More Than One Way to Skin a Kumquat

My recent piece on citrus seems to have struck a chord, based on the multiple comments and the fact that GenomeWeb's blog picked up on it as well. That's all very gratifying, tbut also stirred me to notice what I had missed on the subject. No, not the obvious point that getting some genome sequences is just a tiny first step to my grand bioengineering dream. And not what the TIGS review pointed out, that American markets in particular have tended to favor uniformity over quality or novelty (though perhaps that is changing, at least in high-end markets). Nope, what bugs me now is missing the obvious about kumquats.

Now, as I mentioned, they're hard to find. I checked some mail order places and the seasons apparently vary depending on where they are grown. But at Christmas time I could find only one market -- and I checked a half dozen -- which was selling them. Even the same high end chain that sold them next to work didn't offer them at the outlet nearest my home. So, don't be embarassed if you've never tried one.

The first beauty of a kumquat is you eat the whole thing -- skin and all (it is advisable to spit the pip). But the second beauty is within that -- the two very different tastes. The skin is thin but very sweet, whereas the flesh is tart.

Natural kumquats therefore are a binary package, and an unusual one. I'm trying to think of other fruits eaten skin-on for which the skin has a distinctive and pleasant taste. I eat lots of fruit skins, but most are just texture & roughage as far as I can tell. Concord grapes are an obvious exception -- I'll confess to swiping them from my neighbor's trellis growing up. The pulp is gteen and much like a seedless green grape in taste (but decidedly NOT seedless!) whereas the skin has the delicious Concord-ness to it. Many other grapes are probably similar. Certainly the winemakers use skin-in or no skin as a point of control over taste.

Now, with all citrus the skin and pulp can have very different aromas. Orange zest adds a distinctive flavor which is different than adding orange juice to a recipe. With a bit of genetic sleuthing (GFP limes?), the promoters responsible for specific production in skin and flesh can be worked out. And then the engineering can get another dimension -- different tastes in kumquat skin and pulp.

Clearly what I have in mind is a lot of genetically engineered fruit, which I will be happy to taste. GMO foods have not met much acceptance, but as some have pointed out before a significant issue is that most engineered traits have been to benefit producers (pest / pesticide resistance) with no benefit to the consumer beyond price. Early attempts at longer shelf life tomatoes and carrots flopped, but that's still more of a benefit for the producer than the consumer. Nutritionally-augmented foods (e.g. "golden rice") address nutritional needs which Western activists don't face.

Present something really novel and exciting in terms of flavor experience, and then you'll see a real separation of those who are truly committed to a no-GMO purity and those who can be tempted away. Furthermore, simply rewiring existing citrus biosynthetic pathways would dodge some of the other arguments raised against GMOs, in terms of introducing allergens or such.

It is a bit of optimistic to think I'll ever see a line of flavor-augmented mix-and-match kumquats. But if anyone starts making some, I'll be happy to volunteer for the taste testing squad.

Celebrating Citrus

I've been on a citrus kick at work lately, trying out different varieties I picked up at one of the adjacent grocery stores (curiously, we're sandwiched between 2). When I was growing up I think I knew only seeded oranges, navel oranges, tangerines, tangelos, grapefruit, lemons and limes. Through some combination of better awareness and better availability, there's a lot more I can find. I gained some notoriety this week by bringing a pummelo to a breakfast meeting; if you haven't seen one, they make grapefruit look small. Tastewise, it's a bit milder and a bit sweeter than a grapefruit.

A lot of this is seasonal, as I've been finding. Kumquats are a nearly perfect desk snack -- completely neat except for the need to spit the pips -- but seem to be available only around the New Year -- and then only in a few stores. Amongst the treats currently available are clementines -- almost as good a desk snack as kumquats though you do need to peel them and some wonderful non-orange oranges. Cara cara oranges turn out to be delightfully pink on the inside whereas the blood oranges are precisely named -- after one knife slip I found myself searching my skin in vain for the source of the red spots on the table.

