Tag Archives: cinco de mayo

Cinco de Mayo: Avocados

This post will take a break from the May Bouquet series to highlight another holiday- Cinco de Mayo (the 5th of May). In America, this usually means two for one margaritas and supper that features things like tacos and guacamole. In Mexican history, it celebrates the Battle of Puebla, an unlikely victory for the Mexican army over the French in 1862. On a plant science blog, Cinco de Mayo means highlighting a tree that had just about the same odds of surviving as the Mexican army did. I’m talking about the Hass avocado.

Hass avocados Copyright Courtesy of the Hass Avocado Board

Before I recount the unlikely beginnings of the world’s most common avocado variety, let’s consider the avocado as a plant and not just the green mushy base of your guacamole. Avocados are native to Mexico and Central America, and Mexico is the world leader in avocado production. The trees grow to more than 60 feet tall and prefer tropical and subtropical climates. Avocados are climacteric (plant biology word of the day) meaning the fruit will mature on the tree, but it doesn’t ripen. This means that avocados will remain hard as rocks on the tree until eventually they just fall off.* This trait is somewhat useful for the produce industry because leaving the fruit on the tree until demand increases is a convenient and profitable strategy. For example, you may not want to harvest as many of your avocados in March, but a lot more leading up to May when people want guacamole for Cinco de Mayo.

Ethylene via Wikipedia

So, how does the fruit ripen off the tree? The mature avocados will ripen off the tree in about two weeks at room temperature. If there are bananas or apples nearby the process can be even faster. This is because these fruits produce ethylene gas, a plant hormone, which among other things stimulates fruit ripening. Commercial produce distributors also take advantage of these properties and treat unripe fruits with ethylene gas in special rooms to control the timing of ripening. This takes a lot of the guesswork out of the timelines for getting ripe avocados to your supermarket.

For those of you fond of science experiments in the kitchen, one fun activity is sprouting the large seed inside the avocados you eat. You can stick four toothpicks around the middle of an avocado seed and submerge the root end in water. Then you wait. Within a month or two it will produce roots then split and sprout. Of course, you will have to wait another 4 – 6 years before it will produce any fruit.

A picture of a avocado seed, punctured with 4 toothpicks and hung halfway inside a glass with water, so that germination would start. Credit: KVDP via Wikipedia

The Hass avocado variety began as such a sprouted seedling, the result of a cross or trial from A. R. Rideout. It was purchased by Rudolph Hass as an addition to his new avocado orchard in California. Hass intended to use it as rootstock for grafting a scion of Fuerte, the standard variety at the time. The history tells that Hass tried grafting to that stock three separate times, but nothing ever took to it. Such recalcitrance even wore down the patience of an orchardist, and Hass was ready to chop it down. His children convinced him to just let it grow.** They actually preferred the taste of the avocados it produced and it bore well. Hass patented the tree in 1935, naming the variety after himself, and in an agreement with H.H. Brokaw, produced the initial grafts of Hass seedlings. It took some time to change the minds of consumers because the Hass avocado has such dark and bumpy skin compared to the smoother green Fuerte variety. However, the proof is in the taste and the Hass is the winner with a richer, nuttier flavor. Today the Hass variety accounts for the overwhelming majority of the avocado market in the United States (80 – 95% depending on the sources listed below) with more than $1 billion per year in revenues for U.S. agriculture. Sadly, the original Hass mother tree succumbed to root rot in 2002, but the popularity of its avocados with consumers has ensured its genes will live on for many generations to come.

Guacamole Copyright Courtesy of the Hass Avocado Board

As you’re enjoying avocados or guacamole today to celebrate an unlikely victory for Mexico, remember the unlikely biological victory of the Hass avocado. Use this knowledge to impress your friends. After a couple of margaritas, you’ll sound like a genius.



*Useful FYI for any of you out there that may have an avocado tree in your yard and may be cursing your tree as to why it doesn’t produce anything like you see in the produce section of your grocery store.

**Yeah, it’s kinda a theme of mine to take every opportunity to reference the Lorax on this blog.

References and Links: