Developing rice lines with various amylose contents is necessary to diverse usages of rice in terms of raw materials for processed food production, and thereby to promote rice consumption in Korea. A rice mutant line, ‘Namil(SA)-dull1’ was established through sodium azide mutagenesis on ‘Namil’, a non-glutinous Korean Japonica rice cultivar. Namil(SA)-dull1’ had dull endosperm characteristics and the evaluated amylose content was 12.2%. A total of 94 F2 progenies from a cross between ‘Namil(SA)-dull1’ and ‘Milyang23’, a non-glutinous Tongil-type rice cultivar, was used for genetic studies on the endosperm amylose content. Association analyses, between marker genotypes of 53 SSR anchor markers and evaluated amylose contents of each 94 F2:3 seeds, initially localized rice chromosome 6 as the harboring place for the modified allele(s) directing low amylose content of ‘Namil(SA)-dull1’. By increasing SSR marker density on the putative chromosomal region followed by association analyses, the target region was narrowed down 0.94 Mbp segment, expanding from 28.95 Mbp to 29.89 Mbp, on rice chromosome 6 pseudomolecule. Among the SSR loci, RM7555 explained 84.2% of total variation of amylose contents in the F2 population. Further physical mapping on the target region directing low amylose content of ‘Namil(SA)-dull1’ would increase the breeding efficiency in developing promising rice cultivars with various endosperm characteristics.

Amylose content of rice endosperm is one of the determinants of rice eating quality. This study was conducted to elucidate the mode of inheritance of dull gene in Milyang262, tentatively designated as du7(t), and to identify the molecular marker for du7(t) to be employed in marker-assisted breeding and gene pyramiding. Genetic analysis was carried out on F2 population derived from a cross between Junam and Milyang262. The low amylose content of Milyang262 was indicated to be under single recessive control. Allelism tests were as well conducted by crossing Milyang262 with Baegjinju and Baegokchal, which harbor du1 and wx gene, respectively. du7(t) was demonstrated to be inherited independently to du1 and wx. F2 population of Baegokchal/Milyang262 was used for molecular mapping. Linkage analysis was conducted on a population consisted of 120 individuals by several SSR markers. Initial mapping indicated that du7(t) is located on the end of long arm of chromosome 6 between SSR marker RM20590 and RM3509. To fine map the gene, a bigger population and several additional markers were employed. du7(t) was further mapped to a 1.74 Mb region between two SSR markers (RM6926 and RM412). Furthermore, we indentified three SSR markers that co-segregated with du(t) i.e. RM6811, RM3765, and RM176.

다양한 용도의 가공용 품종을 육성할 목적으로 1995년 하계에 아밀로스함량이 낮은 일품벼 변이체 Ilpum (MNU)-10-2-GH1-3을 모본으로 하고 양질 내도복성인 서안벼를 부본으로 교배하여 SR21716-30-2-3-1을 선발하여 '수원491호'로 계통명을 부여한 후 2003년-2005년 3개년 간 지역적응시험을 실시한 결과 그 우수성이 인정되어 2005년 12월 직무육성 신품종 선정위원회에서 국가목록등재품종으로 선정됨과 동시에 '백진주1호'로

백진주'는 1991년 하계에 개화 후 수정된 양질다수성 품종인 일품벼 수정난을 26±1℃ 암조건에서 1 mM의 MNU 용액에 45분간 침지한 후 24시간 동안 수세하였다. 처리한 식물체를 온실에서 등숙시켜 종실을 수확하여 돌연변이 M1세대 697개체를 얻었다. 1992년 하계 온실에서 M2세대 15개체를 선발하여 1992/'93 동계 온실에서 M3 집단을 육성하였다. M4 세대부터는 포장에서 계통 선발법에 의해 주요 병해충 및 미질검정을 병행하여 다양한

Dull grains segregated from F3 and F4 of the crosses between two dull mutants and a glutinous cultivar were compared with non-glutinous and glutinous segregants for their physicochemical properties. Amylose content of dull rice grain segregated from the dull/glutinous cross showed the intermediate value between glutinous and non-glutinous rice grain, whether it is controlled by the recessive or dominant gene. Alkali digestibility value (ADV) of dull rice grain was lower than that of glutinous or non-glutinous rice. A positive correlation was found between ADV and amylose content of homozygous non-glutinous or dull F4 grains, but a negative relationship was observed in glutinous grains. Protein content of dull grain was significantly higher than that of glutinous or non-glutinous grain segregated from the same cross, while those of glutinous and non-glutinous grains were not different. Among gelatinization characteristics, initial pasting temperature and peak viscosity of dull grains were higher than glutinous rice, and were not different with non-glutinous grain. Hot, cool and consistency viscosities of dull grain were intermediate between glutinous and non-glutinous rices. Dull grains showed the highest breakdown viscosity and the lowest setback viscosity among the three endosperm types.