This experiments were carried out to know the response to Brown Planthopper(BPH) resistance genes at rice seedling stage using Biotype 1 for develoment of resistant cultivars. Varieties with Bph1, Bph3 and Bph18 genes showed a very strong resistance response, BpH2, Bph6, bph7 and Bph9 genes exhibited moderate resistance. Bph5 and Bph8 gene retention varieties and Nampyeongbyeo showed a very weak sensitivity in response to BPH. After 72 hours, Nampyeong(no gene) and IR72(Bph3 gene) were showed a feed-preference 690% and 0%, respectively. Results of Antixenosis and seedling resistance response to BPH were grouped into similar by specific resistance genes. Ten days after inoculation, BPH survival rate of vareities with resistance genes were below 30%, whereas Nampyeongbyeo was more than 70%. The results showed that Bph3 and Bph18 genes are highly resistant response against BPH, these genes are very useful for improve the rice cultivars with various resistance genes

‘Ondami’, a japonica rice cultivar developed from a cross between Hitomebore having a high grain quality and Sangju27 adaptable to southern mid-mountainous area was developed by the rice breeding team of Sangju Substation, NICS, RDA in 2013. The heading date of ‘Ondami’ is july 27 which is same with ‘Odae’ in Southern mid-mountainous area, mid mountainous, southern alpine area and north-east coastal area of South Korea. ‘Ondami’ has 70cm culm length, 19cm panicle length which is 2cm shorter than those of ‘Odae’ and 78 spikelets per panicle. In reaction to biotic and abiotic stresses, it shows strong resistance to blast, but is susceptible to bacterial blight, virus diseases, and insect pests. The milled rice of ‘Ondami’ exhibits translucent and, relatively clear non-glutinous endosperm, and medium short grain shape. This variety has a higher head rice milling recovery ratio(73.1%) and lower amylose content(18.8%) than that of ‘Odae’. The milled rice yield performance of this variety was about 5.29 MT/ha in ordinary cultivation of local adaptability test for three years. ‘Ondami’ could be adaptable to Southern mid-mountainous area, mid mountainous, southern alpine area and north-east coastal area of South Korea.

A doubled haploid (DH) lines derived from the cross between high-yielding japonica rice cultivars ‘Deuraechan’ and ‘Boramchan’ was developed to increase diversity of panicle and yield-related traits and select high-yielding lines. Panicle and yield-related traits of DH population consisting of 163 lines and 13 selected high-yielding lines were analyzed using correlation, principal component, and path analysis. Among panicle-related traits, number of spikelets on secondary rachis-branches (SRBs) was more highly correlated with and had more positive effect on number of spikelets (NS) than number of spikelets on primary rachis-branches (PRBs) per panicle. In the DH population, NS had the most positive effect on yield, whereas panicle number per hill (PN) was in the selected lines. PN was significantly positive correlated with ratio of ripened grain (RGG) in both case. The enhancement of ripening and increase of total spikelets number by increasing PN had more effect on yield than increase of total spiekelts number by increasing NS in the selected lines. Among 13 lines, four lines, AC60, AC152, AC156, and AC161 showed higher yield than Deuraechan (481 kg/10a) and Boramchan (558 kg/10a). Deuraechan exhibited panicle-weight type with low tiller and heavy panicles and Boramchan was slightly panicle-number type with more PN and higher RGG. Selected high-yielding lines showed medium characteristics of parents with improved yield potential. These elite lines could be utilized to develop high-yielding japonica rice.

‘Chindeul’, a new japonica rice cultivar developed from a cross between HR22538-GHB-36-4 having brown planthopper (BPH) resistance and Iksan471 having a good eating-quality and high yield, was developed by the rice breeding team of Department of Rice and Winter Cereal Crop, NICS, RDA in 2012. This variety has about 124 days growth duration from transplanting to harvesting in west-southern coast, Honam and Youngnam plain of Korea. It has 83 cm culm length and tolerance to lodging. In reaction to biotic and abiotic stresses, it shows resistance to bacterial blight pathogen races from K1 to K3, stripe virus and brown planthopper. The milled rice of ‘Chindeul’ exhibits translucent, relatively clear non-glutinous endosperm and medium short grain. It has lower protein content of 5.9% and good palatability of cooked rice compared with Nampyeongbyeo. The milled rice yield performance of this variety is about 5.61 MT/ha in local adaptability test for three years. ‘Chindeul’ would be useful genetic resources for multi-resistance breeding program against disease and insect.

