Rice from all over the world, born from only two strains

Rice is an important edible crop worldwide, with as many as half of the world’s population as a staple food. However, as a result of analyzing the genome of about 3,000 rice species, it is said that rice around the world can be classified into only two strains.

As agriculture is expected to be seriously affected by climate change in the near future, it is pointed out that understanding the genetic diversity of rice, an important plant crop, and strengthening food security against climate change is an urgent need.

A research team at the University of Queensland, Australia, focused on the 3KRGP (3000 Rice Genomes Project) database, which decoded the genomes of 3,018 rice species collected from around the world. 3KRGP is an international project that deciphers the genome of 3,018 rice plants grown in 89 countries around the world, centered on RRI in the Philippines.

As a result of obtaining and classifying the rice chloroplast genome from the 3KRGP, the research team found that all 3,018 species belonged to two groups in the A strain group or the B strain group. The two lines of rice grown by humans are distant relatives of the Australian or Asian wild species. The research team estimates that two kinds of wild rice that branched 1 million years ago were cultivated separately.

When it comes to rice varieties, japonica and ndica are famous, but this distinction is not directly related to the three specific strains this time around. In fact, most of the A strains were Indica, but some varieties such as tropical japonica and temperate japonica were included. Although this type of rice was included in the B strain group, it was significantly different from the proportion of the A strain group.

Regarding the results of this study, the research team explained that the seed is stored in the maternal gene of rice, and since rice farmers have been collecting seeds from rice paddies for generations, rice from various regions is well suited to the wild there. In addition, research on the process of cultivation of rice will serve as a clue to the efforts that mankind has made to improve rice by adopting the variety of wild rice into the rice gene pool. Although it is not known, he explained that understanding the maternal genotype will be important from the standpoint of rice performance.

In the future, the research team plans to investigate the relationship of various rice strains to develop ways to analyze rice data more efficiently. Related information can be found here .