The research also confirms that Indus populations were the earliest people to use complex multi-cropping strategies across both seasons, growing foods during summer (rice, millets and beans) and winter (wheat, barley and pulses), which required different watering regimes.
The findings suggest a network of regional farmers supplied assorted produce to the markets of the ancient cities of the Indus Valley civilisation, which stretched across what is now Pakistan and northwest India during the Bronze Age.
Researchers, including those from Banaras Hindu University (BHU) in Uttar Pradesh and the University of Oxford in the UK, found evidence of domesticated rice in South Asia as much as 430 years earlier.
"We found evidence for an entirely separate domestication process in ancient South Asia, likely based around the wild species Oryza nivara," said Jennifer Bates from University of Cambridge in the UK.
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"While wetland rice is more productive, and took over to a large extent when introduced from China, our findings appear to show there was already a long-held and sustainable culture of rice production in India as a widespread summer addition to the winter cropping during the Indus civilisation," she said.
The location of the Indus in a part of the world that received both summer and winter rains may have encouraged the development of seasonal crop rotation before other major civilisations of the time, such as Ancient Egypt and China's Shang Dynasty, said Cameron Petrie from University of Cambridge.
"However, the area inhabited by the Indus is at a meteorological crossroads, and we found evidence of year-long farming that predates its appearance in the other ancient river valley civilisations," he said.
The study was published in the journals Antiquity and Journal of Archaeological Science.