Screening potatoes for micronutrients

Yet more about iron (and other assorted micronutrients). A recent post of mine elicited a comment from Glenn to the effect that breeders have screened germplasm collections of the major staples for micronutrient composition. I was skeptical about the extent to which this has been done (though not, I must add, about the fact that there will be much more of it in the future). Another post, this one by Jeremy, suggested that there was precious little information out there about variety-level nutritional information.

Well, I’ve now come across a paper that allows us to put some numbers on the amount of screening that has been done for one staple crop, the potato. There’s only an abstract freely available online, but a paper by CIP scientists reports (among other things) on micronutrient levels in native potato varieties in Peru:

Several studies have reported mineral concentrations in improved potatoes… However, limited information was available about the mineral concentration of potato germplasm and breeding materials until 2006. A detailed study was undertaken to determine the levels of Fe and Zn in 37 native varieties, both grown by farmers as well as from the collection under custody at CIP.

The potatoes were grown in a couple of different places. There was lots of variation, both genetic and due to the environment where they were grown, and also an interaction between these factors. And the heritability was high, suggesting that there is potential for improvement through selection and breeding.

But let’s remember that the total CIP potato collection amounts to over 7,500 accessions. That means that some 0.5% has been screened. A good start, but still only a start.

A famous Italian lentil

I spent the weekend in the Abruzzo region of Italy, which is kind of in the middle of the peninsula, both north-south and east-west. L’Aquila, the seat of the provincial government, is a couple of hours’ drive east of Rome. One of the places we visited was Santo Stefano di Sessanio, which is actually in the Gran Sasso National Park. It’s a pleasant enough medieval village, very well restored, though it has a whiff of Disneyland about it these days, especially in the summer.

Anyway, one of the many interesting things about this place is that it is famous for a particular kind of lentil — very small, tasty and apparently not needing to be soaked before cooking. And expensive. I don’t think the Lenticchia di Santo Stefano (photo below) has been protected like France’s Puy lentil, though.

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Incidentally, I came across that last link purely by coincidence today. I was going to talk about the Santo Stefano lentil anyway, but then a Google alert sent me to a posting in the Cookthink blog which mentions an article in The New Yorker about the place where I work, and refers back to the earlier piece about lentils.

Ethiopia goes for decaf

Reuters reports that Ethiopian coffee farmers will soon be able to grow a variety which is naturally low in caffeine. Details are sketchy. The whole thing seems to be based on the following statement by Mr Abera Deressa, State Minister of Agriculture and Rural Development, at an unnamed coffee research conference:

“Coffee research centres are in the process of planting seedlings of natural coffee with low caffeine varieties, to enable Ethiopia to supply the world market within the shortest possible time.”

The article mentions the 2004 controversy between the Ethiopian government and Brazilian researcher Paulo Mazzafera, who

declared he had discovered a variety of naturally decaffeinated coffee from 6,000 specimens collected in Ethiopia in the 1980s. The find sparked a dispute with Ethiopian authorities who accused him of taking the bushes without permission.

However, it is not clear whether the low-caffeine variety now being planted in research centres has anything to do with the one Mazzafera identified.

Decaffeinated coffee accounts for 10 percent of total coffee sales in the world, a multibillion-dollar industry. Natural decaf brews could dominate over the current chemically caffeine-reduced options in today’s health-conscious market.

The story has been picked up all over the place. It should run and run. Hopefully we’ll get some more details soon.

Wheats and gluten

Sometimes it takes some personal connection to get me motivated enough to try and understand something a little more fully. Laziness, I guess. Anyway, for example, I vaguely knew about the gluten seed storage proteins of wheat and the coeliac disease they cause in about 1% of the population. But I decided to delve a little deeper only when an old friend I hadn’t seen for a while visited today and told me that she was a sufferer, and that she needed to know how to describe the condition in italian so she wouldn’t get into trouble eating in restaurants here in Rome.

Having sorted that out, I was interested to know whether there are differences among wheat species in the “toxicity” of their glutens. You’ll remember that wheat comes in a polyploid series: diploid, tetraploids and hexaploids. And that three distinct genomes are involved: AA, BB and DD. Diploid einkorn (AA) and BB genome species got together to form tetraploid emmer and durum wheat (AABB). And these hybridized with wild diploid Triticum tauschii to make hexaploid (AABBDD) bread wheat.

It turns out that differences in gluten toxicity do exist. An analysis of the ancestral A, B and D genomes of wheat found that DNA sequences associated with 4 peptides that have been identified as triggering a response in coeliac patients are not distributed at random. For example, the B genome sequences analyzed did not reveal any of the “guilty” sequences.

On the basis of such insight, breeding strategies can be designed to generate less toxic varieties of wheat which may be tolerated by at least part of the [coelic disease] patient population.

Oh, and coeliac disease is called celiachia in italian.