What this strawberry needs is a name that says "dry and sandy"...

The University of California strawberry breeding program (the southern branch, based in Irvine) has released two new strawberry varieties, Benicia (formerly C225) and Mojave (formerly C227).

The southern California strawberry industry is kind of hurting these days, with increasing yields and increasing acreages (as well as competition from Mexico and elsewhere) pushing down prices and cutting into profit, so I'm sure these will be welcomed, though the last release from this program, 'Palomar', has not really caught on.

I've tried these varieties, when they were in limited trials, and I have to say I don't see any of them really setting the world on fire, though. The flavor was definitely better than 'Ventana', which is the current standard, but didn't exactly knock my socks off, and the fact that they're actually talking about how soft 'Mojave' is seems like a bad, bad sign. I'll take anything that pushes the quality standards above 'Ventana', which is an insult to strawberries, but since yields appear to be no higher they're not likely to be much of a fix for what ails the industry.

(And yeah, I've got a certain bias here, but I call 'em like I see 'em)

There's much more info on these in this presentation, but they're not named yet, so just look for the testing numbers (poor C226, so close to a shot at the big time).

How do I get in on this racket?

Apparently a Japanese grower is raking in big bucks for gigantic strawberries:

Berries, $841 apiece (Rockhampton Morning Bulletin)

Now, granted, it's 841 Australian dollars...that's only US$540. But still...

80 grams seems like a big strawberry, but I've seen several selections that averaged close to fifty, so I don't think it would be hard to get a variety with primary fruits of 80 grams, and at $841 apiece, one could afford to harvest the primaries and pitch the rest.

The statement about fructose is, in my opinion, off base, though. Although there is a relationship between size and sweetness, it's not a terribly strong one. Plus, fructose is not the only sugar in strawberries--in fact sucrose generally accounts for around half of the sugars, and glucose is important as well.

New strawberries from the University of Florida

I added these to the "New Cultivars" section in the sidebar a while ago, but this is the first article I've seen on the new U.F. cultivars, Radiance and Elyana:

Safeguarding Strawberries (American Vegetable Grower)

I saw plants of both these varieties last week, and I was struck by how odd a plant 'Radiance' is. It's got sort of a soft, floppy look, like it's just slightly water stressed.

Journal of Genetics

I just discovered that just about every article ever in the Journal of Genetics is available online! (I say "just about", because they appear to have missed a couple). The Journal of Genetics was the site of some of the great early articles in fruit genetics, and by virtue of being so darn old, people rarely seem to have copies of them floating around, so the fact that they are now just a click away is pretty darn cool.

I was also interested to note that the Journal of Genetics followed editor J.B.S. Haldane (yes, that Haldane) to India when he moved there in 1957--so the journal is currently published by the Indian Academy of Sciences.

Anyway, as an example of the goodies lurking in depths of the Journal of Genetics, I present one of my favorite series of papers, by C.W. Richardson. They're favorites for two reasons. First, they were some of the first attempts at serious genetics in strawberries, a crop that is near and dear to my heart. But second, and frankly more importantly, they have some of the least informative titles ever. I always hate when I have to cite them, because I always have to actually pull out the papers and look through them, because its impossible to remember which facts go with which...

A Preliminary Note on the Genetics of Fragaria (1914)
A Further Note on the Genetics of Fragaria (1918)
Some Notes on Fragaria (1920)
Notes on Fragaria (1923)*

* This last one, unfortunately, is one of the ones they seem to have missed scanning--there's a link, but no PDF.

Update: A friend of mine found the missing paper! It's been accidentally included at the end of the previous article! (Just scroll down...)

Fruit Genetics Friday #7: Plant Sex Chromosomes Part II: Strawberries

A couple weeks back, in the very infrequent Fruit Genetics Friday series, I discussed sex chromosomes in fruit, specifically papaya. At the time, the only two fruit crops I knew of with sex chromosomes were papaya and kiwi. Monday I opened my e-mail to a paper, forwarded to me by a friend who is also one of the authors, describing a very interesting development in this area:

Genetic mapping of sex determination in a wild strawberry, Fragaria virginiana, reveals earliest form of sex chromosome (Heredity)

(Unfortunately, for non-subscribers, this will just be an abstract, but I'll try to hit the good stuff).

