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Some of Tom Wagners varities of potato
Copyright Anja Egeriis anja.egeriis@gmail.com

Tom Wagner from USA gave a workshop at the organic farm Hegnstrup outside Copenhagen in Denmark.

Tom shared his lifelong fascination in potatoes and tomatoes (tater & mater). For 56 years he has been crossing and selecting on potatoes and tomatoes, and he still has many ideas to improve varieties. Tom is best known for his tomato Green Zebra.

Tom Wagner explains what to watch out for in a tomato flower for breeding
Copyright Anja Egeriis anja.egeriis@gmail.com

It is a pleasure to dive deep in to details with such an experienced breeder as Tom. He showed us how the first flower in a cluster often have a deformed style. The shape makes it more sensitive to later insect pollination, at a point we would think we had control of the pollination. He also recommended looking at the little scar in the flower end of the ripe tomato. Is it a tiny spot, the style was well shaped, a larger irregular brown scar suggest the style was deformed, with an increased risk of unintended crossing.

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Tom gently tear off the anthers of the tomato flower
Copyright Anja Egeriis anja.egeriis@gmail.com

Tom gently tear off the anthers of a tomato flower. Then he knock it over his thumb nail to release any pollen, to learn if there is any ripe pollen. There was none, meaning this flower can be crossed. He already had noticed the green shine in the yellow anthers, suggesting they were not releasing pollen yet.

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Tom pollinate a tomato flower
Copyright Anja Egeriis anja.egeriis@gmail.com

Then he pick a well developed flower of an other tomato variety, knock it gently over a brown clay tray and we can all see the pollen collected on the tray. With the tip of a brush he transfer the pollen from the tray to the stigma. Then he removes the petals, so insects will not be attracted, and add a tag to remember what he did to the flower (later tomato). Last he pick the older flowers, not letting them take any energy from his pollinated flower.

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We gather closely to see every detail
Copyright Anja Egeriis anja.egeriis@gmail.com

Tom Wagner thinks in combining good genes. For both potato and tomato this include resistance to late blight. He also want hairy plants, as insect find the plant fur unattractive. In this way both insect damage and insect transfer of disease by their bites are reduced.

He has developed potato varieties that can stay in ground all winter for eating or replanting in April, without any sprouting. They do need a mulch in case of severe frost.

He has also develop a potato I think of as a CO2-reduced potato. It is tasty, yellow fleshed and only take a 5 minute boil before eating. A 75% reduction of CO2 in the boiling process.

For the tiny garden he developed a series of potatoes with huge flamboyant flowers, the photos made me think of Dahlias, with more usefull tubers.

As Tom has no land of his own, he is totally dependent of others cooperating with him. Tom sends out a lot of not yet stabilised hybrids to others, for them to select on according to his guidance for some generations. He find that they usually stabilise in the 5th. or 6th. generation.

One of Toms interesting techniques is the preselection. He has gained the capacity to read the phenotype already at the seedling stage, allowing him to sort out most of the unattractive seedlings before transplant. This saves a lot of space in the gardens. In the shape of the young leaves he read the shape of the tubers to come later, round or elongated. When he wish a potato resistant to late frosts, he look for seedlings that will be first in afternoon to gather their leaves on top of the growing tip, thus protecting it from frost. These techniques show how deep he understand these crops.

At transplant of potato seedlings, it is very important to bury 1 or 2 of the normal leaves in the ground, otherwise you won’t get a proper tuber production.

Tom believe we ordinary people should take responsibility to maintain and improve the heritage form our ancestors. He believe we should do the F1 hybrids bottom up (by ourselves), and share them generously, keeping hybrids fertile in future generations and maintain the inherited gene pool. We can afford the longterm investment, whereas the few remaining multinational seed companies breed for the next ten years only, and for shareholders that’s a very long perspective compared to the normal 5 year perspective.

To ease our work on potatoes, he also breed to improve fruit setting in potatoes. Most modern potatoes set no fruits at all. To grow new and better varieties we need the seeds!

Ps. At Bifurcated Carrots you can read the plan for Tom Wagners tour in Europe