Hard News: Science: it's complicated
401 Responses
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recordari, in reply to
As you know, it's Knowledge Bro.
The entropic trope. The existence of which is predicated on the amount of 'bro-ness' and the the extent to which knowledge of any theory is a priori.
In which case it's actually a priori knowledge, bro.
But you knew that.
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recordari, in reply to
It was only when it got its scary name that it became a bad thing.
Hmm, maybe. Although there are some in The Greens who I would expect to see through the semantics and make policy based on the merits of the science. So far it appears their position hasn't changed from this.
Hang on, did I just expect scientific based politics? I'll go drink some GM Kool Aid.
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Sofie Bribiesca, in reply to
The bulk of what is available in NZ is done that way, I’m told.
Well yes so I am told too. ;)
I don’t think considerations like that come up with corn.
And you're telling me, a Mexi can? Y'know, staple an' all, :)
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Some figures on small producers vs agribiz in this article.
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Ian Dalziel, in reply to
kernel sanders...
And you're telling me, a Mexi can? Y'know, staple an' all, :)
ear, ear... that's 'maizing!
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He NZlemming. If the water didn't satisfy you, how long was the piece of string?? :-)
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nzlemming, in reply to
Just long enough to tie the vacuum to the glass tube :-D
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Sofie Bribiesca, in reply to
You're funny ;)
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Bart Janssen, in reply to
but it has been known that growers of that plant claim to clone.
Cloning plants is usually really easy. Any time you take a cutting in your garden you are cloning the plant. So it has exactly the same genetic material as the parent plant you took the cutting from.
The plus compared to seed propagation is you get (usually) exactly the same as the parent. The plus for seed is you usually get a lot more plants a lot quicker when you grow from seed.
Things like apple, kiwifruit, orchids are all clonally propagated. Partly because when you take seed from Royal Gala apples and plant them you get pretty much the full range of diversity back, everything from little crab apples to big juicy tasteless watery things that nobody wants.
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Bart Janssen, in reply to
ill-informed puff piece
Huh? I read it somewhat differently Joe. What Steve Tanskley's work has shown is that because tomato has been inbred for some 500 years a lot of the diversity we see in heirloom tomatoes is not "real". Instead of being a visual display of genetic diversity it is instead a few mutations in what is otherwise a fairly narrow genetic range.
As a result heirlooms have some problems. They have lost some of the disease resistance present in the wild progenitors. You could get that back by a program of cross breeding which would take about 20-50 years or you ca pull the genes directly from the wild species to improve the heirloom varieties.
In practice, cracking and splitting of fruit is rarely if ever caused by “fungal infections”.
So that bit was not well written. Yes Joe cultural practice affect disease susceptibility, but what they are referring to is experimental comparisons that show some of these varieties do not have resistance genes present in wild progenitors and in some of the commercial varieties.
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Bart Janssen, in reply to
The real doozy is the claim that “any plant that sets only two fruits, as heirlooms sometimes do, is bound to produce juicier, sweeter and more flavorful fruit than varieties that set 100, as commercial types do.”
Seriously, growing tomato varieties purely for flavour isn’t something akin to bonsai cultivation.
The relationship between yield and flavour is nothing new. The fewer fruit you have the more flavour you get in those fruit. There is also a relationship (very often) between fruit size and flavour eg big tasteless strawberries or apple. But the best example is from the wine industry where it's been known for hundreds of years that vigorous high yielding vines produce weak insipid wine. The white Zinfandel produced in the Central Valley of CA versus the big rich meaty red Zinfandel produced in Amador County or Russian River. Or closer to home cheap Aussie Shiraz versus Hawkes Bay Syrah.
What is authors are really saying is it is important to figure out if the flavour difference comes from cultural practice - vine ripe and low yield versus high yield and picked green - OR from differences in the genes that produce flavour. If you can show a particular variety has better flavour from the genes then you can use that in breeding programs and expect to get improved varieties. It's one of the difficulties in studying a trait like flavour where so many things like environment affect the trait in which you are interested.
BTW I've said this before but it's worth saying again. I have a good friend who works on tomato flavour genes and he has shown that those genes all stop working when the fruit is put at 4 C and never start working again So never never never put your tomatoes in the fridge, the flavour will disappear and never come back even when they are warmed.
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Joe Wylie, in reply to
What Steve Tanskley's work has shown is that because tomato has been inbred for some 500 years a lot of the diversity we see in heirloom tomatoes is not "real". Instead of being a visual display of genetic diversity it is instead a few mutations in what is otherwise a fairly narrow genetic range.
As a result heirlooms have some problems. They have lost some of the disease resistance present in the wild progenitors. You could get that back by a program of cross breeding which would take about 20-50 years or you ca pull the genes directly from the wild species to improve the heirloom varieties.
Understood, and being something of a tomato appreciator I'd love to see it happen. Instead Tankley's work appears to suffer from the same ill-informed presumption that led to the Flavr Savr fiasco. The lesson from that exercise in scientific hubris would appear to be that GM varieties derived from unsuitable stock, developed with scant regard for the qualities that customers prize, can be inferior in most respects to the products of traditional breeding. An awful waste of resources.
Tanksley - and the article's author - appear to believe that afficionados of "heritage" fruit are misled by their quirky names and shapes into according them an almost mystical je ne sais quoi. In practice, no more so than wine grape varietals. What really bothered me about that piece is the casual suggestion that without GM assistance, flavour and yield are mutually exclusive. If he's really working with stock that only set two useable fruit per plant then he'd appear to be on a hiding to nowhere.
