Perennial Rice (PR23)

Topic- Agriculture [GS Paper-3]

Context-  Researchers at the Yunnan University (China) developed a variety of perennial rice named PR23 by crossbreeding regular annual rice Oryza sativa with a wild perennial variety from Africa. 

Key Highlights 

• In 2021, the rice variety was grown by more than 44,000 farmers in southern China. 
• Rice is a staple crop which feeds an estimated four billion people around the world.
• The research on perennial rice began in early 1990s at the Yunnan Academy after a failed attempt in the 1970s.
• The first variety of the perennial rice was released to Chinese growers in 2018.
• Perennial crops are considered as those that are more permanent, requiring a few growth cycles before fruit is produced. 
• Perennial rice are varieties of long-lived rice and are capable of regrowing season after season without reseeding. 
• It can reduce the drudgery of annual trans-plantation which is a difficult 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 rice cultivation 

• Labour Force: The current production methods are labour-intensive which makes it expensive.
• Environmental impacts: 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

• Their yields started to drop in the fifth year, which suggests that farmers will need to replant periodically.
• Researchers also are not sure if the perennial plants emit less methane than conventional ones do.
• As the plants’ roots are deeper and larger, farmers must work harder when they do eventually replant the perennials.
• As 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.
• Farmers also needed to spray herbicide treatments more often on fields planted with PR23.

Significance of the Perennial crops

• The 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.
• Cultivator profits from perennial rice ranged from 17% to 161% above annual rice. 
• Growing the perennial crop is much cheaper since it requires less labour, seeds and chemical inputs.
•  Perennial crops 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. 
• The perennial varieties were preferred by farmers as it saved 58% in labour and 49% in other input costs, over each regrowth cycle. 
• The study claims it can transform farming by improving livelihoods, enhancing soil quality and by inspiring research on other grains.

Data about Paddy Cultivation in India

• India is the world’s second largest rice producer after China and serves as the largest exporter with a 40% share in global trade. 
• Paddy production has increased from 53.6 million tons in FY 1980 to 120 million tons in FY2020-21.
• The country also has the largest area under rice cultivation.
• Paddy is a tropical plant, and it flourishes comfortably in a hot and humid climate.
• Rice is basically grown in rain-fed areas that receive heavy annual rainfall. Hence it is fundamentally a kharif crop in India. 
• Globally India is the leading exporter of Basmati Rice.
• The state, West Bengal has the highest production of rice in India.
• Rice 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 which can help counter the impact of climate change on food security and rural incomes.

Way Ahead

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

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