Yong-Jae Won

QTL Detection Associated with Eating Quality Based on Palatability Test in Japonica Rice (Oryza sativa L.)

A recombinant inbred line (RIL) population derived from the cross between Ilpumbyeo (a Japonica of high eating quality) and Moroberekan (a tropical Japonica type of low eating quality) was used for mapping QTLs associated with grain physicochemical properties and eating quality traits in rice. A total of 182 recombinant inbred lines were evaluated for two physicochemical traits, alkali digestive value and amylose content, and five traits associated with eating quality including glossiness of cooked rice determined by Toyo-taste meter, and glossiness, stickiness, hardness and overall evaluation for taste evaluation by panels. A total of 30 QTLs associated with seven traits in 10 loci on chromosomes 1, 3, 5, 6, 10, and 12 were identified. The most critical regions for eating quality were on chromosomes 3, 5 and 6 by Ilpumbyeo alleles, whereas Moroberekan contributed a total of 6 loci on chromosomes 1, 10 and 12. The QTL region on chromosome 5 contains the novel alleles for eating quality from Ilpumbyeo. MAS using DNA markers tightly linked with those QTLs will be useful for breeding Japonica cultivars with high eating quality.

Morphological and starch characteristics of the Japonica rice mutant variety Seolgaeng for dry-milled flour

Producing good-quality, fine rice flour is more difficult than wheat flour because the rice grain is harder. The non-glutinous Japonica-type variety Seolgaeng, derived from N-methyl-N-nitrosourea (MNU) mutagenesis, and four other varieties, representing a range of amylose contents, were evaluated in this study. Dry-milled Seolgaeng rice flour exhibited an average particle size that is <70 μm, a more uniform particle-size proportion than other varieties. Moreover, we noted significant differences in the damaged starch content in flour from Seolgaeng compared to the other varieties (p<0.05). Seolgaeng flour showed a round starch structure, which would lead to better friability, finer particle size, and less damage to the endosperm during dry milling. Indeed, among all varieties evaluated in this study, dry-milled Seolgaeng flour had the finest particle size (averaging <70 μm) and exhibited less damaged starch. With its round starch granules, Seolgaeng is a suitable candidate for drymilled rice flour.

A high biomass yield and whole crop silage rice cultivar 'Mogyang'.

‘Mogyang’, a new high biomass yield and whole crop silage rice (Oryza sativa L.) cultivar, is developed by the rice breeding team of National Institute of Crop Science, R.D.A., Suwon, Korea, during the period from was to 2010 and released in 2011. It was derived from a cross between SR24592-HB2319/IR73165-B-6-1-1. This cultivar has about 118 days of growth duration from seeding to heading and has long and erect leaves (culm length 93 cm). It has tough thick culm with strong lodging tolerance. This cultivar has a few less tillers per hill and markedly more spikelet numbers per panicle. ‘Mogyang’ has wide and stay green leaf compared other whole crop silage varieties. This new variety has grain shattering resistance and disease resistance for blast and dwarf virus. This variety has good qualities for whole crop silage with high TDN (Total Digestive Nutrient) yield and low NDF (Neutral Detergent Fiber) and low ADF (Acid Detergent Fiber) compared to common high grain yield varieties. The biomass and TDN yield performance of ‘Mogyang’ was 59.5% (chemical properties), 17.7 MT/ha (biomass yield), individually in local adaptability test for three years. ‘Mogyang’ is adaptable to central plain area, southern plain area of Korea.

Comparative Analysis of Durable Resistance between Sequential Planting and Nursery Screening to Rice Blast

Blast resistance of 29 rice cultivars confirmed as a durable resistance in the evaluation of sequential planting from 2004 to 2006 was evaluated to nursery screening in 14 test sites during 11 years in Korea. The average disease severity (ADS) of 29 rice varieties against rice blast showed 3.5 degree; however, the difference of disease severity among the varieties was from 1.9 to 4.8. The 29 varieties were grouped into resistance less than 3.0 ADS degree including 12 varieties and moderate resistance over 3.1 ADS degree including 17 varieties. Among the 12 rice cultivars presented low ADS, 4 rice cultivars, Ungwang, Pungmi 1, Sinunbong 1, and Dasan 1 were constantly appeared high resistant reaction during 11 years in all test sites and the others were showed various diseases severity across the test years and the test sites. Twenty-one rice cultivars including Gopum were more variable among the test sites while the others were higher variable among the test years. These results indicated that durable resistance test against rice blast using sequential planting is a very efficient screening method to predict durability and nursery test for long periods and also useful method to predict indirectly durable resistance of rice cultivars.

Lodging and Pre-harvest Sprouting Tolerant, High Quality and Suitable for Processing Cooked Rice ‘Jungmo1017’

The ‘Jungmo1017’ is a japonica rice variety developed from a cross between Suweon462 which has a good plant architecture, cold tolerance, moderately tolerant to leaf blast and bacterial blight and medium maturing habit, and Yeongdeog34 which has translucent milled rice and good milling properties, by the rice breeding team at NICS, RDA in 2011. The heading date of ‘Jungmo1017’ is August 16 and it is six days later than ‘Hwaseong’. ‘Jungmo1017’ has 65 cm of culm length which is 18 cm shorter than those of ‘Hwaseong’ and 93 spikelet per panicle. The pre-harvest sprouting rate of ‘Jungmo1017’ is 8.6% that is lower than 27.7% of ‘Hwaseong’ on local adaptability test (LAT). It showed resistance to blast diseases and moderately resistant to bacterial blight (K1 race) and stripe virus, but susceptible to other races (K2, K3 and K3a) of bacterial blight, viruses and planthoppers. The milled rice of this variety exhibits translucent, clear non-glutinous endosperm and medium short grain shape. It has better palatability index of cooked rice (0.53) than that of ‘Hwaseong’. ‘Jungmo1017’ showed lower protein content (6.4%) and amylose content (18.0%). ‘Jungmo1017’ could use aseptic-packaged cooked rice or processing cooked rice because its hardness of cooked rice is soft, setback and balance is low and palatability of cold and aseptic rice showed high score. The characters related to milling is better than those of ‘Hwaseong’. ‘Jungmo1017’ showed 5.01 MT/ha of milled rice productivity at 7 sites of middle plain, southern mid-mountainous and south-east coastal area in ordinary cultivation. ‘Jungmo1017’ could be adaptable to the middle plain area in Korea.