ENVIRONMENTALLY-INDUCED POLYMORPHISMS DETECTED BY RAPD ANALYSIS OF SOYBEAN SEED DNA

Experiments were performed to determine if RAPD profiles developed usi ng total DNA isolated from soybean seed could be affected by the physi ological state or the quality of the seed. RAPD profiles were develope d using template DNA isolated from a single seed lot of soybean (Glyci ne max L. cv. Kirby). High quality seeds were used to produce four pop ulations varying in either quality or physiological state: untreated c ontrol seed ambient temperature and humidity storage for 12 months, ac celerated aging at 41 degrees C and 100% relative humidity for 48 h, a nd controlled hydration (seed priming). One hundred and eighty-eight p rimers were used to create separate RAPD profiles from total DNA isola ted from each set of seed and from soybean leaf tissue. Sixteen polymo rphisms from 14 primers were identified as a result of seed treatments . Six primers showed nine polymorphisms in RAPD profiles of ambient-st ored seed DNA, while four and two primers produced polymorphisms in re actions using accelerated aged or primed-seed template DNA, respective ly. Two primers showed a polymorphic fragment in vegetative DNA not ob served in any of the seed DNA samples. Ten of the observed polymorphis ms were due to the appearance of a DNA fragment in response to a speci fic seed treatment while six were the result of the treatment-induced loss of a DNA fragment. The six polymorphisms resulting from the loss of a major fragment were all due to ambient-temperature seed storage. Results were reproducibly obtained from multiple DNA isolations using three separate DNA isolation procedures involving either multiple seed or a single seed as the template source. Therefore, genetically ident ical seed can consistently display RAPD polymorphisms as a response to the environmental exposure.