I see that some nurseries say their mulberry is self-fertile but I thought that male don’t produce fruit and only females do? Can someone help me clarify how to ensure a tree that produces fruit?
Some trees grow both male and female flowers so the male will pollinate the females.
Some fruits will also fruit without the male flowers
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This is a grafted tree so it’s female. Mulberries females are self fruitful, meaning they will produce fruit even if there is no pollen involved
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There are no wild mulberries near my place.
My gerardi produced gobs of fruit with no others present.
Now I have a few others… silk hope, oscar, lawson dawson, kip paker.
Adding 2 or 3 more this spring.
TNHunter
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To add to what has already been said, male pollen is needed to create viable seed but not for fruit production.
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So if I root cuttings from a female tree, will that guarantee fruit?
Nurseries who call mulberries “self-fertile” are misunderstanding what that means. As already said above, most female mulberries will set fruit even if planted in isolation. However, this fruit will be seedless (unless it is a variety which also sets some male flowers). This means it is not self-fertile as no pollination happens and no seeds are produced.
In short, female mulberries simply set fruit via parthenocarpy which does not require any pollination at all.
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Generally Yes
I believe they are looking for the term “self-fruitful”.
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Yes, I wish people would call this “self fruitful” which is inclusive of self fertile. Its easier to understand, more accurate for the general concern of growers - do they need another variety, and just as easy to say.
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If I wanted to obtain seeds or form easy hybrids, could I graft a male branch into a mostly female tree? That way they’d be corssing by being so close to each other.
As long at there are no graft incompatibilities and you’re grafting a male of a species that is cross-compatible with the female, then yes, you can graft a male branch onto a female tree for pollination.
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How can we find out which varieties are cross compatible?
Aren’t all Morus spp. Cross compatible reguardless of the variety?
I know Morus alba & Morus rubra cross naturally in the wild.
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As I understand it, although M. alba & M. rubra will hybridize, the resulting hybrid may not set seed well (not sure if they’re sterile or just reduced fertility). I’m not aware of any confirmed hybrids using M. nigra, so that may be a challenging one to use as well. Of course there are also other Morus species which would need trial and error to determine compatibility.
That’s just pollination…
In terms of graft compatibility, I’ve been finding that M. nigra will have delayed graft failure on at least certain other Morus, not sure if the one I’ve been trying is a pure M. alba or an alba x rubra hybrid… Who knows what other incompatibilities might exist without documentation.
Trial and error is probably the way to go here.
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I haven’t studied mulberries past as wild edible so Idk how they hybridize. That being said, are they sterile due to an lack of introgression? Surely both parent species are still present where the hybrid offspring is growing for it to be pollinated by both parents no?
I agree, everything here is trial & effort + so many combinations haven’t been tried yet to know. Also I’m pretty sure reciprocally grafted scions increases pollen compatibility too!
I’m not a breeder or geneticist, but in my explorations, I’ve come across, and introduced, a couple of decent rubraXalba hybrids.
I’ve seen reports that ‘Illinois Everbearing’ is a triploid, and does not produce viable seeds.
Eliza Greenman has opined that hybrids with a M.rubra pollen parent appear to be more ‘fit’ than the reciprocal cross. IDK if she’s specifically addressing fruit quality, foliage edibility, or overall plant health.
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Interesting, I wonder why this is or what is going on? Is this the case in all Morus alba x Morus rubra hybrids? Makes me wonder if the hybrid offspring can’t reproduce from seeds, how is it slowly introgressing with Morus rubra and outcompeting pure M. rubra?
I haven’t looked into Morus breeding yet, been focusing on studing Laportea as of right now.
Sorry for being late to the party, but here’s a link to Mark Travis’ writeup on some confirmed (12n!) M. macroura x nigra hybrids.
And a snippet:
“ Until 2020 I was convinced that a cross between a highly polyploid 308 chromosome Morus nigra and a 28 chromosome mulberry species was impossible (outside of a laboratory). I wish to present the verified work of some of the various hybrids that a Belgium nurseryman (Dithmar Guillaume) has obtained with Morus nigra as one of the parents.
Morus nigra x Pakistan mulberry (Morus macroura)
The pictures presented here are seedling hybrid mulberry plants from crosses between Morus macroura ‘Pakistan’ female (2N=28 chromosomes) and a Morus nigra male pollinator (sic) (22N=308 chromosomes). Analysis performed by a Belgium university showed that the offspring had a polyploidy level of 12N, or 168 chromosomes, with a 95% confidence (1N from mother and 11N from father).”
M. alba tends to produce way more pollen than M. rubra - which results in the native reds producing mostly hybrid offspring (which may or may not be sterile), whereas the albas keep producing mostly more alba offspring (and some - possibly sterile - hybrids). I think it’s specifically the triploids that are thought to be mostly sterile.
Some hybrids are definitely fertile tho.
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Here in middle Tennessee, albas are so early they don’t have any chance of pollinating the reds, unless they rebloom. There is typically a gap of 4-5 weeks from the end of the alba bloom and the start of the rubra bloom. This may be why rubras hold their own so well in the south. I think rubras are also much better adapted here.
I have confirmed that Illinois Everbearing and Gerardi are both diploid by flow cytometry. Both do have reduced fertility, but I have been told by a reliable source that both will produce viable fertile offspring.
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