Intergeneric hybrids

The other day someone linked to my post on strawberry x raspberry hybrids on Reddit and my blog post got a lot of views.  While this was really nice, I made the mistake of reading some of the comments in Reddit.  My opinion of humanity dropped somewhat when I noticed that many of the people arguing had little to no understanding of what they were saying.  Their claims were based on aggression and making up a guess on the spot, rather than any form of evidence or research.

One person claimed that intergeneric hybrids (hybrids between two different genera) cannot exist.  This person likened the possibility of a strawberry raspberry hybrid to crossing a human with a goat.  Initially I was tempted to make nasty comments about this person's lack of basic knowledge.

Then I thought about it some more and decided rather than chastise them for their ignorance and belittle them for making claims that they clearly have never researched, maybe this could be used as an educational activity.

Bumpy irregular strawberry x raspberry hybrid

Intergeneric hybrids do occur in nature.  They have been seen in plants as well as animals.

Some closely related genera are possible to hybridise, while others will never hybridise.  The ones that are possible are always closely related genera.  Strawberry (Fragaria) and raspberry (Rubus) are relatively closely related.  Human and goat are not.  Even with this knowledge trying to compare the possible cross between Rubus and Fragaria to a goat/human hybrid is completely absurd.

Intergeneric hybrids occur in animals as well as plants.  Intergeneric hybrids can be found among mammals (they are strangely common in cetaceans), birds, and reptiles as can be seen in the examples below:

Mammals: Tursiops Delphinus hybrid: https://www.nrcresearchpress.com/doi/abs/10.1139/z03-150#.XVeMDEdS_IU

Birds: Cairina Anas hybrid: https://www.cambridge.org/core/journals/proceedings-of-the-royal-society-of-edinburgh/article/xivgenetical-and-cytological-studies-of-the-intergeneric-hybrid-of-cairina-moschata-and-anas-platyrhyncha-platyrhyncha/F7FE7498CE0DA4A1641EA75E13882A3F

Reptiles:  Pituophis Pantherophis hybrid: https://bioone.org/journals/Journal-of-Herpetology/volume-46/issue-2/10-260/Two-Naturally-Occurring-Intergeneric-Hybrid-Snakes-Pituophis-catenifer-sayi-/10.1670/10-260.short

Plants and animals are biologically very different.  Many things that are common in plants are extremely rare or impossible in animals.

Proving the existence of intergeneric hybrids in animals quickly rules out the human cross goat argument, but does not do anything to back up the possibility of a strawberry x raspberry hybrid, so let's move onto plants.

Leaf edges curl - I am unsure if the cause is genetic or environmental

Intergeneric hybrids among plants:
Most people with a basic understanding of agriculture can tell you that triticale is a wheat rye hybrid.  It is common and grown on commercial scale.  Australia produces around 800,000 tonnes of triticale grain per year.  This alone proves that intergeneric hybrids among plants are possible .

Fifteen seconds on a search engine returns many thousands of intergeneric hybrids among plants, below are a few examples:

Triticum Secale hybrid: https://en.wikipedia.org/wiki/Triticale

Citrus Citropsis hybrid: http://era.daf.qld.gov.au/id/eprint/4475/

Citrus Fortunella hybrid: https://pdfs.semanticscholar.org/51b9/124a3d04b4479dbab065b7bc58088a86dbfa.pdf

Maleae intergeneric hybrids:  https://en.wikipedia.org/wiki/Maleae

Malus Pyrus (commonly known as Zwintz-scher’s Hybrid) hybrid: https://www.researchgate.net/profile/Stefan_Martens/publication/261771797_F1_hybrid_of_cultivated_apple_Malus_domestica_and_European_pear_Pyrus_communis_with_fertile_F2_offspring/links/02e7e53577214e7655000000/F1-hybrid-of-cultivated-apple-Malus-domestica-and-European-pear-Pyrus-communis-with-fertile-F2-offspring.pdf

Sorbus Pyrus hybrid: https://www.actahort.org/books/918/918_123.htm

To add more weight to the possibility of a strawberry raspberry hybrid, there are intergeneric hybrids between strawberries and Potentilla:

Fragaria Potentilla hybrid: https://www.actahort.org/books/348/348_19.htm

Now that we have demonstrated intergeneric hybrids do occur in plants (and animals), and that Fragaria are known to hybridise with closely related genera, I guess the next step it to look at my strawberry raspberry hybrid and answer some questions I have received over them.

Elongated petiolule - this is not seen in the parent species

Are you 100% certain this is a strawberry raspberry hybrid?
When attempting this cross I emasculated the flowers and bagged them prior to hand pollination.  I attempted reciprocal crosses between plants of the same ploidy to increase chances of success.  A a control I emasculated and bagged some flowers but didn't pollinate them, all aborted early and none produced seed.  I tried many crosses, planted many seeds and very few germinated, out of those most died early.  The leaves, flowers, and fruits of the surviving plant are different from the parent varieties.  Strawberry seeds planted at the same time as the hybrid seeds began flowering around 5 months old, this hybrid plant took around 10 months and then the first few sets of flowers aborted without setting fruit.  The parent strawberry throws a lot of runners from a very young age, this plant is over a year old and has not yet thrown any runners.  I have saved seed from this plant and they seem to have less than 5% germination rate, while the strawberry parent's seeds usually have over 95% germination.  Even with all of this, there is still an incredibly small chance that some tiny ant crawled in under the bag and pollinated the flower, so without genetic testing I cannot be completely certain it is a hybrid.  To answer the question: I am not certain that this is a hybrid.

Has this been independently tested and proven to be a strawberry raspberry hybrid? 
Not yet.  I would love someone to test this genetically to conclusively determine if it is a hybrid.  I don't know how to get this done in Australia.  If you are able to help please let me know.  Edit to add: I sent samples of these plants to the CSIRO who have since tested them.  They are true intergeneric strawberry raspberry hybrids.  The results can be seen here.

Unripe berry - lumpy and forked at the end

It can't be a hybrid because the berry is bumpy and ugly.  

If anything its unique looks add to the possibility that it may be a true hybrid.  This is just one of the morphological abnormalities that can be observed between this plant and the strawberry parent.  Other morphological abnormalities include the length of petiolules, flowers always being subtended by a leaf, inconsistent flower structure (such as extra petals and fewer stamens), and the absence of runners.  Germination time/percentage, early death of large numbers of seedlings, and the greatly extended time from germination to maturity are among the other factors that suggest this plant may not just be a strawberry.

This looks like a strawberry, why doesn’t it look more like an equal mix of raspberry and strawberry?  

In wide crosses there is often, but not always, asymmetric expression patterns and phenotypic similarity with the seed parent.  I am not sure why it happens in some crosses but not others.  Most of the papers I have read on this phenomenon appear to be based on interspecific crosses rather than intergeneric crosses, but there are a few papers written on triticale that suggest this strong maternal effect in intergeneric hybrids is relatively common (www.fao.org/3/a-y5553e.pdf).  So while I don't know why this happens, I know that it does happen often.

Flowers always subtended by a leaf

Some poorly worded question about fruit types eg strawberry produce achenes on a fleshy receptacle while raspberry produce drupes.

I am not quite sure what the question is here, or how this would ever support or disprove this possibly being a hybrid, so I will take a stab and try to guess what they are asking.  Usually several genes interact to create what we see in a plant or animal.  Some genes are dominant over others and if both genes are present you often only see the effects from one (ie one is dominant and the other is recessive).  The fruiting structure that we see is due to the genes present in the plant and how the genes interact with each other.  This is unexplored territory, we have little understanding of what phenotype a plant will display when it is heterozygous for fruiting in drupes and producing achenes on a receptacle.  Both parents were diploid (2n = 2x = 14) so if this is a true hybrid it and any seedlings it produces could shed light on genetic interactions that are as yet unknown.

If these are possible why hasn’t anyone done this before?  

This is one of the most common questions, it makes little sense and appears to be a self-fulfilling prophecy.  Our collective scientific knowledge in any given area isn’t as far along as people think it is.  There are plenty of things we have never attempted and all areas of science break new ground all the time.  As no one ever attempts to do this cross you assume it can’t be done.  Wouldn’t it be better if it was attempted, then proven to be possible or not to be possible?  In the past this hybrid was created using somatic fusion and the resultant plant was apparently viable, I am unsure if it fruited and have not seen any pictures of the plant.  My attempt at crossing strawberry and raspberry involved cross pollination (similar to Burbank's attempt) rather than somatic protoplast fusion.  Unlike Burbank’s attempt, I used plants of the same ploidy to increase the chance of success.  Not all that long ago crossing plum and apricot was thought impossible because no one had attempted it, today you can buy plumcots from the shops!  

