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‘Alchanmi’, a japonica rice variety, was developed from a cross between ‘Junam’ and ‘Chilbo’ by a rice breeding team at the National Institute of Crop Science and Icheon, Agricultural Technology Center in 2018. The heading date of ‘Alchanmi’ was August 10 in the middle plain area—two days later than that of ‘Hwaseong’. ‘Alchanmi’ had a culm length of 69 cm, 16 cm shorter than that of ‘Hwaseong’, and 103 spikelets per panicle. The viviparous germination rate of ‘Alchanmi’ was 24.4%. It showed resistance to blast, bacterial blight (K1, K2, K3 race), and stripe virus, but was susceptible to the K3a race of bacterial blight, dwarf and black streak dwarf viruses, and plant hoppers. The milled rice of this variety exhibited a translucent and medium short grain shape. The cooked rice grains of ‘Alchanmi’ had an excellent palatability index (0.7) and showed lower amylose content (18.6%) than that of ‘Hwaseong’. The grain milling characteristics of ‘Alchanmi’ were better than those of ‘Hwaseong’, especially the head rice milling recovery ratio and head rice ratio (96.2%). ‘Alchanmi’ showed 5.83 MT/ha of milled rice productivity at 6 sites under ordinary cultivation (Registration No. 8132). [ABSTRACT FROM AUTHOR]

The rice variety ‘Youngjin’ is a japonica rice (Oryza sativa L.) with good eating quality, lodging tolerance, and resistance to the rice stripe virus (RSV) and bacterial blight disease (BB). It was developed by the rice breeding team of the Department of Southern Crop, NICS, RDA, in 2016. This variety was derived from a three-way cross between ‘Iksan486’, ‘YR22722-B-B-B-25-1’, and ‘Chengmu,’ with good eating quality, in the summer of 2007. The pedigree of ‘Youngjin’ was YR27874Acp46-1, and was designated as ‘Miyang283’ in 2012. After local adaptability tests at five different locations from 2014 to 2016, it was released under the name ‘Youngjin’ in 2016. ‘Youngjin’ is a mid-late maturing ecotype with a short culm length of 67 cm. This variety was found to be resistant to the K1, K2, and K3 races of BB, and RSV, and moderately resistant to leaf blast disease. The milled rice kernels of ‘Youngjin’ were translucent and clear, without white core and belly, and had good eating quality, according to a panel test. This variety showed a lower percentage of cracked kernels compared to other susceptible cultivars. The milled rice yield of ‘Youngjin’ was 568 kg/10a, under normal levels of fertilization, determined by the local adaptability tests. This cultivar is adaptable to the Yeongnam plain area (Registration No. 7653). [ABSTRACT FROM AUTHOR]

‘Sangbo’ is a japonica rice (Oryza sativa L.) variety with high head rice grain ratio and good ripened grain color, as well as resistance to rice dwarf virus (RDV) and bacterial blight disease (BB). It was developed by the rice breeding team of the Yeongdeok Branch of the National Institute of Crop Science, RDA, Korea, in 2015. This variety was derived in the 2002 summer season from a cross between ‘Yeongdeog32’, with high eating quality, and ‘Nampyeong’, with a high milling ratio. In 2012, a promising line, YR24256-142-5-3-1-1-2, selected by the pedigree breeding method, was designated the name, ‘Yeongdeog59’. After performing a local adaptability test at nine locations from 2013 to 2015, ‘Yeongdeog59’ was released with the name ‘Sangbo’ in 2015. ‘Sangbo’ has a culm length of 77 cm and a medium-late growth duration. This variety was resistant to K1, K2, and K3 races of bacterial blight, along with the dwarf virus, and was moderately resistant to leaf blast disease. Based on the results of a panel test, ‘Sangbo’ has translucent and clear milled rice kernel without white core and belly rice, and good eating quality. The yield potential of ‘Sangbo’ in milled rice was approximately 6.21 MT/ha at the ordinary fertilizer level of the local adaptability test (LAT). This cultivar would be adaptable to the middle plain, south plain, Yeongnam plain, east coastal area, and south mid-mountainous areas of Korea. [ABSTRACT FROM AUTHOR]

Limitation of genetic diversity in japonica rice breeding populations is often identified as a potential obstacle for the development of high yielding cultivars. The use of diverse germplasm in rice breeding has been suggested as one way of combating this problem. This study was conducted to improve the genetic diversity for rice, by developing an advanced backcross population derived from a backcross ‘Junam’ as recurrent parent and ‘IR72’ as a donor parent. Among them, we selected a promising line ‘YR24438-B-B-B-B-132’ containing bacterial blight resistance gene Xa4. Testing in the replicated yield trial in 2009, the ‘YR24438-B-B-B-B-132’ line was selected, and it was designated as ‘Milyang298’. The local adaptability test of ‘Milyang298’ was carried out at three locations from 2014 to 2016 and it was named ‘MY298BB’. The average culm length in the replicated yield trials was 87 cm, which is 15 cm taller than recurrent parent ‘Junam’. Number of spikelets per panicle was significantly lower than in ‘Junam’ but the number of tillers per hill was higher. This variety is resistant to bacterial blight race K1, K2, K3, and K3a.However ‘MY298BB’ showed early leaf senescence at the mature stage and the chlorophyll content of ‘MY298BB’ was significantly lower than that of the recurrent parent ‘Junam’. Moreover the grain filling ratio and yield were significantly lower in ‘MY298BB’ than those of recurrent parent ‘Junam’. Therefore, understanding the leaf senescence mechanism would be useful for improving yield potential in rice. [ABSTRACT FROM AUTHOR]