People were excited about the discovery of sex chromosomes in papaya, because it represented one of the most primitive sex chromosomes yet found in plants. Well, it turns out that F. virginiana, one of the ancestors of our cultivated strawberry, has sex chromosomes too (counter to what I said in that earlier post, incidentally), and these are even younger in their development! They're also really unusual in how they operate. In papaya and kiwi, as well as most other plants and lots of animals, the homogametic sex is the female (as in 'XX') and the heterogametic sex is male ('XY'). This seems to be the more typical arrangement, but strawberries, oddly enough, have the opposite arrangement.

So if you recall the arrangement in papaya, you had two critical loci. One, which we'll call "F" is a suppressor of femaleness, and the other is a promoter of maleness, which we'll call "M". So the two "wild type" chromosomes (which I'll call X and Y, since it puts it in terms people are familiar with and is essentially correct, even though the terminology isn't really used consistently in plants) consist of:

f---m (X chromosome)

F---M (Y chromosome)


So a female would be XX, or (fm)/(fm), so no maleness promoted and no femaleness suppressed. And male would be XY, with the femaleness suppressed, and maleness promoted. Hermaphrodites are generally a mutation of the Y chromosome (which we'll call the Y⁺ chromosome), so that the suppression of female development ceases to function, but male development still takes place:

(f)---M (Y⁺ chromosome)

So the sexes are basically female (XX), male (XY), and hermaphrodite (XY⁺). (because the YY isn't viable, you can't get a homozygous, true-breeding hermaphrodite).

Well, turns out strawberry has a different arrangement. The roles of the genes are kind of reversed. You have a dominant promoter of femaleness (which we'll call 'G' (for "gyn-", as used in the paper)), and a dominant gene for male sterility (which the paper calls 'A', as in "andro-"). And in this case we'll use Z and W (the system from birds) rather than the XY system.

So the arrangement is:

g---a (Z chromosome)

G---A (W chromosome)

So the sexes are female (ZW) and male (ZZ). This actually fits with some old research dating as far back as the 1920's suggesting that the female is the heterogametic sex. This was backed up by Ahmadi and Bringhurst, who suggested a single locus with three alleles, F, H, and M (in decreasing order of dominance). I kind of suspect many of these single locus, three allele systems, which have been proposed in other species as well, turn out to be variations on the two locus system, like in strawberry or papaya.

Here's a cool bit: The strawberry sex chromosome is pretty primitive, and so recombination in between these loci isn't fully suppressed, and you actually get crossover between them 5.7% of the time. As a result, you can get variations, namely hermaphrodites (resulting from a G/a recombinant) or a neuter (the result of a g/A recombinant). That suggests something which is only barely functioning as a sex chromosome.

Because the sex chromosome seems to have evolved very recently, what I'm curious about is how widespread in related species it is. I think it quite likely that the other major octoploid species, Fragaria chiloensis, and its offspring with F. virginiana, the cultivated F. x ananassa, share this scheme. But do the lower ploidy strawberries?

If diploid strawberries possessed sex chromosomes previous to the evolution of octoploids, then the octoploids should have eight sex chromosomes. Having this many would probably result in a mess (although it seems to work out alright for the short-beaked echidna), and the fact that sex inheritance seems to be pretty simple suggest that if the octoploid had eight sex chromosomes, then six of them have probably ceased to function as such.

Though there may be some exceptions (there are a bunch of east Asian diploid species I'm not really familiar with) the diploids I'm aware of, F. vesca, F. viridis, and F. nubicola seem to be almost (but not quite) uniformly hermaphrodite. Yet a number of higher ploidy species in addition to the octoploids, including the hexaploid F. moschata and the tetraploid F. orientalis are at least partially dioecious. It may be that polyploidy, by creating "backup" copies of the chromosomes possessing the sex controlling loci, allows divergence of one pair into more specialized sex chromosomes.

I'd be curious to know if closely-related genera such as Rubus and Potentilla share this system. Research suggests that in both of these species, the females are the heterogametic sex. If they possessed similar sex chromosomes, that would suggest that the strawberry's sex chromosomes have remained in their primitive state for a long time, or that something about the common ancestor was prone to the development of such an arrangement.

