Yeon-Gyu Kim

Identification of Quantitative Trait Loci Associated with Rice Eating Quality Traits Using a Population of Recombinant Inbred Lines Derived from a Cross between Two Temperate japonica Cultivars

Improved eating quality is a major breeding target in japonica rice due to market demand. In this study, we performed genetic analysis to identify quantitative trait loci (QTLs) that control rice eating quality traits using 192 recombinant inbred lines (RILs) derived from a cross between two japonica cultivars, ‘Suweon365’ and ‘Chucheongbyeo’. We evaluated the stickiness (ST) and overall evaluation (OE) of cooked rice using a sensory test, the glossiness of cooked rice (GCR) using a Toyo-taste meter, and measured the amylose content (AC), protein content (PC), alkali digestion value (ADV), and days to heading (DH) of the RILs in the years 2006 and 2007. Our analysis revealed 21 QTLs on chromosomes 1, 4, 6, 7, 8, and 11. QTLs on chromosomes 6, 7, and 8 were detected for three traits related to eating quality in both years. QTLs for ST and OE were identified by a sensory test in the same region of the QTLs for AC, PC, ADV, GCR and DH on chromosome 8. QTL effects on the GCR were verified using QTL-NILs (near-isogenic lines) of BC3F4–6 in the Suweon365 background, a low eating quality variety, and some BC1F3 lines. Chucheongbyeo alleles at QTLs on chromosomes 7 and 8 increased the GCR in the NILs and backcrossed lines. The QTLs identified by our analysis will be applicable to future marker-assisted selection (MAS) strategies for improving the eating quality of japonica rice.

Changes in Quality Properties of Brown Rice after Germination

The objective of this study was to evaluate quality properties, including amylose, alkali digestion value (ADV), and amylogram, of brown rice and germinated brown rice of some cultivars in Korea for rice processing products. The protein content of brown rice was significantly higher than those of germinated brown rice. The amylose content of the samples ranged from 17.09 to 18.85%. Alkali digestion value (ADV) of brown rice and germinated brown rice were described as a grade of 2-5 and 4-7, respectively. In a rapid visco analyzer (RVA) examination, pasting temperature of brown rice and germinated brown rice was 67.93-68.05℃. In addition, the pasting characteristics of brown rice were significantly higher than those of germinated brown rice. A texture analysis test showed that germinated brown rice Haiami had the lowest hardness and germinated brown rice Samkwang had the highest adhesiveness.

Expression levels of three bacterial blight resistance genes against K3a race of Korea by molecular and phenotype analysis in japonica rice (O. sativa L.)

Bacterial blight, caused by Xanthomonas oryzae pv. oryzae (Xoo) is a destructive disease of rice in the major rice growing countries of Asia. In 2003, a serious bacterial blight epidemic occurred in the southwestern coastal areas in Korea, causing significant yield loss due to the emergence of a new race, K3a. IR24 near-isogenic lines containing Xa4, xa5, Xa7 and Xa21 genes conferred different degrees of resistance to the most virulent K3a isolate, HB01009 in an inoculation experiment in the greenhouse. Expression levels of the resistance genes, Xa4, xa5 and Xa21 were studied in two F2 populations derived from the crosses between elite japonica cultivars and an advanced backcross breeding line possessing Xa4, xa5 and Xa21 genes. F2 progenies segregated for K3a resistance (R) and susceptible (S) phenotypes in a ratio of 3(R):1(S) indicated that K3a resistance was controlled by a major dominant gene. Three PCR markers tightly linked to the resistance genes Xa4, xa5 and Xa21 confirmed the presence of the genes and their interaction with each gene. This study demonstrated that the Xa21 gene dominantly contributed to K3a resistance. However, the Xa4 gene also contributed to the full expression of resistance. The level of expression of strong resistance to K3a race was attributed to the presence of Xa21 and Xa4 genes irrespective of the presence of xa5 gene. Our results suggest that the R-gene combinations of Xa4+Xa21 could be a useful and effective strategy toward improving resistance to K3a race of Korean japonica cultivars.

Resistance Genes and Their Effects to Blast in Korean Rice Varieties (Oryza sativa L.)

