Japonica rice, especially Northeast rice, is significantly different from Southern Indica rice in starch structure. Northern japonica rice contains a high level of amylopectin, which is confirmed not only in the scientific literature, but also in national standards. The amylose content of high-quality japonica rice is usually 15% to 20%, compared to the amylose content requirement of high-quality indica rice, which is more relaxed, meeting 15% to 24%.
Confusingly, however, although japonica rice is also grown in other parts of China, they seem to taste far inferior to Northeast rice. This raises the question: what are the factors that contribute to the unique taste and quality of Tohoku rice?
It has been suggested that this may be related to the unique temperature, light, soil and moisture conditions in the Northeast. The combination of these factors provides unique conditions for the growth of japonica rice. However, this view begs another question: since rice originated in the middle and lower reaches of the Yangtze River 9,000 years ago, and rice was rarely cultivated in the north in history, why did the south overtake the north in the quality of japonica rice?
We need to study in depth the growing conditions and environmental adaptability of japonica rice in different regions. Perhaps by comparing the genotype and growth process of japonica rice in different regions, we can find the root cause of the difference in the quality of japonica rice. In this way, we can not only better understand the mechanism of japonica rice quality formation, but also provide useful reference for improving the quality of japonica rice in other regions.