UGANDA – Researchers at Yunnan University have developed a variety of perennial rice named PR23 by cross-breeding regular annual rice Oryza sativa with a wild perennial variety from Africa.
The variety is capable of regrowing season after season without reseeding, perhaps, answering to nature sustainability highlights in agronomic, economic and environmental indicators for rice production.
Nature sustainability report says that the retooled crop is changing the lives of more than 55,752 smallholder farmers in Southern China and Uganda.
Farmers are adopting the new crop because it is economically advantageous and less labor-intensive compared to regular annual rice farming.
According to Dr. Shilai Zhang, a professor at Yunnan University’s School of Agriculture, perennial rice delivers significant labor and cost savings to farmers. However, farmers need to master new cultivation techniques to maintain high yields.
Together with a team of experts, Dr. Zhang hybridized annual rice with its perennial African relative Oryza longistaminata which was cultivated on large scale in 2016 and released for commercialization in 2018.
Unlike regular rice which is planted every season, PR23 can yield eight consecutive harvests across four years (as these plants with stronger roots grow back vigorously after each harvest).
PR23 also had higher yields, reported at 6.8 tons per hectare, compared to regular irrigated rice (6.7 tons per hectare).
“But growing it is much cheaper since it requires less labor, seeds and chemical inputs” says Eric Sacks, professor in the Department of Crop Sciences at the University of Illinois, a partner in the research.
Farmers growing perennial rice put in almost 60% less labor and spent nearly half on seed, fertilizer, and other inputs while enjoying similar yields to annual rice. This is why perennial rice cultivation hit 15,533 hectares in 2021, including 44,752 smallholder farms.
According to the research findings reported in the journal Nature Sustainability in November 2022, growing perennial rice over a period of four years has remarkable environmental benefits such as soils accumulating close to a ton of organic carbon (per hectare per year) along with increases in water available to plants.
However, the researchers recommend re-sowing of the perennial rice after four years following dropping yields in the fifth year of the crop’s cultivation due to several factors.