplanted on April 25 was characterized by a significant increase in A chains with DP > 12, and a decrease in long chains $DP{\geq}37$ compared to that transplanted on June 25. In contrast, the amylopectin structure of the chalky Dongan rice cultivar transplanted on April 25 exhibited further decrease in 13 < DP < 19 than that transplanted on June 25. In the Ungwang rice cultivar, the amylopectin structure of the translucent Ungwang rice cultivar transplanted on April 25 and June 25 was characterized by a significant decrease in the lengths of total amylopectin chains. Furthermore, the amylopectin structure of the chalky Ungwangbyeo rice cultivar transplanted on April 25 was characterized by a significant increase in 7 < DP < 30, while a significant decrease was observed in that transplanted on June 25. These results indicate that the amylopectin structure is altered by different transplanting dates depending on the characteristics of the rice cultivar.

• The Korean Journal of Food And Nutrition
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• v.34 no.5
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• pp.458-467
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• 2021

The effect of 16 cultivars on the quality of the rice porridge was investigated. The 'Geunnun' had the highest water absorption rate, but the 'Segyejinmi' yield (w/w) was the highest. The total sugar content of the rice porridge was 0.29~8.10%, showing significant variation among the cultivars. High amylose 'Dodamssal' and 'Hwaseonchalbyeo' glutinous rice displayed rotational viscosities of <20,000 cP. Rotational viscosities for boiled rice cultivars were 30,000~40,000 cP, representing an intermediate level, and the rotational viscosities of 'Geonyang2' and 'Hanareum4' were over 50,000 cP. These results suggest that the viscosity of rice porridge varies significantly among raw material cultivars. Among other variables affecting the texture profile of rice porridge, there were significant differences in hardness and gumminess among the cultivars. As a raw material, 'Baekokchal', a kind of glutinous rice, is known to be whiter than the non-glutinous rice, but after processing to porridge, it showed the lowest L value (71.1). Starch degrading enzyme activity was not significant in most types of rice porridges within 30 or 60 minutes. Therefore, enzymatic starch degradation is thought to be completed within 30 minutes. Among the tested raw materials, 'Miho' was 73.5 ㎍/mg, indicating the best digestibility in vitro.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.705-709
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• 1998

Temporal and spatial distribution of Korean rice blast fungus (Pyricularia grisea) race KI-409 that has been rapidely increased since 1993 and became predominant in 1995 in Korea were investigated. Varietal resistance of current commercial cultivars of rice to the race was also tested in this study. The race KI-409 was first isolated from rice cv. Namyangbyeo in 1985. Since 1985 the race had been isolated mainly from the rice cultivars having BL1 BL7 pedigree as a resistance source. Distribution ratio of the race in 1995 was 23.7% in average and became a predominant in the P. grisea population in Korea. The race distributed widely and found in all the eight provinces in Korea. Many commercial cultivars such as Chucheongbyeo as well as those with BL1 or BL7 as a genetic background were found to be susceptible to the race KI-409.

• The Plant Pathology Journal
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• v.25 no.3
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• pp.231-235
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• 2009

Viral infections and root growth were examined to elucidate the relationship between viral resistance and root growth in 26 Korean hulless barley cultivars. Viral resistance was estimated in experimental filed of Honam agricultural research institute for 3 years. Length and number of seminal and adventitious roots were examined for evaluation of root growth in both field and green-house conditions 30 days after seeding. Dominant viral infection occurred in Korean hulless barley by Barley yellow mosaic virus (BaYMV) in fields; however, susceptible cultivars were infected by either BaYMV, Barley mild mosaic virus (BaMMV) or both. Only four cultivars, including Donghanchalssalbori, Kwangwhalssalbori, Namhossalbori and Naehanssalbori, presented stable resistance to viral infections. Susceptible cultivars to viral infection in fields showed shorter seminal root length and fewer adventitious root number than resistant cultivars. Resistant cultivars showed better root growth and significant difference in adventitious root length in green house conditions. Increase in the number of seminal roots in resistant cultivars was derived from decreased damage of roots by the viral infection compared to the susceptible cultivars.

