I came across an interesting slide presentation looking into identifying current and new cultivars with better HLB resistance.

Some quick notes:
Apparently Poncirus has the most resistance to HLB, and certain other current cultivars show some tolerance. For example Jackson and Triumph grapefruit hybrids are more tolerant than Marsh and Flame grapefruits. There are some pretty shocking pics of the trees side by side.

Also of note, it is mentioned that they are testing some "near commercial quality, advanced Poncirus hybrids" I wonder what these are? A couple of hybrids are mentioned: Gnarlyglo (which is 1/16 Poncirus) and 1-4-59 (which is apparently 1/4 Poncirus... and may have some additional cold tolerance).
Maybe there's still hope for a truly cold hardy good tasting citrus, of course it would only be a side benefit from development of HLB resistant cultivars.

Here's a link to the presentation:
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&ved=0CEEQFjAD&url=http%3A%2F%2Fwww.citrusresearch.org%2Fwp-content%2Fuploads%2FStover_Ed_Is_there_useful_resistance_HLB.pdf&ei=uFKdUezBPMqL0QGMsoCgCA&usg=AFQjCNFK4nZOVccinELswhs389F0iSf8eg

Very interesting read! Definitely hope on the HLB front as well as the decent tasting poncirus hybrid front. I can understand the number designators on the experimental hybrids but what a wacky name though for the 'Gnarlyglo'

I can only guess it was named Gnalryglo by some grad student/postdoc on account of its "alligator-hide" like skin. To me, the outward appearance does not appear much different from Dekopon, but without the uniform orange color.



In addition to P. trifoliata, Citrus latipes is mentioned as having good resistance to HLB. According to UCR it has a decent initial taste, but with an unpleasant aftertaste. Apparently it is expected to be quite cold tolerant but is rare in cultivation, especially in the US. Is anyone growing this? What is it like?


Also found another set of slides from the same presenter with some additional info/cultivars in testing.
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=20&ved=0CJoBEBYwEw&url=http%3A%2F%2Fwww.concitver.com%2F3erEIIC2011%2FViernes_23_sep%2FEd_Stover%2FEd_Stover.pdf&ei=zPSdUejOHa6l4AP8tIH4AQ&usg=AFQjCNHq_nc3qRkP5EhIoZwHyFPHzC5I6Q