What I can find in the store is still just a tiny sample of all the citrus known to exist. My brother sent me a New Yorker article on professional flavorists which mentioned many more, including pummelos with quite foul-smelling rinds but yet another delicious flavor of pulp.

Just after the turn of the century, a very good review of citrus genetics was published in Trends in Genetics. The molecular story appears to point to all this wonderful diversity originating from three wild species. Amazing! It gets stranger when you delve into the reproductive biology of citrus -- not only can they be propagated sexually or by cuttings, but they are quite adept at apomixis, the development of a new individual from an unfertilized ovum.

There is, of course, a citrus genome project, hosted at the JGI. And perhaps more predictably, I'm a bit impatient for completion. As the rationale page explains (and from which I've stolen the wonderful image of citrus diversity above), the sweet orange genome is only 382 Mb. When the new HiSeq and SOLiD instruments come on-line, they could sequence several individuals at 40X coverage in one run.

What I'd really like is to have the genetic blueprint for all those wonderful flavors and colors in order to repackage them. Keeping in mind, of course, that some useful characteristics (such as seedlessness) aren't simple traits but products of karytype (I would love a fully seedless kumquat!). Imagine if you could have a whole series of clementine-like fruits, with the size & easy peeling characteristics but with the whole range of other citrus flavors and colors genetically grafted in -- cara cara clementines and blood clementines and ruby red clementines and perhaps even sweet lemontines and key clemenlimes. What a wonderfully healthy snacking then!

A Blight's Genome

Normally this time of year I would be watching the weather forecasts checking for the dreaded early frost which slays tomato plants, often followed by weeks of mild weather that could have permitted further growth. Alas, this year that will clearly not be the case. A wet growing season and commercial stock contaminated with spores has led to an epidemic of late blight, and my tomato plants (as shown, with the night photography accentuating the horror) are being slaughtered. This weekend I'll clear the whole mess out & for the next few years plant somewhere else.

Late blight is particularly horrid as it attacks both foliage and fruits -- many tomato diseases simply kill the foliage. What looked like promising green tomatoes a week ago are now disgusting brown blobs.

Late blight is caused by Phytophora infestans, a fungus-like organism. An even more devastating historical manifestation of this ogre was the Great Irish Potato Famine and remains a scourge of potato farmers. Given my current difficulties with it, I was quite excited to see the publication of the Phytophora infestans genome sequence (by Sanger) in Nature today.

A sizable chunk of the paper is devoted to the general structure of the genome, which tops out at 240Mb. Two related plant pathogens, P.sojae (soybean root rot) and P.ramorum (sudden oak death) come in only at 95Mb and 65Mb respectively. What accounts for the increase? While the genome does not seem to be duplicated as a whole, a number of gene families implicated in plant pathogenesis have been found.

Also in great numbers are transposons. About a third of the genome are Gypsy-type retrotransposons. Several other classes of transposons are present also. In the end, just over a quarter (26%) of the genome is non-repetitive. While these transposons do not themselves appear to contain phytopathological genes, their presence appears to be driving expansion of some key families of such genes. Comparison of genomic scaffolds with the other two sequenced Phytophora show striking overall conservation of conserved genes, but with local rearrangements and expansion of the zones between conserved genes (Figure 1 plus S18 and S19). Continuing evolutionary activity in this space is shown by the fact that some of these genes are apparently inactivated but have only small numbers of mutations, suggesting very recent conversion to pseudogenes. A transposon polymorphism was also found -- an insertion in one haplotype which is absent in another (figure S9)

A curious additional effect shown off in two-D plots of 5' vs. 3' intergenic length (Figure 2. Overall this distribution is a huge blob, but for some of the pathogenesis gene classes are clustered in the quadrant where both intergenic regions are large -- conversely many of the core genes are clustered in the graph in the "both small" quadrant. Supplemental Figure S2 shows rather strikingly how splayed the distribution is for P.infestans -- other genomes show much tighter distributions but P.infestans seems to have quite a few intergenic regions at about every possible scale.

The news item accompanying the paper puts some perspective on all this: P.infestans is armed with lots of anti-plant weapons which enable it to evolve evasions to plant resistance mechanisms. A quoted plant scientist offers a glum perspective

After taking 15 years to incorporate this resistance in a cultivar, it would take Phytophthora infestans only a couple of years to defeat it.

