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UNIQUE CHARACTERISTICS OF THE SIX SUPER DWARF CROP PLANTS UNDER STUDY AT UTAH STATE UNIVERSITY.   Bruce Bugbee, Jonathan Frantz, Shryl Clawson, and Steve Klassen. Utah State University. Logan.

   Two decades ago, we began a wheat breeding program to develop a dwarf wheat line that was adapted to controlled environment conditions.  This work led to the release of USU-Apogee in 1996, which was the first example of a genetic change for the spaceflight environment.  However, at 50 cm tall, USU-Apogee is too tall for long-term studies on the ISS.  We recently released USU-Perigee (25 cm tall), a super-dwarf successor to USU-Apogee.  We have continued to search the world germplasm collection to identify extremely dwarf lines of the major crop species. To date, we have identified and characterized super-dwarf germplasm of rice (cv. Super-Dwarf), tomato (cv. Micro-Tina), pepper (cv. Triton), and soybeans (cv. Hoyt).  Here we review important environmental responses for each of these unique crop species.  Our studies include temperature and photoperiod effects on time to flowering and duration of the life cycle, productivity in extremely low light, intumescence susceptibility, and ethylene sensitivity.

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