 

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. 

Graft hybrid attempt

Graft hybrids are a topic of much controversy, has been studied only briefly, and at this point in time the concept is very poorly understood.

For years it was believed that DNA did not cross the graft union further than a few adjoining cells, then it became clear that metabolites and some DNA could cross the graft union but there was controversy over how far this would travel or if any changes could be inherited by seeds.  Then it started to look as though DNA transfer can be heritable and passed on through seeds to some extent.

While there is still a lot of controversy over this topic, it is now pretty clear that DNA can cross the graft union under some situations and may cause heritable changes to be incorporated into seeds.

Graft hybridisation is not the same as cross pollinating where half of the DNA from each parent is passed on.  We are not sure how much DNA from each parent is passed on, and it appears in many cases that 0% is passed on.  At the moment there are more questions than there are answers.  I find it fascinating.

Cross pollinating strawberry and raspberry to create a hybrid has a low rate of success and is rather time consuming.  I can see why so few people have ever attempted this.  Around two years ago I made a large number of attempts, planted large numbers of seed, and only have a very small number of fruiting intergeneric hybrid plants to show for my efforts.

Given that heritable changes to DNA can sometimes be incorporated through grafting, it got me thinking.  Perhaps it is possible to use graft hybridisation to cross strawberry and raspberry plants?  Perhaps I graft the two, allow the scion to flower/fruit, collect the seeds, if I plant the seeds they may display some form of genetic cross over between the two plants.

To attempt this, the first question is one of what part to graft.  It may be possible to graft the growing tip of a raspberry onto strawberry roots, I am self-taught at grafting and that sounds difficult.  I worry that I am not up to this kind of grafting and would likely just kill both plants.  So this may not make crossing the two any faster or easier than simply cross pollinating a lot of flowers.

Or, would it be best to graft strawberry scion onto a raspberry plant?  Some strawberry plants can go from seed to fruit in 5 months or less, saving and germinating strawberry seeds is simple.  I guess it is possible to excise the strawberry’s growing bud and graft that to a raspberry somehow, again this sounds like a difficult graft for someone with few grafting skills, so I would probably end up killing both plants.

Assuming that it is even possible to graft a rasberry and a strawberry, this graft may or may not take all that easily as there may be issues with mild incompatibility.  I am self-taught, and don’t have a laboratory, so will be working in the field where insects and birds and children frequently visit and the weather can be downright hostile at times.  If I have any hope of succeeding I need to work with something that is simple to graft to increase my chances of success.

Strawberry runners grafted onto a raspberry cane

I decided to try and graft strawberry runners onto a raspberry cane.  Runners give me a large area to work with so if I mess up I can cut off that part and try again, I can do this several times if needed, until I make a neat cut on just the right angle.  You can't really see in the photos, but some runners are long and others are short, this was partly to see if that made a difference and partly because I had to cut some runners shorter as I made the cut wrong a few times.  I did this with a few plants but only took pictures of the first one.

With runners the young plantlet is still developing, if grafted onto a more mature raspberry cane it will be a kind of ‘mentor graft’ which is said to facilitate DNA exchange.  Given the length of a raspberry cane I can graft large numbers of runners and increase the chances of one working. I ended up grafting more than is in the photographs, about half a dozen runners per raspberry cane.  I wanted to do more but ran out of time and effort.

I grafted several strawberry runners onto a few raspberry plants.  I am unsure if ploidy makes any difference to success rates of grafting two different genus so I used both diploid plants (2n = 2x = 14).  The runners were very thin and difficult to use, but it was all I had available at the time.

To the best of my knowledge, no one has ever attempted anything like this using strawberry and raspberry.  There have been a few attempts using various Solanaceae species that have confirmed genetic material can cross the graft union and these changes can be heritable in the seeds, and at least one intriguing graft hybrid experiment using plums, but nothing with Rubus and Fragaria.

My plan was to graft strawberry runners onto raspberry canes, then when the strawberry plant was large enough I would allow it to root in soil.  Potentially some raspberry genes may have crossed into that strawberry and may be heritable.  I would then allow that strawberry (which had previously been grafted onto a raspberry) to flower and set fruit, I would collect and plant seed, and then see if there were any noticeable difference in those seedlings.

