Abstract:This paper is a further study on the morphogenetic processes of gynogenetic embryoid and callus formation in rice unpollinated ovary culture. Techniques for culture and for specimen preparation were basieany the same as in previously reported experiments in our lab. During early stage of culture, gynogenetic structures within the embryo sacs were predominantly young pear-shaped proembryos. A few of them developed later along a more or less normal pathway into differentiated embryoids. However, most proembryos grew much larger without embryo differentiation and finally turned to callusing. A discussion is given to the morphogenetic aspects of such kind of callus, which is considered to be a structure somewhat similar to the “protocorm” described by Nostog in barley proembryo culture. In this paper, the process of proembryo abortion and the oecurenee of polyembryony are reported as well.