'Ohio Everbearing' black raspberry

When I first heard about the 'Explorer' primocane-fruiting black raspberry, I was convinced it was the first such variety. As it turned out, I was wrong, as numerous such cultivars existed by the turn of the century, although very few ever achieved any importance.

An exception to this, however, is the very first primocane-fruiting black raspberry, 'Ohio Everbearing'. Although not a major commercial success, this variety remains significant as one of the very first cultivated American selections of Rubus, and probably the first named black cap (given the abundance of wild black raspberries, it probably took an unusual trait such as fall-fruiting to warrant a name and cultivation).

'Ohio Everbearing' was discovered in the wild by Nicholas Longworth. Longworth was a self-made millionaire banker from Cincinnati, which in 1804 when he moved there was almost the western frontier. Although his family remained important in local and U.S. politics, and he left an estate worth $10 million when he died in 1863, Longworth's most lasting legacy is as a horticulturist. Often called "The Father of American Viticulture" (a title sometimes applied to his correspondent, John Adlum), Longworth was an avid collector and disseminator of fruit varieties. He championed first the 'Alexander' and then the 'Catawba' grapes and introduced at least one strawberry of his own creation.

Everbearing Black Caps listed in Fred Card's Bush Fruits (1920) American Everbearing Cottier Everbearing [Grigg's] Daily Bearing Earhart Everlasting Every Day Fadely General Negley Hixon's Everbearer Kagy Everbearing King of Cliff's Lum's Autumn Black Raspberry Lum's Yellow Canada Miller's Daily Bearing Munson's Everbearing Mystery Ransom's Everbearing Sweet Home Wonder

Longworth found the original 'Ohio Everbearing' somewhere in central Ohio, where he had retreated in the fall of 1832 to escape cholera outbreaks in Cincinnati. Despite it being September or October, he "found a raspberry in full bearing, a native of our state, the only everbearing raspberry I have ever met with. I introduced it the same winter into my garden, and it is now cultivated by me in preference to all others, and my table is supplied from the beginning of June to frost." Although the variety struggled somewhat on the gravelly soils of his fields, it performed better on clay soils, and Longworth was convinced it might have a future, especially in England. He sent plants there, as did A.J. Downing, though it seems have had little impact there. The legendary Dr. Hogg did note its existence in England as late as 1884, when it was probably gone in the U.S. (Incidentally, in my hypothetical strawberry-themed band, my stage name was going to be "Dr. Hogg").

Longworth was among the foremost horticultural authorities of his day, and an everbearing variety of raspberry would seem to be a major development, so it seems like it should have caught on, but while he and a few others cultivated it commercially, it never seems to have. Black caps, in general, have never attained commercial prominence, perhaps because they were foreign to European tastes, and thus unable to compete with the more familiar red raspberries. Many other everbearers, such as 'Grigg's Daily Bearing', 'Miller's Daily Bearing', and 'Lum's Autumn Black' were selected from its seedlings. (Indeed, I rather suspect most, if not all, of those everbearing black raspberries that appeared in the second half of the nineteenth century may claim it as an ancestor. Most of these seem to originate in Ohio, Kentucky, Indiana, or Illinois, the areas nearest the discovery and commercialization of Longworth's variety).

Primocane-fruiting black raspberries, revisited

I was pleased to find a note in my e-mail this morning from Pete Tallman, developer of the 'Explorer' black raspberry. I mentioned 'Explorer' two years ago (have I really been at this that long?) as an exciting development in a crop in which very little breeding has been done (and, frankly, very little breed success obtained).

Unfortunately, 'Explorer' has not really been a success. I've seen it twice, both times under tunnels: once in Pennsylvania, where it had virtually no fruit and a powdery mildew problem, and another time in upstate New York, where the plants looked healthier but fruit set was still poor, though better. I was rather disappointed, as I'd been pretty excited about the thing.

Tallman's message today explains a big part of the problem: 'Explorer' is not self-fertile. Apparently his field featured things that flowered and provided adequate pollen at the right time, so the problem was never evident under his conditions. This fits with what I saw: the tunnel at Penn State where I saw it had, if I recall, only one other variety in it, while the one in NY, where it had at least some fruit, had several.

While unfortunate, this isn't entirely shocking, as self-incompatibility is fairly common among wild, diploid Rubus, and 'Explorer' is not far removed from the wild source of the primocane-fruiting trait that Tallman discovered. (Not surprisingly, the trait hasn't persisted very long in most commercial types).

Anyway, all is not lost. Tallman has selected another primocane-fruiting black raspberry, dubbed PT-2A4, which does pass the self-compatibility test, and has other desirable traits compared to 'Explorer'. As he describes it:

"Compared to Explorer, the PT-2A4 berries are larger, higher drupelet count, and smaller seeds. PT-2A4 holds my all-time record for a single primocane black raspberry at 3.82 grams. Admittedly, that's a max berry, not an average, but I gotta track something, and average isn't awfuly interesting. Maybe with a little fertilizer this year I could break 4 grams. Unfortuantely, PT-2A4 hasn't captured the reduced thorniness of Explorer, so there remains further breeding down the road to see if I can tie that trait back in again."