• Plant Resources
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• v.6 no.1
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• pp.16-26
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• 2003

Molecular markers are useful tools for evaluating genetic diversity and determining cultivar identity. Present study was conducted to evaluate the genetic diversity within a diverse collection of rice accessions used for Korean breeding programs. Two hundred eighty-seven rice cultivars, composed of temperate japonica, tropical japonica, indica, and Tongil-type of Korean crossing parents were evaluated by means of 15 simple sequence repeat (SSR) markers. A total of 99 alleles were detected, and the number of alleles per marker ranged from 4 to 11, with an average of 6.6 per locus. Polymorphism information content (PIC) for each of the SSR markers ranged from 0.2924 to 0.8102 with an average of 0.5785. These results, with the result that use of only 15 SSR markers made all rice cultivars examined could be uniquely distinguished, imply the efficiency of SSR markers for analysis of genetic diversity in rice. Cluster analysis was performed on similar coefficient matrics calculated from SSR markers to generate a dendogram in which two major groups corresponding to japonica (Group I) and indica and Tongil type rice (group II) with additional subclasses within both major groups. The narrowness of the Korean breeding germplasm was revealed by the fact that most of the Korean-bred and Japan-bred temperate japonica cultivars were concentrated into only 2 of the sub-group I-1 (143 cultivars) and I-2 (58 cultivars) among six sub-groups in major group of japonica. This is because of the japonica accessions used in this study was a very closely related ones because of frequent sharing of the crossing parents with similar genetic background with synergy effect of the inherited genetic difference between indica and japonica. A rice breeding strategy with the use of molecular markers was discussed for overcoming of genetic vulnerability owing to this genetic narrowness.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.256-256
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• 2017

The purpose of this study was to evaluate the effects of rice cultivars (Hangaru, Seolgaeng, Dasan-1 and Anda) on quality characteristics of rice beer. As for moisture content, Hangaru and Seolgaeng that are soft rice were higher than Dasan-1 and Anda as 14.48 and 14.62%, respectively. Dasan-1 and Anda showed higher protein content as compared to other varieties. As for amylose content, Hangaru turned out to be lower than other varieties as 17.71%, whereas reducing sugar content of Hangaru and Seolgaeng was higher than Dasan-1 and Anda. Results of hardness showed that Hangaru and Seolgaeng were measured lower than Dasan-1 and Anda. As a result of measuring alcohol content, pH and color of beer brewed by rice cultivars, no significant difference by cultivars was found, but measurement result of bitterness showed that beer brewed with Hangaru and Seolgaeng showed lower bitterness comparing to the beer brewed with Dasan-1 and Anda. The results of this study suggest that Hangaru and Seolgaeng are considered cultivars suitable for brewing quality of rice beer.

• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.50-54
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• 2001

The amylose content, based on iodine blue value, of eight rice cultivars decreased in order of Nampungbyeo>Whachungbyeo>Punchilmi>Nampung CB243>Whachung du-1>Nampung EM90>Whachungchalbyeo>shr. The amylopectin chain length distribution was obtained by enzyme treatments followed by high-performance size-exclusion chromatographic separation. Chain length distribution profiles of the isoamylase-debranched starches showed distinct patterns according to cultivars. Based on the sensory evaluation result of the bread prepared from gluten and rice flours of eight rice cultivars, chewiness of the product was related with the presence of amylose while the short-chain amylopectin fraction was contributed to the texture and overall quality.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.5
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• pp.288-293
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• 2000