. Chemical control of P.infestans reportedly works only before the infection is apparent and probably involves stuff I'd rather not play with.

A quick side trip to Wikipedia finds that the genus is a pack of blights. Indeed, Phytophora is coined from the Greek for "plant destruction". Other horticultural curses from this genus include alder root rot, rhododendron root rot, cinnamon root rot (not of cinnamon, but rather various woody plants) and fruit rots in a wide variety of useful & yummy fruits including strawberries, cucumbers and coconuts. What an ugly family tree!

The Wikipedia entry also sheds light on why these awfuls are referred to as "fungus-like". While they have a life cycle and some morphology similarities to fungi, their cell walls are mostly cellulose and molecular phylogenetics place them closer to plants than to fungi.

So, the P.infestans genome sequence sheds light how this pathogen can shift its attacks quickly. Unfortunately, as with human genomic medicine, it will take a long time to figure out how to outsmart these assaults, particularly in a manner practical and safe for commercial growers and home gardeners alike.


BJ Haas et al (2009). Genome sequence and analysis of the Irish potato famine pathogen Phytophthora infestans Nature : 10.1038/nature08358

Cilantronomics

We had dinner last night in one of favorite local eateries, a wonderful little Mexican place in a neighboring town. When I sat down, my eye was drawn immediately to my sort of dish -- one with a rich sauce combining the tang of tomatillos with the zing of cilantro. I picked well.

I really do love cilantro. Despite an extensive garden growing up, it was only in my adult life that I encountered this herb. I've been making up ever since. It works well in so many situations, not only in Mexican but also a lot of Asian cooking. The excellent Tibetan buffet in Central Square uses it extensively, particularly in a salad that works equally well before the meal as after, with the bite of cilantro contrasting with sweet cherry tomatoes and mango chunks. I even have a pot of it on my desk, which I share with my neighboring cilantrophiles.

However, not everyone loves cilantro. And it isn't just some folks might not like that little edge -- no, for some it tastes awful. Rather than some herbal bite, they taste soap. Or weirder. What other herb has its own http://www.ihatecilantro.com/?

Is it genetic? Alas, there has been a dearth of research on cilantro tasting -- indeed, it doesn't seem to rate an OMIM entry. There is a compound called PTC which is known to untastable by some, including this correspondent, and is genetically linked (my father can taste it; haven't surveyed the rest of the clan). With the help of some research by one of my office neighbors (and fellow cilantro fan), I did learn that 23andMe includes cilantro taste in their questionnaire. It isn't clear whether the other public and private genome projects are tracking this key phenotype.

Okay, I jest a bit. But while the ability to taste cilantro, or PTC, or the host of other innocuous traits which are staples of grade school genetics labs (e.g. widow's peak, hitchhiker's thumb, attached earlobes, etc) aren't exactly critical to understand, they will be interesting to understand. Widow's peak doesn't change someone's life, but to understand it is to understand a bit more about how patterns are laid out. The sciences of smell and taste have advanced tremendously over my lifetime; a whole new taste was found! Identification of smell receptors (recognized by a Nobel) and taste receptors have given great insights -- but we still understand very little.

Are there practical applications for smell & taste research? Of course. But to me the most interesting part is to figure out how it works. PTC doesn't seem so complicated, as the test paper doesn't have any flavor other than paper. But cilantro seems like a much more complicated, and interesting, question. Why does it taste bad rather than just not taste?

Is there an underlying soapiness which I just don't taste? In this case, tasters have a receptor for the magic compound (which is what?) and non-tasters simply lack it. Or does a different receptor bind the compound in tasters, in which case they have a gain-of-function mutation? Or, perhaps they have a partial loss of function -- there are a number of known compounds with concentration-dependent odor, probably due to differential binding to different receptors. In other words, at low concentrations these compounds bind to high-affinity receptors (yielding one perception) and at high concentrations some additional one Or, perhaps a partial gain of function in the non-tasters -- the same model could apply.

