A new biotech rice variety called Scuba or Swarna-Sub1 is going through field trials in India. It’s a long-grained rice (Oryza sativa L. ssp. indica) designed to be ‘climate-ready’ or ‘climate-smart’. That is, it’s designed to grow well as climates change.
The pressure’s on for climate-ready rice because climate change is a particular problem for resource-poor farmers in parts of Asia and Africa. Those farmers’ rice is a staple food for themselves, their families and their customers. Weather is getting harder to predict and paddy fields are getting flooded too deeply, too often.
That’s why the International Rice Research Institute (IRRI) in the Philippines is leading Stress-Tolerant Rice for Africa and South Asia (STRASA).
Lizbeth Edra at IRRI tells us that Scuba or Swarna-Sub1 is one of 16 climate-ready rices now being field-tested in South Asia and Sub-Saharan Africa. This variety is called ‘Scuba’ because it can be completely submerged for up to 17 days without killing it. Its posh name is ‘Swarna-Sub1’ because it was made by introducing the right allele (that is, the right version) of a gene called Sub1A into a popular rice variety called Swarna.
Like other long-grained rices, Swarna is grown in paddy fields where it’s partly, but not completely submerged. Deep flooding can drown Swarna.
Don’t be fooled when Scuba (Swarna-Sub1) is called a biotech crop. Making it didn’t involve genetic modification (GM, genetic engineering). No gene was inserted from a foreign species. Instead, rice varieties were crossed and biotech was used to breed the climate-ready rice.
All domesticated Asian rices carry the Submergence 1 (Sub1) gene cluster. To be able to resist drowning, rice plants need the right allele of a particular gene in that cluster. The gene is Sub1A. Its submergence-tolerant allele is Sub1A-1. Some long-grained rices carry Sub1A-1 but Swarna doesn’t.
To introduce Sub1A-1 into Swarna, scientists crossed a submergence-tolerant variety which carries Sub1A-1 with Swarna. Then they ‘backcrossed’ the offspring with the parent, Swarna. The scientists used marker-assisted selection (MAS) to pick out baby rice plants which had genes you’d expect in Swarna, plus Sub1A-1. This method is called marker-assisted backcrossing. The link I’ve just shown you is to a company offering this biotech to labs, but I don’t think that particular company was involved in making this particular rice.
It took three rice generations to enhance Swarna with Sub1A-1. Thanks to the fast biotech, the job was done in under three years. More experiments made it clear that the most submergence-tolerant plants had two copies of Sub1A-1. They were homozygous for this allele.
So there it was: Scuba rice, ready to test in farmers’ paddy fields. The field trials are happening right now.
Umesh Singh of IRRI says the trials, by millions of Indian farmers, are moving faster than previous biotech field trials because ‘[W]e assist government agencies and private seed companies to multiply and distribute seeds to farmers at a faster pace.’ The aim is to get Scuba rice ready for commercial release as soon as possible.
Early results are promising. Oryza tells us that in the trials, Scuba rice yielded 45% more than ordinary Swarna but it tasted just as good. IRRI calls Scuba rice Odisha’s food for a goddess. Odisha is the eastern Indian state where many of the participating farmers live and work.
Climate-ready biotech crops get me thinking. Not that it’s up to me. It’s up to farmers. Should farmers embrace biotech crops, such as Scuba rice, that might produce food when growing conditions change? Or should they continue with the wisdom that’s led smallholders like themselves to embrace crop diversity?
Both of those things at the same time, I think. Scuba rice may be one of the ‘multiple approaches’ which the International Service for the Acquisition of Agri-biotech Applications (ISAAA) tells us that the world needs to feed growing populations. ‘These [approaches] include: good governance, improved infrastructure, farmer education, improved seed quality and delivery systems, inputs, market access, fair trade and appropriate technologies that integrate proven indigenous knowledge practices with emerging technologies such as modern biotechnology.’
[Edit] Here’s an article about how IRRI gives farmers chance to improve their lives. And here’s a 2010 article from the UK Department for International Development (which part-funds IRRI) about how South Asian farmers survive flooding.
My fellow blogger applpy at Thought + Food is excited about Scuba Rice, asking ‘Will there be a second Green Revolution?’
Science on the Land 
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I followed the link here from your reblog of my post (thanks for that!). As you explain, the modification here relates to another rice variety, it is still different from conventional cross breeding. A similar case is that of non-browning apples which does not involve genes from any other crop but it is being talked about and classified as a GM variety, whereas it would me more similar to the Swarna case. There is controversy around the apple but , so far, not for the rice. That is interesting, I think!
Both Scuba rice and Arctic apples (the nonbrowning apples) are classed* as biotech crops but only the apples are classed* as GM. To make Scuba rice, scientists crossbred rice varieties then used marker-assisted selection (MAS) to choose the plants they wanted. To make Arctic apples, scientists used the bacterium Agrobacterium tumefaciens to insert ‘antisense’ DNA sequences to ‘silence’ a gene they didn’t want https://argylesock.wordpress.com/2014/01/18/gm-apples/
*When I said ‘classed’ here I meant ‘classed under current US law’. There, crops made by the Agrobacterium method are classed as GM whereas crops made by MAS are not https://argylesock.wordpress.com/2013/11/18/is-the-law-about-genetic-modification-out-of-date/
Thank you, that clarifies it for me !
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