Two rice cultivars (Oryza sativa L.), Hwa-seongbyeo of Japonica type and Taebackbyeo of Indica/Japonica type, were cultivated with hydroponic culture to examine nitrogen effects on the growth responses, contents and utilizations of carbohydrates, and the ripening velocity of grains with three different N levels. Plant height and tiller number were clearly increased to 80 ppm N level compared to 40 ppm N level and then they were slightly decreased in N level of 120 ppm. Higher dry weights were appeared with 80 ppm N level than did with other N levels, showing statistically differences in both cultivars and N levels, while dry weight of roots was heavier with decreasing the N levels. Therefore, T/R ratios were not significantly different among N levels, although there was statistically differences between rice cultivars. After the flowering stage, higher water-soluble carbohydrate (WSC) and water-insoluble carbohydrate (WISC) were contained in stem compared with other parts, showing that WISC of sheath and stem, unlike WSC, was significantly different among N levels. Starch of grain, WISC, was remarkedly increased from 3.0% at just after the flowering to 52.0% and 75.0% at 15 and 30 day after the flowering, respectively, showing that lower N application had faster accumulation of starch in rice grains. N would affect the contents of carbohydrates of each tissue, and starch accumulation in rice grains.

• Current Research on Agriculture and Life Sciences
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• v.20
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• pp.65-70
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• 2002

This study was conducted to investigate allelopathic potential of various crosses of rice cultivars using their inhibitory effect on barnyardgrass growth under field conditions, and to determine PAL activity and phenolic compounds involved in phenylpropanoid pathway from selected crosses of rice cultivars. Under field conditions, Kouketsumochi, Woo co chin yu possessed higher allelopathic potential inhibiting over 90% of barnyardgrass growth. Crosses of Kouketsumochi/Woo co chin yu, Dongjinbeyo/Kouketsumochi, Dongjinbeyo/Woo co chin yu showed over 80% inhibitory effects on barnyardgrass growth. The highest PAL activity, $63.46{\mu}kats/kg$ proteins was detected in Kouketsumochi which is the most important enzyme in phenylpropanoid pathway and also higher PAL activity in crosses with Kouketsumochi. Content of cinnamate was $2.64{\mu}g/g$ f.w. in Kouketsumochi which was 2 to 5 times higher than other rice cultivars tested, indicating that higher PAL activity resulted in more cinnamate. The similar trends in cinnamate content and PAL activity were observed in crosses of rice cultivars with Kouketsumochi.

• Korean Journal of Weed Science
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• v.16 no.3
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• pp.210-220
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• 1996

Ten-day-old seedlings of the oxyfluorfen-tolerant and -susceptible rice cultivars with barnyardgrass, a typical susceptible weed were soaked in oxyfluorfen at $10^{-6}M$ for 2 hrs kept for 24 hrs in the dark, and exposed to light for 0, 2, 4, or 6 hrs to investigate changes in the activity and isozyme of antioxidative enzymes. The activities of antioxidative enzymes of APOX, CAL, POX, NR, GR, MDAR and SOD in the tolerant and susceptible rice cultivate themselves didn't show any difference but the activity in the susceptible barnyardgrass was very low in comparison with rice cultivars. The activity of lipoxygenase tended to be some slightly higher in the susceptible rice cultivars and barnyardgrass than in the tolerant rice cultivars. The activities of MDAR, POX, GR and SOD, antioxidative enzymes, were higher in the tolerant rice cultivars than in the susceptible rice cultivars and barnyardgrass after the treatment of oxyfluorfen. After the treatment of oxyfluorfen, in the change of POX isozyme, the activity of C band in the tolerant rice cultivars increased with increased concentration but it didn't in the susceptible rice cultivar. The activity of B band decreased slightly at $10^{-4}M$ in the susceptible barnyardgrass. Isozyme of GR, SOD and AO by the treatment of oxyfluorfen, the activity of each band between the tolerant and susceptible rice cultivars showed no difference but GR isozyme C band was disappeared in the susceptible barnyardgrass at $10^{-4}M$. In the change of esterase isozyme resulting from the treatment of oxyfluorfen, the activities of B, C and D bands decreased more in the susceptible rice cultivars than in tolerant rice cultivars, and A band was disappeared in the susceptible barnyardgrass at $10^{-4}M$.