• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.3
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• pp.264-274
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• 1993

This study was carried out to assess the agronomic characters and physicochemical properties of floury and chalky-endosperm mutant lines induced by chemical mutagen treatment to rice varieties, Hwacheongbyeo and IR24. Linkage analysis of a floury-endosperm gene was carried out using linkage testers. The grain size of brown rice of the mutants was smaller than that of the original varieties. The l, 000-grain and 1$\ell$ weight were lighter in the mutants compared with those in the original varieties. The compound starch granules in the endosperm cell of the mutants showed a loosely-packed crystalline structure. Amylose contents in mutants ranged from 16.9 to 28.5%. Crude protein contents of the mutants were not significantly different from the original rice variety, Hwacheongbyeo, but white core mutant(line 47106) derived from IR24 showed higher protein(l1.32%) compared with IR24(8.30%). The mutants showed slightly harder gel characteristics, and much lower viscosity in Amylograph than original varieties. Steamed rice-cakes from mutant lines showed greater volume than those from original varieties. During the process of alcohol fermentation, Brix in the mutants(especially floury mutants) decreased faster and the alcohol production after 10-day fermentation was much greater in the mutants than in the original varieties. Three different gene loci for floury endosperm characteristics were identified from the allelism test among mutant lines, and the genes were tentatively symbolized as flo-a, flo-b and flo-c, respectively. A floury gene, flo-a, was linked with lg(liguleless) gene in the linkage group N, with R.V. 5.76$\pm$1.72%.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.211-211
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• 2005

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.284-293
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• 2020

Rice consumption in Korea has been decreasing as the eating habits of the Korean people have diversified with rapid economic growth. Recently, floury endosperm rice cultivars were developed to boost rice consumption and replace wheat flour consumption with rice flour, which is vulnerable to viviparity under wet weather during the grain-filling stage because of its loosely packed starch granule structures. To overcome this limitation, it is necessary to find a suitable rice transplanting date to produce high-quality rice flour by altering the heading ecology type and changing the cultivation time by region. We examined four floury endosperm rice cultivars (FERC) in the Cheongju (central plain area) and Boeun (mid-mountainous area) regions of Korea from 2017 to 2019. Of the FERCs, the mid-late maturing types (MMT) Seolgaeng (SG), Hangaru (HGR), and Shingil (SGL) exhibited high yield and yield components after transplanting May 30 in both regions; the early maturing type (EMT) Garumi 2 (GRM2) also exhibited high yield after transplanting June 20 in Cheongju. In addition, MMTs showed the same tendency as the characteristics shown in Cheongju when grown in the Boeun region, and EMT displayed high yield and yield components after transplanting June 10. The FERCs could easily present pre-harvest sprouting in the rainy season during the grain-filling stage after 20 days post-heading because the mean temperature and frequency of more three-day rainfalls have increased over the last 5 years from the previous annual averages. Viviparity of HGR and GRM2 decreased as the transplanting date was delayed, with decreases of 2.3%-4.6% in HGR and 11.9%-23.1% in GRM2 according to the region. SGL was generally resistant to viviparity because of the Tongil type. To minimize pre-harvest sprouting and produce high yield of rice flour in the Chungbuk province, the most suitable transplanting time was the end of May in MMT and the middle and end of June in EMT.

• Food Science and Preservation
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• v.30 no.4
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• pp.630-641
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• 2023

The quality characteristics of muffins with different types of rice flour, such as soft flour (CON), soft rice flour (SRF), floury rice flour (FRF), and rice flour (RF) were assessed by using Image J program, which includes their particle size analysis, moisture content, pH, color, specific volume, baking loss rate, texture. (D[4, 3]) is weighted mean diameter, which is directly obtained in particle size measurements showed large values in the order of rice flour, floury rice flour, soft rice flour, and soft flour. The moisture content was high in the CON and SRF groups with small particle sizes. There was no significant difference in pH, L and b value. The a value was significantly low only in the RF group with large particle size. The smaller the particle size, the higher the specific volume and baking loss rate. Image J showed that the number of pores decreased when fewer smaller particles were the powder, but the pores were larger. Among the rice flours, the SRF group, excluding the CON group, scored high in all the acceptability elements. The results from this study can be used as basic data that can contribute to research on various rice-processed foods.

• Korean Journal of Breeding Science
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• v.41 no.2
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• pp.84-91
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• 2009

Rice consumption per capta, in South Korea, has been decreased dramatically, owing to the changes of living patterns. Because of not only the major energy source of Korean people but also major income source of Korean farmers, diversifying end-use-quality of rice has been demanded. To the context, 'Suweon 472', a high yielding and early mature japonica line and released as 'Namilbyeo' to framers in 2002, was treated with a chemical mutagen, Sodium Azide to find endosperm mutant types. A total of nine endosperm mutat lines, including five waxy, one dull, two floury, and one white core type, were identified from the 3,542 mutatagen treated lines. Amylose contents, iodine reaction, disintegration in alkali solution, gelatinization in urea solution and amylogram properties of those nine endosperm mutant lines were evaluated to address the possibility as new genetic materials for diversifying rice quality of Korean japonica cultivars. All embryo mutants were clearly differentiated from their wild type, 'Suweon 472', in terms of physic-chemical properties evaluated. The endosperm mutant lines would be very useful in expanding untiliztation of rice through opening new rice markets of processed foods from Korean japonica rice.

