Wheat genome finally decoded, can help tackle climate change

New Delhi, September 2

It took the best scientific minds from 20 nations, including India, to scale what is considered as the “Mt Everest of the genome world”.

After 13 years of painstaking effort, a global community of scientists has decoded the gigantic bread wheat genome (Chinese Spring variety), a feat that breeders hope will help address the productivity and climate resilience issues, especially in India, the world’s second-largest producer of the grain.

The group of scientists, known as the International Wheat Genome Sequencing Consortium (IWGSC), published this month a detailed description of the genome of bread wheat, the world’s most widely cultivated crop.

Wheat is the staple food of more than a third of the global human population and accounts for almost 20 per cent of the total calories and protein consumed by humans worldwide, more than any other single food source. It also serves as an important source of vitamins and minerals, according to a IWGSC press release.

The reference genome provides a roadmap to improve and innovate the crop just like the advances that rice (Oryza sativa L) had witnessed, following the unravelling of its genome in 2005. Rice was the first crop genome that was sequenced.

“The high-quality reference genome generated by the global community will help in better understanding of the basic biology of wheat plant and identifying genes underlying important traits,” Kuldeep Singh, senior molecular geneticist and director of National Bureau of Plant Genetic Resources, told Mongabay-India.

This achievement will enhance the wheat breeders’ toolbox and pave the way for development of wheat varieties with higher yields, enhanced nutritional quality, improved sustainability and varieties that are better adapted to climate challenges, he said.

Kuldeep Singh (formerly with Punjab Agricultural University), Nagendra Singh from the ICAR-National Research Centre on Plant Biotechnology (New Delhi), and JP Khurana from the University of Delhi spearheaded the Indian effort (comprising 18 scientists) to sequence chromosome 2A of the genome.

Kuldeep Singh explained that the major challenges to wheat productivity in future in India would pertain to enhancing yields by 2050 and accelerating the breeding of climate-resilient wheat varieties.

“One challenge is to improve its yield by 60-70 per cent in next 32 years (by 2050) when India’s population stabilises at 1.66 billion. This translates to roughly 2 per cent per annum and our current rate of improvement is 1-1.5 per cent,” Kuldeep Singh said.

Cracking the genome came with its own set of hurdles – the enormity of the genome and its complexity. At 17 Giga bases, the bread wheat genome is five times as large as the human genome and 40-fold larger than the rice genome.

This is because bread wheat essentially is three species rolled into one, said Kuldeep Singh.

Bread wheat is an allopolyploid — which means it has evolved in nature by the natural crossing of three different but very closely related species, each contributing seven pairs of chromosomes which are referred to as A, B and D genomes, making a total of 21 pairs of chromosomes.

“Hence, major challenges were to bring together larger number of countries and resources for undertaking this gigantic task. However, technological advances in flow cytometry-based sorting of individual chromosomes, high throughput DNA sequencing techniques and improved algorithms made it possible for the international community to achieve this task at a cost much lower than it was achieved for in human or rice genomes,” he explained. — IANS

Staple food

• 20% Wheat accounts for one-fifth of total calories and protein consumed by humans worldwide
• 500 Wheat varieties in India
• 2 India is world’s second-largest producer of the grain, after China
• 70% Wheat yield needs to increase by 2050 to feed world population

How farmers will benefit

Farmers will benefit from new varieties developed by breeders that will be better adapted to specific field conditions and agronomical practices. The new varieties could be more resistant to drought, need less nitrogen input, or be resistant to diseases, hence requiring less fertilisers or fungicide applications. Farmers will be able to produce better quality seeds, with less impact on the environment, leading to more sustainable production.