I assumed that if this worked there would be a low rate of genetic cross over, so I was planning on growing out a lot of seedlings.

I ran out of time on grafting day and kept some of the runners not grafted but sitting in a glass of water.  They all died after a day, so gave me hope that my poor technique grafting may have been successful.  All of my grafts looked bad for a day or two, then they perked up.  This was a very encouraging sign.

After 8 days there was a preventable mishap.  One hot day most of my strawberry raspberry grafts died.  The plants were in a plastic bag to increase humidity, but it also made a little solar oven which cooked them.  They looked fine in the morning, and were crispy and dead in the evening.  I think it was due to the heat rather than incompatibility issues as the raspberry hosts dropped a lot of their leaves that day.

After that incident I had one single grafted runner that was still alive and growing well.  It was small but growing fast, so I assumed the graft had taken.  This runner had a small plant that then sent out a further runner, so I was confident this had worked.  This grafted runner remained alive for 28 days after the initial heatwave and was developing well, I put a pot of soil under it so it could send down roots, then another heatwave hit and it died before it had a chance to root.

My little strawberry runner survived for 36 days after I had grafted it and had a nice looking little plant ready to set down roots.  This was extremely frustrating.  The rest of summer was record breakingly hot so I didn't try again.  I even lost a lot of my raspberry plants that were growing in the garden.

I hope to give this another try in spring if I have time.  The fact that the last runner lived so long was encouraging, but at this point I don't know if this could work, let alone if my grafting skills are good enough to succeed.  Unfortunately either no one has tried this before, or they haven't bothered making their results accessible, so I will have to do it and learn for myself. 

If I give this another try I plan to write a blog post of the results.  Even if I am unsuccessful it is a good result and worth learning from.  I wish someone else had tried this properly and either failed or succeeded, that way I wouldn't have to start from scratch.  Let's be honest, if this is not going to work then I am just wasting time.

Chilean Guava

For a few years I have been growing a plant with the common name of Chilean guava (Ugni molinae).  I think there has been a push of late to call them "Tazzie Berry" or "Tassie Berry" to make them more marketable while people think they are a new fruit.  According to wikipedia  it is native to Chile and Southern Argentia where the local Spanish name is "murta", and the Mapuche Native American name is "Uñi" or "Uñiberry". 

This is a nice enough looking shrub that grows really nice tasting fruit.  I have read that they were the favorite fruit of England's Queen Victoria.  Perhaps she actually liked them, or perhaps she liked having something that at the time would undoubtedly have been rare and impossible for most people to buy and therefore extremely prestigious, or perhaps a little of each.

I don't think Chilean guava love blazing heat, so I try to grow them in partial shade.  They take frost, but it sometimes damages the new growth, so I try to grow them near a wall where they experience slightly less severe frosts.  Their growth rate is not overly fast and they are evergreen.

Unfortunately I don't think I have quite worked out its preferred growing conditions.  I grow mine in a pot and each year it grows larger and flowers like crazy but I never get huge numbers of ripe fruits.

At the start of the season it is absolutely covered in unopened flowers.  They normally stay like this for so long I begin to wonder if it has flowered but I missed it and they started to turn to berries.  Then they eventually open and I remember that the unopened flowers stay on the shrub for a long time.

Chilean guava unopened flower buds

After what seems like forever, the flowers begin to open.  There are usually hundreds upon hundreds of flowers, almost too many to believe, and they open successively over a very long time.

The flowers are white or light pink and rather pretty.  Oddly enough I have never seen any pollinating insect on them.  I have tried hand pollinating and it has not made a noticeable difference to fruit set.  Over the next few weeks the shrub is incredibly pretty with all of its flowers.

Chilean guava flowers starting to open

Soon enough the petals drop, and each flower begins to turn into a little fruit.  At this stage I look at the many hundreds of fruits and start to expect a massive harvest.  Each branch is loaded down with dozens of tiny unripe fruits.

Chilean guava berries starting to form

Then for some as yet unknown reason, many of the immature fruits begin to abort.  They do this at different stages, some are far more developed than others.  There are literally hundreds of fruits dropping off each day for a few weeks.  I really don't understand why.