• Journal of Crop Science and Biotechnology
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• v.11 no.3
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• pp.181-186
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• 2008

To assess the potential as biofortified rice varieties, new endosperm and grain mutant lines were selected from $M_4$ generation seeds of the rice cultivar Shindongjin, which were either $\gamma$-irradiated or treated with N-methyl-N-nitrosourea(MNU) and lipid, sugar, and tocopherol content were analyzed. Amylose content in non-waxy mutants ranged from 8.8% in SM-4, a dull-type mutant, to 29.5% in SM-51, compared to 18.9% in the parental variety, Shindongjin. SM-23, a floury-type mutant, contained 0.09 ${\mu}g/g$ $\alpha$-tocopherol(40.9% of total tocopherol), was three times higher than in the parental variety. SM-32, a giant embryo-type mutant, had a 2.2-fold higher total tocopherol content, 2.1-fold higher $\alpha$-tocopherol, and 5.5-fold higher $\delta$-tocopherol content(47.3% of total tocopherol) than the parental variety(0.13 ${\mu}g/g$). Total free sugar content was elevated in all selected mutants and 1.2-8.6 times higher than in the parental variety(11.38 ${\mu}g/g$). These increased sugar levels were due to increase in sucrose concentration. SM-23(floury-type mutant) and SM-51(high amylose-type mutant) had 4.6 and 7.0 times more sugar, respectively, than the parental variety(11.38 ${\mu}g/g$). With relatively high concentrations, most mutants showed elevated fatty acid content in the SM 32(giant embryo-type) and SM-51(high amylose-type) mutants, at 124.56 and 89.59 mg/g, respectively. All selected mutants displayed valuable characteristics for the development of new varieties in rice-breeding programs.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.258-264
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• 2000

Starches from the eight varieties of rice were analyzed using scanning electron microscope(SEM), differential scanning calorimetry(DSC) and X-ray diffractometry, and tested on the starch-granule susceptibility to 15% $H_2SO_4$ and glucoamylase. The shape of starch granules from normal rice varieties and low-amylose mutants were polygonal while shrunken and floury mutants were globular. According to DSC, starches from Nampung CB243 showed higher onset temperature$(T_o)$, completion temperature$(T_c)$ and Punchilmi, Nampung EM90 showed higher enthalpy$({\triangle}H)$ of gelatinization than others. shr showed the highest hydrolysis rate to 15% $H_2SO_4$ while Nampung CB243 showed the lowest one. Eight varieties of rice starch granules showed A-type pattern on X-ray diffractograms. The lower amylose content rice varieties showed the higher hydrolysis rate treated with glucoamylase.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.3
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• pp.197-203
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• 1991

Several types of endosperm and embryo mutants were induced by the treatment of MNU (N -methly- N -nitrosourea) on fertilized egg cell of rice plant. These mutants were named as dull. waxy, white core, floury, sugary, shrunken, colored seed coat and giant embryo according to their appearence, micro-scopic feature on SEM and amylose content. White cored mutant was the most frequent one among them. All of the mutants were segregated as controlled by a single recessive gene except 47320 (dull). Futher studies on the genetics and physico-chemical properities of the mutants are ongoing.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.4
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• pp.342-361
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• 2022

In order to evaluate the effect of nitrogen application levels on yield and quality of rice varieties, a field experiment was conducted at National Institute of Crop Science of Korea from 2018 to 2020. Five levels (0, 3, 5, 7, and 9 kg/10a) of nitrogen fertilizer were treated to 21 Korean rice varieties. Yield, yield component, appearance quality, and protein content in rice were analyzed. The average head rice yield for 3 years decreased by 28%, 22%, 11%, and 8%, respectively, when cultivated with 0, 3, 5, and 7 kg/10a nitrogen application compared to cultivation with a standard nitrogen application amount, 9 kg/10a. The number of panicles per hill increased as the amount of nitrogen application increased, but there was no significant change in the number of grains per panicle and 1000-grains weight, and the number of panicles per hill showed relatively small annual variation compared to other yield components. There was no significant difference in the head rice ratio according to the nitrogen application amount, the broken rice ratio slightly decreased, and the floury rice ratio increased. The protein content of rice decreased with increasing nitrogen application in 2018 and 2019, and was the lowest at 7 kg/10a of nitrogen application, and showed a tendency to increase again at 9 kg/10a. In the case of 2020, as the amount of nitrogen application increased, the protein content showed a tendency to continuously increase. In terms of varieties, 13 varieties, including Chilbo, seemed to be capable of low-nitrogen cultivation because loss of the head rice yield was less and the protein content could be lowered to 6% or less according to 7 kg/10a nitrogen application.