Strawberry x Raspberry Hybrid Experiment Update

It is time for an update on my strawberry x raspberry hybrid experiment. 

Strawberry x Raspberry hybrid semi double flower (it is missing a petal)

The plants themselves look unremarkable.  If I knew nothing of their history and you asked me what they looked like I would say strawberry plants.  If you said to take a close look I would notice the odd flowers, and the weird irregular leaves, and I would say a very weird strawberry.  It certainly takes after the strawberry parent in the looks department.  I will write a proper description of the plant, and include pictures of the fruit etc, in a later post.

Two plants survived winter, one is small and appears reluctant to survive, the other is much larger.  I will continue to nurture the smaller plant but am expecting it to result in nothing.

The plants look much like strawberry plants, so much so that I keep asking myself if there is even a remote possibility that a strawberry seed was planted by mistake.  It germinated very quickly, and the cotyledons looked odd, and many plants died of partial or complete albinism, but is there any chance that this was a random strawberry seed?   I keep going over things in my head and am confident that the chances that this was a strawberry seed are incredibly low.

I planted seeds of strawberries and raspberries from both parents at the same time to compare seed grown parent plants with the hybrids.  The raspberry parent seedlings were not going to flower this year (unfortunately they died in the heat this summer).  The strawberry parent seedlings began flowering and sending out runners back in September 2018, while my hybrid just grew more leaves and looked like a strawberry plant.  The parent strawberries were flowering and fruiting for months while the pampered hybrid plant did nothing.

The plant grew very slowly, much slower than I expected, then one day the crown began to elongate.  I read that Burbank’s hybrid looked like a strawberry, then the crown elongated and it grew a cane similar to a raspberry prior to flowering.  This didn’t happen with my plant.

Crown starting to elongate

After the crown elongated somewhat, the point where each leaf petiole joined the crown grew a bud, and the crown divided into several crowns.  This type of crown division is not all that unusual for strawberries.  The crown elongation was at the more extreme end of what is seen in strawberries, but not outside what I would have considered possible.

The crown now has several growing points

Some of the leaves grew odd and irregular.  The petiolules (the little stem that joins each of the leaflets to the petiole) was sometimes very long, and sometimes virtually absent.  Sometimes the leaflets were joined asymmetrically.  Occasionally a leaf would be so asymmetrical that the leaflets were better described as alternate rather than opposite. Most leaves had three leaflets, other times leaves were produced that did not have three leaflets.  Some of the leaves curl at the edges, the plant has done this since it was tiny.

Leaf edges often curl, I don't know if this is caused by genetic or environmental factors

Leaflets not really opposite

Weird leaves

Another odd leaf

Really long petiolules attaching some leaflets

One day a leaf grew with an odd bump on its petiole.  That bump turned out to be a flower bud!

The plant started to flower, this was more than four months after strawberry plants of the same age had started fruiting.  It felt like a really long time to wait.

Flower buds arise from leaf petioles

The first flower was slightly misshapen, it was semi double, and it had six large petals, as well as numerous small petals or half petal half stamens.  I have never seen semi double flowers in the parent strawberry variety.  Then it grew a second flower on the same leaf petiole.  These flowers eventually aborted and did not produce fruit.

The plant started to produce more flowers, most of them was semi double, most were slightly misshapen, some were female flowers that lacked stamens while others were hermaphroditic with low numbers of stamens, and they were all subtended by a leaf.  This subtended by a leaf trait is sometimes seen in the parent variety, but it is strange to see it with every flower.  So far it usually produces multiple flowers from each petiole.  Some flowers had four petals, others five, others six or seven, sometimes that also had tiny petals that were partly stamens, other times they didn't.

Irregular number of petals and part petal part stamen

Five petals on left, five petals and some petal/stamens on the right

Then the plant started to produce some flowers that were single, some of these were on the same stalk as semi double flowers.  The flowers, even on the same stalk, display a lot of diversity and irregularity which I don’t entirely understand. 

Flowers subtended by a leaf

Inconsistent number of petals

Flower stalks always have a leaf attached

The plant is throwing up new flowers most days, so far they are all subtended by a leaf.  They continue to display a lot of slight peculiarities.  Some look like normal strawberry flowers, while others look odd.

Note the odd leaf at the top and the calyx having a bract/leaf

The immature fruit looks similar to an immature strawberry, with achenes on the outside (as opposed to looking like a raspberry made up of drupelets with seeds on the inside).  The achenes sit on the surface of the fleshy receptacle, sometimes they are only just attached and I wonder if the slightest breeze will make them fall off.  Most of the berries abort early, while some started to develop seeds slightly and then abort.

This plant is clearly not a raspberry.  When I compare it to the strawberry parent they are very different in many different ways meaning that it is not a stray strawberry seed that somehow got planted.  Which means that my strawberry x raspberry experiment was a success.

I have since written a post about the strawberry x raspberry hybrid with pictures of the fruit and description of its taste here: https://living-mudflower.blogspot.com/2019/02/strawberry-x-raspberry-intergeneric.html. 

Edit to add: I sent samples of these plants to the CSIRO who tested them and determined that they are true intergeneric strawberry raspberry hybrids.  The results can be seen here.