Hey everyone! I haven’t seen any recent topics that specifically focus on Rubus family breeding (blackberries, raspberries, hybrids, etc). I have seen some posts in other more general threads from @a_Vivaldi and @Favman, so I’m hoping to spark more discussion here! My central question for each of you (and any other interested parties) is “what is(are) your breeding objective(s) and how do you plan to get there?” It seems like both of you have already made a ton of progress here and I’m excited to hear more about your projects!
I’m happy to start us off - I’m solidly in the planning phase as I haven’t conducted any crosses yet. I’m in Salt Lake City, Utah (Zone 7b) and unfortunately blackberries and hybrids seem to be somewhat hit or miss here, or at the very least have dramatically reduced yields compared to environments like the PNW. I’m particular to trailing varieties for the Rubus ursinus flavor/background, so I’m not too interested in the hardier U of Ark erect/semi-erected types. Here’s the crux of my problem: trailing types generally don’t perform well here, but I enjoy their flavor. Raspberries do a little better here, but more so the primocane varieties like Joan J and Caroline. I especially love hybrids (Tayberry especially) and raspberries. My goal is to make a more raspberry forward hybrid than Tayberry that has blackberry like vigor, size, and productivity. I’m planning to take two approaches here:
Cross 6x Tayberry to 2x Raspberry, perhaps a variety like Cascade Delight or even a wild cultivar that I found near Bear Lake, UT that has exceptional flavor but small berry size. I imagine this cross will lead to high flavor offspring with medium/low productivity and mediocre environmental performance.
Cross 6x Newberry to 2x Raspberry (probably same cultivars) to try to get Newberry cold and heat tolerance, productivity, etc. I imagine this cross will lead to high flavor offspring with high/medium productivity and good environmental performance.
It seems like F1s often have poor droplet set, fertility, etc, so I’ll likely cross the F1s to Olympic berry since it should be 4x, already have substantial raspberry genetics, and help achieve my overall goals. The F2 will hopefully be the final product.
Some more info on my environment specifically and why Newberry: looks like I can’t post links, but just search “Selecting Blackberry Cultivars for Utah USU”. Newberry is by far the best performer (table 1 actually copied over the wrong survival value, should be 71.9% survival - see Adaptability of Blackberry Cultivars to a High-Elevation Arid Climate JAPS 2017) and I’m currently trying to source it (I’ve reached out to Kris).
So any thoughts, comments, or suggestions? What are your breeding objectives, how are you getting there, and how far along are you?
What you’re planing sounds doable, who knows what ends up being the cross that works best. Won’t know till you start trying. Do you know what specifically causes issues in your area? Is it the heat, the dry, salty soil?
If you can get ahold of Rubus glaucifolius somehow, I’ve a hunch it would be a good source of climatic adaptability. It’s a very rare raspberry closely related to red raspberry and black caps. It’s native to the West Coast from Oregon down all the way to San Diego. It’s one of the parents, or grandparents, of Bababerry which is a much more heat tolerant raspberry. I’m not aware of any sources of it though, and even Bababerry can be a little tricky to get since only a few places have it and some of them are mislabeled.
How cold does it get in your area?
Might be worth looking into dewberries since you don’t mind trailing. Rubus trivialis might have issues with cold for you, not sure, but it ranges out well into the harsher parts of Texas and northern Mexico. Rubus caesius similarly has a huge range and sounds like it could take some more unforgiving climates. Haven’t grown either myself, full disclosure. And I’m not sure how easily they cross with raspberries or blackberries. I think Rubus caesius in particular is sort of unrelated to either group.
Mine is still fairly small. If in a year or two you still haven’t been able to source it, and presuming mine is still alive, I might be able to send you some.
A problem you may run into is that blackberries have an edible core that stays attached to the cap, while raspberries have a tough inedible core that separates from the cap. When there are 4 blackberry chromosomes and 2 raspberry chromosomes, you get edible blackberry like cores. The tetraploid hybrids you will get from these crosses will have 2 blackberry chromosomes and 2 raspberry chromosomes. From what I recall reading, you will get berries with tough cores that don’t separate well from the caps.
I’m primarily focused on breeding a reliable raspberry or raspberry like hybrid for the South. I’ve a few other things going on as well but the raspberries are the top near term priority.
I’ve a few different routes I’m trying, and am at different stages with each, though not as far along as Favman with any. I’m actively working on diploid hybrids between red raspberry and Mysore raspberry, waiting for flowers on presumed 4X F1 hybrids between 6X Tayberry and Loganberry and red raspberry, and I’ve made crosses but haven’t grown out red raspberry x Dormanred.
The F1 Mysore hybrids have some degree of paternal sterility, not sure just yet how bad it is. I’m in the middle of backcrossing them to both parents and in the fall I’m planning to recreate them but with the parents flipped so I can backcross a maternal red raspberry hybrid back to red raspberry with better chances of fertility. I’m also going to recreate the cross with Fall Gold, which is 50% Rubus pungens, and a primocane black cap. Rubus pungens is a lot closer to Rubus niveus than Rubus idaeus is so I’m curious to see if Fall Gold will work as a bridge. Black caps seem a bit more willing to handle wide crosses, at least with wineberry from what I’ve read, so we’ll see if it crosses better the other way too towards the Mysore end of the subgenus. And I’m probably going to try using Dormanred as a bridge as well for similar reasons since it’s 75% Rubus parvifolius.
And probably more out of curiosity than anything else, I’m going to cross Rubus niveus and Rubus cockburnianus. They’re very closely related so I expect the hybridization will be easy, and then I’ll have an quick way to breed some winter hardiness into Rubus niveus.
On the 4X side, I’ve got Olympic berry as well, which I’m just assuming is 4X. I’m going to try crossing it with 4X blackberries but that’s just a curiosity thing since I’m not sure it’ll work with the raspberry genes in one but not the other. Mostly I’ve got it to cross with my presumed 4X seedlings since I’m expecting it to have marginally better heat tolerance. I’ve got seeds from Tayberry x red raspberry waiting on germination, going to repeat that cross with a few other red raspberry varieties and other 6X varieties such as Newberry and maybe a Columbia series blackberry. I plan to test Tayberry x Mysore and x Dormanred as well to see if that will a shortcut out of the fertility issue. Lastly, in going to recreate the Olympic berry cross but with Tayberry and Newberry as the mothers and a primocane black cap father.
Yeah, I’m very curious to see what the tetraploids I have end up like. The fact that Olympic berry was released and found favor with the public gives me some hope and it’s part of why I figured I’d try. I’m curious also if it matters much which parents are used. Olympic berry is Phenomenal x black cap, I don’t yet know if there’s a specific reason why a more blackberry-like hybrid was used or why a black cap was used (other than for the fruit color, which I believe was one of the reasons). I think Rubus glaucus is currently believed to also be blackberry x black cap, so it seems like that might be a good path to go down. Granted, Rubus glaucus is apomitic, and maybe there’s a reason for that…
And I’ve no idea how good the fruit are on either of them actually are. Olympic berry at least I’m growing, Rubus glaucus has so far bested my attempts to acquire it or germinate it.
But anyway, I’ve got time. It doesn’t hurt me much to do a few extra crosses and grow out various combinations of Tayberry, Loganberry, Newberry, and maybe Columbia Star or something, with red raspberries, black cap, Mysore, and Dormanred. Eventually citrus and to an extent passiflora breeding is probably going to eat up my free time and growing space, but in the meantime, lots of fun with Rubus is to be had.
I will say, they’re not as vigorous or tough as the Mysore hybrids.
Tayberry and Loganberry for me grow and fruit for me but they don’t really thrive. Leaf disease issues, borers, cane blight, Japanese beetles, plenty of problems. Most raspberries are even worse. Heritage is similar. Bababerry is better but not bullet proof. The tetraploids are about what I’d expect given their parents. But the Mysore hybrids just put them to shame.
Thank you! Yes, agreed - it seems like there’s a lot of randomness in these things, and perhaps particularly at the tetraploid level for hybrids.
The issues in my area primarily appear to come from the dry-summer continental climate - it’s too cold in the winter for trailing blackberries (measure by bud survival), and then the summer is too hot and dry. Exact temps are (about ~5 F lowest low in winter and Summers average 90F but we usually have a few ~5 day stints where the temp is over 100F. We just set a record temp the other week at 109 F). So ideally I need to hold onto both cold and heat tolerance genes. The soil is mildly alkaline, but in the relevant USU study I think they amended their soil and followed best practices for blackberry cultivation? For me at least, I’ll address that so I’m not as worried about the soil.
I haven’t heard of Rubus glaucifolius, I will look into it! I have some ties to California, so maybe I can figure something out. I also didn’t know that about the Bababerry - very cool! I do have Rubus caesius that I started from seeds. So that could be interesting! And I’ll check out Rubus trivialis, too. Thanks for the insight!
That’s a lot of crosses Which direction in terms of ploidy usually confers better fertility? 6x mother, 2x pollen donor? Or is your sterility in the F1 Mysore hybrids potentially caused by something else?
In more generalized terms, are you taking the wild Rubus species already in the area and breeding them to raspberries that essentially complement their weaknesses? Ie higher yields, larger fruit, etc?
Yes, definitely crossing my fingers that Olympic berry is 4x! Makes sense on using it as an F1 stabilizer. Looking forward to hear how things progress!
Agreed, interesting notes on the tetraploid hybrids and pedicel-berry detachment. Perhaps that will be an issue with some of the F1 and then maybe it can be corrected for by making an F2 generation. We’ll find out and I’ll be sure to share @kiwinut !
And that sounds like a great combo on the different fruit plans. Citrus is so slow (currently growing a Prague Citsuma). Like you said, fun times to be had!
