The Hass avocado tree Persea americana cv. 'Hass' was derived from a single hybrid tree of P. americana var. drymifolia and P. americana var. guatemalensis, and it is propagated clonally by grafting.

Although the avocado has an ancient cultivation history in Mexico and Central to South America , its extreme worldwide popularity as an oily, nuttyflavored fruit with highly beneficial nutritional properties dates mainly from the early 20th century . Cultivated avocados occur in 3 landraces with possibly independent cultivation origins that reflect their current distribution: the Mexican, Guatemalan, and West Indian varieties . The principal industrial avocado cultivar is known as Hass, after the grower who first patented it in 1935.  Hass represents a hybrid between the Guatemalan and Mexican races, but its precise breeding history is unknown .