COMPARATIVE SEED ECOPHYSIOLOGY OF WILD AND CULTIVATED CARICA-PAPAYA TREES FROM A TROPICAL RAIN-FOREST REGION IN MEXICO

To ascertain the effects of centuries of cultivation practices on seed behavior and dormancy mechanisms, we compared seed size and germinati on characteristics of wild and cultivated (domesticated) populations o f Carica papaya L. Germination experiments were carried out under vari ous conditions of temperature, light, seed soaking and gibberellic aci d treatments. Wild papaya seeds showed responses to treatment that are characteristic of seeds of many rain forest pioneer trees. Seeds were small and light sensitive, whereas cultivated papaya seeds were 33% l arger and their light responses as well as other physiological traits indicated that cultivation had resulted in a lessening in the importan ce of specific environmental conditions for dormancy breaking and germ ination.