He also included a link to his website, which includes a page for PT-2A4.

Okay, so I'm not all-knowing.

A few posts ago I mentioned a primocane-fruiting black raspberry, and said that I thought this was the first one out there. Apparently I was wrong, as a search of the Corvallis USDA repository turned up PI 553754 - 'Black Knight'. And that, in turn, was a seedling of something called 'Johnson Everbearing', which from the sounds of it was likely primocane-fruiting too.

The online record says it's from Illinois and was introduced in 1973, apparently by an H. Boll. Beyond that I know nothing of 'Black Knight', and even less about 'Johnson Everbearing', but I'd be interested to hear if anyone else knows anything.

That said, some of my excitement over the 'Explorer' black raspberry was warranted, in the sense that this is almost certainly a new source of the trait (since it was found in wild plants) and may have a different mechanism or inheritance.

'Explorer' primocane fruiting black raspberry!

I could be wrong, but I believe this is the first instance of primocane-fruiting I've heard of in black raspberry.

'Explorer' Black Raspberry

Pete Tallman, by the way, is a private grower/breeder from Colorado. From what I've heard, he's got a very impressive program, and he appears fairly active in NAFEX.

For those of you wondering what primocane fruiting is, and why it's a big deal, here's the basics:

The above-ground portions of brambles (Rubus species) are biennial. Normally, canes grow one year, overwinter, then produce fruit and die. During their first year, they're called "primocanes", during the second, fruiting, year, they are called "floricanes". Primocane-fruiting cultivars, however, deviate from this plan by producing flowers at the tips of their primocanes (portions of the primocanes that flower die and do not flower the next season, so such canes are not flowering twice). This is important for a couple of reasons: a) It removes the requirement to overwinter canes and simplifies care. Because fruit is being borne on first year canes, after the fruit is harvested the plants can be mowed down and allowed to grow back completely each year, and as a result there's less danger of damage from severe cold, because the roots and crowns are less susceptible to damage than the canes. b) It extends the harvest season. Generally, the existing canes from the previous year flower in the spring or early summer, while the primocanes are growing. Once the primocanes have grown, they begin flowering, generally considerably later in the season, sometimes continuing until frost. This can provide new opportunities and markets for growers.

Primocane-fruiting red raspberries have been around for a while, and make up a significant proportion of the industry. For reasons that aren't clear to me, they're frequently called 'fall-fruiting raspberries', yet one never hears 'fall-fruiting' applied to blackberries, despite a similar trait.

Primocane-fruiting blackberries are a relatively new development. The first two cultivars, 'Prime-Jim' and 'Prime-Jan', were released recently by the University of Arkansas, and more are in the pipeline. The trait was introduced from a single source, a wild diploid selection called 'Hilquist', which was weakly primocane-fruiting. The trait is a single recessive gene, but in the tetraploid blackberry breeding program managed to go unnoticed for many years, until it was developed by Dr. Jim Moore and his graduate student (now Dr.) Jose Lopez-Medina, and later Dr. John Clark. Researchers in Europe have also been working on transferring the raspberry primocane-fruiting trait into blackberries, but to my knowledge no cultivars have resulted from this effort.

So far as I can remember, however, I hadn't heard anything about primocane-fruiting black raspberries. Although theoretically crossable with red raspberries and blackberries, this is frequently too difficult to be practical (purple raspberries, as you might have suspected, are hybrids of red and black raspberries). On top of this, the native germplasm base has been shown to be surprisingly uniform at the genetic level, limiting the breeding potential. So the discovery of a new trait in black raspberry is rather exciting in general.

New Black Raspberry Virus Discovered

Robert Martin, a USDA pathologist in Oregon, has described a new virus believed responsible for the growing scourge of "black raspberry decline". The disease has serious repercussions, markedly shortening the lifespan of plantings and reducing yields. Decline diseases are frequently the result of mixed infections of many viruses, making it difficult to pin down the effects of any one of them or precisely define symptoms. This new bug, however, is sufficient to cause disease all by its lonesome, and it appears readily transmitted by aphids. It's been given the catchy name "Black Raspberry Decline Associated Virus" (just rolls right off the tongue, doesn't it?), or "BRDaV".

One thing that became disturbingly clear when I was working with brambles (in my case blackberries), is that practically all of them are all but dripping with viruses. Pretty much every plant you look in. Frequently you can't see anything resembling symptoms, but they're there, lowering vigor, reducing yield, making the plants that much more susceptible to stress. And, if you're a nursery owner, just waiting to stand in the way of you shipping your plants out of state. The usual solution is to use meristem culture (the meristem region, where plants do their active growth, is comprised of cells with few or no virus particles, so plants grown from this small patch of cells will be clean). The problem is, of course, in a world chock-full of Rubus viruses, how long do they really stay clean? And do we really want to know?