Temperate japonica is used as the parent for crossing in the breeding of new rice cultivars in Korea, and the grain shape of the developed lines or cultivars is a semi-round and medium-short grain length. To overcome the current low quantity of japonica cultivar germplasm and deterioration in quality caused by climate change, it is necessary to diversify the grain characteristics of japonica. Most of the United States (US) cultivars are classified as medium, long, extra-long, and half spindle- and spindle-shaped grains. The qSW5 allelotype, a major gene involved in grain width, is found in all US cultivars. In addition, the US cultivar ‘Saber’ has both qgl3 and GS3_B alleles, which have low allele frequencies among Korean rice cultivars, and ‘A020’ had gw8, an allele with a reduced grain width. The pasting properties and texture of medium-grain length and half-spindle-shaped cultivars were relatively similar to those of the Korean rice cultivar, but different from those of long-grain and long spindle-shaped cultivars. Therefore, grain shape is associated with pasting properties and texture traits. Among the rice cultivars in the US, tropical japonica belongs to the same japonica as the Korean rice cultivar; however, its grain shape is similar to that of indica. As grain shape is also related to grain quality, US cultivars can be used as a useful genetic resource for diversifying the grain characteristics of Korean japonica cultivars and breeding new cultivars.

Citations

Citations to this article as recorded by  

• QTL Analysis for Yield and Grain-Related Traits Using the Recombinant Inbred Lines Derived from a Cross between ‘Boramchan’ and ‘Pecos’
  Hyun-Su Park, Chang-Min Lee, Jeonghwan Seo, Songhee Park, Keon-Mi Lee, Jae-Ryoung Park, O-Young Jeong
  Korean Journal of Breeding Science.2025; 57(2): 131.     CrossRef
• Analysis of Yield- and Quality-Related Traits of Risotto Rice Varieties in a Korean Environment
  Songhee Park, Jeonghwan Seo, Chang-Min Lee, Jae-Ryoung Park, Keonmi Lee, O-Young Jeong, Youngjun Mo, Hyun-Su Park
  Korean Journal of Breeding Science.2025; 57(1): 13.     CrossRef
• Quantitative Trait Locus Analysis for Quality-Related Traits Using the Recombinant Inbred Lines Derived from a Cross between “Boramchan” and “Pecos” Japonica Rice
  Hyun-Su Park, Chang-Min Lee, Jeonghwan Seo, Songhee Park, Hyeonso Ji, Keon-Mi Lee, Jae-Ryoung Park, O-Young Jeong
  Korean Journal of Breeding Science.2025; 57(4): 373.     CrossRef
• Quantitative Trait Loci Analysis of Quality-Related Traits Using Recombinant Inbred Lines Derived from a Cross between ‘Chamdongjin’ and ‘Younghojinmi’
  Hyun-Su Park, Jeonghwan Seo, Chang-Min Lee, Songhee Park, Keon-Mi Lee, Jae-Ryoung Park, O-Young Jeong
  Korean Journal of Breeding Science.2024; 56(4): 395.     CrossRef
• Analysis of Agricultural Traits of O. sativa and O. glaberrima under Korean Climatic Conditions
  Jae-Ryoung Park, Hyun-Su Park, Jeonghwan Seo, Chang-Min Lee, Songhee Park, Mina Jin, Keon Mi Lee, Keunpyo Lee, Sukyeung Lee, Ebrima Jallow, O-Young Jeong
  Korean Journal of Breeding Science.2024; 56(2): 97.     CrossRef