Mutation breeding of rice increases food security across Asia

The International Symposium on Plant Mutation Breeding and Biotechnology is taking place at the IAEA headquarters in Vienna, Austria, from 27 to 31 August 2018. (Photo: F. Nassif/IAEA)

The use of radiation in improving crop varieties offers an effective means of adapting agricultural crops to changing weather conditions, while also increasing yields to feed a growing population, agreed speakers at a session at the International Symposium on Plant Mutation Breeding and Biotechnology yesterday.

Rice is the staple crop in many countries, particularly in Asia, but yields of traditional varieties have fallen in recent years due to changing weather patterns, including higher temperatures, severe droughts, floods, salinity and diseases, coupled with more erratic rainfall.

Irradiation induces changes in the DNA and speeds up the natural process of mutation in plants, increasing the diversity in crop varieties available to farmers. These new varieties possess favourable traits – some including stronger climate resilience and higher yields.

Speakers from several countries shared success stories on the contribution and impact of mutant varieties developed through irradiation on agricultural productivity and therefore food security.

Vietnam: Producing crop diversity

Through mutation breeding, Vietnam’s Institute of Agriculture and Genetics has over the last three decades introduced 46 new varieties of rice suited to the different production areas of the country.

Supported by the IAEA and the Food and Agriculture Organization of the United Nations (FAO), Vietnamese rice farmers have witnessed an increase in rice yields, shorter growth duration for rice crops, as well as increased resistance to erratic weather conditions. For example, over 3 million farmers have benefitted from the adoption of the DT-10 rice mutant variety, which has a 40% higher yield than traditional varieties.

Mutation breeding has had many advantages for Vietnam, said Ham Le Huy of the Institute of Agriculture and Genetics. “Vietnam used to be very poor and therefore had little funding to work with, as well as low technical capacities,” he said. “Mutation breeding is therefore very relevant to developing countries in order to increase agricultural production.”

Bangladesh: Rice variety in drought

Similarly, rice is a staple in Bangladeshi cuisine and meals are not considered complete without it. However, “the population of Bangladesh is increasing and the land is decreasing,” said Mirza Mofazzal Islam from the Bangladesh Institute of Nuclear Agriculture, highlighting the need for increased yields in conjunction with improved sustainability of agricultural practices.

Additionally, droughts have become one of the greatest challenges to agricultural productivity in Bangladesh. Most of the damage occurs between March and June, the hottest months of the year, Mofazzal Islam said.

In response, plant breeders from the Institute developed improved mutant rice lines, which can be cultivated in dry conditions. As the starting point, they took a rice variety called New Rice for Africa (NERICA), developed in West Africa, treated it with radiation and tested the different mutant lines for their growth duration, plant height and adaptability to Bangladesh’s climate. Two out of the six mutant lines have been selected for early maturity, higher yield and adaptability, and will soon be released for commercial cultivation.

India: Increasing high value crops of rice

India is the world’s largest exporter of rice, but its farmers face major agricultural constraints in rice production, said Vikash Kumar of the Bhabha Atomic Research Centre. These include salinity, consequences of climate change, including the resurgence of diseases, and the underutilization of the range of rice varieties found in India.

There is a need also for improving quality and satisfying demand for different types of rice across the country, while increasing farmers’ income, he said.

This has led experts to produce a wide range of rice varieties, including the variety CSR-30, developed in the early 2000s, which has improved salt tolerance and is therefore best suited for coastal regions.

On top of using their gamma irradiator, researchers at Bhabha Atomic Research Centre are considering using electron beam and ion beam technologies, in order to produce further mutant rice varieties.