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How many rice varieties are there in India?

Prior to the green revolution in the 1960s, India was home to more than 100,000 rice varieties, encompassing a stunning diversity in taste, nutrition, pest-resistance and, crucially in this age of climate change and natural disasters, adaptability to a range of conditions.

Ok, I’ll bite. That’s from a recent blog post from UNEP. Let’s assume that what they mean by “varieties” is farmers’ landraces. How do they know how many there are?

Fortunately, there’s a link in the post, which takes you to a 2009 piece by Dr Debal Deb, from the Centre for Interdisciplinary Studies, India.

Until the advent of the Green Revolution in the 1960s, India was believed to have been home to about 110,000 rice varieties (Richharia and Govindasamy 1990), most of which have gone extinct from farm fields. Perhaps a few thousand varieties are still surviving on marginal farms, where no modern cultivar can grow. In the eastern state of West Bengal, about 5600 rice varieties were cultivated, of which 3500 varieties of rice were shipped to the International Rice Research Institute (IRRI) of the Philippines during the period from 1975 to 1983 (Deb 2005). After an extensive search over the past fourteen years for extant rice varieties in West Bengal and a few neighboring states, I was able to rescue only 610 rice landraces from marginal farms. All others–about 5000–have disappeared from farm fields. The 610 extant rice varieties are grown every year on my conservation farm, Basudha. Every year, these seeds are distributed to willing farmers from the Vrihi seed bank free of charge.

Ok, so we’ve gone from “was home” to “was believed to have been home.” “Richharia and Govindasamy 1990” is Rices of India, by R.H. Richharia and S. Govindasamy, published by the Academy of Development Science, Karjat. I couldn’t find it online, though it’s cited a few times on Google Scholar, but Dr Deb does provides a helpful note:

The only reliable data are given in Richharia and Govindasamy (1990), who estimated that about 200,000 varieties existed in India until the advent of the Green Revolution. Assuming many of these folk varieties were synonymous, an estimated 110,000 varieties were in cultivation. Such astounding figures win credibility from the fact that Dr. Richharia collected 22,000 folk varieties (currently in custody of Raipur University) from Chhattisgarh alone – one of the 28 States of India. ((FAO (2003) Genetic diversity in rice. In: Sustainable rice production for food security. International Rice Commission/ FAO. Rome. (web publication).))

Ah, so it was actually 200,000, but 110,000 after you account, somehow or other, for synonyms. If you want another data point, this is what that FAO publication quoted at the end said about numbers of varieties, though for Asia as a whole:

The quality preferences of rice consumers have resulted in a wide diversity of varieties specific to different localities. Although the exact diversity cannot be gauged, it is estimated to be around 140,000 different genotypes.

But there’s more. The recently retired head of the IRRI genebank, Dr Ruaraidh Sackville Hamilton, had this to say in 2006:

The M.S. Swaminathan Research Foundation in India claims that India alone has 100,000 traditional varieties still in use by farmers around the country, and another 300,000 that have become extinct… India’s 100,000 may be an overestimate, but, even if it is, it’s probably not too wildly out. If the small Southeast Asian countries each have 10,000, India could easily have more than 50,000.

But note that’s 100,000 varieties in use now, not “until the advent of the Green Revolution.”

So which is it? How many rice varieties are there in India? Don’t get me wrong, I’d really like to know. I just don’t think we can, at least just now. What we can be fairly confident about, though, is the number of samples in genebanks. For example, IRRI has 16,746 rice accessions from India. NBPGR, India’s national genebank, has 86,011. Oh look, that makes about 100,000.

LATER: I don’t want to spoil the story, but I just remembered that Bob Rhoades estimated there were once 30,000 rice traditional varieties in India.

Genetic diversity indicators go wild

A little follow-up on my post from a few days back on the post-2020 biodiversity framework. A letter to Science suggests that the genetic level of variation is being neglected, in particular for wild species.

The post-2020 framework should explicitly commit to maintaining genetic diversity within all species and to implementing strategies to halt genetic erosion and preserve adaptive potential of populations of both wild and domesticated species. The framework should also define indicators of progress toward this goal. Such indicators could include collecting data on the number of species, populations, or metapopulations that are large enough to maintain genetic diversity as well as those that are not. A widely used measure in this context is the “genetically effective population size,” which quantifies the rate at which a population loses genetic variation. When the effective size is measured as 500 “ideal individuals,” the population is considered “genetically safe.” We therefore suggest monitoring the number of populations above and below the genetically effective size of 500. The effective size is assessed from genetic or demographic data and is usually much lower — by about an order of magnitude — than the total number of mature individuals. Another indicator could be the number of species or populations in which genetic diversity is being monitored by national agencies or universities using DNA-markers. A third indicator could be measuring rates of loss of distinct populations within species.

Interesting to see that the crop diversity conservation community is slightly ahead of the curve on this.

Panic in the air

500-odd accessions in the genebank in Cali, Colombia, according to Genesys, but alas only about 20 geo-referenced. Nice drone shot, though.

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