The weird fruit that Hass it all: Swetha Sivakumar on the avocado

Half an avocado (about 34 gm) contains only 0.2 gm of sugar.

This is rather baffling, considering that the avocado is a fruit. Fruits tend to be sweet, in order to entice animals to consume them and thus help spread their seeds.

So why does the avocado have so little sugar, such high fat content, and its exceptionally large seed? The answer is as simple as it is intriguing: It evolved to cater to animals that no longer exist.

Scientists believe that the fruit flourished in the Cenozoic era, and helped feed supersized mammals such as the mammoth and giant sloth, who swallowed it whole and excreted the seed later, at a fair distance from the mother plant.

At the end of what is popularly known as the last ice age, about 13,000 years ago, this plant should have gone extinct. What likely helped it survive is its heterozygosity. Let’s look at what that means.

My husband loves avocados, but rails against the prices every time we buy them. So he recently decided to bury an avocado in our garden, and nurture it into a tree. Even if it takes seven years to bear fruit, he says, it will be worth it. The thing is, the kind of avocado we eat isn’t typically grown like this, via raw seeds; it is, instead, grown via grafts.

This is because the avocado plant has not evolved to prioritise traits such as flavour and texture. Instead, what gets passed down in its DNA, reinforced over and over in overlapping genomic markers, are traits such as cold tolerance and resilience to certain pests. The flavour of the fruit, as a result, varies wildly from tree to tree.

For this reason, farmers tend to not trust raw seeds; they rely on cuttings from a tree that has already yielded tasty fruit. All Hass avocados, for instance — and these account for 80% of avocados consumed worldwide today — can be traced to a single tree planted by Rudolph Hass, a postman in California, in 1925.

He got lucky. His plant wouldn’t take any grafts, so he let it grow, and it bore fruit that was creamier and tastier than any avocado he had eaten. The fruit was so exceptional that he patented the variant, and there have since been millions of trees grown using cuttings from his original. The patent expired upon his death, in 1952, and anyone can now grow a Hass from a cutting.

There are more than 1,000 such varieties currently cultivated around the world, according to data from the College of Natural & Agricultural Sciences at University of California, Riverside. The most recognisable include the Fuerte, Gwen, Pinkerton and Zutano. Some are smooth on the outside; others, wrinkled; some are green, others purple or black. The Hass dominates partly because it’s delicious, and partly because its thick, black skin makes it among the most durable strains in what is a notoriously delicate fruit.

It is not ideal to depend so heavily on one variety, however. From about the 1890s until the 1950s, Gros Michel bananas were grown across Central America and shipped across Europe and North America, for instance. They were preferred for their delicate flavour and texture. When a fungus struck the variant, the species was all but wiped out.

Back to the avocado, the first domesticated versions were grown by tribes in present-day Mexico about 5,000 years ago. By 500 BCE, the fruit had the beginnings of its modern English name: ahuacatl, the word for testicles in the Aztec language of Nahuatl. Spanish conquerors pronounced it aguacate.

By 1915, traders were trying to pitch it to Californians with a trendy nickname; for some reason, they settled on “alligator pear”. Thankfully, the tag didn’t catch on. Also thankfully, the fruit did.

Nutritionally, the avocado is quite incredible. The flesh is 72% water, 6.8% fibre, 2% protein and 15% fats. It is versatile and can be used in a variety of ways. Worldwide, sales hit an estimated $10 billion in 2021; research platform Statista estimates that the figure will double by 2026.

Demand, and prices, are so high that gangs are targeting avocado orchards around the world, from the US to New Zealand. Cartels in Mexico target avocado traders, extracting protection money in exchange for safe passage for the produce.

Meanwhile, in our backyard, there’s about a 1 in 10,000 chance that, in seven years, the tree we’ve planted will begin yielding delicious fruit. My husband is hopeful. He may have found the next Hass, he says. I guess you never know… until you know.

(To reach Swetha Sivakumar with questions or feedback, email [email protected])