North American Fruit Explorers mailing list at ibiblio

["philip sauber" <mrtejas@lycos.com>]

This type of "improving" has been going on for about 100 years starting with 
Swingle of the USDA in the early part of the century.  The following crosses 
resulted:

trifoliate x grapefruit  - Swingle citrumelo
trfoliate x sweet orange - various citranges
trifoliate x sour orange - citradia
citrange x kumquat - thomasville citrangequat
citrange x mandarin - citrangarin

The crosses taste cannot really be described as edible to the average person. 
 They are mostly used for citrus rootstock.  The Florida Citrus arboretum has 
many examples of these crosses.

In the last 50 years, various citrus "nuts" in the Houston, TX area have kept 
trying, mostly with inedible results.
trifoliate x clemenine - ciclem
yuzu x clementine - 10degree tangerine
changsha x yuzu , etc.

The general consensus is that "hybrids of trifoliate orange lose hardiness 
before the undesirable aspects of flavor(from trifoliate orange) are bred 
out" ("Citrus for the Gulf Coast" self published by Stewart Nagle.)

The best hybrid I have tasted is the SanCitChang or Sanford citrange x 
chansha mandarin.  It was close to satsuma in flavor.  Nagle describes it as 
"cold hardy enough to survive in Dallas, TX but fruit of most has too much 
"bite" for most palates."  Maybe I tasted a particularly good example.  

For someone like me (lives near Houston, TX) who can effortlessly grow 
satsumas(one of the best tasting of the mandarins), growing any trifoliate 
hybrids is not really worth it because they don't taste as good.

However, I do grow one trifolate hybrid.  It is an edible flying dragon 
(cortorted form of trifoliate orange) cross of unknown origin discovered in a 
batch of flying dragon seedlings in Houston, TX.  It is probably flying 
dragon x sweet orange.  The tree is even more contorted and thorny than 
flying dragon.  The fruit is smallish and makes an acceptable but not great 
lime substitute when green and has only a hint of the the nasty trifoliate 
flavor when ripe. The cold hardyness of this cross hasn't been tested as only 
about 6 trees exist in the Houston, TX area. To read more about this "dragon 
lime":

http://members.fortunecity.com/pjsauber/DragonLime.htm

However, the mostly disappointing results to date shouldn't discourage the 
die-hard citrus breeder.  Most seedling fruit trees(monoembryonic citrus 
included) that don't come true from seed can produce a new commercial variety 
about 1 in 10,000 tries.  Perhaps 10,000 tries haven't been made for 
trifoliate crosses yet!





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