Subscribe print version with complimentary e-version @Rs.530 per annum; Subscribe only e-version @Rs.400 per annum. || !! ATTENTION ADVERTISERS !! Advertisers are requested to give full details of job Vacancies/ Minimum size will now be 200 sq.cm for shorter advertisements || Click here to become an e-resource aggregator of Publications Division || New Advertisement Policy || ||

Special Content


Issue no 16, 20 - 26 July 2024

Using Radiation to Improve Crop Varieties

 

Are you aware that nuclear energy is a boon to food and agriculture?  You'll be surprised to know that nuclear radiations contribute significantly to preparation of advanced crop varieties using mutation-breeding technologies fostered by Department of Atomic Energy (DAE). Let's learn about this wonderful scientific breakthrough.

 

The biodiversity we observe around us stems from spontaneous genetic mutations. These mutations, occurring in living organisms, are passed on to subsequent generations and are a fundamental driver of evolution. The frequency of such mutations can be increased through radiation, which is used to induce genetic changes that produce desirable traits in crops. Mutation breeding, a crucial breeding method, has significantly contributed to crop improvement by introducing unique genetic variability, developing superior varieties, and refining popular varieties in various crops.

 Thanks to organisations like the Department of Atomic Energy (DAE) under the Government of India, efforts are being made to ensure the nation's food security. Scientists at the Bhabha Atomic Research Centre (BARC), the premier multi-disciplinary R&D institution under the DAE, have leveraged mutation-breeding technologies to develop advanced crop varieties with increased yield, disease resistance, better adaptability, and early maturity.

Need for Mutations in Crops Plants

Scientists have conducted extensive experiments to demonstrate that radiation-induced mutations can be harnessed to enhance crop plants. Although the mutation process was initially random, mutants exhibiting desired traits could be selectively bred, transferring those traits to cultivated crop varieties through traditional breeding methods. This pioneering work led to the emergence of mutation breeding as a distinct scientific field, resulting in development of crop plants with a range of novel and beneficial characteristics. These advancements included increased yields through higher pod or seed counts per plant, enhanced disease and insect resistance, improved oil content and protein quality, adjusted maturity periods, and adaptability to various soil conditions. These mutant varieties also played a crucial role in meeting global food demands amidst growing populations and diminishing water resources.

According to the Food and Agricultural Organisation (FAO) statistics, between 2009 and 2050, it is anticipated that the global population will grow by more than a third, amounting to an increase of 2.3 billion individuals.This clearly indicates that market demand for food will also continue to grow. In this case different innovative methods will be required to enhance the crop production of desired quality so as to ensure safe and nutritious food to all.

Mutation Breeding Success in Plant Varieties

While inducing mutations through radiation exposure is a straight forward task, the comprehensive process of developing a reliable cultivar with the desired mutation is notably time-consuming. Therefore, the challenge for a small team of fewer than a dozen scientists at Bhabha Atomic Research Centre (BARC), Trombay, Mumbai, working within limited experimental field areas, was to effect a lasting impact on the national agricultural sector and leverage the advantages of nuclear applications for farmers. This imperative led them to explore 25 different varieties of groundnut, pulses, oilseeds, rice, and jute.

Trombay Groundnut (TG): Generally, groundnut exhibits limited genetic variability. However, among the induced mutants, two high-yielding Trombay groundnut varieties, TG-1 and TG-3, stand out. TG-1 is notable for its large seeds, while TG-3 boasts a higher number of branches. The isolation of these agriculturally superior mutants marked a pivotal turn in research. Subsequently, radiation-induced mutants have been utilised as one parent in hybridisation processes to develop newer TG cultivars (variety). Hybridisation refers to the cross-breeding of parent plants that are genetically dissimilar with superior features. This approach facilitates the amalgamation of superior agronomic traits such as early maturity, larger seed size, high oil content, increased harvest index (the ratio of harvested grain to total shoot dry matter), moderate seed dormancy, and tolerance to pests and diseases, thereby enhancing the overall yield.

New mutants or mutant derivatives are systematically evaluated in national trials. The first commercially released TG mutant variety, TG-1, was introduced under the name 'Vikram', while TG-17 represented the first TG mutant derivative. Presently, ten TG varieties have been released by DAE for commercial cultivation.

Trombay Mustard (TM): Rapeseed-mustard stands as India's second most significant oilseed crop, following groundnut, covering a quarter of the cultivated land and contributing significantly to total production. The genetic enhancement initiative began in the late 1960s, with the isolation of the first Indian yellow seed coat mutant, extensively utilised in cross-breeding programmes. This endeavour yielded numerous high-yielding yellow seed coat lines, leading to the development of two prominent varieties, TM-2 and TM-4, tailored for the North Eastern Hilly (NEH) Region of Assam in 1987.

