Reproductive isolation is a better way of thinking of species differentiation, of which hybrid sterility is just one possible mechanism. Populations can be prevented from interbreeding through many mechanisms; for example, geographic isolation (they grow in different areas), temporal isolation (they bloom at different times), mechanical isolation (for example, the pollinator for one species can’t reach the stigma of the other species), etc. For many species, multiple mechanisms are at play.
In flowering plants, sterility of hybrid offspring is probably a less important factor than in animals, mammals in particular. That said, it’s fairly common for plants to undergo chromosome duplication, generating a new population that can no longer produce fertile offspring with its neighbors. The same process can also restore fertility to an infertile hybrid, giving rise to a new species of hybrid origin. You can also have situations such as “ring species” where neighboring populations are interfertile, but the populations at opposite ends of the geographic range are too distantly related to interbreed, although this is more common in animals.
Today I finished the summer pruning of the mulberry cultivars (all in pots). The most aggressive of them by a long shot has been the AgriStarts Dwarf Everbearing. None of them turned out to be M. nigra except two ‘Persian’ I recently acquired from One Green World (not shown).
Are there any such hybrids available? Have their fruits been evaluated for quality? A berry with the flavor of nigra and the ease of care & propagation from alba would be quite a treasure.
I think they meant it was likely alba x rubra. I actually think it may be straight alba, or very nearly so. It resembles mill run albas in every respect except that it has great flavor with pronounced acidity- a rare thing in alba it seems
I noticed that some years back a number of Morus accessions were listed as x nigra hybrids. Its pretty clear they didnt do much dilligence at that point. They seem to be correcting that now.
Im curious what youre take on Morus bombycis is @Richard . Just another alba? I have a sizeable tree. Its morphology seems pretty unique
@hobilus
When Howard Frost left UCR, Oscar moved into his house on a culdesac at the university, which was later named Frost street. Small world.
There’s no doubt that Oscar crossed something to create that plant, but it’s unknown if it was true M. nigra. He was an excellent caretaker of plants and the university gardens but I’ve no idea about his horticultural knowledge. Given his address, you’d think he was an expert. A $25 ploidy test would solve this query.
There’s a lot of contention about Morus bombycis. GRIN declares it a synonym of Morus australis. There’s a paper describing it as an important browsing food for elephants in Africa. Other overseas authors describe it as M. alba. Kew declares it as a synonym of Morus indica which GRIN also states is a synonym of Morus australis.
interesting to hear some of the backstory. I had no idea of its origins. Id love to know if you come up with any more details- gossip or otherwise. Was the variety bred during his (Oscar’s) tenure there? What year might that have been?
Now that I think about it, the leaves are distinctive in shape. I know this isn’t necessarily all that telling in Morus, but Oscar makes only 3 lobed palmate leaves IME.
The fruit is excellent. The first few years i wasnt as smitten with it but now that the trees have sized up, the size and intensity of flavor have greatly increased.
Amazing if thats true, since its such a hardy and rugged tree. I grew some cuttings of it (‘contorted’ that is) in a nurse bed and had an impossible time digging them out the second year. The roots had gone at least 8 ft in all directions- like perfect 1/4” diameter yellow ropes! The sex is very unstable, which isnt that odd in itself, but someone here on the forum (as you probably saw) says that the fruit suddenly went from pea sized to over 1” long. That almost strikes me as polygama dioecious territory there.
you have to give it a few years. lucille whitman describes it as perhaps her favorite I believe, and she grows some true nigras. I didnt agree until a couple of years ago. Pot culture might limit it somewhat too, though I was able to grow some respectable DMOR9 fruit size and flavor-wise in a 15 gallon container.
Yes, like most cultivars. For the black cultivars, to date I’ve only rated M. macroura as excellent in taste. My favorite cultivar here is I.E. for the length of harvest.
Oscar so far is my favorite too. Mostly because it grows well in a 6a marine environment ( hot-cold and wet-dry with nothing in between). Even many so called hybrids with rubra have dieback in the winter but Oscar has none so far. Rubra grows all over around here
Most are not that good but I did find a couple trees with decent tasting fruit. One I would rate as excellent. But that tree is dying. I should try to save it via grafting. The mother tree was damaged from prolonged flooding.