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giovanni tiso, in reply to
So never never never put your tomatoes in the fridge, the flavour will disappear and never come back even when they are warmed.
Yeah, we so needed science to tell us that :-)
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One can argue that "taste" (as in food) is to a substantial degree a political/cultural construct though. (E.g: if one's environment is aspirant working class male, then e.g. Heineken is perceived as a drinkable product - if middle class hipster, then it's revolting and you want hop-filled designer beers with twee names. Does becoming conscious of the corporate ownership of the brewery alter the taste of the beer?)
We tend to find food products that are expensive to produce (rarity, low yields, tricky cultivation) desirable. Is this because they absolutely taste pleasant, or because we live in a society that elevates conspicuous consumption?
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giovanni tiso, in reply to
We tend to find food products that are expensive to produce (rarity, low yields, tricky cultivation) desirable. Is this because they absolutely taste pleasant, or because we live in a society that elevates conspicuous consumption?
It's because they absolutely taste pleasant.
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Joe Wylie, in reply to
The relationship between yield and flavour is nothing new. The fewer fruit you have the more flavour you get in those fruit.
Not my experience. Tigerella, a 1930s hybrid, produces as well as many commercial varieties, with a superior flavour demonstrated by blind testing. Occasionally it's resurrected for commercial purposes, but it suffers from a thicker skin than most consumers prefer. Oxheart is another heavy yielder with a flavour everybody loves. The remarkable variety of fruit size and shape makes it a farmer's market favourite, but probably counts against it being a commercial variety.
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Bart Janssen, in reply to
Tanksley – and the article’s author
Knowing Steve I'd say the emphasis you are reading into the article is from the journalist not Steve himself.
Steve Tanksley's work is aimed at understanding what really contributes to the domestic tomato we know as compared to the wild progenitors. Once we understand how it works then you can make plans to improve varieties with some real confidence of success.
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Bart Janssen, in reply to
Yeah, we so needed science to tell us that :-)
Yeah obvious answer is obvious. Although I wish our local fruit world understood that :(.
But to be fair it was quite interesting to find out exactly why the flavour disappears and never comes back.
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Bart Janssen, in reply to
What really bothered me about that piece is the casual suggestion that without GM assistance, flavour and yield are mutually exclusive. If he’s really working with stock that only set two useable fruit per plant then he’d appear to be on a hiding to nowhere.
Trust me the article is much more a failure of journalism than a representation of Steve Tanksley's ignorance. He really is very smart and has a deep knowledge of both the science and the industry.
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Bart Janssen, in reply to
One can argue that “taste” (as in food) is to a substantial degree a political/cultural construct though.
We have a sensory science team here where I work that do a lot of work teasing apart cultural preferences. In no small part because Japan is very important to the kiwifruit industry. They are starting to get numbers and statistics to test dogma about who likes what.
I guess for me as a scientist what is really exciting is the work that we (and others) are starting to make progress on concerning figuring out just which chemicals people can detect and how that varies from person to person and the correlating that with genotype. Even in the small studies we've done here we've found genes linked with the ability to detect important fruit flavour compounds. That sounds boring I guess but it is a really big step in starting to understand why some people like some foods.
The really interesting next step is to try and correlate the ability to detect a compound with whether you like the compound or a fruit containing the compound. It could go either way and certainly cultural experiences could play a big role as well.
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recordari, in reply to
e.g. Heineken is perceived as a drinkable product - if middle class hipster, then it's revolting and you want hop-filled designer beers with twee names.
There's no accounting for taste. Heineken has given me a headache right from being an impoverished student through to this state of entitlement I find myself in now.
On a recent trip to Asia I discovered that if I could buy bulk stubby cans of Sapporo draft I'd be a happy man. I've also just discovered that as much as I like wheat beer, it gives my gas, and makes me excessively phlegm-matic.
NB# This thread was always going to end up in a beer discussion, I'm just giving it a nudge.
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Emma Hart, in reply to
I guess for me as a scientist what is really exciting is the work that we (and others) are starting to make progress on concerning figuring out just which chemicals people can detect and how that varies from person to person and the correlating that with genotype. Even in the small studies we’ve done here we’ve found genes linked with the ability to detect important fruit flavour compounds. That sounds boring I guess but it is a really big step in starting to understand why some people like some foods
It sounds bloody fascinating. Thursday night, at some point you can expect to listen to my "How can people drink nutrasweet when it tastes like electrical tape?" rant.
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Ian Dalziel, in reply to
You say Te Mata, I say to martyr...**
But to be fair it was quite interesting to find out exactly why the flavour disappears and never comes back.
But where does it go?
Entropy? -
Rich Lock, in reply to
Is this because they absolutely taste pleasant, or because we live in a society that elevates conspicuous consumption?
While there may be an element of that in it, I'm reasonably confident that you could ask any backyard cultivator which has more taste: homegrown or supermarket, and they'd point to the homegrown. Although obviously backyard cultivators are all just doing it before it becomes fashionable.
It's kg yield that is maximised to maximise profit. It isn't the taste.
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Bart Janssen, in reply to
But where does it go?
Entropy?Well actually yes. Some of the key flavour compounds that people associate with tomato-y-ness are not very stable and degrade fairly quickly - becoming less complex chemicals i.e. entropy. They are only present in detectable concentrations if they are continually being produced - by enzymes that die at 4 C.
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