According to a 2019 genetic study, the Hass avocado is about 61% Mexican in its ancestry.
The figure describes the estimated contribution of Mexican avocado varieties, or botanical race, to the Hass genome—not the percentage of Hass fruit grown in Mexico and not a measurement of its nutritional composition. The same study estimated the remaining ancestry at about 39% Guatemalan.
Hass is therefore a hybrid cultivar rather than a purely Mexican avocado. Its genetic history helps explain why the variety combines traits associated with different avocado groups. Researchers sequenced avocado genomes to study the crop’s evolution, diversity, disease resistance, and potential for future breeding.
The cultivar also has a distinctive human history. Rudolph Hass first grew the tree in California, and he patented it in 1935. All commercial Hass trees descend from a single original mother tree through grafting. Hass became globally dominant because of its flavor, yield, shelf life, and skin that darkens as the fruit ripens.