ABSTRACT
Function-assisted selection for cold-resistant rice varieties with aroma in high-latitude regions

Rongsheng Wang1, 2, Kun Li1, 2, Wei Zhang1, 2, Juntao Ma1, 2, Yongli Wang1, 2, Lingwei Deng1, 2, Hui Liu1, 2, Yongqing Tao1, 2, Guohua Ding3, Guang Yang3, Guomin Zhang1, 2, and Fengchen Mu1, 2*
 
Rice (Oryza sativa L.) varieties in high-latitude regions exhibit a pronounced characteristic of narrow genetic basis. Hybridization between geographically distant japonica and locally cultivated varieties can lead to slower stability in offspring due to significant genetic differences in parent lines. The increasing precision in functional gene mapping and cloning, combined with the use of molecular markers, allows the targeted introduction of desirable genes and reduces the reliance on field selection methods. However, this method does not analyze functional differences between parental genes, and the selected lines are disconnected from field production and even variety approval, hindering their potential for market adoption. Therefore, this study explored gene sequence polymorphism and developed specific detection markers with the aim to address the needs in rice production in cold regions. A stable new rice line named ‘Songkegeng 119’ with aroma and cold tolerance was created by aggregating the aroma gene BADH2 (betaine aldehyde dehydrogenase 2) from the high-quality ‘Wuxianggeng 9’ in Jiangsu Province and the cold-tolerance gene CTB4a (cold tolerance at booting stage 4a) from the main cv. Songgeng 12 in Heilongjiang Province. ‘Songkegeng 119’ underwent various tests and was approved in 2022. The phenotype and genomic analysis of ‘Songkegeng 119’ indicated that function-assisted breeding could accurately and efficiently screen for desired functional genes. This can be combined with the selection of agronomic traits to obtain high-quality, high-yield, stress-tolerant, and aromatic rice varieties. This finding provides theoretical support for the polymerization of more functional genes in the future, and also serves as a practical test for the theory of function-assisted selection breeding.
Keywords: Aroma, breeding by design, cold tolerance, function-assisted selection, Oryza sativa, rice.
1Heilongjiang Academy of Agricultural Sciences, Biotechnology Research Institute, Harbin, Heilongjiang, China.
2Heilongjiang Laboratory of Crop and Livestock Molecular Breeding, Harbin, Heilongjiang, China.
3Heilongjiang Academy of Agricultural Sciences, Institute of Farming and Cultivation, Harbin, Heilongjiang, China.
*Corresponding author (mfc888221@163.com)