No, I wouldn't recommend basing an R01 application on the science of cilantro taste. Nor is it likely to tease a few million from some VCs as the core of a business plan. Cilantro haters will probably never have the option of genetic therapy to alter their perception. But it is still an interesting scientific question, and I look forward to personal genomics shedding some light on it.

Laying the groundwork for the one ton tomato

Somewhere in life I've heard a children's/novelty song about a one ton tomato; eventually (if I remember correctly) it ends up as a similar quantity of ketchup.

Nearly half-ton pumpkins show up pretty regularly at the big agricultural fairs every fall, but tomatoes aren't in that league. But, the difference between an ancestral tomato (small berries) and a multi-pound beefsteak is nothing to sneeze at. Domestication has made great strides.

A paper last month in Nature Genetics laid out part of this process. Interestingly, there are two different developmental processes that have been utilized to enlarge tomatoes. A tomato fruit is composed of multiple subunits, the carpels. One change has increased the number of cells per carpel by tinkering with the cell cycle -- a much more delicious change than what a similar process will yield in a person. The new work details the genetic change which increased the number of carpels.

Of course, of interest is how universal these mechanisms are. Most domestic fruits are greatly enlarged over their wild counterparts -- though perhaps raspberries show very little enlargement & blueberries it is a small multiple. On the other end are those monster curcurbits at the fair and their watermelon cousins.

But getting back to the title. Now the question is whether these mechanisms have reached their biological maximum or simply what a few mutations can do (there are also practical considerations, such as the stem strength required to support larger tomatoes). Or, can we use this new knowledge to bring up the laggards -- or figure out why there are no fist-sized raspberries or basketball-like blueberries? A strawberry the size of my dog? Of course, purely economic forces might lead to the fruits commanding the most money per unit weight -- perhaps pomegranates will have an order of magnitude more seeds! Healthy for you -- so long as you watch where you eat them.

Do you prefer tomatoes or tomatomatoes?

My print version of Science showed up and the cover looks more like some foodie rag. I guessed wrong at first that they were peppers -- right family, wrong fruit. Nope, they are tomatoes.

I like growing tomatoes, though end-of-season output far outpaces my ability to consume them. It's fun growing different varieties, as there are so many different shapes, colors, sizes and flavors. Of course, all of the yard grown ones whip the store cardboard versions. On the other hand, it's hard to grow them around here this time of year -- though I once did have a rampant cherry tomato plant in the tearoom at Harvard (with bunsen burner supports & such staking it up!), though I didn't get any tomatoes until it dawned on me that I needed to play honeybee for the blossoms. When I interviewed at Millennium, someone had a tomato plant growing in the sequencing area (I'm sure the lab safety folks wouldn't let that happen any more!).

Anyway, the Science cover is for an interesting paper showing that a local gene duplication led to elongation of the fruit in one variety. Longer genes, longer fruit! The duplication is recent and was triggered by a retrotransposon, which altered the transcriptional environment around the gene. Cool!

Slow can be good

My usual mode of commuting is to walk to a station, take a train into Boston & then things get interesting. The biotech zone of Cambridge is not particularly near North Station, nor are there truly convenient transit connections.

There is a little blue bus sponsored by a consortium headed by MIT which starts at North Station & ends at my office. It's a good option, with a few caveats. First, Codon doesn't belong to the consortium (nor will they take us, we're too small), so it's $1 a ride. That adds up over a week. Second, the route maximizes coverage of employers over minimizing travel time, so other options can beat the bus, especially if you aren't in sync. Third, one needs options when the bus is running late or has just been missed.

For the part of Cambridge I'm now based in, any reasonable option is centered around the Red Line, but will also involve a bit of walking. Since the streets are in a pretty ordered grid in Cambridgeport, and we're a few blocks in each dimension from the subway station, there are a variety of reasonable routes.

The big advantage to walking is that you see things you would miss at the speed of a car or even the bus. Everything is closer & you have more time. I like spotting dogs & cats and looking at the details of gardens. There is one crazily cut & painted fence which I pass routinely, whose various designs & inscriptions could keep me interested for months.

