Following a 3-wk pretreatment with 150 mM NaCl, Sorghum plants were able to survive exposure to 300 mM NaCl, a lethal concentration for nonpretreated plants. This response is termed salt adaptation. Although the population was initially homogeneous, Na-includer and Na-excluder individuals coexisted after the achievement of the salt-adaptation response, and a large diversity in size of the seeds produced was observed at the end of the life cycle. Offspring of salt-adapted plants were exposed to a new salt-adaptation treatment. Even in the absence of selection, the proportion of Na-excluder individuals in the progeny was significantly increased. Offspring germinated from small seeds differed significantly from plants first-exposed to a salt-adaptation treatment, whereas offspring from large seeds displayed intermediate characteristics. This suggests that some of the adaptive changes were transmitted through embryo imprinting. The importance of this phenomenon for emergence of a newly adapted ecotype is discussed.