Perennial Rice (PR23)



    • Recently, researchers at the Yunnan University (China) have developed a variety of perennial rice named PR23 by crossbreeding regular annual rice Oryza sativa with a wild perennial variety from Africa. 
      • In 2021, the variety was grown by more than 44,000 farmers in southern China.  


    • Rice is a staple crop that feeds an estimated four billion people around the world.
    • Work on perennial rice began in early 1990s at the Yunnan Academy after a failed attempt in the 1970s.
    • The first variety was released to Chinese growers in 2018.

    What is the perennial variety of crops/ rice?

    • Perennial crops are typically considered as those that are more permanent, requiring a few growth cycles before fruit is produced. 
    • Perennial rice are varieties of long-lived rice that are capable of regrowing season after season without reseeding
      • It can reduce the drudgery of annual trans-plantation which is a tough task and generate savings on seeds and other inputs.  
    • Perennial rice like many other perennial plants can spread by horizontal stems below or just above the surface of the soil but they also reproduce sexually by producing flowers, pollen and seeds. 

    Issues with the current techniques of growing rice

    • Labour intensive: The current production methods are labour-intensive and expensive.
    • Environmental effects: Rice is grown in flooded fields that are habitat for methane-producing microbes. Rice production currently releases an estimated 34 million tons of methane per year.

    Issues with Perennial crops/rice

    • Drop in yield: Their yields started to drop in the fifth year, suggesting that farmers will need to replant periodically.
    • Methane emissions: Researchers also don’t know if the perennial plants emit less methane than conventional ones do.
    • Difficult task: Since the plants’ roots are deeper and larger, farmers must work harder when they do eventually replant the perennials.
    • Issue of weeds: Because farmers don’t till and plow as frequently with perennial rice, fungi and pathogens may build up in the soil, and weeds and insects can prosper in the fields.
    • Herbicide treatment: Farmers needed to spray herbicide treatments more often on fields planted with PR23.

    Significance of the Perennial crops/ rice

    • This variety of rice does not need to be planted every year: 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.
    • Productivity: Farmer profits from perennial rice ranged from 17% to 161% above annual rice. 
    • Cheap: growing it is much cheaper since it requires less labour, seeds and chemical inputs.
    • Environmental benefits: Perennials reduce soil erosion as they reduce soil disturbances because plants are left in place to grow for multiple years, thus there is less mechanical disturbance by farm equipment. 
    • Low labour and input costs: The perennial varieties were preferred by farmers since it saved 58% in labour and 49% in other input costs, over each regrowth cycle. 
    • It can transform farming: The researchers claim it can transform farming by improving livelihoods, enhancing soil quality and by inspiring research on other grains.

    Learnings for India/ Data about Paddy in India

    • India is the world’s second largest rice producer after China and the largest exporter with a 40% share in global trade. 
      • Production has increased from 53.6 million tons in FY 1980 to 120 million tons in FY2020-21.
      • India has the largest area under rice cultivation.
      • It is a tropical plant, and it flourishes comfortably in a hot and humid climate.
      • Rice is mainly grown in rain-fed areas that receive heavy annual rainfall. That is why it is fundamentally a kharif crop in India. 
      • India is the leading exporter of the Basmati Rice to the global market.
      • West Bengal has the highest production of rice in India.
    • It is grown during both summer and winter crop seasons. 
    • China’s early success has another lesson for India: to raise investments in public research and agricultural sciences. This can help counter the impact of climate change on food security and rural incomes.

    Way Forward

    • Diet for many: Rice feeds about half of the world, and its farming and consumption are primarily in Asia. 
    • Most crops grown today were once perennial but bred to be annual to make them more productive. 
    • Perennial rice could be a transformational innovation if it proves to be economically sustainable.

    Source: LM