The other, perhaps less novel, but no less cool, aspect of the paper is that it introduces the first SSR-based map of the octoploid strawberry. Including two markers linked to the sex loci!

Anyway, all told, pretty cool, huh?

Eurosemillas' secret California strawberry breeding program?

I saw this a while back and didn't say anything, but I came across this article again and thought I'd post it, because its ridiculousness amuses me:

Company from Cordoba creates five new varieties of strawberries (FreshPlaza)

Why is this ridiculous? Look at the names:

• Palomar
• Monterey
• Albión
• Portola
• San Andreas

Sound familiar? Maybe because, through sheer bizarre coincidence, the University of California has released varieties with the exact same names! What a crazy world, huh?

(Except the Spanish seem to have felt the need to put an accent mark on the "o" in Albion--kind of odd, since everyone I know puts the accent on the first syllable...)

Eurosemillas is the international licensee for all the U.C. strawberry varieties, but I'm not sure the rights involved in that include the right to claim to have actually bred the varieties. Although I suspect it pains the European ego slightly to be growing so much of American varieties.

Holy vesca, Batman!

I just stumbled across a site that offers seeds of a stunning range of Fragaria vesca (a diploid species of strawberry) varieties. I have never seen so many available in one place...it's hard enough to find at all.

Alpine Strawberries

They also have a blog, which is entirely useless and empty, but I'll link to it anyway:

Alpine Strawberries Blog

I am so going to order about a zillion varieties of these. I have 'Mignonette' germinating on a window sill right now (the first cotyledons popped up a few days ago!) and I used to have 'Alexandria' and 'Yellow Wonder' at home and Hawaii-4 in the lab, but none of these made the cross-country trip (some of them didn't even live that long...turns out vesca isn't happy outside under the Florida sun.)

For completists bent on getting their hands on every last vesca variety, you might also try 'Intensity' from Oikos Tree Crops.

Of course, you could also turn to the USDA repository in Corvallis, but try not to use that when you can buy them commercially...

Update: Strangely, the best page on the whole site, the one I stumbled onto via Google, doesn't seem to be linked to from anywhere inside, or if it is, I can't seem to find it (and the site map link is broken). So to make sure you don't miss it, here it is.

Update 2:A friend just wrote to me to warn me that his browser is giving him a "phishing" warning when he goes to the alpine strawberry site. Although I've corresponded with the proprietor and feel fairly safe that this site and the PayPal links within it are legit, I have not yet done business with them, so I can't truly vouch for it. I think it's probably fine, but I wanted to pass the info along.

'Galletta' Strawberry

North Carolina State University has released a new plasticulture strawberry, 'Galletta'. I swear this thing was released months ago, but I just stumbled across this thing, and since I haven't been posting I might as well go along with the idea that it's new. For those of you keeping close track of such things, I apologize if I'm horribly behind the times.

NCSU has a fairly long history of strawberry breeding, but I haven't heard too much about the varieties in recent years. Their releases have been a mix of varieties for plasticulture and those for the older matted row system. I remember when the earlier plasticulture variety, 'Bish', was released, but I haven't seen too much of it since.

North Carolina has a decent-sized strawberry industry, but most of it is for local consumption. Despite a number of local varieties, the bulk of the industry seems to focus on California and Florida varieties.

'Galletta', as the story explains, is named for Gene Galletta, who worked as a small fruit breeder at both NC State and the USDA. He died in 2002.

Anyhow, without further ado:

North Carolina Releases New Strawberry Variety (Southeast Farm Press)

Why not drink your berries?

Sure, everyone knows that strawberries are both good and good for you. But you know what else is extra good and extra good for you? Apparently, strawberries with booze! (Sure, there's all those details about detrimental effects of alcohol. But if you'd have been drinking anyway, why not drop a few strawberries in there and make yourself feel a little better about it?)

Update: Reader bhive1 makes the problematic observation that the article in question doesn't actually say any of those things. (See comments). Luckily, here in Blogger-land we are untroubled by journalistic ethics that might require us to check if the things we report are actually true.

