Fragraria x vescana hybrids

[nicollas]

Hybrids of Fragraria x vescana by Annelise Baueur, seem great to make a long lived ground cover . From Progress in breeding decaploid fragaria x vescana hybrids :

Their cultivation is of increasing interest. The
advantages they offer, in ecological and economic terms, are based on their hybrid character. Phenotypically they
demonstrate heterosis. This is characterized by a strong production of runners during the first year, resulting in a
dense stand of runnerplants which can be used as a 'meadow-culture'. Physiologically, they combine the short-day
sensitivity of F. x ananassa with the day-neutral reaction of F. vesca. Compared with F. x ananassa, the vegetative
growth of the F. x vescana hybrids - expressed in the strong runner production - ceases only with low temperatures.
Thus, there is only a very short peri od for sidecrown formation, compared with F. x ananassa, and the senescence
is strongly retarded. Contrary to the short-living F. x ananassa cvs the F. x vescana 'meadow-culture' can be
cropped for many years with a minimum of care. Spraying against botrytis is not required.

[Marches]

The question is whether these hybrids can cross freely in the garden setting outside of the lab with Garden strawberries or Alpines. If they can they'd be very useful, if not then it won't be us amateurs breeding them.

However I did some research into the Fragaria species, it seems Alpines can cross breed quite well with other diploid species (not Garden strawberries). Whether this could lead to a size and firmness improvement is open to question though as all the diploids bear small fruit.
Musk strawberries (moschata) also can breed with diploids like Alpines but with limited fertility and they can cross with Garden strawberries too.
I edited the English Wikipedia article on Fragaria this morning under uncategorised hybrids, the references are all there.

For my part I would like to breed some hybrid strawberries using Fragaria x vescana, but if its not fertile in a garden setting I'll play around with diploids.

[darrenabbey]

Over the last few years I collected isolates of F. vesca from all around Minnesota and Wisconsin, then let winter (and abject last of care) select them for robustness. One isolate from a lake-shore in northern MN survived everything I threw at it and spread madly while doing so. All of my garden strawberries died this winter, even though I was taking pains to protect them from the winter cold. I had the idea of hybridizing between the extremely hardy survivor isolate of F. vesca and some nice garden strawberries, with the end goal of selecting out some nicely winter-hardy and productive strawberry plants.

The ploidy mismatch between the species (F. vesca, 2n; F. x ananassa, 8n) would result in a sterile pentaploid.  To make F. x vescana, researchers doubled the genome of F. vesca (2n -> 4n) and then crossed it to F. x ananassa (8n)...  This should have resulted in a fertile hexaploid hybrid, but the resulting plant was instead decaploid (10n). A decaploid might result from the expected diploid male gamete joining with an unreduced octaploid female gamete.

F. x vescana (10n) crossed to F. x ananassa (8n) should produce a nonaploid (9n) hybrid with fertility issues.
F. x vescana (10n) crossed to F. alpina (2n) should produce a fertile hexaploid (6n) hybrid.

I've been thinking about ordering some colchicine for use in doubling the ploidy of [my super-hardy] Fragaria vesca twice (2n -> 4n -> 8n), so it can then be crossed with the garden strawberry without ploidy-mismatch issues in the first or later generations.

[Marches]

May 25, 2016 0:46:21 GMT -5 darrenabbey said:

Over the last few years I collected isolates of F. vesca from all around Minnesota and Wisconsin, then let winter (and abject last of care) select them for robustness. One isolate from a lake-shore in northern MN survived everything I threw at it and spread madly while doing so. All of my garden strawberries died this winter, even though I was taking pains to protect them from the winter cold. I had the idea of hybridizing between the extremely hardy survivor isolate of F. vesca and some nice garden strawberries, with the end goal of selecting out some nicely winter-hardy and productive strawberry plants.

The ploidy mismatch between the species (F. vesca, 2n; F. x ananassa, 8n) would result in a sterile pentaploid.  To make F. x vescana, researchers doubled the genome of F. vesca (2n -> 4n) and then crossed it to F. x ananassa (8n)...  This should have resulted in a fertile hexaploid hybrid, but the resulting plant was instead decaploid (10n). A decaploid might result from the expected diploid male gamete joining with an unreduced octaploid female gamete.

F. x vescana (10n) crossed to F. x ananassa (8n) should produce a nonaploid (9n) hybrid with fertility issues.
F. x vescana (10n) crossed to F. alpina (2n) should produce a fertile hexaploid (6n) hybrid.

I've been thinking about ordering some colchicine for use in doubling the ploidy of [my super-hardy] Fragaria vesca twice (2n -> 4n -> 8n), so it can then be crossed with the garden strawberry without ploidy-mismatch issues in the first or later generations.

So could Fragaria x vescanas cross breed with each other freely? That'd be useful.

[darrenabbey]

Assuming every variety by that name is decaploid, they should indeed. If some varieties are instead the expected hexaploid, then the ploidy ratios start getting complicated. At some point, infertility due to odd chromosome copy counts may arise depending on the ploidies involved in various crosses. (6n x 10n -> 8n; 8n x 6n -> 7n; 8n x 10 -> 9n)

[Marches]

Been looking into strawberries more, considering getting a few species and breeding for wild (alpine-like) flavour and good productivity.
Been thinking that what I'm looking for in vescana crosses could just come from back crossing with F.virginiana as it seems to have most of the traits of F.vesca.

F.vesca with F.virdis to pick up the flavour and growing attributes of virdis but productivity of vesca is also something I've thought about but not sure how fertile the crosses are, I do have a lot of PDFs on Fragaria species crossing and their fertility that I'm going to type up into a spreadsheet or chart.

[darrenabbey]

Something I read recently (not sure where, no link) suggested that the fertility issues caused by odd numbers of chromosomes wouldn't be an overwhelming issue in plant breeding. The first few generations might have 10-20% fertility until the chromosomes sort themselves out, but that just means you have to try and grow more seeds.