Today I stumbled into an ethical dilemma: is it okay to taste the raspberries when someone's canes are sprawled through the fence & onto the public sidewalk? I resisted, but not by much. It was also a big surprise to find that Altus has a peach tree in their parking lot, which is laden with peaches. There's also a few grape arbors around, so if you know the right way to walk this time of year one can find the wonderful aroma of overripe Concords.

By far the biggest pleasant surprise I've ever had in the neighborhood happened a year or so into my Millennium career. I was walking from Fort Washington (a building now entirely occupied by Vertex, which at the time subleased it to MLNM), in a foul mood from the meeting which had just ended. I was pretty much staring at the sidewalk directly in front of my feet when a jarring thought came from my peripheral vision. Did I really just see a chicken? Sure enough, the little garden had 2 or 3 beautiful poultry strutting & scratching. I saw them there off-and-on for several years, but I haven't seen them for a long while so I assume they're gone. I really do miss the Cambridge Chickens.

King of the Migrators

I've been lucky enough lately to see a number of monarch butterflies -- or one of their imitators, which I can't keep straight from monarchs nor can I keep straight which kind of mimics they are. I enjoy seeing any butterflies, which is why it pains me that I see them so rarely in my own yard. Despite nearly zero pesticide use & plantings of all sorts of host and nectar plants, neither this house nor the previous one has seen many butterflies -- lots of dragonflies & bumblebees (and far too many mosquitos), but no butterflies.

Monarchs are amazing creatures on many scales (including their own scales!), but perhaps most amazing is their migration -- each year they schlep off to Mexico for the winter. Most amazingly is the fact that the monarchs which fly south for the winter clearly are homing in on a location they have never before visited -- it was their ancestors a few generations back who flew back. How they do this is still being worked out, but clearly the core of the guidance information must be inherited. Environmental triggers are apparently critical as well; the Wikipedia article notes that monarchs which have taken up residence in mild climes such as Bermuda do not migrate.

I once had an amazing monarch experience. We were going into the city one fall day, and I noted on one of the parkways a number of monarchs flitting across. While we waited for the Orange Line at Wellington, monarchs seemed to pass down the track at a rate of one every half minute or so. For once I didn't mind the long wait for a weekend train. Perhaps it should be rechristened the Orange&Black Line?

As I mused before, one interesting question is how structured are these populations. Are the monarchs I see this year mostly descendants of monarchs who summered here last year, or is everything scrambled? Of course, my solution to this is simple: sequence! With sequencing cheap, one could survey a lot of monarchs (perhaps from museum collections) to find a pool of polymorphisms, which could then be typed on even larger numbers of specimens using chips, directed sequencing or other SNP typing methods. One pleasant side-product would be a draft genome of the monarch.

You say tomasil, I say bamatoe ...

There are some food combinations which reoccur frequently in the culinary arts. The pairing of basil and tomato is not only a dominant part of many Italian dishes, but is a great way to add zing to a BLT (or, if your vegetarian or keep kosher, to have a B for BL). Conventionally this is done by separately growing basil and tomato plants, harvesting the leaves and fruits respectively, and co
mbining them in the kitchen.

An Israeli group has published a shortcut to the process at Nature Biotechnology's advance publication site. By transferring a single enzyme from lemon basil to tomato, the authors report significantly altering the aroma and flavor of the transgenic tomatoes.

If you aren't a gardener, you probably haven't run into lemon basil. There are a whole host of basil varieties with different aromas and flavors, with some strongly suggesting other spices such as cinnamon. Basil is a member of the mint family, many of which show interesting scents. Look down your spice rack: many of the spices which are not from the tropics are mints: oregano, thyme, marjoram, savory, sage, wild bergamot, etc. Many of these come in multiple scents: in addition to peppermint and spearmint, there is lemon mint. Thymes come in a variety of scents, including lemon. If you have an herb garden, gently check the stems of your plants -- if they are square, it is probably a member of the mint family.