‘Huimangchan’ is a new japonica rice variety developed and registered by the rice breeding team of Department of Rice and Winter Cereal Crop, NICS, RDA in 2011. This variety was derived from the three-way cross of ‘Milyang165’, ‘Shindongjin’ and ‘YR19105-Acp222’. This variety has about 126 days of growth duration from transplanting to harvesting in Honam and Youngnam plain of Korea. It is about 91 cm in culm length and tolerance to lodging. In reaction to biotic stresses, it shows moderate resistance to blast, resistance to bacterial blight pathogen races from K1 to K3, and rice stripe virus, but susceptible to other major diseases and insect pests. The milled rice of ‘Huimangchan’ has high quality, midium short grain. The milled rice yield of this variety is about 6.18 T/ha in local adaptability test for three years. ‘Huymangchan’ would be adaptable to Middle plain, Honam plain and Youngnam plain area of Korea.

‘Sanhomi’, a new japonica rice cultivar developed from a cross between Sangmibyeo and F₁ plant derived from the cross between Sangju24 and Hwayeongbyeo having bacterial blight and rice stripe virus resistance was developed by the rice breeding team of Sangju Substation, NICS, RDA in 2012. This variety has about 114 days of growth duration from transplanting to harvesting in southern mid-mountainous area of South Korea. It has 70 cm culm length and tolerance to lodging. In reaction to biotic and abiotic stresses, it shows multiple resistance to blast, bacterial blight and rice stripe virus. The milled rice of ‘Sanhomi’ exhibits translucent and, relatively clear non-glutinous endosperm, and medium short grain. This variety has a higher milled rice recovery (67.3%), better palatability of cooked rice and similar amylose content (19.9%) compared with Odaebyeo. The milled rice yield performance of this variety was about 5.60 MT/ha in local adaptability test for three years. ‘Sanhomi’ would be adaptable to southern mid-mountainous of South Korea.

This study was conducted to develop multi-resistant lines to brown planthopper, bacterial blight, and rice stripe virus using anther culture in rice. A total of 213 double haploid lines were developed the cross between HR26234-12-1-1 conferring resistant to bacterial blight and rice stripe virus and SR30071-3-7-23-6-2-1-1 conferring resistant to brown planthopper, bacterial bight, and rice stripe virus. Using DNA molecular marker, HR26234 and SR30071 were confirmed to have Xa3+xa5+Stvb-i and Bph18+Xa4+Stvb-i, respectively. All double haploid lines carried Stvb-i, and Bph18+Xa3, Bph18+Xa4, Bph18+Xa3+xa5, Bph18+Xa4+xa5, bph18+Xa3, bph18+Xa4, bph18+Xa3+xa5, and bph18+Xa4+xa5 combinations were identified. Segregation distortions such as no combinations carrying Bph18(or bph18)+xa5+Stvb-i and fewer lines carrying Bph18 than bph18 were occurred in DH population. Brown planthopper resistant lines carrying Bph18 showed longer culm length than susceptible lines. Selected Bph18+Xa4+xa5+Stvb-i combination lines with short culm conferred resistant to brown planthopper, bacterial blight, and rice stripe virus, while showed deleterious effects such as spikelet sterility, lower yield, and vulnerable to lodging than standard and comparative varieties. Using anther culture, we rapidly developed multi-resistant lines to brown planthopper, bacterial blight, and rice stripe virus. However, distorted segregation in DH population and linkage drag with Bph18 were obstacles to develop practical multi-resistant cultivars.