Solanum x edinense

Description

Solanum x edinense distribution map
Solanum x edinense distribution map

Solanum x edinense is a natural hybrid species from central Mexico, generally found in areas of potato cultivation. It is thought to be a cross of domesticated S. tuberosumS. demissum. Plants range from three to six feet tall, more similar in form to domesticated potatoes than S. demissum. Flowers are typically blue, less commonly white. Berries are round, similar to the domesticated potato, but often seedless. Some clones appear to be male sterile, while others set small amounts of seed when self-pollinated.  The specific epithet refers to Edinburgh, Scotland and specifically the botanic garden there, where the species was first described.  Its importance as a source of disease resistance was first recognized there when late blight damaged the domesticated potato varieties but left S. x edinense undamaged.

This is an interesting example of similar evolutionary outcomes in North and South America. The North American S. demissum is similar in many ways to the South American S. acaule. They are low-growing, hardy, disease resistant polyploids. Both have crossed with the domesticated potato, producing robust pentaploid hybrids. In South America, the hybrid species is S. curtilobum, with two copies of the domesticated genome and three of the S. acaule genome. In North America, the hybrid is S. x edinense, with two copies of the domesticated genome and three of the S. demissum genome. And the plants of both hybrids are quite similar in size and form.  Just like with S. curtilobum, the plants are fertile (although generally much less self-fertile than S. curtilobum), but the seedlings do not grow true, instead gradually stabilizing as tetraploid over several generations. So, “true” S. x edinense can only be maintained as clones.

Resistances

The resistances of S. x edinense have received little study, but the wild parent, S. demissum, has a wide range of pest and disease resistances and presumably those will be inherited in some of the progeny.  S. demissum was used commonly in domesticated potato breeding in the early to mid-20th century as a source of resistance traits.

Condition Type Level of Resistance Source
Phytophthora infestans (Late Blight) Fungus Resistant  

Glykoalkaloid content

No information, but intentional crosses between the putative parent species have generally segregated for glycoalkaloid content, with some palatable progeny.

Images

Plant of the wild potato species Solanum x edinense
Solanum x edinense plant
     
       
       

Cultivation

Growing considerations for this species are the same as for domesticated potato, although stolons may be longer.

Breeding

This was one of the first wild potato species used in breeding with the domesticated potato.  The variety Brennragis, a S. x edinense x S. tuberosum hybrid, was released in 1936 (Ross 1966).

In the process of recapitulating this hybrid at the Royal Botanic Garden Edginburgh, they found success using S. demissum only as the female parent (Coleman 2018).  They also noted possible cases of hybrid necrosis in the progeny (Coleman 2019).

Crosses with S. tuberosum

Female Male Berry Set
Seed Set Germ Ploidy Source
S. x edinense S. tuberosum 4x Yes Yes Yes 4x+  

Crosses with other species

Female Male Berry Set
Seed Set Germ Ploidy Source
S. commersonii 3x S. x edinense
Yes Yes Yes   Broili 1921

References

Solanum x edinense at Solanaceae Source

Solanum x edinense at GRIN Taxonomy

Solanum x edinense at CIP

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2 thoughts on “Solanum x edinense

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    Max Coleman says:

    At the Royal Botanic Garden Edinburgh we have produced Solanum x edinense by controlled crossing using demissum as mother plants and couple of tuberosum cultivars as fathers. An interesting result has been that the vast majority of offspring show hybrid necrosis. We only have a few good plants. The first has flowered today and is without doubt the desired hybrid.

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