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Friday, May 31, 2013

Tomatoes - from all around the world


Dear Ghazal, I think one of the best souvenirs one can bring home from a journey are plants. Knowing how easy it is to grow tomatoes from seeds, I am constantly on the hunt for some variants from other countries. In particular I like to collect the seeds from the ripe fruits themself, be it from a salat dish in a mediterranean restaurant, be it from an oriental vegetable market or from a small garden in a suburb village. 
After stripping the seeds from its viscous cover using a piece of tissue paper and drying them quickly between some sheets of a newspaper, they can be stored till next spring. Ideally, I remember the stored seeds in February or March, rehydrate them over night in some ml of water and put them about 5mm deep into a shallow box with garden soil. The box can be left under a plastic foil to keep it moist on a warm and sunny place behind the window (I prefer to place them on my office window). After a few days, one should see the first sprouts and than they grow quite fast, which requires the plastic foil to be removed. Since they start to consume water now from the soil and without the plastic foil there is also more evaporation, the box should be checked daily and if necessary, watered. 
Below shows the box after 3 weeks. I had seeded 6 variants of tomatoes, which are (from top left in clockwise order: 
1:  Oxheart-tomatoes (Bulgarian farmers market)
2:  Cocktail-tomatoes (from vegetable salat, Tratoria, Vietri-sul-Mare)
3:  Egg-tomatoes (Penny supermarket, Munich)
4:  Austrian Monster-tomatoes (stolen from my neighbours garden, Munich)
5:  Cherry-tomatoes (Carmel Market, Tel Aviv, Israel)
6:  Vine-tomatoes (Made in Hungary, Aldi supermarket, Munich)

6 tomato variants, 3 weeks after planting seeds.


At this stage one could already see that they grow so dense, that one has to single them out and give each plant some more space. It is crucial at this stage of plant development that each sprout gets sufficient space underground to develop strong and dense roots. This gives them the best condition to withstand drought and resist parasites when they are later transfered out into the garden.
But at this stage it became also obvious that the 6 tomato variants which were collected from locations in different countries had considerably different growth rate. No.6 (Hungarian Vine-Tomatoes) were not growing at all, No. 2 (picked from an salat bowl at an Italian Tratoria) was growing weak.

After pricking them and transfer a single plant from each variant into one large pot, they look as shown below (note that the plants below and above are the same age. Below after 5 days growing separatly, above those which grew the entire 3 weeks together).

Tomatoes from above box, pricked and grown separately for last 5 days. (red cross: tiny plant, variant 5, from Tel-Aviv Carmel market.
Although the tomato is a typical new world plant, meaning it found its way to the European and Asian continent only after Columbus "discovered" America, they became so widespread here that people gave them quite different names. By the way, the offical latin term for tomatoes, Solanum lycopersicum has some indirect relations to Persia. The scientific species epithet lycopersicum means "wolf peach", and comes from German werewolf myths. These said that deadly nightshade (Solanum) was used by witches and sorcerers in potions to transform themselves into werewolves, so the tomato's similar, but much larger, fruit was called the "wolf peach (in German: Pfirsich aka Persian)" when it arrived in Europe. The Aztecs called the fruit xitomatl (pronounced [ʃiːˈtomatɬ]), meaning plump thing with a navel. Most western European languages derived their names for "tomato" from the native-americans Tomatl. The Italians introduced their own term: pomodoro (from pomo d'oro "apple of gold"), and this was also borrowed into Polish and into several other slavic languages. A funny and sometimes confusing convention is found in Russian language, where the plants and the fruits are called "Pomidore", but the juice squeezed from them is called "Tomatnij sok". Also, the Germans had a historical unique name for them: Paradeisapfel (for "apple of paradise", which by the way is another cultural link to Persia, since Paradise originates from the Avestian terms "pairi.daêza", meaning a piece of land surrounded by a wall). Not very common in Germany any more (except in historical cooking- and gardening books), a derivative of it, Paradeiser is still used in the Bavarian and Austrian dialects, and was borrowed from there into modern Hungarian, Slovenian and Serbian.

10 days later, all plants grown very well. I have to transfer them quickly to the garden, before they start blossoming.

3 comments:

  1. Hi michael

    so you are studying tomato genetics in your office now ? Did you quit the mouse projects ? I think you like the tomato project more since they smell better and you have something delicious to eat.
    Take Care
    /ghazal

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  2. Ghazal Dear, In terms of feasibility, mice have certain advantages over tomatoes for genetic studies. First of all, mice reproduction cycle is 3 month, tomatoes needs about 8 month to get the next generation (assuming one has a glass house with artificial light). And in mice we have all the fancy genetic manipulation tools available, like knockout and transgenics etc.
    But tomatoes not only score for their nice smell and taste as compared to mice. One big advantage is that from one parental plant you might easily get several hundreds of offspring. Therefore, tomatoes were one of the first species in which QTLs (for fruit acidity, vit C and sugar content) could be analyzed and used for later breeding strategies.
    (http://www.genetics.org/content/118/2/329.long)
    So the tomatoes were used for the same purpose as you used the backcrossed mice here.
    Take Care
    Michael

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  3. Dear Michael, I had a look in a gardening book, and they mentioned that most of the tomatoes that you buy nowadays are in fact F1 hybrids. Then, the seeds which you picked from the fruits last year now gave rise to F2 plants. I guess its difficult to make any straight genetic analysis from the few plants you have in your pot now.
    I am seeing forward to taste the first ripe tomatoes from your experiment
    Take Care
    /ghazal

    ReplyDelete