'Wendy': a new strawberry cultivar

Despite the fact that I work with strawberries these days, I seem to write almost nothing about them. I'm not sure why that is. Anyway, just came across this, and figured I might as well continue with the cultivar announcements:

Wendy, A New Early Season Strawberry

This is from the Kentville, Nova Scotia breeding program, a well-established program which has produced a number of cultivars I know very little about, aside from their names. There's a pretty serious divide in the strawberry world, between the Florida-California axis down here and pretty much everyone else, and we don't really grow the same cultivars or (in the case of Florida) even compete with them in an substantial way.

Breeding with Fragaria moschata

Especially since I've had a few enquiries lately about F. moschata in the past week or two, I thought I'd share this article with you folks:

Berried Treasure (Smithsonian.com)

It covers the efforts of Harry Swartz (an interesting character) to incorporate the aromatic characters of the musk strawberry into a commercial cultivar, and it's by David Karp, another interesting character (and I mean that in the nicest way) who I had the pleasure of talking with at fairly great length while he researched the article. He's promising a more science-heavy version of the story in an upcoming article, as well as a future book. Karp has a great number of interesting writings about fruit out there...I'm in a bit of a rush now or I'd link to them, but a little Googling should turn up lots, and I think I've linked to several in the past...).

I'm off to water my plants and check out my strawberry hybrids!

Sorbus: Genus of Easy Virtue

I've been poking around for a while, looking things up here and there on the topic of intergeneric crosses. One thing you learn quickly when you start paying attention to plant breeding is that the rules you learned in high school biology about what will reproduce with what go straight out the window. Crosses between species, supposedly not possible, are pretty much the bread and butter of most breeding efforts (to be fair, the real textbook definition of species was 'reproductive isolation', which doesn't mean they can't reproduce, just that they probably won't for whatever reason...but I'm not betting your eighth grade science teacher knew or expressed the difference). That restriction sort of gets bumped up to the next level. In general, you can't make crosses between genera.

In general.

Species and genera are, of course, made by Man, not Nature, and Nature seems to have this thing about finding exceptions to the rules Man has tried to come up with. Intergeneric crosses do work, sometimes. In my yard right now, I have a little plant that looks quite a bit like a strawberry, called 'Lipstick'. Unlike strawberries, however, 'Lipstick' has bright pink flowers. Really quite attractive, though I haven't had fruit yet to attest to it's worth in that respect. It's a cross between Fragaria x ananassa, the cultivated strawberry, and Potentilla palustris, a related species for sure but not a member of the same genus.

Fragaria and Potentilla are both members of the Rosaceae, a family of plants which contains maybe a majority of the fruit crops out there (and yes, as you may have guessed, roses, too). A number of the genera out there are willing to play a little fast and loose with the rules. In addition to Potentilla, strawberries have been crossed with Duchesnea indica, the "false strawberry", and with raspberries. Luther Burbank, perhaps the greatest American fruit breeder (though not a scientist by any means) was perhaps the first to make this cross, which resulted in some rather odd plants.

Burbank was one of the great makers of wide crosses. He crossed apples with pears, apples with rose, pears with quinces, strawberries with dewberries, etc. The Russians were also big on this sort of thing. Partly because their climate is almost universally horrible (I said "almost"...yes I realize parts of it are just lovely), Eastern Bloc breeders have always seemed a little more anxious than most to make weird crosses. One genus that seemed particularly amenable to their fiddling was Sorbus, or mountain ash.

Probably one of the better known intergeneric crosses in the family is 'Shipova', a cross of mountain ash and pear from Yugoslavia. It's available commercially here and there, and is actually pretty good from what I've heard. Russian breeder Ivan Michurin created 'Ivan's Belle', a hybrid between mountain ash and hawthorn, also available here. Hybrids of Sorbus exist with Cotoneaster, Aronia, Mespilus (medlar), and Amelanchier (serviceberry), and it's tempting to wonder how many other obscure ones might work if some one tried them enough. Some of the hybrids, like Sorbaronia have been found occurring naturally!

Ultimately, though, the successes of intergeneric crossing have been few and far between, though its promise to any breeder is obvious: opening up an entire new pool of germplasm. If only it was that easy.