Wednesday, November 4, 2009

Heirloom "Rebuttal" (part 1)

The following is a critique of the contents found in the article cited below:

Article name: How to Grow a Better Tomato: The Case against Heirloom Tomatoes

By Brendan Borrell in Scientific American, March 30, 2009

Article in quotes and italic. My responses follow in standard type and in red-brown.


"Famous for their taste, color and, well, homeliness, heirloom tomatoes tug at the heartstrings of gardeners and advocates of locally grown foods. The tomato aficionado might conclude that, given the immense varieties—which go by such fanciful names as Aunt Gertie's Gold and the Green Zebra—heirlooms must have a more diverse and superior set of genes than their grocery store cousins, those run-of-the-mill hybrid varieties such as beefsteak, cherry and plum."

Already, we can see where this is going. The whole article reminds me of the stupid TV commercials that show people struggling mightily with the 'old' way of doing things - then smiling while they use the wonderful new product.

"No matter how you slice it, however, their seeming diversity is only skin-deep: heirlooms are actually feeble and inbred—the defective product of breeding experiments that began during the Enlightenment and exploded thanks to enthusiastic backyard gardeners from Victorian England to Depression-era West Virginia. Heirlooms are the tomato equivalent of the pug—that "purebred" dog with the convoluted nose that snorts and hacks when it tries to catch a breath."

And, there it is. Oh, the woeful state of humanity. We struggle so! But, the reality is that the author already shows little effort in checking background and history.

  1. A number of the 'heirloom' varieties grown were actually developed by professional or academic seed producers. One cultivar we grow, Wisconsin 55, was developed at the University of Wisconsin in, well, 1955. In this case, I might call these 'heritage' tomatoes since they usually have a commercial background. Oh, those silly, hick, backyard gardeners...who happen to sell seed across the nation.... Woe upon them!
  2. Before one denigrates origins, one might want to consider the options available to the people who maintained heirloom seed. I'm sorry, but my forebears didn't necessarily have the money to buy or time to wait for seed mailed to them each Spring. Do you suppose they were clever enough to save seed for the next year? Oh, those sad, sad people - forced to figure out that you can save seed and use it the next season. Alas for them!
  3. And, what did people select for? Production, taste and plant vitality typically. How naive of them to select seed from the plants that looked healthiest, produced the best fruit and responded with consistency from year to year! How could they be so blind?
  4. Comparing the highly selective, and perhaps misguided breeding of Pugs and other dogs for shows is far form the point. Why does the Aunt Ruby's German Green exist? Well, a family maintained a seed line over the years because they liked to grow it. In many cases, the line changed somewhat largely because they selected for the best plants and fruit.
  5. In other cases, backyard hobbyists, seed companies and scholars tried to create hybrids of existing strains that produced something new - and that would create seed that would consistently continue to produce in that fashion. If they succeeded - it produced - it tasted good - it handled the elements and diseases well enough - then it continued. Standard principles of natural selection at work - even if artificialized by humanity. They maintained attractive features to those that would see to their continued existence.
So - what were those key features again?
  1. The produced consistently enough to be attractive to those that wanted to grow them as a food source.
  2. The fruit had a taste that was attractive to those who ate the fruit.
  3. The plants were healthy and vital so that they could produce in their environment. Those that were able to adapt to wider environments typically maintained a popularity longer with larger seed companies
  4. The plants produced seed that could reliably recreate this gene pattern for future generations of the plant.

"The irony of all this," says Steven Tanksley, a geneticist at Cornell University, "is all that diversity of heirlooms can be accounted for by a handful of genes. There's probably no more than 10 mutant genes that create the diversity of heirlooms you see." But rather than simply debunking a myth about the heirloom’s diversity, Tanksley's deconstruction of the tomato genome, along with work by others, is showing how an unassuming berry from the Andes became one of the world's top crops. Genetics work will also point the way to sturdier, more flavorful tomatoes—albeit hybrid varieties whose sterile seeds cannot be passed down from generation to generation but must be purchased anew by growers each season.

And there it is! The brand new thing that saves us all from drudgery! Hybrid tomatoes using genetic genome mapping to determine what we want in our plants for production. In a way, I feel for Steven Tanksley as I wonder how much the author understood what he might be trying to say. But, read on.

"Tanksley concludes from his analyses that, in their effort to make bigger, tastier and faster-growing fruit, our ancestors ultimately exploited just 30 mutations out of the tomato’s 35,000 genes. Most of these genes have only small effects on tomato size and shape, but last May in Nature Genetics Tanksley and his colleagues reported that they found a gene they dubbed fasciated that bumps up fruit size by 50 percent."

Tanksley does go on to say a second gene has something to do with fruit size. Now, let me ask this question. If there are a couple of genes in the whole tomato genome that govern size of fruit. What will a geneticist do to increase fruit size? You go it! So, what do you suppose our poor, hapless, stupid, backyard growers were taking advantage of with their natural hybridization? No, it couldn't be that....

"Besides size, tomato farmers also selected for shape. To discover those genes, Esther van der Knaap, a Tanksley alumnus now at The Ohio State University, says she went straight for the heirlooms (...) She plucked a gene called SUN from one heirloom tomato and inserted it into a wild relative. As a result, the tiny fruits bulged like pears, a remarkable makeover that made the cover of the journal Science last March.SUN's effect dwarfs that of another shape gene called OVATE—yet another Tanksley discovery—and both seem to have been nurtured in Europe in the last several hundred years to ease mechanical harvesting and processing."

Yes, those same, less than diverse heirlooms that are so inbred. The geneticists went there to identify the genes that provided the characteristics that provide the outward diversity the humans have found useful or attractive. I suspect if you took the time to do so - a geneticist would point out that a relatively small number of genes have something to do with characteristics of any living being that are easily distinguished by unaided senses. And, thus we have some of the diversity we appreciate...and use.

Part II at some later date.

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