Population growth, food supply and Yuan Longping,  the father of hybrid rice  

In 1798, just about the time when the world population was about to reach one billion, Thomas Malthus, a British economist-cum-demographer theorised that, "human population increases in geometric sequence, while food production increases in arithmetic sequence".

He predicted: "Humans would eventually be unable to produce enough food to sustain the society. As a consequence, their standard of living will go down to subsistence level". 

For a while, his prediction seemed true for many regions. However, the theory was eventually proven wrong and criticised.

Nevertheless, the complex relationship between population growth, food production and food security should neither be underestimated, nor be overlooked. In the modern day, if one region is unable to produce enough food for its population, it can easily import food from other regions. At the time Malthus formulated the theory, it was basically an agrarian society with little surplus food anywhere. Transportation was difficult, so food had to come from a society's own production.

From the 1920s, many countries started facing high population growth as well as severe food crises owing to lack of productivity. As a result, many countries started trying to implement family planning, as well as attempting to increase food production. However, the productivity per unit of land was very low due to lack of technological innovation.

Population growth versus food production

Malthus' population growth versus food production and food supply theory was based on a certain assumption that as the population grows, land will remain the same (more or less). Malthus, however, may not have predicted the future technological changes.

Food crisis in Asia

Around 60% of the world population lives in Asia and another 17% in Africa. Rice is one of the three most important food crops, along with wheat and maize. It is the staple food for 60% of the total global population. It also dominates agricultural production in most of the rainfed Asia.

By the 1950s, it became even more important to grow more rice because urbanisation was gathering pace with income growth. Rice, the single most important commodity in the daily lives of all the Asian poor, became a matter of survival for millions of landless rural populations. Thus, the increasing production of rice is entwined with food supply for 70% of the world population.

CYMMIT, Norman Borlaug and wheat productivity

During the 1960s, the productivity of two other staples - wheat and maize - increased when American agronomist Dr Norman Borlaug's CYMMIT developed a pilot program sponsored by the Mexican Government in the 1940s, assisted by Rockefeller and Ford Foundation.

Under his leadership and hard work, the program developed higher-yielding wheat varieties through genetic improvement and new farming techniques, which helped Mexico attain self-sufficiency in wheat (staple food in Mexico) production in the 1950s. 

IRRI and rice productivity

Against such a backdrop, the International Rice Research Institute (IRRI) in Manila was established in 1960 with the mission to increase rice productivity. IRRI scientists and breeders followed similar breeding principles and techniques used for wheat. Its mission turned out to be a big success.

Many new high-yielding rice varieties were developed by following the basic breeding principle introduced by Dr Norman for wheat. As a result, the productivity and production of rice kept pace with the growth in Asia's population. 

In 1965, when I was a student of Intermediate Science in Cumilla Victoria College, there was a Japanese specialist in Cumilla who made tireless efforts to convince farmers to cultivate newly introduced high-yielding varieties developed by IRRI. It took almost a decade to popularise the newly-developed high-yielding varieties, known as "High-Yielding Crop Varieties'', among the small farmers in Bangladesh.

Rising demand for rice and Dr Yuan Longping - The idealistic optimist

Given the expediency of the situation, raising productivity beyond the IRRI's high-yielding variety was an absolute necessity. Rising demand necessitated further productivity increase of rice.

This could only be achieved by improving the yield. But during that period most of the rice scientists in the world, including the ones at IRRI, were of the view that "rice could not be crossbred and/or hybridised". 

Dr Yuan Longping, a rice scientist in China, was a holdout. Dr Yuan was determined to develop hybrid rice. Beginning in the late 1960s, his research on rice was further stimulated by the "great leap forward" movement in China.

When all other rice scientists thought crossbred rice was not a possibility, he never stopped pursuing his goal. Obviously, the task was not an easy one. He had to work relentlessly for three years before he could develop the high-yield hybrid in 1973.

However, large-scale cultivation was not possible immediately. The technology related to the production of hybrid seeds was not easily obtainable either. So an additional three years of experiment were needed to produce the commercial hybrid seeds and to make it available to farmers.

Later in the 1990s, he developed the high-yielding hybrid rice of a two line variety, which means hybrid rice seeds are cultivated with the "male sterile and restorer lines only". The two line hybrids are even more high-yielding. 

Dr Yuan kept on experimenting until his final days to increase the productivity of rice. By 2004 the yield increased to 12 tons per hectare, and 15 tons in 2015. He passed away on May 22, 2021 at a hospital in Changsha, China.

His work in the 1970s improved the yield of rice 20% more than all other conventional varieties, including high-yielding varieties (HYV), developed by IRRI. It transformed the Chinese agriculture as the country now produces over 200 million tons of rice a year, more than any other nation in the world. 

Sadly, Prof Yuan Longping was not awarded the Nobel Prize. But he is frequently cited as a leader of the Green Revolution because of his dedication to develop high-yielding hybrid rice. Even more importantly, he is popularly known in the world as "father of hybrid rice".

Hybrid rice cultivation in Bangladesh

In Bangladesh hybrid rice cultivation started in 2000. By 2020 about 10% of total rice production is of hybrid variety. And it is increasing every year. All rice producing countries in the world today have adopted the hybrid rice variety. 

Source: DAE (HYV : high-yielding variety)

The table shows that at the moment, Bangladeshi farmers are cultivating hybrid rice in only about 4% of the land during Aus; 3.32% during Aman; and 19% during Boro. Comprising all three seasons, it stands at about 9.72% of rice producing acreages.

However, hybrid variety yield is 1.885 tons per acre (average of all three seasons), while yield of other varieties are 1.270 tons per acre. Overall, in all three seasons, only about 9.72% of land is cultivated with hybrids, but producing 13.78% of total rice production.

Hybrid varieties (HB), like high-yielding varieties (HYV) need better land and water management, as well as chemical fertilisers and pesticides. Scientists in China, IRRI, Manila and around the world, including Bangladesh, are now researching to develop hybrid varieties which will require less water, chemical fertilisers and pesticides, which will be more suitable during the Aus and Aman and more suitable to consumer preferences. In addition, developing varieties will be suitable for production even in salt water. 

As the new varieties are being developed to suit the Aus and Aman season, based on present trends, I am confident that by 2030 an average 30% of the total rice cultivation will be of hybrid variety; and the total acreage may reach 11,608,599 acres. At the present rate of yield advantage of 614 kg per acre, the total extra production may be 7,127,680 tons of rice.

Conclusion

At present, the rise in population is about 1% in developed countries and 2.5% in developing countries, which is largely offsetting increased output and productivity in farms. The population growth inevitably leads to food scarcity. That acts as a catalyst for increasing agricultural productivity.

However, the policy environment needs to be favourable for this effect to occur. Combinations of above conditions will stimulate the scientific process to innovate and motivate farmers to invest in adopting new varieties, new tools and technologies. Thus, there is a complex relationship between population growth, technological innovation and food supplies. Thomas Malthus probably could not predict such a complex relationship.

Full credit goes to Dr Yuan Longping who understood such a complex relationship. His effort was not limited to China only but also to other countries of Asia and Africa. In addition, he worked closely with the policymakers to change the policy environment to induce and encourage farmers' interest to increase the production of rice by adopting new varieties, new tools and techniques. Dr Yuan is not here anymore, but his creativity, vision, determination and achievement opened the horizon for many to carry on his work to eliminate hunger in the future.

Abdul Awal Mintoo has an M.Sc. in Agricultural Economics. He is a former President of FBCCI