A total of 98 varieties consisting of 88 japonica and 10 Tongil-type of rice were analyzed to resistant genes and their effects to blast. The 13 major blast resistance (R) genes against Magnaporthe oryzae were screened in a number of Korean rice varieties using molecular markers. Twenty-eight (28.6%) were found to contain the Pia gene originating from Japanese japonica rice genotypes. The Pib gene from BL1 and BL7 was incorporated into 39 Korean japonica varieties, whereas this same gene from the IRRI-bred indica varieties was detected in all Tongil-type variety. The Pii gene was found in 17 of the japonica varieties. The Pii gene in Korean rice varieties originates from the Korean japonica variety Nongbaeg, and Japanese japonica varieties Hitomebore, Inabawase, and Todorokiwase. The Pi5 gene, which clusters with Pii on chromosome 9, was identified only in an Tongil-type, Taebaeg. Thirty-four varieties were found to contain alleles of the resistance gene Pita or Pia-2. The Pita gene in japonica varieties was inherited from the Japanese japonica genotype Shimokita, and the Pita-2 gene was from Fuji280 and Sadominori. Seventeen japonica and one Tongil-type varieties contained the Piz gene, which in the japonica varieties originates from Fukuhikari and 54BC-68. The Piz-t gene contained in three Tongil-type varieties was derived from IRRI-bred indica rice varieties. The Pi9(t) gene locus that is present in Korean japonica and Tongil-type varieties was not inherited from the original Pi9 gene from wild rice Oryza minuta. The Pik-multiple allele genes Pik, Pik-m, and Pik-p were identified in 24 of the varieties tested. The Pit gene inherited from the indica rice K59 was not found in any of the Korean rice varieties tested. In haplotype analysis for the loci related to two QTLs as well as five major resistant genes and, two

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

R

A Late-Maturing and Whole Crop Silage Rice Cultivar `Mogwoo`

genes Piz and Pita showed stable resistant effects to blast nurseries and isolates in~Korea.

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

‘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.

A Medium-Maturing, Black Pericarp and Aromatic Rice Variety ‘Sheonhyangheukmi’

`Mogwoo`, a new high yield and whole crop silage rice (Oryza sativa L.) cultivar, was developed by the rice breeding team of the National Institute of Crop Science, RDA, Suwon, Korea, from 1999 to 2009, and was released in 2010. It was derived in 1999 from a cross between Dasanbyeo, having a high yield, and Suweon431/IR71190-45-2-1. A promising line, SR25848-C99-1-2-1, selected by the pedigree breeding method, was designated the name of `Suweon 519` in 2007. This cultivar has about 155 days of growth period from seeding to heading, and is tolerance to lodging, with erect pubescent leaves as well as a long and thick culm. This cultivar has the same number of tillers per hill and higher spikelet numbers per panicle compared to Nokyang. `Mogwoo` has longer leaves compared with other Tongil-type varieties. This new variety is resistant to grain shattering, leaf blast, bacterial leaf blight, and small brown planthopper. The biomass yield of `Mogwoo` was 1,956 kg/10a in a regional test over three years. The result shows that `Mogwoo` is adaptable to central and south-east plain areas of Korea.

Fine mapping of a yield-enhancing QTL cluster associated with transgressive variation in an Oryza sativa x O. rufipogon cross

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.

Construction of a deep coverage BAC library from Capsicum annuum, 'CM334'

Sheonhyangheukmi, black pericarp and aromatic rice (Oryza sativa L.) variety, was developed by the rice breeding team of National Institute of Crop Science (NICS), RDA in 2011. This variety was derived from the cross between Suweon477 and CG2-2-75-4-1-22-3 in 2002 summer season, and selected by a promising line, SR28684-9-2-2-2, was selected and designated as the line of Suweon532 in 2009. The local adaptability test of Suweon532 was carried out from 2009 to 2011 and it was named as Sheonhyangheukmi in 2011. This variety is medium matured with heading date of August 11 in central plain area of Korea. This variety is about 89 cm tall culm length and 122 spikelets per panicle. Its 1,000 grain-weight of brown rice is 17.0 g. This variety is susceptible to leaf blast and and insect pest, but resistant to bacterial leaf blight and moderately resistant to stripe virus disease. This variety has tolerance to unfavorable environment such as cold. Milled rice of Sheonhyanghuekmi is non-glutinous and aromatic endorsperm. This variety has higher anthocyanin content compared to black pigmented variety Heukjinju. The yield potential of Sheonhyangheukmi in brown rice was about 4.75 MT/ha at ordinary fertilizer level in local adaptability test for three years. This variety would be adaptable to the southern plain and middle plain of Korea.