If this were due to lack of pollination they should have aborted earlier.  Perhaps the soil isn't right, maybe they need more water, or frost or heat or wind gets them.  Hopefully I work out how to stop this as I would love to pick thousands of these fruit from each small shrub.

Chilean guava covered in unripe fruits

Tiny fruits starting to abort

Eventually a few of the fruits ripen after they reach pea size.  I don't think I have taken any pictures of the ripe fruit as they are usually eaten pretty fast.  It would be nice if there was some commercial grower of these as they taste nice and I am sure there would be a market for them.

I am bad a describing taste.  To me they taste really good, a bit like strawberry crossed with a pine tree.  That sounds dreadful.  Perhaps someone else would be better at describing the taste than I am!  Even though my description is not flattering they really do taste good.  They smell great, similar to some tropical fruit mixed with pine tree.  I really don't think I am doing this justice.

The texture of the flesh is like a firm slightly dry banana.  Again this sounds bad, but it is really very nice.  I don't think I am all that good at describing this kind of thing.  I am better skilled at growing/breeding/eating things than I am at describing them.

The leaves smell like spices when crushed.  I tried eating one once and was not impressed with the taste or the texture as they were very tough.  I grow them for the fruits, and for the flowers, I don't even know if the leaves are toxic so I don't intend to eat the leaves again.

Over the season we sometimes get hail and crazy wind, invariably it breaks of a few small branches.  I try to use these to grow a few new plants.  I am told that Chilean guava is simple to grow from cuttings, for me they sometimes take a few weeks and other times take a few months to grow roots.

If I have any spare cutting grown plants that have strong roots and are actively I sell them through my for sale page.  If you are interested have a look.  I don't take pre-orders because I can't guarantee how long it will take for them to root.

Yellow fruited raspberries in Australia

This past summer I had a few people comment on my yellow fruited raspberries.  Most people were taken by their stunning colour.  The people who tasted them were amazed by their delicately floral and surprisingly sweet taste.  They are an impressive plant and something that always generates interest in the garden.

Yellow fruited raspberries, productive and tasty

These yellow raspberries are a slightly different version of the regular red raspberries.  There are very few places in Australia to get yellow fruited raspberries and I count myself lucky to have had a chance to grow them.  The plants look like ordinary red raspberries, they grow the same, they spread the same, they flower the same, but the fruit is yellow instead of red, and it tastes different.

I would almost say yellow raspberries feel different in the mouth, but I grow a few varieties of red raspberries and each of them feels slightly different in the mouth, so this trait probably isn't unique to yellow raspberries.

The yellow fruited raspberries I grow are quite productive.  Sometimes they grow a few flowers, but mostly they have clusters.  The berries don't all ripen at once, so the harvest gets spread out somewhat.

Yellow fruited raspberries - this cluster eventually had nine raspberries

Spreading out the harvest instead of ripening all at once means that if birds happen to steal some, of if there is a swarm of bugs, or if the weather turns dreadfully hot and the plants get fried, I should still get to enjoy some of these yellow raspberries.

Yellow fruited raspberries - berries don't ripen all at once

There is a story that birds ignore yellow raspberries (and yellow or white strawberries) and will only eat the red ones.  Many passerine birds do see red especially well, so this story almost seems logical.  Many people swear by it, and I even see places advertise white or yellow strawberries to 'beat the birds'.

Birds, however, are not that simplistic.  If they were they would have all died out long ago.  Birds eat yellow raspberries in my garden just as much as the red ones, perhaps a little more so.  I don't lose a lot of berries to birds, so I normally just let them share.  Strangely enough, I lose far more white or yellow strawberries to birds than I do red ones when they are grown side by side, but that is a story for another time.

If you have trouble with birds, net your raspberries to protect them, don't rely on their colour to stop birds from taking them.

Yellow raspberries taste similar to a red raspberry, but yellow raspberries tend to be sweeter and more floral.  I quite like them and my kids seem to prefer them to the red raspberries.  While I enjoy the taste of yellow raspberries, I grow both red and yellow fruiting raspberry plants.  If I had to chose a favourite I think I prefer most of the red ones.

Yellow fruiting raspberries

Over winter when my plants are dormant I sell yellow fruited raspberry plants (as well as a few varieties of thornless red raspberries).  I don't have huge numbers, but I should have a few extras most winters.  I can post them, but not to WA or Tasmania or outside of Australia.  If you are interested they are listed on my for sale page.