It’s a very uncommon plant from what I can tell. The foothills near San Diego have the most southern population, along with Rubus leucodermis. That’s way, way further south than most raspberries will grow and in a less mild Mediterranean climate than you get in central and northern California, a bit closer to what you have. Those populations of Rubus glaucifolius and Rubus leucodermis got to be pretty darn tough.
There’s also Rubus pringlei, a black raspberry native to the highlands of Mexico, that might be worth looking into, but I’ve less information if it’s actually a useful parent.
I myself am hoping to collect some Rubus occidentalis from a population I know of at the very southeastern edge of its natural range. Should have some next year if the landowner is able to save some of the fruit.
I’ve always done 6X maternal, 2X paternal. My understanding is going the other way tends to lead to more issues and failures.
With the Mysore hybrids, both parents are diploid. The sterility in that case is something Favman found some literature describing. Basically, there’s an incompatibility between the purely maternal mitochondrial genome and the hybrid genome which causes pollen to fail to develop or to die early. So it’s a male sterility issue caused by the wide genetic difference between Rubus idaeus and Rubus niveus and the evolution of some critical difference in their mitochondria. Crucially, the sterility direction depends on the maternal parent, so backcrossing can only restore fertility in the direction of the maternal parent.
Uhh, sort of. On the diploid level, I’m taking wild raspberry relatives from climates similar to or more subtropical than mine, or varieties already bred from those, and crossing them with improved raspberry varieties. The main idea is to breed for adaptation to a cold winter humid subtropical climate and the associated pest and disease pressure.
The observations for these species in San Diego on iNaturalist are all north-facing slopes at over 5,000 feet near riparian areas, so they’re probably less tough than you would think. At over 6,000 feet, Palomar Mountain in San Diego acts as a last refuge for several Northern Californian species that probably had extended ranges during the Ice Age.
Those populations of Rubus pringlei down in the seasonally dry mountains in Sinaola and Durango would probably be a better bet, but I’m not gonna volunteer to go and try to collect seed from those.
Hi, I am in the subtropics with hot, humid, wet Summers and Mild dry, Winters. I only get about 100hrs of chilling but this year has been unusually warm and I have only had about 10 hours of chilling so far.
I am breeding to try and get Rubus hybrids to flower and fruit in low chill areas. I also hate thorns and spines, so I am breeding for thornless. I also want primocane fruiting. I have bred red raspberries that do this but I want more interesting flavours, so I am breeding with Black raspberries and Blackberries as well.
I have a 6x thornless, weak primocane fruiting Blackberry/raspberry hybrid that I have backcrossed to raspberry to give 4x blackberry raspberry hybrids. I am going to backcross these to produce a triploid with BRR chromosomes. I will then double the chromosomes to produce a hybrid with BBRRRR hexaploid. It should be heavily raspberry, large fruit, thornless, strongly primocane fruiting. I am hoping the core stays with the fruit. so it will be a raspberry flavoured blackberry.
I am also going to cross it with Tayberry, to eventually get a primocane, genetically thornless, low chill, Tayberry type fruit.
I am also going to be crossing with Karaka Black blackberry, to try and increase fruit size.
My Mysore crosses have all been self sterlie, so I am going to try and double their chromosomes to see if this corrects this fault. I want a thornless, primocane fruiting, low chill, Black raspberry.
I have abandoned my R.parvifloius hybrids. Too weak and poor fertility, very sour fruit.
Should be really easy to tell which ones doubled and which ones are still triploid haha
But also this just seems like a really good idea, I’m super curious how it turns out for you! If I had time, I personally would love to recreate Loganberry/Tayberry type hybrids but with the newer East Coast blackberries that are sweet, large, primocane fruiting, thornless, and erect. But creating, and verifying, octaploid versions of them and a tetraploid raspberry sounds tedious and expensive.
Ahh, very cool! I haven’t heard of many triploids before, how tough do you think that step will be?
I love the plan! In your experience, how difficult is it to determine how many chromosomes of B and R a cross gets? For example, Tayberry is presumably BBBBRR. If you cross it with a raspberry (RR), you could get BBBR, BBRR, or BRRR, right?
Speaking of this, does anyone have a tetraploid raspberry? Obviously many universities and commercial breeders do, but I haven’t found any on the market and am not too keen to mess with colchicine.
Which pairs with the gamete from a diploid raspberry, which is just
R
R
R
R
R
R
R
Since each chromosome now has two blackberry and two raspberry copies, those copies pair up together and you get the final tetraploid:
BB RR
BB RR
BB RR
BB RR
BB RR
BB RR
BB RR
BB RR
I might be completely off base though. The existence of Newberry and Columbia Star and other West Coast blackberries seems to imply that some degree of BR pairing can happen and that the gametes derived from those might get different combinations of B B R, B B B, or maybe even B R R. Not sure, this is well out of my wheelhouse.
Which direction in terms of ploidy usually confers better fertility? 6x mother, 2x pollen donor? Or is your sterility in the F1 Mysore hybrids potentially caused by something else?
