That David Karp article is on this Web site:
http://www.e-cookbooks.net/articles/avocado.htm

But the last paragraph cites a different person as making the discovery:

"The Hass dynasty might seem set to continue indefinitely, but in San Luis 
Obispo County, at the northern end of the avocado's range, a potential usurper
looms: a large, seedless avocado, discovered by William Martony on a surfing 
trip to Costa Rica. He and his partners patented the prodigy as "Fruta De Oro"
and are hoping for their first crop this year. The time may be ripe, since 
there aren't any giant ground sloths around anymore to disperse avocado 
seeds."

There's no date on the article, but the Web page says copyright 2003.
And a check of the page freshness indicates "last modified 19-Feb-2004."

Hmmmm....


> RE:
>> Citation:
>> "The skin isn't great but...The Heart is Pure Gold"
>> by David Karp
>> "Fruit Gardener" magazine, May & June 2004,
>> vol. 36, #3, p. 8-11, 25
>> Published by Californian Rare Fruit Growers
>> 
>> 
>> From p. 25:
>> 
>> "The Hass [avocado] dynasty might thus seem set to continue
>> indefinitely, but in San Luis Obispo County [california], at
>> the northern end of the avocado's [commercial cultivation] range,
>> a potential usurper looms:
>> 
>> a large, completely seedless avocado,
>> 
>> discovered by Jack Gibson on a surfing trip to Costa Rica.He
>> and his partners patented the prodigy as "Fruta de Oro" and
>> are hoping for their first crop this year. The time may be ripe,
>> since there aren't any giant ground sloths around anymore to
>> disperse avocado seeds."