M. L. Arpaia (University of California, Riverside)
GemTM (registered under the name 3-29-5) was selected by the University of California and is now managed internationally by Westfalia. However, before Westfalia undertook the international management, researchers at the university evaluated the cultivar over a number of years. The detail below includes some of that data.
The first controlled breeding of avocados in California started in 1937 by J. W. Lesley at UC Riverside, and in 1939 by W.E. Lammerts at UCLA. Bob Bergh took over the UC Riverside breeding program in 1956 and twenty years after planting and screening around 15000 seedlings from promising parents, ‘Gwen’, ‘Whitsell’ and ‘Esther’ were released to the industry in 1982.
A second wave of about 60000 seedlings predominantly derived from ‘Gwen’, ‘Whitsell’, ‘Hass’ and ‘Pinkerton’ hybrids, were planted on private properties across the industry. These massive plantings yielded only a handful of selections with commercial potential including the named varieties ‘Lamb Hass’, ‘Sir Prize’, ‘Harvest’, and ‘GEM’.
In 1985, seed was collected from a ‘Gwen’ tree and planted the year thereafter. During 1992, promising selections from this planting was topworked to bulk up material and gain more information on specific selections (3-29-5 was part of these). International testing of material soon began thereafter under Non-Propagation and Testing Agreements. In 2003, the cultivar 3-29-5 was patented as a new variety in the USA.
The differences observed between Hass and Gem includes: