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 germination characteristics of wild and cultivated (domesticated) populations of Carica papaya L. Germination experiments were carried out under various conditions of temperature, light, seed soaking and gibberellic acid 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% larger and their light responses as well as other physiological traits indicated that cultivation had resulted in a lessening in the importance of specific environmental conditions for dormancy breaking and germination.