M. Tomita
Published: February 28, 2024
Genet. Mol. Res. 23(1): GMR19224
DOI: https://doi.org/10.4238/gmr19224

Cite this Article:
M. Tomita (2024). Whole genome sequencing and trait investigation revealed a semidwarf isogenic rice variety with a genome and grain quality similar to the high-demand cultivar Koshihikari. Genet. Mol. Res. 23(1): GMR19224. https://doi.org/10.4238/gmr19224

About the Authors
M. Tomita

Corresponding Author
M. Tomita
Email: tomita.motonori@shizuoka.ac.jp

ABSTRACT

The leading japanese rice cultivar, Koshihikari, is in high demand globally due to its superior food quality. However, Koshihikari has had a reduction in yield and a loss of quality due to lodging and immature chalky grains, which has been linked to global warming and the changing climate. The semidwarf gene sd1 encoding a defective C20 oxidase in the gibberellin (GA) biosynthesis pathway (GA 20 oxidase, OsGA20ox2) was introduced into the Koshihikari genome through 14 backcrosses and the genome was surveyed with a next-generation sequencer. Trait investigation was conducted in six locations in japan for plant height, panicle numbers, yield, grain weight, quality, sensory taste, etc. The introgression of sd1 resulted in a semidwarf phenotype designated as Hikarishinseiki, which is 21.4 cm shorter than Koshihikari. Hikarishinseiki has the same genome as Koshihikari, except for the sd1 region. The taste and quality of Hikarishinseiki were equivalent to those of Koshihikari. Hikarishinseiki is registered under USDA Plant Variety Protection No. 201000072, as the first semidwarf isogenic Koshihikari using Jukkoku-derived sd1 in areas other than Japan.

Key words: Defective GA 20-oxidase gene, Hikarishinseiki, Rice, Semidwarf.