TM-2, a radiation-induced direct mutant (a mutation gives rise to a mutant) from parent plant RL-9, and TM-4, a recombinant (to combine DNA from different organisms to create something new) of TM-1 and the national check variety 'Varuna', emerged as outcomes of this breeding programme. In recent years, too many morphological mutants (structural variants/structurally different mutants), including yellow seed coat variants, have been identified across various strains. “Strain refers to a specific genetic variant that is characterised by a unique genetic, physiological, or structural features”. Consequently, ongoing efforts aim to cultivate high-yielding plant varieties.

Trombay Pulses: The pulse crop enhancement initiative kicked off in the early 1970s, focusing on three key crops: pigeonpea (arhar dal), mungbean (moong dal/ green gram), and blackgram (urad dal). Its aim was to induce mutations for enhancing yield, quality, as well as resistance to diseases and pests. Subsequently, soybean and cowpea were included in this programme. Numerous mutants exhibiting modified traits were identified and utilised for genetic analysis and cross-breeding endeavours. The persistent endeavours toward pulse variety development bore fruit with the commercial release of eleven varieties. Among these, four were mungbean varieties, four were blackgram varieties, two were pigeonpea varieties, and one was a soybean variety, all ready for cultivation.

As technology progresses, new initiatives have been initiated to bring these mutant cultivars directly to farmers in the fields. There's a surge in interest in biological research, particularly with the introduction of advanced genomics and proteomics tools. Genomics is the study of an organism's entire genome, which includes all of its genes. It involves mapping, sequencing, and analysing the structure, function, and evolution of genomes. Proteomics, on the other hand, is the study of an organism's entire set of proteins and their functions. It involves analysing the structure, function, and interactions of proteins within cells and organisms. Understanding the impacts of acute and chronic radiation exposure on various living systems is of heightened interest, particularly as the world faces the potential necessity of relying on nuclear power due to the depletion of natural non-renewable resources.

 

 

Interview

Dr. Ajit Kumar Mohanty

Chairman, AEC & Secretary Department of Atomic Energy (DAE)

 

What radiations DAE uses for mutation breeding for crop improvement?

BARC has been engaged in using gamma rays, beta particles, neutrons, X-rays, and electron-beam in cereals, pulses, oil seeds and millets. Using radiation-induced mutagenesis, hundreds of mutants with desirable characters have been developed in these crops. Such mutants were directly utilised or judiciously blended to develop more than 60 improved-crop varieties. Depen-ding on the objective, such crops may have characteristics like increased yield, better disease or drough-tresistance, earlier maturity etc. Examples include:

(a) Trombay Groundnut Varieties have improved oil content and are suited for different agro-climatic conditions.

(b) Trombay Wheat varieties are resistant to diseases such as rust and have better grain quality and yield.

(c) Trombay Rice Varieties have been developed to be high-yielding and disease-resistant, suitable for both irrigated and rainfed conditions.

(d) Trombay Mungbean Varieties are known for their higher yield, early maturity, and resistance to yellow mosaic virus and powdery mildew.

(e) Trombay Blackgram Varieties are resistant to yellow mosaic virus and other diseases, with better yield and quality.

(f) Trombay Soybean Varieties have been developed for higher yield and resistance to diseases.

Detailed information on the above varieties is also available on BARC Website on: https://www.barc.gov.in

Do these radiations have ill-effects in the long-term?

Crop varieties bred using radiation are equally safe as the varieties developed through conventional breeding, since radiation does not pass on to further generations of the bred variety. The use of radiation does not pose any danger, in short or long term, to the end-consumer of the crop produce. Let us understand it. In nature, occurrence of genetic change, referred to as mutation, is evolutionarily a slow and gradual process. The frequency of such mutations can be increased through atomic radiations. These radiations bring genetic changes which are manifested into desirable characteristics in crops. Mutation breeding, being one of the important breeding methods, has contributed significantly to crop improvement. They are completely safe compared to the conventional use of chemicals for achieving desired results. The use of radiation for advanced crops does not pose any risk to the farmers,sellers or the consumers at all.

Please tell us about other significant projects undertaken by DAE for the benefit of mankind?

The vision of the DAE is to empower India through technology, creation of more wealth and providing better quality of life to its citizens. To this end, DAE is engaged in increasing the share of nuclear power, building and operation of research reactors for production of radio isotopes and carrying out radiation technology applications in the field of medicine,agriculture and industry, cancer care, water related technologies, waste management etc.

 

Contributed by: Science Media Communication Cell (SMCC), CSIR-NIScPR, New Delhi.