Of particular interest is the pleiotrophic ffects of the transgene. The inserted gene, geraniol synthase under the control of a ripening-specific promoter, catalyzes the formation of geraniol, an aromatic alcohol original extracted from geraniums. Geraniol itslef apparetnly has a rose-like aroma, but a number of other compounds derivable from geraniol were also increased, such as various aldehydes and esters with other aromas such as lemon-like. This reflects the fact that tomatoes possess many enzymes capable of acting on geraniol. Conversely, the geraniol was synthesized from precursors that feed into the synthesis of the red pigment lycopene and a related compound phytoene, and both of these compounds were markedly lower in the transgenic plants. The tomatoes appear to still be quite red, and well within the wide range of crimsonosity found in tomato varieties. This should come as no surprise to many gardeners: catalogs always warn that trying to grow spearmint or peppermint from seed is not guaranteed to get the right scent. Presumably there are many polymorphisms in monoterpene processing enzymes in the mint genome, and depending on which you assort together you get a different potion of fragrant compounds.

Volunteers sniff-tested and taste-tested (well, got some squirted in the back of their nose -- 'retro-nasal'). Testers generally preferred the smell and 'taste' of the transgenics. Most marketed transgenic plants affect properties key to growers but not consumers; you can't really tell if you have transgenic corn flakes or soy milk without PCR or an immunoassay (or similar). But with this transgenic plant, the nose knows.

Of course, the next line in the alluded-to song is "Let's call the whole thing off". There are many who oppose this sort of tinkering with agricultural plants for a variety of reasons. Myself, I'd leap at a chance to try one. I love tomatoes, provided they are fresh from the garden, and having one more variety to try would be fun!

Note: you need a Nature Biotechnology subscription to access the article. However, Nature is pretty liberal about giving out complimentary subscriptions (I once accidently acquired two), so keep your eye out for an offer.

Evolution's Spurs

As I've commented previously, it is pleasing when a new biological finding can be related to something both familiar and pleasing. In this case, Nature has, with perfect timing, carries a paper about one of my favorite garden plants.

I like to garden but my attention to it is somewhat erratic. As a result, for the ornamentals I have a strong bias towards plants which are perennial or nearly so; in theory you plant them once and enjoy for many years afterwards. There are a few catches, however. First, the hardiness guides in plant catalogs are only rough guides, and the local microenvironment determine whether a plant will actually thrive. As a result, I sometimes end up with very expensive annuals (perennials tend to sell for 2-10X the price of an annual). At a previous residence I couldn't get one wet soil-loving plant (Lobelia cardinalis) to overwinter until I put one directly under the downspout, though about 40 miles to the south I've seen it run rampant on the sides of cranberry bog irrigation ditches. Another species (Gaura lindheimeri) refuses to overwinter for me, but a gardener (and former MLNM employee) a few towns over has a magnificent specimen.

A good perennial garden also requires a certain attention to detail. In particular, many perennials have very restricted bloom times, since they must invest energy in surviving the winter and reappearing in the spring. Many annuals bloom all summer; annuals are grasshoppers, perennials ants. So to get color throughout the garden season, a mixture of plants is needed. Certain times of the mid-summer and early fall are awash in choices, but right after the bulbs fade in early summer can be challenging.

Columbines, species of the genus Aquilegia, are wonderful perennials. While the individual plants are short-lived, plants in a favorable environment will reseed vigorously. They are in bloom now, which is why the new paper's timing is so good. Many of the flowers are bicolor. The foliage is generally a neat mound, often with a bluish tint, making them attractive even when not in bloom. The seed heads are distinctive & visually interesting. Examples of two of mine, one established & one newly planted, show some of these features.

The signature feature of Aquilegia are the spurs. Depending on the species and variety, these can be nearly non-existent to quite large . I'll confess I had never pondered the biology behind the variation, but that is now remedied.

Figure 2 of the paper shows a remarkable correlation between who pollinates a columbine and the length of its spurs. Three major pollinators were explored: bumble bees, hummingbirds & hawk moths.