Strawberry x Raspberry intergeneric hybrid berry taste

Earlier I wrote a post on strawberry x raspberry hybrid experiment update, now it is time for a description of the berries (botanically they are not berries, but let's move on).

I tried to think of how to describe the taste of these berries, saying "they are really delicious", or "I like them", probably isn’t all that useful to anyone.  So I thought hard about how to describe the taste of strawberry x raspberry hybrid berries.

To me they are sour, but not in a bad way, and certainly not as sour as store bought strawberries or raspberries.  They taste like strawberry mixed with something tropical.  They taste warm (is warm a taste) and floral (is floral a taste) and really nice.  They are very fragrant, the smell is delicious and similar to the taste.  The fragrance is like strawberry mixed with something tropical.  That is the best description I can come up with.

I asked someone else to describe their taste, and was given the following elaborate and rather fancy description.

• They taste sour and warm with a delicately intense combination of wild strawberries, apricots, bananas, and raspberries. They have the unmistakable heavenly scent of a lolly shop.

Wow, I don't know what to say.  I guess they are far better at words than I am.

I asked someone else to describe the taste and was told:

• are AMAZING!!!!!!!! They’re little flavour explosions!  So YUMMY!!!! 

Than when I asked for a better description was told:

• Booom!

I guess the taste of strawberry x raspberry hybrid berries inspires the overuse of exclamation marks and capitalisation?  In all seriousness, they do taste sensational and unlike anything else I have eaten, so their taste causing a lot of excitement is understandable.

The texture of strawberry x raspberry hybrid berries is different from that of either parent.  Perhaps something akin to a ripe pear, but without any grittiness that pears often have. 

The hybrid berries all look similar to strawberries.  They have achenes (the true fruits that most people refer to as 'seeds') on the outside of a fleshy receptacle.  These achenes are barely attached to the receptacle, and I wonder if they would fall off from the lightest hint of a breeze, yet somehow they stay attached.  The skin and achenes are red, and the flesh is white all the way through.

They are vaguely strawberry shaped, but all of them are odd looking, lumpy, bumpy, and bulbous.  They all have irregular bumps, some are curved, in some the end is slightly forked, or the berry is twisted, some are short and fat while others are elongated.  The weird shapes do not appear to have been caused from issues with pollination.

At this stage I don't know if they are self-pollinating, or if they are being pollinated by strawberry or raspberry plants growing near by.  I don't know if any of these seeds are viable and will grow.  I have many breeding experiments I want to try with this hybrid and will try to write more blog posts as I discover more.

All the following images are of strawberry x raspberry hybrid fruit off the same plant.

Strawberry x raspberry hybrid fruit, has lumps and the end is slightly forked

Strawberry x raspberry hybrid, note the base is bulbous

Strawberry x raspberry hybrid, note the irregular shape and the leaf arising from the calyx

Strawberry x raspberry hybrid, berries are all irregular

Strawberry x raspberry hybrid berry

Strawberry x raspberry hybrid

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.

 

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)

How to prune raspberries

In order to correctly prune raspberries or blackberries or any of their many hybrids it is important to understand their basic growth habit as well as what you want to get from them. 

If you don’t understand their growth you will never get the full potential from them.  If you don’t know what you want from them you are wasting your time in pruning them at all.

Floricane blackberry will not fruit well if pruned like this

Established brambleberries grow from a crown, each year they put up new growth, this new growth is referred to as a primocane.  The primo part of this word means 'first' as they are first year growth.

After the growing season is over the primocane will sit over winter and not do a great deal that you can see, the following season this older growth is referred to as a floricane.  Floricanes were originally the only canes that flowered, but we have since bred some varieties that can flower on their primocanes.   Knowing about floricane and primocane is important so you can prune them properly.

Raspberries

How to prevent thornless berries reverting to thorny

Thornlessness in brambleberries appears to be influenced by at least three different factors.  Scientists and plant breeders have understood these factors reasonably well for quite some time.  Each of them has different advantages and disadvantages.   But how do you keep a thornless berry thornless, and how do you prevent a brambleberry from reverting to being thorny?

First, let me tell you about my experience growing a "thornless youngberry", then let me explain the three different ways that brambleberries can be thornless, then I will explain what you do about each of the three types.

Thornless youngberry starting to ripen