The Alligator Pear
Well, as you're probably gathering by now, this blog is something of an on-again-off-again kind of a venture. Real life, with all its associated distractions, keeps me pretty busy these days, but I fully intend to keep updates coming. So fear not.
A while back, I promised Avocado Lady, one of the few users of the Fruit Blog Forum, a post on avocados. So here it is.
I have to admit that, botanical technicalities aside, part of me has a hard time believing tha avocados are fruits and not vegetables. Somewhere early in my formative years they got firmly shelved in my brain with the veggies, and I can't quite pry them out of that role. I think it's the whole guacamole thing. Guacamole just doesn't seem like something you make out of fruit.
The reality is, of course, that avocados are indeed fruit. Some of the West Indian types, grown mainly in Florida and the Caribbean, seem a little more like fruit to me, maybe because of the lower oil content and sort of nutty, creamy taste (Fruit aren't supposed to be oily, in my book). (Except when they're nuts, I guess.) There are really three types of avocado. The Mexican type, Persea americana var. drymifolia and related hybrids, are thin skinned, with a high oil content. There's also the aforementioned West Indian avocado, Persea americana var. americana which are larger (and blander) than the rest, lacking the characteristic anise-scent, and the Guatemalan type, Persea nubigena var. guatemalensis, which is high in oil like the Mexican but with a thicker, rougher skin. All three are interfertile, and most commercial cultivars are hybrids between the groups, though there is a tendency to group cultivars into these three groups based on their characteristics, regardless of their genetic background.
The avocado is probably a native of southern Mexico, but had spread into north to southern Texas and south into Peru and Ecuador by the time of the European conquest, with a fairly impressive record of improvement in fruit size. The new arrivals accelerated the avocado's spread, distributing it first to the Caribbean (it is recorded in Jamaica before 1700), then the Philippines, Hawaii, southeast Asia and the Indian subcontinent. In the native Aztec language, Nahuatl, it was called ahuacatl, meaning "testicle", no doubt due to its shape. (The Aztec name is still used in parts of Mexico. Nahuatl also gave us tomatl (tomato), xocolatl (chocolate), cacaotl (cacao), and coyotl (coyote). See a pattern?). The Spanish were notoriously bad with the Aztec's 'tl' sound, and changed the name to aguacate which remains the standard Spanish term. Other Spanish speakers confused it with abogado (meaning 'lawyer', which, though less logical, is vaguely more appealing than 'testicle'), which gave us our own avocado. The common name "alligator pear" is probably a reference to the green, bumpy skin, although some have attributed this to yet another mispronunciation. It's also been called "butter pear" or "vegetable butter", likely due to the oily flesh.
It's a member of the Lauraceae, which makes it a cousin of such things as cinnamon and sassafras. More closely related is the genus Beilschmiedia, commonly called the Anay (try Googling for "Anay" and you'll turn up a million misspellings of the word "any" and very little real info.) Locally collected and consumed in Mexico, the anay is very similar to the avocado in many ways, with an extremely oily and high protein flesh. (To save you the pain of googling for information, a nice article on the anay from the California Avocado Society is available as PDF here.)
The tree is evergreen, and extremely dense and fast-growing (it has been known to approach heights of 100 feet). Grown from seed, the tree remains in a juvenile state for many years, sometimes up to two decades, during which it produces no fruit. This is overcome commercially by grafting wood from mature trees onto seedling rootstock, which usually bears within a year or two. Flowers occur in panicles of several hundred, but very few actually set fruit, generally only one per panicle. While the flowers contain both male and female organs, they are either "type A", in which shed pollen in the morning and are receptive in the afternoon, or "type B", which are the reverse. Strangely (to me, anyway), the fruit can hang on the tree for well over a year, ripening only after picking. This convenient feature allows growers a great deal of flexibility in timing production to match the market.
In the United States, the bulk of the industry is located in California, with a smaller industry in Florida. Both of these are dwarfed by the larger industries in Mexico and the Dominican Republic. South Africa and Mediterranean regions export substantial amounts of the crop as well. Brazil produces a lot of avocados, but very little of the crop is for export. The tree is limited largely by it's lack of hardiness, and most tolerate only mild freezes, though some Mexican types can survive as low as 19°F.
At least 90% of the California avocado production is a single cultivar: 'Hass'. 'Hass' is frequently considered a Guatemalan type, but in reality it is probably a hybrid between a Guatemalan and a Mexican avocado. The cultivar got its start in 1926, when mailman Rudolph Hass planted several avocado seedlings, with the intention of grafting a cultivated variety onto it. Two variation on the story exist: in one, Hass never gets around to grafting the seedlings, in another Hass grafted the popular cultivar 'Fuerte' onto his seedlings, but one of the seedlings stubbornly rejected his attempts at grafting. This would probably have doomed most rootsock avocado trees to the brushpile, but this particular seedling proved to have remarkably good fruit, and Hass spared it. Whatever the exact story, Hass eventually patented it and named it after himself. 'Hass' is easy to peel and a reliable producer, and had the unusual characteristic of turning a deep purple, almost black, when ripe. While this would seem convenient, the dark color initially turned off many buyers, thinking the fruit had gone bad.
Other cultivars abound: 'Fuerte', originating sometime before 1911, is probably one of the earliest named cultivars. Widely grown in South America and Australia, it is another Guatemalan x Mexican hybrid like 'Hass'. While 'Hass' dominates the U.S. market, 'Fuerte' has long been the prefered cultivar in Europe, and is often considered superior in flavor. 'Zutano', a Mexican cultivar, is grown largely for it's cold hardiness, despite inferior quality, poor handling qualities, and disease problems (Another cold hardy variety is 'Bacon', which is recommended for higher altitude areas.) A few Mexican cultivars are grown in Florida, such as 'Brogdon', but the industry is mostly West Indian types and their hybrids, such as 'Booth 7' and 'Booth 9', and 'Lula', which has an unusually high oil content for a West Indian type (Florida has tried to capitalize on their low oil avocados by marketing them as 'Slimcados'.)
Avocado is blessed with a wonderfully diverse range of germplasm, and active breeding continues in many locations, including South Africa, Taiwan, Israel, and California. The California program, located at the University of California in Riverside, has a wonderful website, which includes a cultivar database of over a 1,000 varieties, if my meager offerings above are inadequate for you needs.
Other useful pages include the avocado page of the California Rare Fruit Growers Society, here, and the always fascinating New Crops database at Purdue University, here.
Again, my apologies to everybody for my long absence. I'd like to promise I'll do better in the future, but I know myself too well for that. Thanks for your patience!
Update: Some one just passed along this great page of avocado info from UCLA.