The key focus of the paper is distinguishing between two evolutionary models. Both Darwin & Wallace had proposed that such long spurs could evolve through a co-evolutionary race between polinator and flower. Longer spurs mean the pollinator must approach the flower more closely to reach the nectar, increasing pollen transfer. Longer tongues on the pollinators will be favored, as they can reach down longer tubes. This model would tend to suggest gradual, consistent changes in spur length.

A competing hypothesis is that spur length changes abruptly when the pollinator shifts. After long periods of stasis, the introduction of a new pollinator drives a short-term co-evolutionary race.

There is a lot of nice data, which I'm still chewing on, in the paper favoring the latter model. The authors used a large set of polymorphisms in the genome to generate a phylogeny. Regression analysis using this phylogeny showed that inferred pollinator shifts are correlated with large changes in spur length. Interestingly, their phylogeny suggests that there have been only two major shifts in pollinator strategy, each time going from a short-tongue to long-tongue pollinator (bumble bee -> hummingbird and hummingbird -> hawk moth). One interesting supporting piece of evidence: in Eurasia there are no hummingbirds, and there are also no Aquilegia known to be pollinated by hawk moths.

By a nice coincidence I was looking something else up & discovered that the Joint Genome Institute has commenced the sequencing of an Aquilegia species. Aquilegia's family is the first branching of the dicots, and therefore represents an important window into family-level evolution of plants.


One additional consideration in garden planning is what creatures your choices will attract: some are desirable, others not. I won't plant major hosts for Japanese beetles unless I really like them (raspberries escape the edict). On the other hand, bumble bees and hummingbirds are on my desired list (though I've never been able to attract a hummingbird) whereas I'm neutral on hawk moths. So, perhaps I should go to the garden center with a caliper in hand, and only get a few of the super-long spurs just to wonder at them.

Purple & White

When I was out in the garden yesterday a smile was brought to my face by some purple blossoms immediately adjacent to some white ones. Those blossoms have so many personal resonances: a bi-annual race, gustatory delight, visual fun & a bit of history. And this year, I am excessively pleased with myself because thinking about those plants led me to a successful guess as to the climate & weather of a distant city I have never had the pleasure of visiting.

Gardening in New England has some distinct challenges, and this year opened up with Mother Nature's nastiest tricks. I actually got some of the seeds for those plants in on time, as soon as the ground thawed, only to watch two successive late spring snowfalls. So my rare early jump was completely defeated.

The need for the jump is clear. Plants which can be seeded early are cool weather crops, and most do very poorly in warm weather. Before you know it, the heat of summer is upon us and those cool weather crops fade in one way or another. Some truly die, but others 'bolt' by launching flower stalks that simultaneously degrade the flavor of the vegetable. We are already experiencing 90 degree (F) days, so the race is on.

The plant in question is visually fun because it sends thin curling tendrils to wrap around anything it encounters. As a kid I loved uncurling them gently and wrapping them around a support.

If you hadn't guessed the plant already, the history & weather bits are a giveaway, as the city I guessed has much cooler summers than Boston is Brno, or Breunn as Brother Gregor would have known it. Those beautiful flowers are on my pea plants, and it occurred to me that while there were probably many considerations in their choice as a model, being able to grow them frequently would be a plus -- and in Boston you can't do much with peas for most of the summer. The second race does begin in mid-to-late summer, if you try to seed a second crop. The other New England weather treachery is the early late frost, usually followed by a long burst of warm autumn to truly twist the pruning knife in your side -- if that killer frost hadn't arrived, another 5-6 weeks of fresh produce would have come in.

Which, of course, is the main reason I do it. I don't grow large quantities of vegetables, but it really is a magic moment when you nearly instantly transfer something you grew from the plant to your mouth and then savor all its sensuous delights. For peas it is sweetness & crunch.

That choice of peas was quite lucky, as pea genetics are relatively straightforward. Many plants have horribly complicated genetics, and indeed one of the then luminaries whom Mendel corresponded with suggested he repeat his experiments in hawkweek, which is one of those many genetic messes.

Of course, later workers would tease apart some of those messes to lead to interesting discoveries, and more are sure to come. But right now, I just want to discover some pods before my peas wilt in the summer heat.