Root development at the seedling stage is an important trait for the early growth of rice. In this study, the root length and weight of 211 Korean landrace rice at the seedling stage were evaluated, and the average root length and weight were 6.94 cm and 48.18 mg, respectively. Principal component analysis (PCA) of 211 accessions based on 70,849 SNPs presented three subgroups. Two quantitative trait loci (QTLs) associated with root length were detected on chromosomes 3 and 6 using genome-wide association study (GWAS). Four haplotypes were identified using associated SNPs for the two root length QTLs. The average root length of Hap2 and Hap 3 was 7.32 cm and 6.56 cm, respectively, and were significantly different. Gene expression analysis in the candidate regions of QTLs for root length at the seedling stage showed that several genes were expressed in the root. QTLs associated with root length at the seedling stage identified in this study may be applied to improve the root length trait and detect candidate genes.

‘Golden queen 3’, an aromatic rice variety, was developed by Seedpia inc. (Suwon, Korea) breeding company in 2014. This cultivar was derived from a cross between ‘HJ-11’, a high-yield, aromatic line, and ‘JCH33M-15-1-9-1’, which has a low amylose content. During the F₃-F₈ generation, breeding lines were selected using a pedigree breeding method. The most promising line (JS9-3-73-15-5-1-5-3-1-1) was advanced and named ‘SP005’ in 2013. This variety was headed on August 13, two days later than ‘Hwayeong’ in the ‘in middle plane’ is commonly used to distinguish rice cultivation areas in Korea, so I think it's no problem to the understanding for readers (including farmers). The culm and panicle lengths of this variety were 75.7 cm and 20.1 cm, respectively. It has approximately 14.7 tillers per hill and 104.8 spikelets per panicle, and the 1000-grain weight was 21.8 g. The yield performance was 5.47 MT/ha in the local adaptability test, and the amylose content of this variety was 12.5%. 2-Acetyl-1-pyrroline was detected as the major volatile ingredient in aromatic rice, and a 1 bp insertion on the 14th exon (badh2.7 allele) was identified in the Badh2 gene. (Registration No. 7308).

The Jinsang 2 cultivar is a new late-maturing, low amylose rice variety with a medium to short culm created by the Seedpia Inc. breeding company in 2012. This variety was derived from a cross between Junam, a high-yield and lodging tolerant source, and DM3-8-72-9, which was derived from a cross between Donjinchal and Milkyqueen, with a low amylose content and superior agronomic traits. A general single seed descent method was applied to develop Jinsang 2 in the F3-F4 generations. During the F5-F8 generations, the breeding lines were selected through a pedigree breeding method. A promising line, JS6-B-52-8-3-5-1-B-B-B, was selected and named HJ-6 in 2011. This variety headed on the 25^th of August, which was 14 days later than Hwayoung. The culm and panicle length of the variety was 71.6 cm and 19.9 cm, respectively. The milled rice from the variety had a dull and medium- to short-grain, and the 1,000-grain weight was around 20.0 g. It had a low amylose content of 12.2% and a low protein content of 6.8%. The yield performance of Jinsang 2 milled rice was about 5.36 MT/ha from the ordinary culture replicated yield trial test.

Magnesium is important not only for the growth of rice itself, but also as an essential micronutrient component of half of the world population who are supported by rice. Here, we performed genome-wide association study (GWAS) with high-resolution density SNPs to identify natural allelic variation in Mg²⁺ increase from rice set, which is derived from a total 24,368 rice germplasms. The range of the concentration and distribution of Mg²⁺ in 295 core accessions of brown rice grain were wide, from 18.17mg/L to 57.11mg/L, with mean 39.71mg/L. In particular, GWAS result shows that the high peak found on chromosomes 3 and 11. The new natural variants identified through haplotyping analysis would be useful to develop new rice varieties with improved storage ability of the valuable mineral through the future molecular breeding.

‘Hyowon 4’, a new medium maturing glutinous rice variety was developed by the rice breeding team of Pusan National University in 2013. This cultivar was derived from a cross between ‘Boseokchal’ and ‘Donna’ with good glutinous property. During F3~F8 generation, breeding lines were selected by a pedigree breeding method. As a result, the promising line (JS23-4-39-14-5-1-1-1) with good glutinous property was advanced and designated as the name of ‘SP 106’ in 2012. This variety headed on Aug. 15, which is 2 days later than ‘Dongjinchal’ in middle plane. The culm length and panicle length of this variety was 82.4 cm and 21.1 cm, respectively. This variety has about 13.9 tillers per a hill and 100 spikelets per a panicle. The ratio of ripened grain is about 92.0% and 1000-grain weight was 20.9 g in brown rice. The yield performance was 5.03 MT/ha in local adaptability test.

"Hyowon 5’, a new aromatic rice variety with high yield was derived from a cross between 'Dasan’ as a high yield source and ‘IR841-1-1-2’ as a donor for aroma. A general pedigree breeding method was applied to develop Hyowon 5. In F₈ generation, a promising line, JS14-12-36-8-5-3-1-1-1, was selected and designated as the name of ‘SP 102’ in 2012. This variety headed on Aug. 14 , which is 3 days later than ‘Hwayoung’ in middle plane. The brown rice of this aromatic variety ‘Hyowon 5’ exhibited 51 odor-active volatiles including a pop corn-flavoring 2-acetyl-1-pyrroline which is exclusively detected in aroma rice varieties. The Culm length and panicle length of this variety was 83.2 cm and 26.4 cm, respectively. This variety has about 14.9 tillers per hill and 124.5 spikelet numbers per panicle. The 1000-grain weight was 20.9 g in brown rice. The yield performance of brown rice was 6.27 MT/ha in local adaptability test.

'Hyowon 2’, a new medium-late maturing glutinous rice variety with short clum and lodging tolerance was developed by the rice breeding team of Pusan National University in 2013. This cultivar was derived from a cross between 'Junam’ as a short clum source and ‘Donna’ with a good glutinous properties. During selected by the pedigree breeding method, until F8 generation. As a result, a promising line, JS22-3-24-1-6-2-1-1-1, was advanced and designated as the name of ‘SP 105’ in 2012. This variety headed on Aug. 22 is 9 days later than ‘Dongjinchal’ in middle plane. The Culm length and panicle length of this variety was 65.6 cm and 22.5 cm, respectively. This variety has about 14.4 tillers per hill and 113 spikelet numbers per panicle. The ratio of ripened grain is about 93.0% and 1000-grain weight was 18.4 g in brown rice. This variety has higher α-tocotrienol content compared to that of ‘Hwasunchal’. The yield performance of brown rice was 4.81 MT/ha in local adaptability test.

‘Jinsang’ is a new japonica rice variety was derived from a cross between ‘Yumetsukushi’ as a high grain quality and ‘Milky queen’ with low amylose content and good eating quality in 2000, and selected by pedigree breeding method until M8 generation. As a result, a promising line, JCH33M-15-1-9-1-5-1-1-1, was advanced and designated as the name of ‘HJ-2’ in 2009. This variety has about 111 days to heading after sowing and has 75.2 cm culm height. Milled rice of that shows dull and medium short grain and 1,000-grain weight was about 20.9 g. It has low amylose content of 11.9% and lower protein content of 6.8%. The yield potential of ‘Jinsang’ in brown rice was about 4.57 MT/ha by ordinary culture in replicated yield trial test.